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TOOTH PREPARATIONS CLOVIS PAGANI

^

QUINTESSENCE PUBLISHING

tooth preparations

CLOVIS PAGANI

TOOTH

PREPARATIONS S C I E

C E & A R T

QUINTESSENCE PUBLISHING Berlin, Barcelona, Chicago, Istanbul, London, Milan, Moscow, New Delhi, Paris, Prague, Sao Paulo, Seoul, Singapore, Tokyo, Warsaw

First published in Portuguese "Prepares Dentarios" © Editora Napoleao Ltda., Brazil 2014 Rua Prof. Carlos Liepin, 534 - Bela Vista - New Odessa Sao Paulo - Brazil - CEP 13460-000 Phone: +55 19 3466 2063; Fax: +55 19 3498 2339 www.editoranapoleao.com

A CIP record for this book is available from the British Library ISBN: 978-1-78698-001-4

.

QUINTESSENCE PUBLISHING UNITED KINGDOM Quintessence Publishing Co. Ltd, Grafton Road, New Malden, Surrey KT3 3 AB, Great Britain www.quintpub.co.uk Copyright © 2017 Quintessence Publishing Co. Ltd All rights reserved. This book or any part thereof may not be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, or otherwise, without prior written permission of the publisher.

Graphic Design: Trago Digital Layout: Deoclesio Alessandro Ferro,

Jeferson Luis da Silva, Agatha Suelyn Gonsalves Illustrations: Daniel Guimaraes, Elissa Soares, Ariane Soares, Luis Ricardo Vigentin, Marcelo Cesar Lozari Origuela Translation: Annelies Van Ende, Fabio Luiz Andretti Technical and Scientific Review: Fabio Luiz Andretti, Ana Paula Prolo Text Revision: Marise Ferreira Zappa

Printed and bound in Germany

PREFACE When I was invited to write the Preface for this book, I must confess that I did not realize the commitment at the time. When the book arrived in my hands, however, I began to gradually feel the responsibility that I was facing. Suddenly, that friend and colleague of 40 years turned into an earnest steward

demanding of me an accurate analysis of his work - a most powerful and comprehensive one, as he confidently said. I realized then that our friendship could not interfere with that analytical process, since scientific purpose was the ab solute criterion of the action to be performed. I had no alternative but to start reading. And then everything changed! I found myself facing a work of undeniable value. From its prodigious and exciting cover, I as the reader could already anticipate the wonder I would ex perience from then on. Care and good taste impressed me throughout my reading; the book awakened in me the enthusiasm and desire to use it as my sovereign guide in my clinical activity. This is said without exaggeration, dear readers, for those who venerate books, as I do - I feel them, hold them, squeeze them - this book is both a privilege and an ecstatic pleasure. To those for whom it is intended, this book will be invaluable; an investment comparable to that made by acquiring the venerable handbook Shillingburg introduced to clinical and restorative dentistry at the time. I state without hesita tion that this book will enjoy the same success and have the same significance for dental practitioners; furthermore, this work is up-to-date, has magnificent 3 D illustrations, and has a clear and objective meticulousness on the part of the author and his collaborators. The book is divided into eight carefully written chapters, providing the reader with essential theory, sound practice, and reliable guidance for further studies. Chapter 1 is an introduction to indirect restorations. It explains skillfully and strongly the theory and practice of this important and ongoing stage of everyday practice. Chapter 2 deals with restorative planning, and it is marvelous! The explanations lead not only to an understanding of the subject matter, but to how to incorporate it into professional practice. In Chapter 3, the principles and sequences of preparation are very clearly detailed, and are supported by sophisticated illustrations, the quality of which is in keeping with the best and most outstanding in dental books published to date. Chapters 4 and 5 focus on intracoronal and extracoronal restorations, and the same textual and illustrative quality is maintained. Chapter 6 presents conservative preparations, the focus being on preservation in operative procedure and the observation of biology. The chapter also covers the appropriate tools for conservative dental procedures. Chapter 7 discusses compromised teeth with the same attention to detail and care. Chapter 8 is about adhesive milled restorations. The mater ial is well founded and presented in an innovative and clear manner, showing

that the issue should no longer be considered inaccessible, or a matter for the privileged few, due to the technology available in dentistry today, which should be used properly and with discretion. I would like to honor and congratulate Professor Clovis Pagani and his col laborators for the esthetic consistency and relevance of this work. The editing is true perfection. To future privileged readers of this book, it is my hope that the knowledge you assimilate from it will make you more competent, more skilled, and more professional. That is indeed what I wish for myself!

Happy reading!

Jose Roberto Rodrigues, Associate Professor Former Director, School of Dentistry Sao Jose dos Campos - UNESP

INTRODUCTION More than merely specific expertise is expected from dental professionals today; they are required to be skilled in human relationships, be able to com-

municate with their patients, take responsibility based on self-criticism, and, above all, be accurate in their practice of dental operatory. In the past, the pioneers of our profession claimed that the success of restorative practice depended more than 60 percent on the technical refinement applied to cavity preparations. This assumption still applies, and with more relevance than ever before. The new materials require accurate measurements, dimensions, and customization for dental procedures. Underlying this is the importance of preserving dental tissue and function at all cost, as well as the sovereignty of esthetics, the main measure of dental success for much of contemporary soci ety. While new technologies serve as auxiliary and complementary tools in the routine of the modern dental practitioner, the suitability of clinical and restora tive choices also plays a major part in the success of clinical practice today. Although traditional remnants of restorative practice still persist, cosmetic dentistry is undeniably the main movement that is at the heart of, and is shaping, the dentistry profession today. Patients are demanding that dental professionals adhere consistently to the rules of esthetics; philosophical principles that derive from the fundamental works of Aristotle. In the book that you hold in your hands, dear reader and colleague, we have tried to approach - without semantic tricks and unnecessary erudition - the significance of knowing the background and basic principles of current prac tices of cavity preparation; these being, in essence, utility and functionality. Professionalism in dentistry is not about geographical location, the ergonomic arrangement of pieces of work equipment, or dazzling waiting rooms. Rather, it is mainly about skills and the refinement of operative details - in short, the essential, non-negotiable principles of precision, care, and a sound biological and scientific knowledge base. You will find in this work a step-by-step approach to the current requirements demanded by cavity preparation in every indication that may arise, to enable you to accomplish successful clinical and restorative treatments. You will see, for example, that a detailed and comprehensive planning phase is mandatory in order to carry out cavity preparation efficiently and effectively. You will understand that the sequence of cavity preparation respects periodontal health, the protection of the pulp- dentin complex, the tooth remnant,

occlusion, and the mechanical function of the elements to be restored. The first and only purpose of this book is to provide colleagues who care about the quality of their clinical activities the close attention to detail and the cavity preparation steps that have never gone out of fashion. Indeed, how could a philosophy of practice that carries with it the essential factors for success ever go out of style? We hope, dear colleagues, that this book gives you the opportunity to prac tice a dentistry that has as its foundation the principles of quality, honesty, and the true fire that earns our profession its place amongst the elite professions in the world today. Thank you for your attention, we wish you all success. Clovis Pagani

DEDICATION I dedicate this work to the countless individuals and professors who participated in my academic and professional training, whom I shall never forget. I want to thank and honor:

Prof. Dr. Armando Curti Junior Prof. Dr . Cervantes Jardim Prof. Tit. Dan Mihail Fichman Prof. Dr . Delcio Pasin Prof. Dr . Henrique Cerveira Neto Prof. Dr. Joao Candido Carvalho Prof. Dr. Joao Vieira de Morais Prof. Adj. Jose Roberto Rodrigues Prof. Tit. Julio Jorge D'Albuquerque Lossio

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Prof. Dr Marcelo Augusto Galante Prof. Dr. Marco Antonio Bottino Prof. Tit. Maria Amelia Maximo de Araujo Prof. Dr. Newton Jose Giachetti Prof. Dr. Pedro Americo Machado Bastos Prof. Dr. Ruy Fonseca Brunetti To the School of Dentistry of Saojose dos Campos - ICT - Sao Paulo State Uni versity - UNESP. To the professors of the Department of Restorative Dentistry, School of Dentistry - ICT - Universidade Estadual Paulista - UNESP. To the Napoleao Publishing Elouse - Leonardo, Guilherme and all employees for the friendship, caring, dedication, and promptness in the preparation of

this work. To the students Beatriz, Isabella and Geraldo, and all undergraduate and graduate students, you are surely the main reason for this work.

I have been a teacher for 40 years and have taught many people during that time, but most importantly I am a learner.

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I GIVE INFINITE THANKS TO GOD, WHO ALWAYS SUPPORTS ME

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AUTHOR CLOVIS PAGANI Master in Clinical Dentistry, Faculty of Dentistry, University of Sao Paulo - USP Doctor in Clinical Dentistry, Faculty of Dentistry, University of Sao Paulo - USP

Head of the Department of Restorative Dentistry, Faculty of Dentistry of Sao Jose dos Campos, Sao Paulo State University - ICT - UNESP

Professor of the Post-Graduate Program of Restorative Dentistry (Master and Doctorate) of the Faculty of Dentistry of Sao Jose dos Campos, Sao Paulo State Univer sity - ICT - UNESP

Specialist in Aesthetic and Prosthetic Dentistry

SPECIAL THANKS To my parents Francesco (in memoriam) and Malvira (in memoriam), thank you for my existence I am grateful for the love and care you gave me during my whole

.

life. YOU were my first teachers. To my brother Giacomo, you were a guide, friend, and always a reference. To my dear and beloved wife Marcia. Thank you for believing I could do anything, for not letting me falter and especially for being a partner and the mother of our three wonderful children The pain decreases over time, but the missing... To my dear children Rodrigo, Vinicius, and Lucas, I cherish the understanding and inspiration, you are the main stimulus in everything I do. You always have been and will be the main reason for my battle in this life. To dear Ana Lucia Sampaio Galante, for your support and encouragement. Thank you also for being at my side in times of sorrow and joy.

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If this step is an achievement, it is not only mine, IT'S OURS. I love you all.

f

CO- AUTHOR EDUARDO GALERA DA SILVA Master in Partial Fixed Prosthesis - ICT FOSJC - UNESP Doctor in Partial Fixed Prosthesis - FOUSP

Specialist in Prosthetic Dentistry - CRO SP Professor responsible for the Nocturnal Integrated Clinic - ICT FOSJC - UNESP

SPECIAL THANKS To my parents, Joao and Alice, who by being an ex-

ample of character have guided my familial and professional life. To my wife Ana Paula, for the encouragement and motivation in all the moments of our lives. To our daughters, Julia and Luisa, for the joy you bring to us. To my friend Professor Clovis Pagani, mentor of this work, for your idealism and objectivity.

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CO - AUTHOR DANIEL MARANHA DA ROCHA Adjunct Professor of the Department of Odontology of Lagarto from the Federal University of Sergipe Master in Restorative Dentistry - Aesthetic Dentistry Institute of Science and Technology of Sao Jose dos Campos - UNESP Doctor in Restorative Dentistry - Aesthetic Dentistry Institute of Science and Technology of Sao Jose dos Campos - UNESP

SPECIAL THANKS To my godfather Francisco Saliby (in memoriam), great encourager and professional and personal example, I owe to him my being the professional that I

have become. To my wife Milena, for the unconditional support and love, thank you for always being present, sharing joy and giving strength to overcome the obstacles on the pathway. My parents Cesar and Beatriz, for the example in life and for the dedication of every day that made it possible for me to get where I am today. To my sister Rita, for all the times we've spent together and the great gift you gave us. To my friend Clovis Pagani, for the opportunity to participate in this magnificent project.

