瓷贴面生物力学研究及临床应用

贴面已经成为一种广泛应用于前牙美容的修复方法。本文主要总结近年来国内外学者在瓷贴面设计及操作方面的生物力学研究成果,以期更好地指导临床工作。     

Microleakage in porcelain laminate veneers

The effectiveness of two dentine-enamel bonding agents has been investigated in vitro when used together with an unfilled, low viscosity resin in eliminating the microleakage of porcelain laminate veneers. The restoration margins were located below and above the amelocemental junction of extracted maxillary central incisors. The bonded specimens were thermocycled and investigated for microleakage by employing a standard dye penetration technique. Leakage was scored at the cervical and incisal margins. Tenure was found more effective than Creation 3 in 1 in preventing leakage at both the cervical enamel and dentine/composite lute interfaces. With Tenure dentine bonding agent, the leakage observed at the cervical dentine/composite lute interface was found to be similar to that observed at the cervical enamel/composite lute interface. Sealing of finished veneer margins reduced the leakage at all interfaces.     

Direct composite veneers versus etched porcelain laminate veneers

It would appear that over the years, the inherent weakness in composite veneering has been the composite itself. The etched porcelain restoration offers the advantages of increased strength, color, stability, and biocompatibility for a veneering material using composite merely as a luting agent. With the ongoing development of porcelain material, it is possible that the etched porcelain restoration will all but replace direct bonding in most clinical situations.     

全瓷贴面修复的临床效果评估

目的评价全瓷贴面修复后的临床疗效。方法对完成修复1~8年的25例患者133个贴面进行复查,对修复体边缘适合性、边缘染色、继发龋、颜色匹配、解剖形态、牙髓活力、隐裂、折断和脱落9项指标进行评估。以绝对失败贴面数来描述存留率,用绝对失败和相对失败的贴面总数来描述成功率,寿命表法计算全瓷贴面1~8年的存留率和成功率。结果全瓷贴面1~8年存留率分别为100.0%、99.2%、97.6%、96.7%、94.7%、93.2%、89.3%和89.3%,1~8年成功率分别为100.0%、98.5%、96.1%、94.4%、90.5%、84.5%、80.9%和80.9%。结论全瓷贴面近期和远期的修复效果良好。     

Refining the art of porcelain laminate veneers

As with any other operative or restorative technique, the long-term results, both esthetic and functional, depend directly on [figure: see text] the effort made by the dentist. Attention to detail, allowing enough time, and a steady hand are necessary to obtain the desired result. A few operative tips have been provided to aid the dentist in achieving these sometimes-elusive maximum results. Proper diagnosis, canine-guided occlusion, and attention to detail will help you give your patients that dazzling new smile!     

Tooth preparation techniques for porcelain laminate veneers

OBJECTIVE: The purpose of this study was to determine the effect that two guides to tooth preparation had on an operator's ability to appropriately and consistently prepare teeth for porcelain laminate veneers. STUDY DESIGN: In-vitro study. MATERIALS AND METHODS: Thirty typodont central incisor teeth were randomly allocated into three groups and a general dental practitioner was asked to prepare the teeth for porcelain laminate veneers. Group A were prepared freehand while Groups B and C were prepared with the assistance of a silicone index and depth preparation bur respectively. Images of the prepared teeth were used to calculate the mean labial depth of preparation and incisal reduction of teeth in each group. RESULTS: The mean labial reduction for Groups A, B and C was 0.37 mm (SD 0.13), 0.62 mm (SD 0.17) and 0.61 mm (SD 0.15) and the mean incisal reduction for Groups A, B and C was 1.0 mm (SD 0.28), 1.0 mm (SD 0.38) and 1.03 mm (SD 0.26) respectively. CONCLUSION: It is suggested that consideration be given to the use of a silicone index or depth gauge bur when teeth are prepared for porcelain laminate veneers.     

Incisal-edge strength of porcelain laminate veneers restoring mandibular incisors.

Porcelain laminate veneers can be used to increase incisal-edge length. The purpose of this study was to determine the fracture resistance of porcelain veneer restorations on Cymel 1077 mandibular incisors that were incisally reduced 0.0, 0.5, 1.0, and 2.0 mm. Variables studied were incisal-edge length and the angle of applied force. Sixty-one porcelain laminate veneers were made to restore incisal-edge length and bonded to the prepared teeth. Samples were fractured at force angles of 130 degrees and 137 degrees. No significant difference was found between varying incisal-edge lengths (P > .05). However, the lower applied angle required greater average force to fracture (P = .005) as tested by ANOVA.     

Stress analysis of porcelain laminate veneers. (1)

The stress distributions in the porcelain laminates under various kinds loading are analysed numberically in order to make clean the reason of their exfoliation or fracture. The two-dimensional finite element method is used to determine the principal stresses developed in the porcelain laminated and the teeth substance of a restored maxillary central incisor. The thicknesses of enamel preparations are assumed to be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm and 0.8 mm in the analysis. As a result of this analysis, the following points are made clear: 1) The stress concentration are observed at the vicinity of a loading point and in the cervical regions, independently of the loading conditions on its location and direction. 2) In case of the vertical loading, the location of loading point has no effect on the overall stress magnitude and distribution. 3) In the case when the load is applied in the 45 degrees-direction to the vertical axis, the overall stress level is increased, as the location of loading point is far from the supporting regions. 4) In the case when the load is applied normal to the vertical axis at the incisal edge, the high stress is obtained in comparison with other loading conditions.     

Esthetic management of perimolysis with porcelain laminate veneers

This report deals with the dental manifestations of bulimia nervosa. Differential diagnosis of perimolysis was identified and compared with other manifestations of systemic or exogenous causal factors. Conservative cosmetic dental management of the dental erosion that occurred as a result of bulimia nervosa was described and discussed in comparison with other currently accepted treatment modalities.     

Clinical performance of porcelain laminate veneers without incisal overlapping: 3-year results

The aim of this clinical trial was to evaluate the performance of 135 porcelain laminate veneers placed on anterior teeth without incisal preparation. Only 0.3–0.5 mm of the facial enamel was removed using a tapered round-ended diamond bur. The veneers were fabricated from a sintered feldspathic porcelain, etched and silanized and then bonded with a light-cured composite lute. The veneers were yearly examined clinically for debonding, chipping, marginal integrity and staining. After 3 years of service all veneers were retained. Incisal chipping occurred in seven veneered teeth. Wear and staining were negligible. It was concluded that this minimal porcelain veneer restoration with no incisal overlapping was conservative, predictable and successful.     

310个烤瓷贴面远期临床效果的回顾性分析

目的 评价完成修复1～8年的310个长石质烤瓷贴面的远期临床效果,以期为临床提供参考.方法 对完成修复1～8年的310个前牙或前磨牙长石质烤瓷贴而进行复查,参照改良美国公共健康协会(United States Public Health Service,USPHS)评价标准对烤瓷贴面的修复体完整度、修复体磨耗、颜色满意度、边缘染色、边缘适合性、继发龋、牙本质敏感症状及牙龈指数(gingival index,GI)8项指标进行评估,寿命表法统计烤瓷贴面1～8年存留率.结果 烤瓷贴面1～8年存留率分别为98.7%、98.0%、93.8%、93.2%、89.7%、81.8%、76.3%、76.3%.结论 烤瓷贴面修复技术的远期临床效果良好.