A Prospective Ten-Year Clinical Trial of Porcelain Veneers
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A Prospective Ten-year Clinical Trial of Porcelain Veneers Marleen Peumansa/Jan De Munckb/Steffen Fieuwsc/Paul Lambrechtsd/ Guido Vanherlee/Bart Van Meerbeekf Purpose: The aim of this in vivo study was to evaluate the clinical performance of porcelain veneers after 5 and 10 years of clinical service. Materials and Methods: A single operator placed porcelain laminates on 87 maxillary anterior teeth in 25 patients. All restorations were recalled at 5 years and 93% of the restorations at 10 years. Clinical performance was as- sessed in terms of esthetics, marginal integrity, retention, clinical microleakage, caries recurrence, fracture, vitality, and patient satisfaction. Failures were recorded either as “clinically unacceptable but repairable” or as “clinically unacceptable with replacement needed”. Results: Porcelain veneers maintained their esthetic appearance after 10 years of clinical service. None of the ve- neers were lost. The percentage of restorations that remained “clinically acceptable” (without need for intervention) significantly decreased from an average of 92% (95 CI: 90% to 94%) at 5 years to 64% (95 CI: 51% to 77%) at 10 years. Fractures of porcelain (11%) and large marginal defects (20%) were the main reason for failure. Marginal defects were especially noticed at locations where the veneer ended in an existing composite filling. At such vul- nerable locations, severe marginal discoloration (19%) and caries recurrence (10%) were frequently observed. Most of the restorations that present one or more “clinically unacceptable” problems (28%) were repairable. Only 4% of the restorations needed to be replaced at the 10-year recall. Conclusion: It was concluded that labial porcelain veneers represent a reliable, effective procedure for conserva- tive treatment of unesthetic anterior teeth. Occlusion, preparation design, presence of composite fillings, and the adhesive used to bond veneers to tooth substrate are covariables that contribute to the clinical outcome of these restorations in the long term. Key words: porcelain veneers, adhesion, clinical trial. J Adhes Dent 2004; 6: 65–76. Submitted for publication: 05.03.03; accepted for publication: 09.07.03. a Clinical Instructor and Research Associate, Leuven BIOMAT Research Cluster, Reprint requests: Marleen Peumans, Leuven BIOMAT Research Cluster, Depart- Department of Conservative Dentistry, School of Dentistry, Oral Pathology ment of Conservative Dentistry, School of Dentistry, Oral Pathology and Maxil- and Maxillofacial Surgery, Catholic University of Leuven, Leuven, Belgium. lo-Facial Surgery, Catholic University of Leuven, Kapucijnenvoer, 7, B-3000, Leu- b PhD student, Leuven BIOMAT Research Cluster, Department of Conservative ven, Belgium. Tel: +32-16-332436 or +32-16-332480; Fax: +32-16-332752. Dentistry, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Cath- e-mail: [email protected] olic University of Leuven, Leuven, Belgium. c PhD student, Leuven BIOMAT Research Cluster, Biostatistical Centre, Catholic University of Leuven, Leuven, Belgium. d Full Professor, Leuven BIOMAT Research Cluster, Department of Conserva- orcelain veneers have been a popular means of con- tive Dentistry, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Catholic University of Leuven, Leuven, Belgium. P servatively restoring unesthetic anterior teeth since e Full Professor Emeritus, Leuven BIOMAT Research Cluster, Department of the beginning of the 1980s. At that time Calamia, Simo- Conservative Dentistry, School of Dentistry, Oral Pathology and Maxillo-Facial nsen, and Horn introduced special acid-etching proce- Surgery, Catholic University of Leuven, Leuven, Belgium. dures that substantially improved the long-term retention f Professor, Leuven BIOMAT Research Cluster, Department of Conservative 2,11,38 Dentistry, School of Dentistry, Oral Pathology and Maxillo-Facial Surgery, of porcelain veneers. They demonstrated that the Catholic University of Leuven, Leuven, Belgium. bond strength of a hydrofluoric acid-etched and silanized Vol 6, No 1, 2004 65 Peumans et al veneer to the luting resin composite is routinely greater contact points were retained. The shape of the cervical than the bond strength of the same luting resin to the margin was a chamfer and was generally located equigingi- etched enamel surface. As with any new procedure, the vally. The incisal edge was shortened and a shoulder was different aspects of this new approach were analyzed in prepared on the palatal side over a distance of 2 to 3 mm. many in vitro studies.31 With the help of these results, the All porcelain veneers were fabricated by the same clinical technique has continued to be refined and the in- technician using