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CONTRIBUTORS RODRIGO FURTADO DE CARVALHO Specialist in Prosthodontics, Bauru School of Dentistry, University of Sao Paulo

( USP)

Master in Dental Clinic, Emphasis in Prosthodontics, School of Dentistry, Federal University ofjuiz de Fora (UFJF)

PhD, Restorative Dentistry, Emphasis in Prosthodontics, School of Dentistry of Sao Jose dos Campos, Paulista State University (ICT - UNESP)

DENNISJ. FASBINDER, DDS, ABGD Head of the Department of Cariology, Restorative Sciences and Faculty of Dentistry, University of Michigan

Endodontics,

Director of the Computerized Dentistry Postgraduate Program and Computerized Dentistry Center of the School of Michigan

GISELE NEIVA, DDS, MS Clinical Associate Professor and Director of Restorative Dentistry Graduate Clinic of the Department of Cariology, Restorative Sciences and Endodontics at the University School of Dentistry Michigan Master in Restorative Dentistry and in Clinical Research and Biostatistics from

the University of Michigan

LUN I bN

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INTRODUCTION TO INDIRECT RESTORATIONS

RESTORATION PLANNING

PRINCIPLES OF CAVITY PREPARATION

INTRACORONAL RESTORATIONS

EXTRACORONAL RESTORATIONS

CONSERVATIVE PREPARATIONS: MINIMALLY INVASIVE DENTISTRY

PREPARATION OF ENDODONTICALLY COMPROMISED TEETH

MILLED ADHESIVE RESTORATIONS

INTRODUCTION TO INDIRECT

INTRODUCTION The replacement of missing natural teeth by artificial ones has long been a concern of humans. One of the difficulties encountered in making these replacements is realizing a treatment that restores function and esthetics in a satisfactory manner and ensures clinical longevity without overloading the abutment teeth 3 6 The preparation of a tooth to receive an indirect restoration can be con ceptualized as a selective grinding process of enamel and/or dentin in various quantities, areas, extensions, and predetermined forms This grinding process is accomplished within a pre-established operative sequence of steps, employing instruments with specific forms and dimensions to create space for a single restoration or a fixed or removable prosthesis 2 3 7 Indirect restorations are among the main restorative options indicated for teeth with extensive coronal destruction. This type of restoration is manufac tured on a gypsum model in the laboratory and then luted to the tooth that was previously prepared and impressioned. Indirect restorations may be indicated for the reconstruction of one or more elements of an arch. The main indications for indirect restorations are depicted in Figures 1-1 to 1-7.1 7

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"

-

.

.--

-

Fig 1-1 Teeth with extensive coronal destruction.

I i

.

Fig 1-3 Replacement of direct restorations

Fig 1- 2 Teeth with fractured cusps,

Fig 1- 4 Correction of the position of extruded, non-occluding or

malpositioned teeth.

Fig 1- 5 Teeth with malformation,

such as hypoplasia and amelogenesis imperfecta.

Fig 1- 6 Closure of small diastemas.

Fig 1-7 Teeth with short clinical crowns.

I n t r o d u c t i o n

t

wm '

INTRACORONAL RESTORATIONS Intracoronal restorations are those that fit within the anatomic contour of the tooth's clinical crown; those that do not cover any cusp are classified as inlays ( Fig 1 -8). In the absence of one or more dental elements, a fixed partial prosthesis is indicated, in which the replaced missing tooth, called a pontic, is connected to the remaining neighboring teeth, called abutment teeth, which have intra - or extracoronal preparations (Fig 1 - 9).

Fig 1- 8 Intracoronal restoration. Occlusal ( A). Mesio-occlusal (B).

Fig 1- 9 Fixed partial prosthesis.

EXTRACORONAL RESTORATIONS Extracoronal restorations are those that cover the external surface of the tooth's clinical crown. Full - contour extracoronal restorations cover the entire outer surface of the tooth; partial- contour extracoronal restorations cover one or more parts of the surface of the tooth (Fig 1 -10).

Chapter

01

Fig 1-10 Extracoronal full-contour restoration ( A). Extracoronal partial-contour restoration (B ).

I n t r o d u c t i o n

t o

indirect restorations

n

L1+ A

Crowns are extracoronal restorations in which the external surface of the clinical crown of a single tooth is covered by a single piece. The main functions of crowns are to re establish the morphology and function of the lost coronary portions of the tooth and to protect the remaining dentition. When some surfaces of the clinical crown are covered, the indirect restoration is called a partial- contour extra coronal restoration, and can be classified as either an onlay or an overlay. Onlays are those restor ations that cover one or more cusps of a tooth. When the

coverage extends partially to the buccal and lingual surfaces, they are called overlay restorations (Fig 1-11A and B). Ceramic veneers are par tial-contour restorations. Interest in these restorations has grown in recent years, mainly due to the increasing search for improved esthetics, in conjunction with the development of ceramic materials and adhesive dentistry. For ceramic veneers, a thin layer of ceramic material is applied that is cemented to the tooth using resin cement (Fig 1-11 C).

Fiy 1-11 Onlay ( A). Overlay (B). Anterior veneer (C) ,

REFERENCES 1. Concei ao EN . Dentistica - Saude e Estetica, ed 2 , Porto Alegre: Artmed, 2007. 2. Martignoni M, Schonenberger A. Precisao em protese fixa . Sao Paulo: Santos, 1998. 3. Mezzomo E, Suzuki RM . Reabilitagao Oral Contem poranea . Sao Paulo: Santos, 2006. 4. Saito T. Preparos denials funcionais em protese fixa, ed 2. Sao Paulo : Santos, 1999.

^

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5. Shillingburg PIT, Hobo S, Whitsett LD. Fundamentos de protese fixa, ed 4. Sao Paulo : Quintessence, 2007. 6. Touati B, Miara P, Nathanson D , Inlays e Onlays cerami cas. In: Odontologia estetica e restauragoes ceramicas. Sao Paulo: Santos, 2000:259-291. 7. Vieira FLT, Silva CHV, Menezes Filho PF, Vieira CE . Estetica odontologica: solugoes clinicas. Nova Odessa. Sao Paulo: Napoleao, 2012. -

CHAPTER 02

RESTORATION

INTRODUCTION , There are a wide variety of alternative treatments for restoring decayed bro the , greater the es of y alternativ ken, and missing teeth. The greater the availabilit and limneed to know the particular properties of materials and the advantages comes itations of treatment techniques. Every patient seeking dental treatment Restora . ns expectatio , and s , motivation to the dental office with specific needs rehabili a guide that tive planning involves the application of scientific concepts tation, based on the observation of the patient's needs and expectations. Much sensitivity is required to understand that people are unique in their reactions. Knowing howto reverse pessimistic or misguided beliefs and expectations is one of the challenges for the clinician. The first contact with a patient is not only the chance to diagnose the dental problem, but also an opportunity to build trust between the patient and the dental team. Fradeani ( 2006) stated that the first step toward success is to establish a relationship of trust with patients.5 This relationship is fundamental to creating a relaxed and friendly atmosphere, where patients feel free to express themselves with confidence.6 This initial conversation, which should take place before the intraoral examination, should ideally reduce the tension usually present during the first consultation. It is predominantly psychological, and serves as the opportunity for the clinician to get to know the patient's personality, way of being/thinking, and emotional needs. The patient also has the chance to evaluate his or her confidence in the team and the treatment

setting.1 , 26 According to Telles, Hollweg, and Castellucci, the teeth symbolize strength anxi and insecurity to lead can aggression, and an active attitude Losing them only ety Therefore, teeth help to improve people's self-image Usually, patients seek treatment when they experience problems related to esthetics, despite their awareness of the complexity of their dental problems. To achieve treatment success, the clinician should suggest a treatment plan that meets the patient's needs and expectations This approach can be summed up in four stages: recognizing and understanding the problem; exploring and identifying the problem; interpreting and explaining the problem; and offering solutions to the problem based

.

.

.

.

on a unique biopsychosocial model.26

DIAGNOSTICS The diagnostic process is extremely important to achieve a successful reha bilitation Through this process, the patient’s treatment needs and wishes are identified. Data collection occurs in several interrelated steps that guide the development of the treatment plan.

.

ANAMNESIS A questionnaire (Fig 2- 1 ) about the patient's medical and dental history is an essential tool to obtain information during the diagnostic process Various types of information can be collected in this way.

.

Medical history Takingthe medical history provides information relating to pre-existing systemic diseases Based on this information, certain adjustments of conduct may be required in the course of treatment to ensure its success. Systemic diseases such as diabetes and hypertension, for example, require caution when surgical procedures are required. As important as knowing about the patient's chronic or acute systemic diseases is knowing the medications indicated for their treatment. In some cases, the side effects of these medications can influence future oral problems A number of pre- existing conditions may induce immunosuppression and hyposalivation (decreased salivary flow), thus increasing the risk of developing major oral pathologies (caries and periodontal disease). Evaluation of the family history can reveal a genetic predisposition to the development of diseases, as well as cultural factors and insights into a patient's lifestyle.

.

.

Survey of eating habits and the presence of parafunction Certain habits, such as smoking or chewing hard objects, may be deleterious to the patient and negatively influence the treatment outcome. Some occupations are hazardous; for example, wine tasters are more likely to develop non-carious lesions. The presence of wear facets on anterior and posterior teeth, and the excessive wear of the tooth structure, may indicate the presence of parafunctions such as bruxism, which could limit certain types of treatment. A cariogenic diet associated with poor chemo-mechanical control of dental biofilm limits the implementation of prosthetic restorative treatment because the risk of caries and the development of periodontal disease can decrease the longevity of treatment

.

Dental history It is important to know the frequency of visits to the dentist, dental treatment history, oral hygiene habits, and treatment expectations

.

R e s t o r a t i o n

p l a n n i n g

PHOTO

DATE

CLINICAL RECORD No .

PATIENT IDENTIFICATION Name:

TIN:

SSN : Date of birth:

Nationality:

Place of birth:

Age:

. Gender:

Marital status:

Skin color:

Education level: No.:

Home address:

City:

ZIP:

Phone number( s) for contact: (

State:

)

Descendancy: Father 's name:

Mother 's name:

Legal guardian / responsible party: Referred by:

Work information: Profession:

...Working hours:

Function:

.Company name: No .: .

Work address:

ZIP:

City:

Phone number ( s ) for contact : (

)

Address for correspondence:

Partner 's name:

Socioeconomical aspect:

How many people are living at the residency? How many dependants?

Patient's signature

Fig 2-1

Example questionnaire to be employed.

/

/ /

This record is strictly confidential , Answer It truthfully so that your treatment can be properly planned and executed. 1 - What is the reason for your visit? 2 - Which treatment would you like to have done? 3 - How frequently do you visit the dentist? 4 - How many times per day do you brush your teeth? 5 - Did you receive brushing instructions from a professional?

(

) Yes

( ) No

( ) Don't know

6 - Do you use dental floss?

(

) Yes ( ) No

( ) Don't know

7 - Do your gums often bleed?

(

) Yes ( ) No ( ) Don't know

8 - Are your teeth sensitive to temperature changes? 9 - Are your teeth sensitive to sweet foods?

(

) Yes

( ) No

( ) Don't know

(

) Yes ( ) No

( ) Don't know

10 - Do you have the habit of sucking on your fingers?

(

) Yes ( ) No ( ) Don't know

11 - Do you have the habit of biting on objects? 12 - Do you frequently bite your tongue, lips, cheeks? 13 - Do you usually breathe through your mouth?

(

) Yes ( ) No

(

) Yes

(

) Yes ( ) No

( ) Don't know

14 - Do you frequently drink coffee / soft drinks? 15 - Do you frequently have aphthous ulcers?

(

) Yes

( ) Don't know

(

) Yes ( ) No ( ) Don’t know

16 - Do you have herpes labialis?

(

) Yes

( ) No ( ) Don't know

17 - Do you ever notice that your teeth have some mobility?

(

) Yes

( ) No ( ) Don't know

( ) Don’t know

( ) No ( ) Don’t know ( ) No

18 - Have you ever undergone chemotherapy or radiotherapy? ( ) Yes ( ) No ( ) Don't know Why? 19 - Have you ever lived in a rural area?

