Bonded Porcelain Restorationsin the Anterior Dentition:A Biomimetic Approach

Pascal Magne, PD, DR MED DENTSenior Lecturer Department of Fixed Prosthodontics and OcclusionUniversity of GenevaSchool of DentistryGeneva, Switzerland

Urs Belser, PROF, DR MED DENTProfessor and HeadDepartment of Fixed Prosthodontics and OcclusionUniversity of GenevaSchool of DentistryGeneva, Switzerland

Quintessence Publishing Co, IncChicago, Berlin, London, Copenhagen, Tokyo, Paris, Barcelona, Milano,São Paulo, New Delhi, Moscow, Prague, Warsaw, and Istanbul

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FOREWORD 19PREFACE 20

C H A P T E R 1

UNDERSTANDING THE INTACT TOOTH AND 23

THE BIOMIMETIC PRINCIPLE

• B i o l o g y , M e c h a n i c s , F u n c t i o n , a n d E s t h e t i c s• O p t i m a l C o m p l i a n c e a n d F l e x i b i l i t y• R a t i o n a l i z e d A n t e r i o r To o t h S h a p e• M e c h a n i c s a n d G e o m e t r y D u r i n g F u n c t i o n• P h y s i o l o g i c E n a m e l C r a c k i n g a n d t h e D E J• N a t u r a l To o t h A g i n g a n d E n a m e l T h i n n i n g• B i o m i m e t i c s A p p l i e d t o M e c h a n i c s

C H A P T E R 2

NATURAL ORAL ESTHETICS 57

• G e n e r a l C o n s i d e r a t i o n s• F u n d a m e n t a l C r i t e r i a• E s t h e t i c I n t e g r a t i o n

C H A P T E R 3

ULTRACONSERVATIVE TREATMENT OPTIONS 99

• C h e m i c a l T r e a t m e n t s a n d B i o m i m e t i c s• N i g h t g u a r d V i t a l B l e a c h i n g• M i c r o a b r a s i o n a n d M e g a b r a s i o n• N o n v i t a l Wa l k i n g B l e a c h Te c h n i q u e• R e a t t a c h m e n t o f a To o t h F r a g m e n t• S i m p l i f i e d D i r e c t C o m p o s i t e s

TA B L E O F C O N T E N T SCopyrig

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C H A P T E R 4

EVOLUTION OF INDICATIONS FOR ANTERIOR BONDED 129

PORCELAIN RESTORATIONS

• H i s t o r i c P e r s p e c t i v e• Ty p e I : Te e t h R e s i s t a n t t o B l e a c h i n g• Ty p e I I : M a j o r M o r p h o l o g i c M o d i f i c a t i o n s• Ty p e I I I : E x t e n s i v e R e s t o r a t i o n i n t h e A d u l t• C o m b i n e d I n d i c a t i o n s• B i o l o g i c C o n s i d e r a t i o n s• P e r s p e c t i v e s f o r O c c l u s a l V e n e e r s i n P o s t e r i o r T e e t h

C H A P T E R 5

INITIAL TREATMENT PLANNING AND DIAGNOSTIC APPROACH 179

• I n t e r a c t i v e P a t i e n t - O p e r a t o r y - L a b o r a t o r y R e l a t i o n s h i p s• P a t i e n t M a n a g e m e n t b y t h e O p e r a t o r y Te a m• P a t i e n t M a n a g e m e n t b y t h e L a b o r a t o r y Te a m• Tr e a t m e n t P l a n n i n g a n d I n i t i a l T h e r a p y• D i a g n o s t i c Wa x u p• D i a g n o s t i c M o c k - u p• P e c u l i a r C a s e s• S u m m a r y o f D i a g n o s t i c A p p r o a c h e s• C l i n i c a l P h o t o g r a p h y• S h a d e D o c u m e n t a t i o n

C H A P T E R 6

TOOTH PREPARATION, IMPRESSION, 239

AND PROVISIONALIZATION

• G e n e r a l C o n s i d e r a t i o n s• T i s s u e R e d u c t i o n• M a r g i n C o n f i g u r a t i o n a n d L o c a l i z a t i o n• P e c u l i a r S i t u a t i o n s• I m m e d i a t e D e n t i n B o n d i n g• D e f i n i t i v e I m p r e s s i o n s• D i r e c t P r o v i s i o n a l s a n d P r o v i s i o n a l B o n d i n g