a feldspathic porcelain (GC Cosmotech dication for porcelain veneers has gradually been extend- Porcelain, GC, Tokyo, Japan) on a refractory investment ed. Most recently, restoration of crown-fractured incisors material (GC Cosmotech Vest, GC). The inner side of the and worn-down dentitions have been proposed as new in- veneers was etched with 5% hydrofluoric acid (GC Hydro- dications for porcelain veneers.15 fluoric Acid, GC) for 60 s, followed by ultrasonic cleaning A number of medium-term clinical studies have con- in a bath with distilled water for 10 min. Silanization was firmed the favorable clinical performance of these restora- performed with the G-Cera Primer (GC Cosmotech Bond- tions, as their maintenance of esthetics was excellent, pa- ing Set, GC). tient satisfaction was high, and no adverse effects on gin- At the second visit, the porcelain veneers were adhe- gival health were present.31 Most studies reported a low sively luted under rubber-dam isolation. The preparation failure rate (0% to 7%).1,7,23,39 Higher failure rates (14% surface was etched with 35% phosphoric acid (Scotchgel, to 33%) were noted in other clinical trials,6,36,37,49 proba- 3M, St Paul, MN, USA) followed by the application of bly due to some predisposing factors such as unfavorable Scotchbond 2 (3M) without light curing it separately. The occlusion and articulation, excessive loss of dental tis- composite luting agent – G-Cera Porcelain Veneer Bond- sue, use of inappropriate luting agents, unprepared teeth, ing System (GC): 80 veneers; Porcelite (Kerr, Basel, Swit- and partial adhesion to large exposed dentin surfaces. zerland): 7 veneers – was applied to the inside of the por- Nevertheless, porcelain veneers are considered more du- celain veneer, which was immediately fit into place and rable than direct composite veneers, on the condition that light cured with a Visilux 2 Visible Light Curing Unit (3M) patients were adequately selected and the veneers were for 2 min on each side. The cemented porcelain veneers prepared following a meticulous clinical procedure.31 were finished by removing all excess luting composite us- However, questions remain with regard to what we may ing microfine diamonds (Esthetic Trimming Diamond set, expect in the long term: are they as durable as complete Goldstein, Komet, Lemgo, Germany) under continuous crowns or will there be an increased number of failures af- water cooling. Finally, the roughened porcelain margins ter long-term clinical service? Only a few clinical studies were polished using a diamond polishing paste (Komet) have reported the performance of porcelain veneers over on a rotating rubber cup. The interproximal surfaces were a period of more than 9 years.5,8,40,44 Very little informa- finished with Sof-Lex polishing strips (3M). tion is available from standardized long-term studies that Color slides were made preoperatively, after prepara- reveal clear data on the overall clinical performance of tion, and immediately postoperatively (= baseline). All pa- these restorations.5 The aim of this in vivo study was to tients were recalled between April 1995 and October 1996, evaluate the clinical performance of porcelain veneers af- when the restorations were 5 to 6 years old. In addition, a ter 5 and 10 years of clinical service as part of a prospec- 10-year recall took place between January 2001 and June tive clinical trial. 2001 with a recall rate of 93% (81 out of 87 restorations). Evaluation Procedure MATERIALS AND METHODS At both recalls, esthetics, marginal integrity, tooth vitality (TV), fracture rate (FR), and patient satisfaction (PS) were In this investigation, 87 porcelain veneers were placed in evaluated. 25 patients in 1990 and 1991. The porcelain veneers Esthetic performance was assessed clinically at chair- were prepared only on maxillary teeth (central incisors, lat- side in terms of color match (CM) and surface roughness eral incisors, canines, and first premolars). The age of the (SR). Marginal integrity was evaluated in terms of margin- patients varied from 19 to 69 years. All veneers were al adaptation and retention (MA/R), clinical microleakage placed to improve esthetics by replacing worn and discol- (CMi) and caries recurrence (CR). Color slides of the res- ored composite restorations and veneers, or by correcting torations were made at both assessments. discolored, malformed and/or malaligned anterior teeth.32 Marginal adaptation and clinical microleakage were The porcelain veneers were placed by a single experi- judged at four different locations of the restored tooth: enced operator following a meticulous clinical procedure, mesiocervically, mid-buccocervically, distocervically, and which was described in detail in the previous 5-year re- palato-incisally.32 All scores of marginal adaptation and port.32