(

) Yes

( ) No ( ) Don’t know

20 - Have you ever had other professions?

(

) Yes

( ) No

( ) Don't know

Which?

21 - Are you currently undergoing medical treatment?

|(

) Yes ( ) No

|(

) Yes ( ) No ( ) Don't know

|(

) Yes

|(

) No

|(

) Yes

|(

) No

|(

) Yes ( ) No ( ) Don't know

|(

) Yes ( ) No

|(

) Yes ( ) No ( ) Don't know

|(

) Yes

|(

) Yes | ( ) No ( ) Don’t know

|(

) Don't know

Which? 22 - Are you currently taking any medication?

|

Which?

23 - Have you ever undergone any surgery?

|(

) Don’t know

Which? 24 - Have you ever been hospitalized?

( ) Don't know

Why?

25 - Have you recently lost or gained weight quickly?

|

|

|

|(

|

|

Why? 26 - Do you practice sports or physical exercise?

) Don't know

Which? How frequently?

Since when?

27 - Are you pregnant? How many months?

28 - Do you consume alcoholic drinks?

|(

) No

( ) Don't know

Which? How frequently?

29 - Do you smoke?

R e s t o r a t i o n

p l a n n i n g

Chapter

02

ALLERGIES 30 - Do you/ did you ever take:

Anticoagulants?

(

) Yes

( ) No

( ) Don't know

Anticonvulsants? Tranquilizers? Antihistamines?

(

) Yes

( ) No

( ) Don't know

(

) Yes

( ) No

( ) Don't know

(

) Yes

( ) No

( ) Don't know

Analgesia?

(

) Yes

( ) No

( ) Don't know

Aspirin?

(

) Yes

( ) No

( ) Don't know

Dipyrone?

(

) Yes

( ) No

( ) Don't know

Antibiotics? Penicillin? Benzylpenicillin ( penicillin G)? Corticosteroids? Sulfonamide? 31 - Have you ever had a reaction to a medicine? Which? 32 - Have you ever undergone dental anesthesia?

(

) Yes

( ) No

( ) Don't know

(

( Yes

( ( No

( ) Don't know

(

( Yes

( ( No

( ) Don't know

(

( Yes

( ) No

( ) Don't know

(

( Yes

( ( No

( ) Don't know

(

( Yes

( ( No

( ) Don't know

(

( Yes

( ( No

( ) Don't know

Did you have a reaction? 33 - Have you ever had an allergic reaction to food? 34 - Have you ever had an allergic reaction to cosmetics?

(

( Yes

( ( No

( ) Don't know

(

( Yes

( ( No

( ) Don't know

(

( Yes

( ( No

( ) Don't know

35 - Do you have any other allergies?

(

( Yes

( ( No

( ) Don't know

(

( Yes ( ( No

( ) Don't know

(

( Yes

( ( No

( ) Don't know

38 - Rhinitis?

(

( Yes ( ( No

( ) Don't know

39 - Bronchitis?

(

( Yes ( ( No

( ) Don't know

40 - Asthma?

(

( Yes ( ( No

( ) Don't know

Which?

RESPIRATORY DISORDERS 36 - Have you ever had pneumonia? 37

-

Sinusitis?

41 - Hemoptysis? ( coughing up blood )

(

( Yes

( ( No

( ) Don't know

42 - Pneumoconiosis? 43 Pulmonary emphysema ?

(

( Yes

( ( No

( ) Don't know

(

( Yes

( ( No

( ) Don't know

44 - Other respiratory problems?

(

( Yes ( ( No

( ) Don't know

( ) Don't know

-

Which?

CARDIOVASCULAR DISORDERS 45 - Do you have a cardiac prosthetic device?

(

( Yes ( ( N o

46 - Do you have a pacemaker ?

(

( Yes ( ( No

( ) Don't know

47 - Do you ever feel palpitations?

(

( Yes ( ( No

( ) Don't know

48 - Do you ever have chest pain?

(

( Yes ( ( No

( ) Don't know

49 - Do you ever feel shortness of breath or fatigue when ( doing light tasks?

( Yes ( ( No

( ) Don’t know

50 - How many pillows do you use when you sleep? 51 - Do you have hypotension ( low blood pressure )?

(

) Yes ( ) N o

( ) Don’t know

52 - Do you hypertension ( high blood pressure )?

(

) Yes

( ) Don't know

( ) No

CARDIOVASCULAR DISORDERS 53 - Do you bleed a lot when you cut yourself or when your teeth ( are extracted?

) Yes ( ) No

54 - Do you have varices? 55 - Have you ever had a heart attack? 56 - Have you ever had a stroke (CVA)?

(

) Yes ( ) No

( ) Don't know

(

) Yes ( ) No

( ) Don't know

(

) Yes ( ) No

( ) Don't know

57 - Do you ever have swollen feet or legs? 58 - Do you/did you ever have any cardiac problem?

(

) Yes ( ) No

( ) Don't know

(

) Yes ( ) No

( ) Don't know

( ) Don't know

Which?

ENDOCRINE DISORDERS 59 - Do you have polyphagia (eating too much)? 60 - Polydipsia ( excessive thirst)?

(

) Yes

( ) No ( ) Don't know

(

) Yes

( ) No ( ) Don't know

61 - Diabetes? 62 - Is your menstruation regular ?

(

) Yes

( ) No ( ) Don't know

(

) Yes

( ) No ( ) Don't know

63 - Do you have hypothyroidism?

(

) Yes

( ) No ( ) Don't know

64 - Hyperthyroidism ?

(

) Yes ( ) No ( ) Don't know

65 - Hypoparathyroidism ?

(

) Yes

( ) No ( ) Don't know

66 - Are you breastfeeding?

(

) Yes

( ) No ( ) Don't know

67 - Do you/ did you ever have any other endocrine problem?

(

) Yes

( ) No ( ) Don't know

Which?

Chapter

02 GASTROINTESTINAL DISORDERS 68 - Do you have gastritis?

(

) Yes ( ) No

( ) Don't know

69 - Do you have ulcers?

(

) Yes ( ) No

( ) Don't know

70 - Have you ever vomited blood? ( ) Yes ( ) No ( ) Don't know 71 - Do you / did you ever have any other gastrointestinal ( ) Yes ( ) No ( ) Don't know problem?

Which?

NEUROLOGICAL DISORDERS 72 - Do you often faint?

(

) Yes

( ) No

( ) Don't know

(

) Yes

( ) No

( ) Don't know

74 - Do you ever have neuralgia in the face?

(

) Yes

( ) No

( ) Don't know

75 - Do you ever have convulsions?

(

) Yes ( ) No

( ) Don't know

73

-

Do you have frequent cephalgias ( headaches)?

76 - Do you have epilepsy?

(

) Yes

( ) No

( ) Don't know

77 - Have you ever been treated by a psychiatrist?

(

) Yes

( ) No

( ) Don't know

(

) Yes

( ) No

( ) Don't know

) Yes ( ) No

( ) Don't know

How long ago?

Why? 78 - Do you feel stressed?

79 - Do you/did you ever have any other neurological problem? (

Which?

R e s t o r a t i o n

p l a n n i n g

RENAL DISORDERS (

) Yes

( ) No


>.

t -

p r e p a r a t i o n

Fig 3-27 Prepar ation of a shoulder or 90-degree butt joint margin

SHOULDER OR 90- DEGREE BUTT 45- DEGREE BEVEL

JOINT

MARGIN WITH

This finish line preparation is indicated for metal-ceramic, anterior or posterior crowns. The bevel on the finish line improves the insertion and marginal fit of the crown. However, this type of termination requires an excessive removal of tooth structure without offering any advantage over chamfers Some authors consider the appearance of the metal ring to be a disadvantage, causing a compromise in esthetics. Other authors attribute to this ring greater resistance to functional loads. Saito (1999)53 offers some cautionary remarks regarding the use of a beveled shoulder with a metal ring. The long bevel, with an inclination of 70 degrees, has the disadvantage of making it difficult to finish and polish the metal infrastructure. The beveled 45 degrees may distort during heat treatment of the ceramic if the metal band has a width of less than 0.5 mm. If the metal band is wider than 1.0 mm, it will resist any distortion; however, the esthetics will be compromised, since the bevel cannot be covered by ceramic (Fig 3-28).

.

m

Fig 3- 28 Preparation ot ”a shoul or 90-degree butt joint margin with a 45- degree bevel.

a

ROUNDED SHOULDER OR 90- DEGREE BUTT JOINT In this type of preparation finish line, the gingival wall forms an angle of 90 degrees relative to the axial reduction, with a rounded axiocervical angle. This finish is suitable for all-ceramic crowns, which need greater reduction in the cervical region of the prepared tooth, providing increased strength and a well-defined preparation line.13 However, this finish behaves inferiorly to the broad chamfer when certain types of ceramic are used, and poses a higher risk of adverse reaction with pulp involvement.48 Furthermore, it is difficult to obtain a clear margin with this finish. In cases where the tooth has abfractions and restorations, it is more difficult to achieve a uniform reduction. In poster ior teeth, uniform wear is impeded by the limited access to the distal surface of the molars. This type of termination reduces the stress concentration and facilitates the flow of the luting agent33 61 (Fig 3-29).

-

-

ROUNDED SHOULDER OR 90- DEGREE BUTT JOINT WITH 45- DEGREE BEVEL In this type of preparation finish line, the gingival wall forms an angle of 90 degrees relative to the axial reduction, with a rounded axiocervical angle, but with the addition of a bevel. This finish line has been indicated for anterior or posterior metal- ceramic crowns; the bevel improves the insertion and marginal fit of the crown54 (Fig 3-30).

M^§x:v Fig 3-30 Preparation of a rounded shoulder ' or 90-degree butt joint with 45-degree bevel;

SHALLOW CHAMFER

.

The shallow chamfer is widely used as a finish line It is suitable for full-metal crowns and lingual preparations of posterior teeth and veneers With this termination it is possible to obtain a thin restoration margin. Wear is minimized and there is sufficient space to assure the material's resistance. The rounded concavity results in lower stress concentrations ( Fig 3-31) The development of modern adhesive technology and ceramic materials with high resistance and increased fracture toughness enable preparation with a minimally invasive approach, which minimizes weakening of the tooth and pulpal irritation.49 As a result of this process, thickness of the infrastructure of the restorations can be decreased, and less invasive finish lines can be prepared, such as the shallow

.

.

.

chamfer 17

Chapter

03

6? 1 .

'

Vs

-

I

/.

Fig 3-31 Preparation shallow chamfer

.

s

Mm:

i

V

WIDE CHAMFER The gingival wall of this type of finish forms a circular segment from the axial wall to the finish line itself. This type of termination is designed for all-ceramic restorations, to enable a lower marginal discrepancy and a better flow of luting agents.230,47 This termination promotes better stress distribution and a sharp finislrline, and allows the clinician to obtain an appropriate contour in the cervical, vestibular, and proximal regions (Fig 3-32)

.

.

t

«

'

V Fig 3-32 Preparation of a wide chamfer

.

re

*5

CHAMFER WITH 45- DEGREE BEVEL The beveled chamfer is carried out when there is the need for a chamfer. However, this chamfer is very wide, resembling the termination in a shoulder, hence the necessity of a bevel to improve adaptation. The beveled chamfer is well suited for metal-ceramic crowns. There is some controversy among authors regarding the need for a metal band on the border of the crown, unless the metal is made thicker for cases such as this (Fig 3 -33).

Chapter

03

Fig 3-33 Preparation ot a chamfer with 45-degree

bevel. P r i n c i p 1 e

MINI- CHAMFER When there is a need to extend a preparation in the apical direction, the retention, resistance, and esthetic appearance of the restoration will improve. The subgingival preparation of the margins is also indicated when caries or another type of loss of dental structure has occurred prior to preparation (abrasions, abfractions, erosions, and fractures) The denomination "chisel edge" refers to the more apical location (involving cementum) of termination of preparation, and resembles a shallow chamfer (Fig 3-34).