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C H A P T E R 7

LABORATORY PROCEDURES 293

• C h o i c e o f R e s t o r a t i v e M a t e r i a l a n d Te c h n i q u e• M a s t e r C a s t s i n t h e R e f r a c t o r y D i e Te c h n i q u e• C e r a m i c L a y e r i n g a n d F i n i s h i n g• S p e c i a l E f f e c t s• C o n f i g u r a t i o n o f t h e C e r a m i c Wo r k p i e c e

C H A P T E R 8

TRY-IN AND ADHESIVE LUTING PROCEDURES 335

• C h o i c e o f L u t i n g C o m p o s i t e R e s i n• T r y - i n a n d P r e p a r a t o r y S t e p s• C o n d i t i o n i n g o f t h e C e r a m i c S u r f a c e• C o n d i t i o n i n g o f t h e To o t h S u r f a c e• P l a c e m e n t o f t h e C e r a m i c R e s t o r a t i o n• F i n a l A d j u s t m e n t s a n d O c c l u s a l C o n t r o l• S p e c i a l C o n s i d e r a t i o n s

C H A P T E R 9

MAINTENANCE AND REPAIRS 371

• M a x i m u m P e r f o r m a n c e , R e d u c e d M a i n t e n a n c e• R o u t i n e P r o f e s s i o n a l H y g i e n e• C o m p l i c a t i o n s a n d R e p a i r s• R e p l a c e m e n t o f C l a s s 3 C o m p o s i t e

GUIDE TO CL IN ICAL CASES 387

INDEX 400

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It is with considerable pleasure that I write the foreword to Dr Magne and Prof Belser’s book, whichtakes the science of esthetic dental reconstruction to a new level both clinically and academically.Dr Magne spent 2 years as a visiting associate professor in the Minnesota Dental Research Centerfor Biomaterials and Biomechanics at the University of Minnesota, where many of the ideas pro-mulgated in this book were hotly debated, refined, and tested in a modeling and experimental en-vironment. In this book, the clinician will find all that he or she could wish for in terms of indicationsand the classic clinical steps for tooth preparation, laboratory procedures, adhesive luting proce-dures, and maintenance protocol. Those who have heard Dr Magne lecture will not be disap-pointed. In fact, they will find much more that is practically and intellectually satisfying.

The central philosophy of the book is the biomimetic principle, that is, the idea that the intact toothin its ideal hues and shades, and perhaps more importantly in its intracoronal anatomy and loca-tion in the arch, is the guide to reconstruction and the determinant of success. The approach is ba-sically conservative and biologically sound. This is in sharp contrast to the porcelain-fused-to-metaltechnique, in which the metal casting with its high elastic modulus makes the underlying dentin hypo-functional. The goal of the authors’ approach is to return all of the prepared dental tissues to fullfunction by the creation of a hard tissue bond that allows functional stress to pass through the tooth,drawing the entire crown into the final esthetic result.

I hope that this book will receive a wide readership and that its principles will be carefully studiedand become fully established in teaching and research, as well as de rigueur in the practice ofrestorative dentistry.

William H. Douglas, BDS, MS, PhDDirector, Minnesota Dental Research Center for Biomaterials and Biomechanics;Chair, Department of Oral Science, University of MinnesotaMinneapolis, Minnesota

F O R E W O R D

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The most exciting developments in dentistry have emerged within the past decade. Oral implantdentistry, guided tissue regeneration, and adhesive restorative dentistry are strategic growth areasboth in research and in clinical practice. However, the many advances in dental materials and tech-nology have generated a plethora of dental products in the marketplace. Clinicians and dental tech-nicians are faced with difficult choices as the number of treatment modalities continues to grow. Fur-ther, changes in technology do not always simplify technique or decrease treatment costs. Prudenceand wisdom need to be combined with knowledge and progress when it comes to improving ourpatients’ welfare.