.

m\ Fig 3-34 Preparation of a mini-chamfer.

rs

135-DEGREE MARGIN OR BEVEL A bevel finish line forms an obtuse angle of 135 degrees with the axial wall of the preparation. The finish can be extended to the intrasulcular region, reaching to the root portion, especially in teeth with periodontal involvement and gingival recession. A full metal- ceramic crown that respects the anatomical contours without exposing a metal collar can be made, as it does not require a depth of high tissue reduction and enables a satisfactory esthetic result (Fig 3-35).

I

Chapter

03

r

W

1

\

^* \ HSS \ i

V Fig 3-35 Preparation of a 135-degree margin or bevel

.

P r i n c i p l e s

o f

c a v i t y

p r e p a r a t i o n

0;

KNIFE- EDGE OR ZERO MARGIN When it comes to reduction, a metal

~~T

'

&

can be

V

'«

vX;. 5fe£>.\

^

Fig 3-36 Preparation of a knife-edge or zero margin

REFERENCES

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.

1. Akbar JH, P etrie CS, Walker MP, Williams K, EickJD. Marginal adaptation of Cerec 3 CAD/CAM composite crowns using two different finish line preparation designs, J Prosthodont 2006;15:155-163. 2. Alkumru H, Hullah WR, Marquis PM, Wilson HJ. Factors affecting the fit of porcelain jacket crowns. Br Dent J 1988;164: 39 43 . 3 . Annerstedt A, Engstrom U, Hansson A, et al , Axial wall convergence of full veneer crown preparations , Documented for dental students and general practitioners . Acta Odontol Scand 1996;54:109-112 4. Att W, Komine F, GerdsT, StrubJR . Marginal adaplation 4 of three different zirconium dioxide Ihree-unit fixed den/al prostlieses. J Prosthet Dent 2009;101:239-247. 5. Ayad MF, Maghrabi AA, Rosenstiel SF. Assessment of // convergence angles of tooth preparations for complete crowns among dental students. J Dent 2005;33:633-638. 6. Balkaya MC, Cinar A, Pamuk S. Influence of firing cycles on the margin distortion of 3 all-ceramic crown systems. J Prosthet Dent 2005;93: 346-355 , 7. Behrend DA . Ceramometal restorations with supragingival margins. J Prosthet Dent 1982;47 : 625-632, 8. Black GV. Operative dentistry. Chicago : Medico-Dental, 1908. 9 . BowieyJF, Kieser J. Axial wall inclination angle and vertical height interactions in molar full crown preparations. J Dent 2007;35 :117-123. 10 . Bowley JF, Lai WT. Surface area improvement with grooves and boxes in mandibular molar crown preparations . ) Prosthet Dent 2007;98:436-444, 11. Busato ALS, Barbosa AN, Bueno M, Baldissera RA . Princfpios gerais do prepare de cavidades . In: Dentfstica: Restauragoes em dentes posteriores . Sao Paulo: Artes Medicas, 1996:39-53 12 , Carranza Junior FA Glickman periodontia clfnica, ed 7. Rio de Janeiro: Guanabara Koogan, 1992 13 . Cheung GS, Lai SC, Ng RP. Fate of vilal pulps beneath a metal- ceramic crown or a bridge retainer. Int EndodJ 2005;38:521-530 . 14 Christensen GJ . Marginal fit of gold inlay castings. J Prosthet Dent 1966;16:297-305 . 15 . Coli P, Karlsson S . Fit of a new pressure-sintered zirconium dioxide coping. IntJ Prosthodont 2004;17:59-64. 16 . Micheli PR, Prates RA, Magalhaes MT, Zezell DM, Micheli G. Analise de temperatura intrapulpar no dareamento dental com laser de diodo in vitro . Rev Assoc Paul Cir Dent 2005;59 :117-121 17. Denry I, Kelly JR , State of the art of zirconia for dental applications . Dent Mater 2008;24:299-307 -

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.

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.

18 . Di Febo G, Carnevale G, Sterrantino SF. Treatment of a case of advanced periodontitis : clinical procedures uti lizing the "combined preparation" technique. Int J Periodontics Restorative Dent 1985;5:52-62. 19 . Garberoglio R, Brannstrom M. Scanning electron microscopic investigation of human dentinal tubules. Arch Oral Biol 1976;21: 355-362. 20 . Gardner FM . Margins of complete crowns - literature review. J Prosthet Dent 1982; 48 : 396 - 400. 21 Goodacre CJ, Campagni WV, Aquilino SA. Tooth prepar ations for complete crowns: an art form based on scien tific principles. J Prosthet Dent 2001;85:363-376, 22. Goodacre CJ. Designing tooth preparations for optimal success. Dent Clin North Am 2004;48:359-385. 23. Hegdahl T, Silness J. Preparation areas resisting displacement of artificial crowns. J Oral Rehabil 1977;4:201-207. 24. Ingber JS, Rose LF, Coslet JG. The "biologic width" a concept in periodontics and restorative dentistry. Alpha Omegan 1977;70: 62 65. 25 . Jameson LM, Malone WF. Crown contours and gingival response. ) Prosthet Dent 1982;47:620-624. 26 Johnston JF, Phillips RW, Dykema RW. Modern Practice in Crown and Bridge Prosthodontics, ed 3. Saunders: Phila delphia, 1971. 27. Komine F, Iwai T, Kobayashi K, Matsumura H. Marginal and internal adaptation of zirconium dioxide ceramic copings and crowns with different finish line designs Dent Mater J 2007;26 : 659 664. 28. Kumbuloglu O, Lassila LV, User A, Vallillu PK. A study of the physical and chemical properties of four resin composite luting cements. IntJ Proslhodont 2004;17:357 363. 29. Lewis RM, Owen MM. A mathematical solution of a problem in full crown construction. J Am Dent Assoc 1959;59:943-947. 30 . Limkangwalmongkol P, Kee E, Chiche GJ, Blatz MB. Comparison of marginal fit between all porcelain margin versus alumina -supported margin on Procera Alumina crowns. J Prosthodont 2009;18:162-166. 31 Magne P, Magne M. Using additional wax-up and intraoral mockup for the preservation of enamel in porcelain laminate veneers [in Portuguese ], Int J Braz Dent 2007;1:24- 31. 32. Martignoni M, Schonenberger A , Precisao em protese fixa. Sao Paulo: Santos, 1998. 33 . McLean JW, Hughes TH . The reinforcement of dental por celain witli ceramic oxides , Br Dent J 1965;119 : 251 -267. 34. Mezzomo E, Suzuki RM. Reabilitapao oral contemporanea. Sao Paulo : Santos, 2006. 35. Miller IF, Belsky MW. The full shoulder preparation for periodontal health. Dent Clin North Am 1965;23 : 83-102.

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-

.

-

-

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.

36. Mondelli j. Fundamentos de dentistica operatoria, ed 2. Sao Paulo: Santos, 2006. 37. Mou SH, Cliai T, WangJS, Shiau YY. Influence of different convergence angles and tooth preparation heights on the internal adaptation of Cerec crowns. J Prosthet Dent 2002;87: 248-255. 38. Murray PE, Hafez AA, Smith Aj, Cox CF. Hierarchy of pulp capping and repair activities responsible for dentin bridge formation . Am ] Dent 2002;15:236-243 . 39. Newcomb GM . The relationship between the location of subgingival crown margins and gingival inflammation j Periodontol 1974;45:151-154. 40. Nicholls Jl. Crown retention. I. Stress analysis of symmet ric restorations.] Prosthet Dent 1974;31:179-184. 41. Padbury AJr , Eber R, Wang HL. Interactions between the gingiva and the margin of restorations. ] Clin Periodontol 2003:30 : 379-385 42. Pagani C, Rocha DM, Saavedra GSFA, Carvalho RF. Previsibilidade e Estetica: A utilizagao do ensaio restaurador ( Mock -up) na construgao da beleza do sorriso. In: Calle gari A, Dias RB (eds). Especialidade em foco: beleza do sorriso. Nova Odessa: Napoleao, 2013:114 145. 43 Pameijer CH, Stanley HR, Ecker G , Biocompatibility of a glass ionomer luting agent 2. Crown cementation . Am J Dent 1991;4:134 141. 44. Parker MH, Calverley MJ, Gardner FM, Gunderson RB . New guidelines for preparation taper. J Prosthodont 1993;2:61-66. 45. Pegoraro LF. Protese fixa . Porto Alegre : Artes Medicas, 2004. 46 . Pera P, Gilodi S, Bassi F, Carossa S . In vitro marginal adaptation of porcelain ceramic crowns. J Prosthet Dent 1994;72:585-590. 47 Pigozzo MN, Lagana DC, Mori M, Gil C, Mantelli AG. Prepares dentais com fi nalidade protetica: uma revisao da literatura Rev Odontol Univ Cid Sao Paulo 2009;21:48 55 . 48 . Quintas AF, Oliveira F, Bottino MA. Vertical marginal discrepancy of ceramic copings with different ceramic ma terials, finish lines, and luting agents: an in vitro evaluation. J Prosthet Dent 2004;92:250-257. 49. Raigrodski Aj. Contemporary materials and technologies for all- ceramic fixed partial dentures : a review of the literature. J Prosthet Dent 2004;92:557-562 . 50. Reeves WG. Restorative margin placement and periodontal health. ] Prosthet Dent 1991;66 :733-736 . 51 Ritter AV, Swift EJ jr. Current restorative concepts of pulp protection. Endod Topics 2003;5:41 48. 52. Rosner D. Function, placement and reproduction of bevels for gold castings. J Prosthet Dent 1963;13:1160-1166. ,

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.

-

.

-

.

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-

53. Saito T. Prepares dentais funcionais em protese fixa, ed 2. Sao Paulo: Santos, 1999. 54 Shillingburg HT, Hobo S, Whilsetl LD. Fundamentos de protese fixa, ed 4. Sao Paulo: Quintessence, 2007. 55. SilnessJ. Periodontal conditions in patients treated with dental bridges, 3. The relationship between the location of the crown margin and the periodontal condition. ] Periodontal Res 1970;5:225-229. 56. Smith CT, Gary JJ, ConkinJE, Franks HL. Effective taper cri terion for the full veneer crown preparation in preclinical prosthodontics. J Prosthodont 1999;8:196-200. 57. Smulson MH, Sieraski SM. Histopathology and diseases of the dental pulp. In: Weine FS (ed). Endodontic thera py, ed 5. St. Louis: Mosby, 1996:84-165. 58. Stanley HR. Dental iatrogenesis, Part 2. Dent Today 1995;14:76-81. 59 . Suarez MJ, Gonzalez de Villaumbrosia P, Pradies G, Lozano JF, Comparison of the marginal fit of Procera AllCeram crowns with two finish lines. Int J Prosthodont 2003;16:229-232. 60. Tan PL, Gratton DG, Diaz Arnold AM, Holmes DC, An in vitro comparison of vertical margins gaps of CAD/CAM titanium and conventional cast restorations. J Prosthodont 2008;17:378-383 . 61. Touati B, Miara P, Nathanson D . Inlays e Onlays ceramicas. In: Odontologia estetica e restauragoes ceramicas. Sao Paulo: Santos, 2000:259 291. 62. Tylman SD, Malone WFP. Tylman'sTheory and Practice of Fixed Prosthodontics, ed 7. St. Louis: Mosby, 1978 . 63. Vieira GF Atlas de anatomia de denies permanentes: coroa dental. Sao Paulo: Santos, 2006. 64. Vigolo P, Fonzi F, An in vitro evaluation of fit of zirconi um-oxide-based ceramic four-unit fixed partial dentures, generated with three different CAD/CAM systems, before and after porcelain firing cycles and after glaze cycles. ] Prosthodont 2008;17:621-626. 65 . Wilson AH Jr, Chan DC, The relationship between preparation convergence and retention of extracoronal retainers. ] Prosthodont 1994;3 :74-78. 66. Yu C, Abbott PV. An overview of the dental pulp: its functions and responses to injury. Aust DentJ 2007;52(suppl 1):S4 S16 . 67 Zach L, Cohen G , Pulp response to externally applied heat. Oral Surg Oral Med Oral Pathol 1965,19:515 530. 68, Zollner A, Gaengler P. Pulp reactions to different preparation techniques on teeth exhibiting periodontal disease . JOral Rehabil 2000;27:93-102. 69. Zuckerman GR. Resistance form for the complete veneer crown: principles of design and analysis. Int ] Prostho dont 1988;1:302-307.

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03

CHAPTER 04

INTRACORONAL

TYPES OF PREPARATIONS Major structural losses with consequent destruction of the cusps or coronal portions of teeth due to caries, fracture or other causes occur relatively often in everyday practice Treatment planning is dependent on a careful examination of the clinical situation, including an analysis of the amount of lost hard tissue, possible pulp involvement, relation of tooth to the other teeth, condition of the periodontium, masticatory forces to which the tooth will be submitted, etc. Cavity preparation does not only comprise the reduction or cutting of hard tooth structures. When there is a need to proceed to a therapeutic or prosthetic reduction to ensure a satisfactory outcome, a number of operative maneuvers are required that are dependent on the characteristics of each situation or case.MO Shillinburg et al12 cited some basic principles related to the tooth structure: preservation of tooth structure, form of retention and form of resistance, durability of the restoration structure, marginal integrity, and preservation of the periodontium. Although these principles should be clinically integrated, compromising one or more of them to favor others is sometimes necessary Thus, the classical principles of cavity preparation advocated by Black, or the suitability of the cavity for an adhesive restoration, are not valid here. It is necessary to make some changes in the preparation of the remaining struc ture using retentive features that compensate for the absence of the original tissue.1 A 5,10-12,14 Some of the main types of intracoronary restorations are: • Inlays - strictly intracoronal preparations; • Onlays - preparations involving some cusps; • Overlays - preparations involving all cusps up to the middle third of the crown.

.

.

The burs and abrasives used for the preparation discussed in this chapter are shown on pages 98 and 99.

I n t r a c o r o n a l

r e s t o/ a t

o n s

rA

T O

TYPES OF BURS AND ABRASIVES

w jEr

^

'

ROUND CARBIDE ROUND SMALL 0

ROUND LARGE 0

PEAR, MEDIUM GRIT

1

PEAR,

FLAME, MEDIUM GRIT

EXTRA-FINE GRIT

, rr

POINTED TAPER , MEDIUM GRIT

i

FLAME, EXTRA -FINE GRIT

[#T* J

ROUNDED TAPER,

POINTED TAPER, EXTRA-FINE GRIT

MEDIUM 0, MEDIUM GRIT

T

WHEEL, MEDIUM GRIT

/

ROUNDED TAPER, MEDIUM 0, MEDIUM GRIT

ROUNDED TAPER, LARGE 0, MEDIUM GRIT

FLAT- END CYLINDER, MEDIUM GRIT

BEVELED CYLINDER, MEDIUM GRIT

ROUNDED SHORT TAPER, MEDIUM GRIT

MULTILAMINATED PEAR (8 TO 36 BLADES)

MULTI LAMINATED

ROUNDED TAPER

( 8 TO 36 BLADES),

LARGE 0

I n t r a c o r o n a l

METAL RESTORATIONS INDICATIONS Metal restorations are considered less esthetic. Due to advances in recent years they have been replaced by other dental materials, yet they still have great applicability and are indicated in everyday practice. Knowledge of the principles of metal restorations is necessary for the understanding and application of basic concepts 8'9'12 One of the great advantages of metal restorations is their biocompatibility They are indicated for: large cavities or extensive reconstructions, prevention of periodontal problems through the reconstruction of contact points, protection of endodontically treated teeth, areas of large masticatory forces, resistance to the application of masticatory forces protecting the remaining structures, retainers for fixed prostheses, splinting, replacement of deficient restorations, teeth that need to be restored in the case where the antagonist is also a metal restoration, support for removable partial dentures, and occlusal reestablishment.8'9

.

.

MAIN TYPES OF INTRACORONAL RESTORATIONS The main intracoronal metal cast restorations are mesio-ocdusal (MO), mesio-occluso-distal (MOD), and disto-occlusal (DO). These may be present as a single box, or they may be more complex with the coverage of one or more cusps.

Inlay In the preparation of an inlay, variations exist that may or may not involve the proximal walls, ie, turning it into an MO or DO preparation. Attention should be paid to preserving the marginal ridges in case there is no need to involve them (Figs 4-1 to 4-4). Preparation of the occlusal box should involve the central third of the main fossa, reducing the coronal height by 1/3, with a 3- to 5-degree taper of the walls. For the preparation of the proximal box, the adjacent tooth should be protected with a metal strip, removing the contact point. The reduction is deepened by 2/ 3 of the coronal height in the gingival direction. The cavosurface angle of the occlusal and proximal boxes should be beveled once, so as not to create a discontinuity between the boxes 2'9

.

Chapter

04

Fig 4-1 Intact tooth (A) , Slicing of the proximal surface, removing the interproximal contact (B), Occlusal and proximal boxes with sharp angles prepared with a flat-end cylindrical diamond bur (C) . Preparation of the proximal box with straight walls, sharp angles, and walls diverging in the occlusal direction (D), Final aspect of the preparation (E,F).

I n t r a c o r o n a l

r e s t o r a t i o n s

Intact tooth ( A). Slicing of the proximal surface (B). Occlusal and proximal boxes with sharp angles prepared with a flat -end cylindrical diamond bur (C) Final aspect of the preparation (D E). Fig 4- 2

.

.

Chapter

04

Fig 4-3 Intact tooth (A) . Slicing of the proximal surface with a tapered diamond bur (B). Vestibular box (C) . Divergence of the vestibular box provided by the diamond bur (D). Final aspect of the preparation (E-G).

Chapter

04

.

Fig 4- 4 Intact tooth (A) Slicing of the proximal surfaces ( B). Proximal box (C). Occlusal box (D). Bevel of the cavosurface angle (E). Final aspect of the preparation (F,G).

I n t r a c o r o n a l

r e s t o r a t i o n s

Maxillary onlay

The preparation is started following the same principles as for inlay. A preparation for a maxillary onlay involves the functional maxillary palatal cusps (Fig 4-5) For the occlusal reduction, orientation grooves should be made, following the dental anatomy. Balancing cusps (buccal) should be reduced by 1.0 mm, and functional ( palatal) cusps by 1.5 mm It is necessary to verify the occlusal reduction to determine if there is enough space for the restorative material This step is created to increase the strength of the metal structure and to reinforce it, preventing deflection and displacement of the restoration 8'12

.

.

.

.

A proximal box is prepared to increase the resistance of the restor ation by increasing its volume. The creation of a beveled finish line im-

proves the marginal adaptation of the restoration (see Fig 4-6)

.

-

Fill 4 5 intact tooth (A), occlusal reduction (B). Reduction of the vestibular surface, form ing an occlusal step (C) Occlusal box with a flat-end cylindrical diamond bur (D), Proximal box with a flat end cylindrical diamond bur

.

-

-

Chapter

04

Mandibular onlay A preparation for a mandibular onlay involves the functional mandibular buccal cusps (Fig 4-7). For the occlusal reduction, orientation grooves should be made, following the dental anatomy. Balancing cusps (lingual) should be reduced by 1.0 mm, and functional (buccal) cusps by 1.5 mm. It is necessary to verify the occlusal wear to determine if there is enough space for the restorative material 8

.^

Fig 4-7 Intact tooth (A). Occlusal box reduction (B) . Proximal box reduction ( C). Functional cusp reduction (D). Beveling of the cavosurface angle alongjts entire length (E,F) . Final aspect of the prepar ation (G).

Overlay The preparation is started following the same principles as for the onlay. The difference is in the greater occlusal reduction, which is applied to both the cusps. It is necessary to verify the occlusal reduction to determine if there is enough space for the restorative material 8 12 Figures 4-8 and 4-9 show the preparation steps for maxillary and mandibular overlays, respectively

.-

.

I L

i A

[©

i

V*

I

\

^ Chapter

.

.

04

Fig 4-8 Intact tooth (A) Preparation of buccal and lingual surfaces with a flatrend cylindrical diamond bur for the cusp coverage (B) Occlusal box with flat-end cylindrical diamond bur (C),C Smoothing of the pulpal wall of the preparation with a flat-end cylindrical diamond bur,( D ') / ^ Proximal box with a flat-end cylindrical diamond bur (E), Beyelirigcrf the bucfcal alingMlTimv; ish line of the preparation (F).' Slicing of the proximal wall, removi.ng the,iot§rprox1rnatcpntact point (G). Final aspect of the preparation (H)

.

.

I

^

^

-

t

i

/ II • '1 I1

\

i '

A .

3a

i

,

Fig 4-9 Intact tooth (A). Occlusal reduction (B). Occlusal and proximal boxes with a flat;dnd tapered diamond bur (C). Reduction for coverage of the supporting and balanGing'cusp'(R).' ' Beveling with a flame-shaped diamond bur (E). Slicing of the proximal surfaces (E)jfFjnal |ispeG of the preparation (G-l).

.

I n t r a c o r o n a l

..

r e s t o, r a t i o n s

£

;

;

METAL- FREE RESTORATIONS INDICATIONS The concept of metal-free restorations in ceramics dates back to the end of the last century, when the first metal-free restorations were made. With the advent of adhesive techniques, cavity preparation for indirect restorations has been simplified, requiring increasingly fewer geometric artifices to achieve retention and stability while preserving dental structure 1 13,14 One of the great advantages of metal-free restorations is their esthetics, which mimic the peculiarities of natural teeth. They are indicated for: teeth presenting caries or traumatic injuries, teeth with restorative needs where the antagonist is also a ceramic restoration, teeth where it is difficult to develop shape retention, esthetic requirements, replacement of deficient restorations, extruded or infraoccluded teeth, teeth that have structural defects or deformations, prevention of periodontal problems through the reconstruction of contact points, protection of endodontically treated teeth, retainers, fixed prostheses, diastema closure in anterior teeth, vital teeth with extensive coronal destruction, and teeth with short clinical crowns.

. ^.

MAIN TYPES OF INTRACORONAL RESTORATIONS The main intracoronal metal-free restorations are mesio -occlusal (MO), mesio -occluso-distal (MOD), and disto-occlusal (DO) These may be present in a single box or they may be more complex, with the coverage of one or more

.

.

cusps

Inlay Figures 4-10 and 4-11 show the preparation steps for maxillary and mandib ular inlays, respectively. In the preparation of a ceramic inlay, variations exist that may or may not involve the proximal walls, turning it into an MO or DO preparation. Attention should be paid to preserving the marginal ridges in case there is no need to involve them. Preparation of the occlusal box should involve the central third of the main fossa, reducing the coronal height by 1/3, with a 7- to 12-degree taper of the walls For the preparation of the proximal box, the adjacent tooth should be protected with a metal strip, removing the contact point. The reduction is deepened by 2/3 of the coronal height in the gingival direction, ensuring that the isthmus has a minimal width of 2 mm to provide adequate resistance to the restoration.3 6 7 14

.