In this perplexing context, no one will contest the need for less expensive, satisfactory, and rationalsubstitutes for current treatments. The answer might come from an emerging interdisciplinary bioma-terial science called biomimetics.1 This concept of medical research involves the investigation of thestructure and physical function of biologic “composites” and the design of new and improved substi-tutes. Biomimetics in dental medicine has increasing relevance. The primary meaning for dentistryrefers to processing material in a manner similar to that by the oral cavity, such as the calcification ofa soft tissue precursor. The secondary meaning refers to the mimicking or recovery of the biome-chanics of the original tooth by the restoration. This, of course, is the goal of restorative dentistry.

Several research disciplines in dental medicine have evolved with the purpose to mimic oral struc-tures. However, this nascent principle is applied mostly at a molecular level, with the aim to enhancewound healing, repair, and regeneration of soft and hard tissues.2,3 When extended to a macro-structural level, biomimetics can trigger innovative applications in restorative dentistry. Restoring ormimicking the biomechanical, structural, and esthetic integrity of teeth is the driving force of thisprocess. Therefore, the objective of this book is to propose new criteria for esthetic restorative den-tistry based on biomimetics.

Biomimetics in restorative dentistry starts with an understanding of hard tissue structure and relatedstress distribution within the intact tooth, which is the focus of the opening chapter of this book. It isimmediately followed by a systematic review of parameters related to natural oral esthetics. Becausethe driving forces of restorative dentistry are maintenance of tooth vitality and maximum conserva-tion of intact hard tissues, a brief chapter describes the ultraconservative treatment options that canprecede a more sophisticated treatment. The core of the book centers on the application of the bio-mimetic principle in the form of bonded porcelain restorations (BPRs). The broad spectrum of indi-cations for BPRs is described, followed by detailed instruction on the treatment planning and diag-nostic approach, which is the first step in learning this technique. The treatment is then describedstep-by-step, including tooth preparation and impression, laboratory procedures related to the fab-rication of the ceramic workpiece, and its final insertion through adhesive luting procedures. Thebook ends with discussion of the follow-up, maintenance, and repair of BPRs.

P R E FA C E

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I would have been unable to achieve this work without the valued collaboration of other dentists,dental technicians, specialists, and researchers. We should always remember that a key elementfor successful and predictable restoration is teamwork and an essential ingredient for teamwork ishumility, to consider others better than oneself. We must try to serve each other rather than expectto be served.

I am fortunate to have studied under Prof Urs Belser; his teaching and guidance have been invalu-able to me.

Special thanks goes to Drs William Douglas, Ralph DeLong, Maria Pintado, Antheunis Versluis, andThomas Korioth at the University of Minnesota for their help and friendship during my 2-year re-search scholarship there. They expanded my vision and knowledge of scientific research in bio-materials and biomechanics.

I extend appreciation to Michel Magne, CDT, for his significant contributions to the chapter on lab-oratory procedures and for his skills in fabricating the ceramic restorations for all of the cases in thisbook. I also acknowledge my patients, who indirectly contributed to the realization of this book,and the private practitioners who donated extracted teeth for the studies and illustrations. Specialthanks in this regard goes to Drs Rosa Serrano of Geneva, Switzerland, and José de Souza Ne-grão of São Paulo, Brazil.

Finally, I give honor and glory to my Lord and Savior, Jesus Christ, who has made all of my projectspossible through his gracious love.

Pascal Magne

References1. Sarikaya M. An introduction to biomimetics: A structural viewpoint. Microsc Res Tech 1994;27:360–375.2. Slavkin HC. Biomimetics: Replacing body parts is no longer science fiction. J Am Dent Assoc 1996;127:1254–1257.3. Mann S. The biomimetics of enamel: A paradigm for organised biomaterial synthesis. Ciba Found Symp 1997;205:261–269.

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C H A P T E R 1

UNDERSTANDING THE INTACT TOOTH AND THE

B IOMIMET IC PR INCIP LE

Mimicry in the field of science involves reproducing or copying a model, areference. If we as dentists want to replace what has been lost, we needto agree on what is the correct reference. The accepted frame of referencemust be the same for the entire profession, and it should be timeless andunchanging. Once this is established, we can then construct appropriateresearch designs, devise valid concepts, and create rational dental treat-ment plans. For the restorative dentist, the unquestionable reference is theintact natural tooth. Remains of Inca civilization in South America as well asmummies in Egypt1 demonstrate age-old principles: the original number,dimensions, and structure of teeth have not changed. While the pattern oforal disease (infections, wear, parafunctions) has been influenced by theever-changing human lifestyle, the original structure of enamel and dentinappears to be the same today as it was 3,000 years ago. In this context,it seems commendable to study and understand the marvelous design ofnatural teeth before considering any further concepts in restorative dentistry.