---

Fig 4-10 Intact tooth (A). Occlusal box with a round- end tapered diamond bur ( B). Proximal box with a round end tapered diamond bur (C). Final aspect of the preparation (D-F). -

n

Fid 4 - 11 Intact tooth (A). Occlusal box with a round-end tapered diamond bur (B), Proximal box with a round-end tapered diamond bur (C). Final aspect of the preparation (occlusal view) (D).

n t r a c o r o n a

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Maxillary onlay The preparation is started following the same principles as for the inlay. The preparation steps for a maxillary premolar are shown in Figure 4-12, and for a maxillary molar in Figures 4-13 and 4-14. A preparation for a maxillary onlay involves the functional maxillary palatal cusps. For the occlusal reduction, orientation grooves should be made, following the dental anatomy Balancing

.

cusps ( vestibular ) should be reduced by 2.0 mm, and functional (palatal) cusps by 2.5 mm. It is necessary to verify the occlusal reduction to determine if there is enough space for the restorative material. This step is created to strengthen and reinforce the ceramic structure, minimizing cracks and fracture of the res toration. Special attention should be paid to the internal angles of the prepar ation, which should be rounded.3^

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Fig 4-12 Intact tooth (A) Occlusal reduction (B). Wear of the vestibular surface forming the occlusal step (C). Reduction of the occlusal box and the buccal cusps with a round-end cylindrical diamond bur (D). Occlusal box with a flat end cylindrical diamond bur (E). Final aspect of the preparation (F-H). -

I n t r a c o r

Chapter

04

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Fig 4 13 Intact tooth (A). Occlusal reduction (B) Occlusal step of the functional cusp with a round-end tapered diamond bur (G) Occlusal box with a round-end tapered diamond bur (D). Proximal box with a round-end tapered diamond bur (E). Wear of the functional. cusps and working cusps (F) Reduction of the functional cusps (0), Final aspect of the preparation (H,I)

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Mandibular onlay A preparation for a mandibular onlay (Figs 4-15 and 4-16) involves the func tional mandibular buccal cusps. For the occlusal reduction, orientation grooves should be made, following the dental anatomy. Balancing cusps (lingual) should be worn by 2.0 mm, and functional (buccal) cusps by 2.5 mm. It is necessary to verify the occlusal wear to determine if there is enough space for the restorative material.3,14

Fig 4 -15 Intact tooth ( A). Reduction of the proximal box ( B). Reduction of the occlusal box (C). Reduction of the balancing cusp (D). Final aspect of the preparation (E,F).

Chapter

04

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4-16

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Overlay The overlay preparation is begun following the same the principles as for the onlay. The difference is in the greater occlusal reduction, which is applied to both the cusps (buccal and lingual) (Figs 4-17 to 4-22) It is necessary to verify the occlusal wear to determine if there is enough space for the restorative material.3.14

.

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Intact tooth ( A). Vestibular reduction with round-end tapered diamond bur (B), Pal atal reduction with round end tapered diamond bur (C). Reduction of the free surfaces with round end tapered diamond burs (D) . Wear and reduction of the functional cusp (E). Wean of .. the proximal box with a round-end tapered diamond bur (F). Wear of the proximal box with a round end tapered diamond bur ( G). Final aspect of the preparation (H-J ). Fig 4-17

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- Intact tooth (A). Wear of the ves tibular surface with a round-end tapered di amond bur ( B). Wear of the palatal surface with round-end tapered diamond bur (C) , Occlusal box with a round end tapered diamond bur (D). Occlusal box with a roundend tapered diamond bur ( E). Proximal box with a round-end tapered diamond bur (F). Proximal box with a round- end tapered diamond bur (G). Occlusal box with a with a round-end tapered diamond bur ( FI ). Reduction of the functional and balancing cusps (I), Final aspect of the preparation Fig 4 1l.i

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Chapter

04

Chapter

04

Fig 4-19 Intact tooth ( A) . Reduction of the occlusal box with a round-end tapered diamond bur (B) . Proximal reduction with a round end tapered diamond bur (C). Vestibular occlusal step with a round-end tapered diamond bur (D) . Reduction of the working and balancing cusps (E). Wear of the lingual surface and formation of the cervical finish line and functional cusp reduction (F) . Final aspect of the preparation (G,H) -

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Fig 4- 20 Final aspect of the preparation (A, B).

Chapter

04

Fig 4- 21 Intact tooth ( A) , Reduction of the proximal box with round-end tapered diamond bur ( B).

I n t r a c o r o n a l

r e s t o r a t i o n s

Fig 4- 21 Reduction of the occlusal box with a round-end tapered diamond bur (C). Reduction of the vestibular and lingual portion with a round-end tapered diamond bur (D) .

Chapter

04

Fig 4- 21 Reduction of the balancing cusps with a round-end tapered diamond bur (E). Final aspect of the preparation (F).

I n t r a c o r o n a l

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Chapter

04

Fig 4- 22 Intact tooth (A). Occlusal reduction (B). Occlusal reduction (C) . Occlusal box with a round-end tapered diamond bur (D) . Proximal box with a round-end tapered diamond bur (E). Reduction of the buccal and lingual surfaces of the cusps with a round-end tapered diamond bur (F) .

I n t r a c o r o n a l

r e s t o r a t i o n s

Fig 4- 22 Final aspect of the preparation (G,H) ,

PECULIARITIES OF PREPARATIONS FOR METAL- FREE RESTORATIONS The tooth preparation for esthetic indirect posterior restorations is different from the classical preparations made for cast metal restorations. These modifications mainly relate to the fragility of these esthetic restorative materials before final cementation. They aim to provide proper resistance for the try- in, adjustment, and cementation of the workpiece. In the adhesive restorations there is no concern regarding the retentive shape, since the preparation must be divergent. Some factors must be observed during cavity preparation: pas sive seating of the workpiece, reduction of points of stress concentration by smoothing the angles, and resistance form of the material. Some characteristics of the preparation can be highlighted: reduction of the occlusal box of 1.5 to 2.0 mm, cusp reduction of 2.0 to 2.5 mm, 1.5 to 3.0- mm width of the occlusal isthmus, 1.0 to 1.5-mm width of the gingival wall, 7- to 12-degree taper, edge of the cavity and cervical finish, beveled or concave butt angle margins, rounded internal angles, and sharp edges in enamel that do not coincide with the occlusal contacts.3 14

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REFERENCES

Chapter

1. Baratieri LN, MonteirojuniorS, Andrada MAC, Vieira LCC, Ritter AV, Cardoso AC. Odontologia Restauradora: funda mentos e possibilidades , Sao Paulo: Santos, 2001. 2. Blaser PK, Lund MR, Cochran MA, Potter RH. Effect of designs of Class 2 preparations on resistance of teeth to fracture . Oper Dent 1983;8: 6-10. 3. Bremer BD, Geurlsen W. Molar fracture resistance after adhesive restoration with ceramic inlays or resin-based composites. Am J Dent 2001;14:216-220. 4. Garber DA, Goldstein RE , Porcelain and composite inlays and onlays : esthetic posterior restorations , Chicago :

Quintessence, 1994. 5 . Garone W. Restauragoes ceramicas em dentes posteriores. Estetica do sorriso : arte e ciencia. Sao Paulo: Santos, 2003 . 6 . Khera SC, Goel VK, Chen RC, Gurusami SA . Parameters of MOD cavity preparations: a 3-D FEM study, Part II. Oper Dent 1991;16 :42-54. 7. Lin CL, Chang CH, Ko CC. Multifactorial analysis of an MOD restored human premolar using auto-mesh finite element approach. J Oral Rehabil 2001;28:576-585.

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8. Martignoni M, Schonenberg A. Precisao em protese fixa Tokyo : Quintessence, 1998. 9 . Mezzomo E, Suzuki RM. Reabilitag3o oral contemporanea. Sao Paulo: Santos, 2006. 10. MondelliJ, Sene F, Ramos RP, Benetti AR. Tooth structure and fracture strength of cavities. Braz Dent J 2007;18:134-138. 11. Robbins JW, Fasbinder DJ, Burgess JO. Posterior inlays and onlays. In: Schwartz RS, Summit JB, Robbins JW ( eds). Fundamentals of operative dentistry: a contemporary approach. Chicago: Quintessence, 1996:229-250. 12. Shillingburg HT, Hobo S, Whitsetl 10, Jacobi R, Brackett SE. Fundamentos de protese fixa, ed 4, Sao Paulo: Quintessence, 2007. 13. Soares CJ, Martins LR, Fonseca RB, Correr-Sobrinho L, Fernandes Neto AJ . Influence of cavity preparation design on fracture resistance of posterior Leucite -reinforced ceramic restorations. J Prosthet Dent 2006;95:421 429. 14. Touati B, Miara P, Nathanson D . Inlays e Onlays ceramicas. In: Odontologia estetica e restauragoes ceramicas. Sao Paulo: Santos, 2000:259 -291.

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PREPARATIONS FOR PARTIAL CROWNS Coronal preparations are made to promote maximum retention and resistance; to preserve the structure of the tooth; and to favor the periodontal health, durability, and marginal integrity of the restoration The classic preparations of the abutment teeth are made without modifications for fixed partial dentures. The teeth may either be intact or damaged The tooth is prepared after a previous restoration of a portion of the crown or a post 7 Partial preparation is one of the most conservative options among the crown preparations and requires little reduction of the dental structure. The indication is based on the concept that the tooth should not be unnecessarily prepared. This preparation has the advantage of a facilitated evaluation of the adaptation of exposed margins. Another advantage is related to the cementation procedure because the cement can flow more easily, thus allowing a more precise seating. In this preparation, the external surface of the tooth remnant serves as a reference to create the most appropriate outline for the restoration.6

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3/4 PARTIAL CROWNS Preparation for a 3 / 4 partial crown prevents the appearance of metal on the buccal surface, which allows for better esthetics. However, this preparation requires more time and skill on the part of the clinician due to its features regarding reduction and parallelism. The success of a 3/4 preparation in the anterior region depends on careful planning of the case before the start of treatment. This type of preparation should be used for abutments for a fixed partial restoration when there is reduced space, in teeth with small restorations. The anatomical shape of the tooth should be considered in the planning, taking into account the biomechanical principles of the preparations This preparation is best suited for longer teeth, while preparation of shorter teeth is difficult,7 Teeth that need to be prepared must have a good alignment in the dental arch and cannot present an accentuated constriction in the cervical region. The presence of a deep overbite requires more reduction. The preparation is conservative, but the tooth should have sufficient buccolingual thickness to allow for the reduction with the preparation.6 7

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Anterior teeth In the preparation for a 3/4 crown, special attention should be given to the reduction of the tooth structure For lingual reduction, approximately 0.7 mm of structure should be removed to create a surface with double concave inclination in the maxillary canines and a smooth, continuous surface in the mandibular canines and incisors (Figs 5-1 and 5-2) The incisal reduction should

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be approximately 0.7 mm, following the natural mesial and distal inclinations of the incisal borders of the canines, and a straight line on incisors. Special attention should be given to the proximal axial reduction, since insufficient preparation in this area causes a reduction of the retentiveness of the restor ation . Proximal grooves must have approximately 1.0 mm of depth and must be parallel to the middle of the incisal third of the buccal surface . Occasionally, the grooves may be replaced by boxes in the case of existing caries or prep arations. The incisal channel follows the incisal anatomy, which is different in canines (inverted V-shape) and incisors ( straight line).6

Fig 5-1 Intact tooth ( A) . Intact tooth (B). Reduction of the cervical portion of the lingual (palatal) surface with a tapered diamond bur (C) . Reduction of the palatal surface with a pear shaped diamond bur ( D ) -

Fig 5-1 Reduction with a tapered diamond bur on the proximal surfaces, preserving the buccal surface (E ). Proximal groove (F) Bevel at the cervical finish line (G). Retention groove (H).

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Chapter

05

Fig 5 -1 Final view of the prep aration , Proximal view (I). 4/5 preparation of inferior tooth 43 (]).

Fly 5 - 2 Intact tooth (A). Occlusal reduction with a round-end tapered bur (B) , Cusp reduction (C). Reduction of the buccal surface (D), Preparation of the proximal grooves with a roundend tapered bur (E) Preparation of the occlusal groove with a flat-end tapered bur (F).

.