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D E N T I N E F F E C T S

Translucency is the appearance between com-plete opacity (like ivory) and complete trans-parency (like glass).29 Teeth, especially incisaledges, show intense characteristics integratingthe wide range of effects defined by translu-cency and transparency.

At one end of the spectrum, as illustrated inFigs 2-7b and 2-7c, areas of bluish trans-parency are present, also showing significantopalescence. Specific porcelains have been

designed to simulate these “enamel” effects(see Chapter 7). At the other end of the spec-trum, more opaque “dentin” effects are foundat the incisal edge as revealed by abrasion/attrition. The inner structure of the dentin coreand its complex architecture become visible inthe form of dentin rays, dentin mamelons,dentin infiltrations, etc (Fig 2-8). Dentin fluores-cence (see criterion 11) is essential to thesekinds of effects.

2 NATURAL ORAL ESTHETICS

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D E N T I N M A M E L O N S

D E N T I N I N F I L T R A T I O N2-8c 2-8d

2-8e

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FIGURE 2-8: DENTIN EFFECTS. The most complex structural elements of the incisal edge can be better understoodby grinding the palatal enamel of extracted teeth (2-8a, 2-8c, 2-8e). Vertical palatal attrition of the incisal edgeemphasizes the underlying dentin rays (2-8a, 2-8b). Dentin architecture usually shows three well-organized dentinmamelons (2-8c, arrowheads). These structures are often seen in the presence of transparent enamel (2-8d). Dentininfiltration effects can also be noted; their direction is precisely defined by the convergence of the dentin rays, inmedian and apical directions; external dentin staining typically results from enamel edge chipping (2-8e, arrowhead)or progressive wear.

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Type IIIB: Extensive loss of enamel

Extensive tooth abrasion is typically found inpeople of older age groups; of the maxillaryteeth, the anterior teeth often exhibit the mostwear (Fig 4-11). However, tooth surface loss isa growing problem in younger individuals.61 Di-etary acids are increasingly popular (especiallysoft drinks). Bulimia, consumption of acidicfoods, acid reflux, and chlorine consumption(from swimming) are other typical etiologic fac-tors in young patients.

Tooth erosion, particularly in young people,presents a considerable challenge to restora-tive dentists. In all cases, preventive and con-servative strategies are essential. Use of neu-

tralizing mouth rinse (eg, bicarbonate solution)and topical application of neutral fluoridatedgels can be recommended. Adhesive dentistryshould be used whenever possible if restora-tion is necessary.

Localized loss of enamel can be easily treatedby direct application of composite resins. Incase of a more extensive wear pattern, bondedporcelain restorations can be proposed andmay include posterior teeth. Type IIIB indicationscan appear somewhat similar to type IIC, butthe former features a more generalized nature(often more than four teeth to treat) as comparedto the latter (which often involves only twoteeth). Another typical type IIIB patient is fea-tured in Figs 8-8g to 8-8j.

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4 EVOLUTION OF INDICATIONS FOR ANTERIOR BONDED PORCELAIN RESTORATIONS

FIGURE 4-11: ENAMEL EROSION OF MAXILLARY ANTERIOR TEETH. The patient presented with severe facial wearof maxillary anterior teeth and infiltrated Class 3 composite resin restorations (4-11a to 4-11c). Note definite dentinexposures on the facial surface of the right and left central incisors (4-11b). Treatment planning included replacementof preexisting restorations, and teeth were prepared according to a diagnostic template; note the proximal marginsextending within the new interdental restorations (especially between the central and lateral incisors) to minimize thevolume of remaining composite restorative material (4-11d). The final porcelain restorations feature minor changes oftooth form and length but substantial recovery of the facial volume (4-11e to 4-11h).

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