4/5 PARTIAL CROWNS The preparation for 4/ 5 partial crowns is one of the most conservative coronal

'preparations, requiring a small reduction of the tooth structure. This prepar ation enahles tbe. precise evaluation of supragingival margins, and facilitates

^

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the flow of the cement, allowingfor better seating This preparation is not indicated in teeth with extensive destruction or when there is need for maximum retention or esthetics.7 The posterior partial crowns differ from the anterior ones due to the inser tion plane that is usually parallel to the long axis of the tooth. The preparations in the maxillary and mandibular teeth differ significantly as regards the working>ajsps. In the maxillary teeth, the preparation does not involve the buccal surface, whereas cuspal coverage is necessary in the buccal cusps of the man ' dibular teeth, since these are the functional cusps.6

Maxillary teeth When preparing 4/ 5 partial crowns for maxillary teeth, attention should be paid to achieving proper occlusal reduction (Figs 5-3 to 5 -6). The reduction of the functional (palatinal) cusp should be approximately 1.5 mm ( Figs 5 - 3 A to D, and 5 - 4B) To minimize the appearance of metal, the angle of the vestibulo -occlusal line should be reduced by 0.5 mm, and the working cusp ( buccal) by 1.0 mm. The axial walls must be reduced by approximately 0.5 mm, Proximal grooves must be approximately 1.0 mm deep, and parallel to the middle of the incisal third of the buccal surface (Figs 5-3E to G, and 5-4C and D ). Occasionally, the grooves may be replaced by boxes due to the existence of preparations or carious lesions (Figs 5- 7 to 5-9) The occlusal groove follows the anatomy ( inverted V-shape) and is 1.0- mm wide (Figs 5 - 3 H and 5-5A) A 7 All line angles of the preparation are smoothed, the margins are beveled, and the proximal boxes are checked for convergence toward the occlusal as pect of the tooth (Figs 5-3 I to M, 5-5B, and 5-6).

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Chapter

Fig 5-3 Intact tooth (A). Occlusal reduction with a tapered diamond bur (B).

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Chapter

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Fig 5 - 3 Occlusal reduction (C). Reduction (bevel) of the supporting cusps (D). Reduction of the lingual (palatal) surface, extending until the removal of the inter proximal contact between the mesial and distal surfaces (E) Proximal groove ( F), Proximal groove (G). Groove on the working cusp, flat -end tapered diamond bur (H) .

Proximal grooves (I). Bevel of the cervical finish line ())• Beveling the working cusp with a flame - shaped diamond bur (K). Final view of the preparation (L,M).

Fig 5-3

Fig 5 - 4 Intact tooth (A). Occlusal reduction with a round-end conical bur (B). Mesial and distal (M and D) proximal reduction with a pointed tapered bur (Q. M and D proximal finishing with a round-end conical bur (D),

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W/y INTRODUCTION The search for excellence in the reestablishment of esthetics and function in cases of rehabilitation led to the improvement and development of techniques in the dental industry This ultimately fulfilled patients' needs for functional, long-lasting restorations, and a beautiful and harmonious smile.1 11 Demand for lifelike, unnoticeable esthetic restorations requires painstaking resources and knowledge from dental professionals in order to deal with the complexity of the procedures involved in the reestablishment of function and esthetics.2 With the growing trend toward ceramic-based, indirect restorative materials, as well as the progress made in adhesive systems and the evolution of restorative materials, minimally invasive preparations have become a reality.3 The underlying premise of minimally invasive preparations is maximal preservation of healthy tooth structure. Thus, the preparation will not follow geometrical patterns, nor should it have boxes or retention grooves. Rather, it is based on the minimum reduction required to provide sufficient thickness to the restorative material to obtain the desired esthetics and function. An important feature of the preparation is to provide a form which facilitates the proper insertion of the restoration.14'15 Minimally invasive preparations can be distinguished from traditional preparations, especially with regard to retention and form of resistance.36 A minimal amount of geometrical preparation is required to facilitate the insertion and positioning of the restoration during the final cementation procedure. Of secondary importance are the geometric and mechanical parameters of a preparation This allows for the maximum preservation of the remaining tissues and therefore a conservative approach (about a quarter of the amount of tooth reduction compared to a full-crown preparation) 13'37-40 43 A key objective in minimally invasive dentistry is to provide sufficient reduction of the tooth, since a restoration requires adequate thickness to provide mechanical strength to the material.41 42'44 Recommended thicknesses are about 0.3 to 0.5 mm for the cervical area, 0.7 mm in the middle and incisal thirds, and a minimum of 1.5 mm for the incisal coverage 16 21 These values correspond to the mean thickness of enamel.22 Accuracy in obtaining these dimensions is the most difficult aspect of tissue reduction because these final thicknesses are closely related to the final volume and shape of the restoration.16 Tooth reduction is guided by the shape, thickness,and position of the future restoration. Therefore, it is of fundamental importance that the shape of the future restoration is known prior to the completion of the preparation (Fig 6-1) Several techniques can be used to obtain the goal of tooth reduction,23 27 such as a diagnostic wax -up followed by a restorative trial (mock-up) that indicates the position of the future restoration 14 28

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Upon approval of the mock -up, the next step is the completion of the prepar ation. The amount of structure that needs to be reduced will be determined by the selected restorative material and the relation between the shade of the substrate and that of the final restoration. Darker substrates require greater reduction to achieve the desired final result with lighter colors, always within the limitations of each case.

Chapter

06

Fig 6-1 Simulation of an initial clinical situation (A). After the diagnostic wax -up on the model ( B). Ideal recontouring of the anatomy (C) .

C o n s e r v a t i v e

p r e p a r a t i o n s

The diagnostic wax-up that represents the original tooth volume should be used as a reference for the tooth preparation. This basic principle saves a significant amount of healthy tissue; not only is the enamel preserved, but also the dentinoenamel junction. The simplest and most important tool for enamel reduction in this technique is a silicone guide made from the wax -up, which is vertically or horizontally sectioned (Fig 6-2) 29 30

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Tig ii - f Buccal reduction With out the aid of a mock-up (A). With the aid of a silicone guide (B)

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PREPARATION FOR VENEERS Veneers are partial extracoronal restorations usually indicated for anterior esthetic rehabilitations. The main purpose of a veneer is to cover the labial-prox imal surfaces and potentially the incisal border of the anterior teeth in an attempt to correct color discrepancies, shape, texture, function, and position of the elements in the dental arch.4 Veneers in anterior teeth have existed in dentistry since the 1930s. This technique was described by Pincus,5 who made temporary veneers for Hollywood actors and actresses to modify their smiles for filming and photo shoots. However, they only began to be used in dentistry in the early 1980s, when in 1983 Simonsen and Calamia,41 and Calamia 6 7 described the porcelain etching process, which solved the problem of the longevity of these restorations by improving their adhesion to dental tissue. The characteristic of minimal invasiveness in preparations for dental veneers has become increasingly important due to the current focus in dentistry on conservative procedures. Veneers are indicated when a conservative solution is sought to resolve esthetic problems 10 The main indications for veneers / laminates are:810 teeth with discoloration that are resistant to whitening procedures, unsatisfactory shape or contours ( size or volume) requiring morphological changes, closing diastemas, minor alignment corrections, restoration of defects in the enamel, teeth with fluorosis, and teeth with small fractures and tooth defor mities. The severity and extent of any of these factors require further evaluation, which is instrumental in achieving the goals of treatment and recovering function and esthetics. However, there are situations in which the use of veneers is less suitable:10 12 cases with reduced interocclusal space, presence of deep bite with slight over jet, bruxism, parafunctional habits, severe dental crowding, periodontal disease, and teeth with extensive restorations that are indicated for a total crown. There are several preparation designs for ceramic veneers,31 which vary according to the extent of the preparation (Table 6-1) The use of different preparation techniques is dependent on several fac tors: amount of remaining tooth structure, presence of previous restorations, length of the clinical crown, and presence of endodontic treatment. Different clinical studies have evaluated the long-term behavior of teeth restored with ceramic veneers, using several preparation designs 32-35 These studies have concluded that ceramic veneers are a good restorative option. Survival and success rates of over 80% for these restorations have been re ported.5

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l

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p r e p a r a t i o n s

Chapter

06

Table 6-1 Types of conservative preparations, extension, and labial and proximal views

CONVENTIONAL

CONVENTIONAL

PREPARATION WITH INCISAL COVERAGE

PREPARATION WITH PALATAL/LINGUAL

EXTENDED PREPARATION

CHAMFER

mu Preservation of the proximal contacts with coverage of the incisal

border

Removal of the proximal

preservation of the proximal contacts with coverage of the incisal border, creating a

the incisal border until the

palatal/lingual chamfer

middle third

contacts with coverage of

Chapter

06

PREPARATION FOR VENEERS The continuing evolution of bonding processes to dental structures makes possible the implementation of more conservative restorative techniques and enables the use of minimally invasive preparations (Figs 6-3 to 6- 8). In teeth with slight or no discolor ation, for example, ceramic veneers with thicknesses ranging from 0.3 to 0.7 mm may be used 33 Based on this philosophy, extremely thin ceramic veneers (0.1 to 0.7 mm) emerged, requiring minimal tooth reduction that is limited to merely smoothing sharp angles and eliminating undercuts. Teeth indicated to receive this type of restoration usually have favorable characteristics such as a good insertion axis and adequate space for the restoration These preparations have very specific indications, where reshaping or correction of tooth volume is necessary by adding material It should be noted that ceramic veneers are of limited use in situations requiring major correction.

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Fig 6-3 Preparation of the central incisor without involvement of the incisal edge. Intact tooth (A). Orientation grooves on the labial surface, with a tapered diamond bur following the inclination of the incisal, middle, and cervical thirds (B). Labial reduc tion (C).

Chapter

06

Fig 6- 3 Labial axial reductions (D). Proximal axial reductions (E). Final preparation from the labial aspect (F). Final preparation from the proximal aspect (G).

C o n s e r v a t i v e

p r e p a r a t i o n s

Fig 6- 4

Preparation of the central incisor with involvement of the Incisal edge. Intact tooth (A). Orientation grooves on the labial surface, with a tapered diamond bur following the inclination of the Incisal, middle, and cervical thirds (B). Incisal reduction (C ).

Fig 6- 4 Reduction of the labial surface, using a tapered diamond bur (D,E ). Axial and proximal reduction of the labial surface (F,G).

f

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Fig 6- 4 M and D proximal incisal reduction (H). Palatal

incisal reduction In the shape of a concave chamfer (I ).

Chapter

06

Fit) 6-6 Preparation of the canine without involving the incisal edge Intact tooth (A,B). Axial, Incisal, and prox-

imal aspects of the preparation of the labial surface with a rounded tapered diamond bur (C,D). Final aspect of the preparation, from the frontal, prox imal, and incisal views (E-G).

C o n s e r v a t i v e

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Preparation of the canine with involvement of the incisal edge. Intact tooth (A, B). Labial reduction with a rounded tapered diamond bur (C,D).

Fig 6-7

Chapter

06

Fig 6-7 Incisal reduction (E-H),

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Fig 6 8 Intact tooth (A) . Labial orientation grooves, using a rounded bur (B). Labial reduction in several planes, using a rounded diamond bur (C F). -

Fig 6- 8 Oblique ( 6) and buccal ( H) views of the finished prepar ation.

C o n s e r v a t i v e

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REFERENCES 1 . Andrade OS, Lobo M . Ultra - thin and conventional ceramic laminates: ultraconservative approach for ceramic restorations [ in Portuguese ] In : Callegari A, Chediek W ( eds). Focus on Specialty : Beauty of the Smile , Nova Odessa: Napoleao, 2014: 58-91. Belser UC, Magne P, Magne M. Ceramic laminate veneers : continuous evolution of Indications . ) Esthet Dent 1997;9:197-207 . 3. Bispo LB . Aesthetic veneers : state of the art Revista Dentistica 2009;8:11-14. http://coral.ufsm br /dentisticaonline /0810.pdf . Accessed 1 January 2015. 4. Bottino MA, Valandro LF, Faria R. Perceplion. Sao Paulo: Artes Medicas, 2009 . Burke FJ, Lucarotti PS. Ten-year outcome of porcelain

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laminate veneers placed within the general denial services in England and Wales. J Dent 2009;37 : 31-38.* 6. Calamia JR . Etched porcelain facial veneers: a new treatment modality based on scientific and clinical evidence. NYJ Dent 1983;53: 255-259. 7. Calamia JR . Etched porcelain veneers: the current state of the art. Quintessence Int 1985;16 : 5-12. 8. Calamita MA, Coachman NS, Sesma N. Tooth preparations and impressions in today's restorative practice. What do we need to know? [in Portuguese] In : Callegari A, Chediek W ( eds ) . Focus on Specially: Beauty of the Smile. Nova Odessa : Napoleao, 2014:244 287. 9. Cherukara GP, Seymour KG, Samarawickrama DY, Zoti L. A study into the variations in the labial reduction of teeth prepared to receive porcelain veneers - a comparison of three clinical techniques. Br Dentf 2002;192:401 -404; discussion 392. 10. Cherukara GP, Seymour KG, Zou L, Samarawickrama DY. Geographic distribution of porcelain veneer preparation depth with various clinical techniques. J Prosthet Dent 2003;89:544-550. 11. Christensen GJ, Christensen RP. Clinical observations of porcelain veneers : a three-year report. J Esthet Dent 1991;3:174-179. 12. Clavijo V, Bocabella L, Kabbach W , Ceramic restorations with minimal tooth preparation: Ullra - thin veneers [ in Portuguese], In: Callegari A, Dias RB ( eds). Focus on Specialty: Beauty of the Smile, Nova Odessa: Napoleao, 2013 : 22-65 . 13. Edelhoff D, Sorensen JA . Tooth structure removal associated with various preparation designs for anterior teeth. J Prosthet Dent 2002;87: 503-509 . -

14. Ferrari M, Patroni S, Bailed P. Measurement of enamel thickness in relation to reduction for etched laminate veneers. Int J Periodontics Restorative Dent 1992;12: 407- 413. 15. Garber DA, Goldstein RE, Feinman RA, Porcelain laminate veneers. Chicago: Quintessence, 1988. 16. Gresnigt M, Ozcan M . Esthetic rehabilitation of anterior teeth with porcelain laminates and sectional veneers, J Can Dent Assoc 2011;77:b143. 17. Gresnigt MM, Kalk W, Ozcan M. Randomized clinical trial of indirect resin composite and ceramic veneers: up to 3-year follow-up. JAdhes Dent 2013;15:181-190 18 . Guess PC, Stappert CF. Midterm results of a 5-year prospective clinical investigation of extended ceramic veneers. Dent Mater 2008;24: 804-813. 19 . Gurel G. The Science and Art of Porcelain Laminate Veneers . Chicago : Quintessence, 2003 . 20. High ton R, Caputo AA, MatyasJ. A photoelastic study of stresses on porcelain laminate preparations . J Prosthet Dent 1987;58:157 161. 21. Kina S, Bruguera A . Invisible: ceramic restorations ed 2. Maringa : Dental Press, 2008. 22. Kina 5, Ferreira AG. Ceramic laminates [ in Portuguese ] , In: Fonseca AS (ed). Cosmetic dentistry: the art of perfection. Sao Paulo : Artes Medicas, 2008:159 198 . 23 . Layton D, Walton T. An up to 16 year prospective study of 304 porcelain veneers. Int J Prosthodont 2007;20: 389 396 . 24. Lehner CR, Margolin MD, Scharer P. Crown and laminate preparations . Standard preparations for esthetic ceram ic crowns and ceramic veneers [in French, German]. Schweiz Monatsschr Zahnmed 1995;105 :1560 1575. 25 . Magne P, Belser U . Bonded Porcelain Restorations in the Anlerior Dentition: A Biomimetic Approach. Chicago: Quintessence, 2002. 26 . Magne P, Belser UC . Novel porcelain laminate preparation approach driven by a diagnostic mock -up , J Esthet Restor Dent 2004;16 : 7 16; discussion 17 18. 27. Magne P, Kwon KR, Belser UC, Hodges JS, Douglas WH. Crack propensity of porcelain laminate veneers : A sim ulated operatory evaluation J Prosthet Dent 1999;81: 327-334. 28. Magne P, Magne M. Use of additive waxup and direct intraoral mock up for enamel preservation with porcelain laminate veneers. EurJ Esthet Dent 2006;1:10-19.

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29 . Magne P, Versluis A, Douglas WH. Effect of luting composite shrinkage and thermal loads on the stress distribution in porcelain laminate veneers. J Prosthet Dent 1999;81:335-344. 30. Marson FC, Kina 5. Aesthetic restoration with ceram ic laminates [in Portuguese] , Rev Dental Press Estet 2010;7:76-86. 31. Napoleao A, Rodrigues T. Clinical cases: restaura oes adesivas ceramicas: uma visao clinica: lentes de contato, fragmentos, facetas e coroas, Nova Odessa: Napoleao, 2014 32 Nocchi E, Silva FB, Pereira junior JCD. Laminados e "lentes de contato" de porcelana: o elo entre biologia e estetica. In: Miyasliila E, Oliveira GG ( eds) . Odonlologia Estetica: os desafi os da clinica diaria. Nova Odessa: Na poleao, 2014:268-293. 33 . Pagani C, Rocha DM, Saavedra GSFA, Carvalho RF. Pre visibilidade e estetica : a utiliza ao do ensaio restaurador ( Mock-up ) na construct) da beleza do sorriso , In: Calle gari A, Dias RB ( eds ). Especialidade em foco: beleza do sorriso. Nova Odessa : Napoleao, 2013 : 114-145 , 34. Pincus CL. Building mouth personality. California: Califor nia Slate Dental Association, 1937. 35. Pini NP, Aguiar FH, Lima DA, Lovadino JR, Terada RS, Pascotto RC. Advances in dental veneers: materials, applications, and techniques . Clin Cosmet Investig Dent 2012;4:9-16. -

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36. Pires LCM. Ultra -thin veneers: laminates and ceramic fragments [in Portuguese], ed 2. Nossa Odessa: Napoleao, 2015. 37. Radz GM. Minimum thickness anterior porcelain restorations. Dent Clin North Am 2011;55:353-370. 38. Scopin de Andrade 0, Borges G, Stefani A, Fujiy F, Batistella P. A step-by- step ultraconservative esthetic rehabilitation using lithium disilicate ceramic. Quintessence Dent Technol 2010;33:114-131. 39. Scopin de Andrade 0, Kina S, Hirata R- Concepts for an ultraconservative approach to indirect anlerior restorations. Quintessence Dent Technol 2011:34:103-119, 40 Scopin de Andrade O, Romanini JC, Hirata R. Ultimate Ceramic Veneers: a Laboratoiy Guided Ultraconservative Preparation Concept for Maximum Enamel Preservation. Quintessence Dent Technol 2012;34:29-43. 41. Simonsen RJ, CalamiaJR.Tensile bond strengths of etched porcelain [abstract 1099]. J Dent Res 1983;62:297. 42. Smales R], Etemadi S. Survival ol ceramic onlays placed with and without metal reinforcement. J Prosthet Dent 2004;91:548-553. 43. Strassler HE. Minimally invasive porcelain veneers: indications for a conservative esthetic dentistry treatment modality. Gen Dent 2007;55:686 694; quiz 695-696, 712. 44. Weinberg LA. Tooth preparation for porcelain laminates , NY Slate Dent ] 1989;55:25-28.

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OF EN DODONTICALLY COMPROMISED TEETH

1 1

ENDODONTICALLY COMPROMISED TEETH The Indication of post -and- core res torations is mainly associated with the form of retention and resistance requirements of the abutment / prosthetic preparation.21'22 One of the criteria for the indication of restor ations is the level of coronal destruc tion when maneuvers are necessary to reinforce and protect the tooth remnant structure.23 The extensive coronal destruction and the amount of remaining tooth tissue are limiting factors for the proper accomplishment of intracoronal or extracoronal preparations (Fig 7-1 ). In such cases, it becomes neces sary to use a post to recover the ana tomical characteristics in order to fa vor the retention of the restoration biomechanically.24 The approach is determined by the presence or ab sence of pulp vitality and the degree of coronal destruction.17 However, placing an intraradicular post does not increase the frac ture resistance.6 A number of re searchers have shown that posts do not reinforce the tooth structure, but in fact weaken it.13'19 Ideally, a post should minimize the tooth stresses by distributing occlusal loads evenly, and should be easy to remove if root canal retreatment is needed. More over, its modulus of elasticity must be similar to that of dentin to avoid root fracture.1 The more tooth struc ture that is preserved, the higher the fracture toughness will be, regardless of the post system used.18

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Fig 7 1 Dental elements with extensive coronal destruction lack sufficient remaining tooth structure for the retention of the restoration Molar (A). Central incisor (B).

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P r e p a r a t i o n o f e n d o d o, n t i c a l l y c o m p r o m i s e d t e e t h

MANAGEMENT OF VITAL TEETH A frequent doubt that arises when planning a restorative prosthetic treatment is the management of teeth with pulp vitality. There are situations where it is indispensable to carry out an endodontic treatment to create the best conditions for prosthetic rehabilitation. However, in cases where the coronal tooth structure is favorable, more conservative procedures are preferred over end-

odontic treatment. For the complete evaluation and planning of indirect restorations in decayed teeth, some modifications may be necessary; therefore, it is essential to initially evaluate the pulp vitality and periodontal conditions. If there is any doubt regarding the pulp condition, endodontic treatment should be indicated prior to the rehabilitation process.4 The periodontal tissues should be evaluated for the presence of fractures with subgingival extension or previous restorations that invade the biological width, which may require surgery prior to restorative procedures.9' 15 Defective restorations should be removed, since there might be carious lesions or even small pulpal exposures. Undermined surfaces and unsupported enamel regions should be avoided, which may all be removed and/or blocked out to promote an adequate form of retention and contour, and ultimately greater resistance of the remaining walls. A basic rule for decision-making is the analysis of the remaining amount of tissue. If this is approximately half the height of the coronal tooth structure, a core buildup material or additional means of retention is necessary, such as parapulpar pins. In situations where the remaining tooth is found to be insufficient to retain the restoration, the tooth should be treated endodontically, followed by the placement of an intraradicular post.17

MANAGEMENT OF DEVITALIZED TEETH If the coronary destruction impairs a core buildup, intraradicular posts are indicated. In endodontically treated teeth, various types of intraradicular posts may be indicated: prefabricated (metal and esthetic) posts or cast metal posts (Fig 7-2). Cast metal posts were considered the best type of intraradicular posts for a long time, especially with regard to their adaptation to the root canal, since they were customized for each tooth. The search for prefabricated posts intensified with the development of new materials. This was combined with the evolution of adhesive systems. The advantages of metal-free prefabricated posts, of which there are sever al types, are less tooth structure wear and better adhesion to dentin through the use of adhesive resin cements. Among the prefabricated posts, fiber-re inforced (carbon and glass) posts have gained popularity because they have

properties similar to the dentin struc ture, especially the modulus of elastici ty, which allows for a better distribution of occlusal forces to the tooth remnant

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Prospective clinical and in vitro stud ies have emphasized their advantages compared to cast metal posts and pre fabricated metal posts.7'11'12'25 When esthetics is paramount, prefabricated pins, particularly glass fiber ones, have greater applicability than metal posts.17 Although cast metal cores were once one of the main alternatives for the restoration of endodontically treated teeth, they have several limitations: chairside time, cost, and loss of weakened tooth structure. Furthermore, due to their high modulus compared to dentin, the major part of the received stresses is trans ferred to the root.17 One of the techniques suitable for filling flared canals is the individualization of the post. The root canal is molded using composite resin associated with a prefabricated fiber post. This technique extends the indication of prefabricated posts, reducing the amount of cement that would be needed to fill the space between the post and the dental structure. The individualization of the post allows for a good adaptation to the root canal, forming a thin uniform layer of resin cement, creating favorable conditions for the retention of the post. -

Chapter

07

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