Reinforcement of bonded crown fractured incisors with porcelain veneers

Abstract A method is described by which porcelain laminate veneers are used to reinforce crown-fractured incisors which have been restored by reattachment of enamel-dentin fragments using enamel etching and a dentin bonding system. In an experimental model using sheep incisors, it was found that fracture strength equal to that of intact incisors could be achieved by employing this method. This is in contrast to fracture strengths of reattached enamel-dentin tooth fragments without porcelain laminates which were only 50% of intact incisors. It is suggested that porcelain laminate veneers may be used to supplement fragment bonding, thereby enhancing dental esthetics and function.     

Correction of congenitally missing lateral incisors with porcelain veneers.

The ability of the dental professional to improve a patient's smile has become a benchmark in modern aesthetic dentistry. When one type of tooth is transformed into another through the restorative process, special care must be taken to ensure correct preparation and gingival contours to create the illusion that the teeth are in their correct position. With accurate digital photographic planning, active patient consultation, detailed tooth preparation, and a meticulous laboratory sequence, porcelain laminate veneers can be functional and can achieve the aesthetic expectations of the patient.     

Gingival health associated with porcelain veneers on maxillary incisors.

The possible detrimental effect of acid-etched resin-bonded prostheses and porcelain veneers on plaque accumulation and gingival health is currently disputed. Some workers recommend no tooth preparation prior to veneering whilst others recommend tooth preparation to prevent adverse gingival soft tissue reactions. In order to test the possible gingival effects of veneers placed without tooth preparation, this study was set up to compare gingival health on veneered and non-veneered maxillary incisors within the same individual during periods of normal tooth cleaning and of no tooth cleaning. No significant differences were noted in plaque or gingival indices, or in gingival crevicular fluid volume, between the 72 veneered and non-veneered sites during either study period. The results of this study suggest that placing porcelain veneers on unprepared teeth does not increase the risk of gingivitis.     

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.     

Fracture resistance of composite resin restorations and porcelain veneers in relation to residual tooth structure in fractured incisors

Abstract – The aim of the present study was to investigate whether there is a direct correlation between the amount of residual tooth structure in a fractured maxillary incisor and the fracture resistance of composite resin restorations or porcelain veneers after cyclic loading. Sixty human‐extracted maxillary central and lateral incisors were mounted in an acrylic block with the coronal aspect of the tooth protruding from the block surface. The teeth were assigned to two groups: 2‐mm incisal fracture and 4‐mm incisal fracture. Then, the teeth were further divided into two different restoration subgroups, porcelain laminate veneer and composite resin restoration, therefore obtaining four groups for the study (n = 15). The specimens were subjected to 1000 cycles of thermocycling and were mechanically tested with a custom‐designed cyclic loading apparatus for 2 × 106 cycles or until they failed. The specimens that survived the cyclic loading were loaded on the incisal edge along the long axis of the tooth with a flat stainless steel applicator until they fractured using a universal testing machine to measure the failure load. Two‐way anova was used to assess the significance of restoration, amount of fracture, and interaction effect (α = 0.05). During the cyclic loading, for the composite resin group, two specimens with 2‐mm fracture and three specimens with 4‐mm fracture failed. For the porcelain veneer group, two specimens with 2‐mm fracture and one specimen with 4‐mm fracture failed. The 2‐way anova did not show statistical significance for restoration (P = 0.584), amount of fracture (P = 0.357), or interaction effect (P = 0.212). A composite resin restoration and a porcelain veneer could perform similarly for replacing a fractured incisor edge up to 4 mm. Other factors such as esthetic and/or cost would be considerations to indicate one treatment over the other.     

Restoration of fixed partial dentures with fractured porcelain veneers using an overcasting

Fracture and loss of the porcelain veneer of a fixed partial denture is troublesome. Dentists have frequently used overcastings to avoid removal of the restoration. However, development of proximal resistance and retention form for the preparation creates a problem because reduction of the connector causes fracture. Nevertheless, a box-type occlusal cavity form in the central portion of the preparation will enhance the stability of the restoration without encroachment on the connectors. This design is more applicable to endodontically treated teeth.     

Treatment of crown fractured incisors with laminate veneer restorations. An experimental study

Abstract A method is described by which crown fractured incisors are restored with cast ceramic (Dicor) laminate veneers after initial treatment with either reattachment of the original crown fragment with a dentin bonding agent, with a composite resin build-up or no treatment (i.e. the veneer alone is used to restore the incisal edge). In order to elucidate the effect of the fragment/composite-tooth bonding interface on fracture strength of the restored teeth, the fracture strengths of the various treatment groups were compared to that of intact teeth supplied with Dicor laminate veneers. In an experimental investigation using central and lateral incisors from sheep, it was found that fracture strength (16.6 ±4.2 MPa) equal to that of intact incisors (16.1 ± 2.6 MPa) could be achieved using laminate veneers made of porcelain on fractured teeth whose crown fragments were reattached using a dentin bonding agent (5). In the present investigation, using the same experimental model but using cast ceramic (Dicor) laminate veneers, the fracture strength of the restored incisors was significantly increased (21.0 ± 3.7 MPa), exceeding that of intact teeth. The fracture strength of intact teeth was also exceeded in veneered incisors which were initially restored with a conventional composite resin build-up (20.2±5.6 MPa). However, the greatest fracture strength (28.2 ±8.9 MPa) was achieved when a Dicor laminate veneer alone was used to restore the fractured ineisal edge. The strength was equivalent to that of intact teeth supplied with Dicor veneers (26.7 ± 6.3 MPa). While fracture strengths of teeth which were initially restored by fragment reattachment and then supplied with veneers exceeded that of intact teeth when veneer preparation was limited to enamel, they were reduced to the half of (hat of intact teeth (i.e. the same strength as teeth initially restored by fragment reattachment and no veneering) if the preparation extended into dentin. In the present experimental model, ii would appear that laminate veneers alone might be used to restore lost incisal edges of crown fractured anterior teeth.     

Treatment of crown fractured incisors with laminate veneer restorations. An experimental study.

A method is described by which crown fractured incisors are restored with cast ceramic (Dicor) laminate veneers after initial treatment with either reattachment of the original crown fragment with a dentin bonding agent, with a composite resin build-up or no treatment (i.e. the veneer alone is used to restore the incisal edge). In order to elucidate the effect of the fragment/composite-tooth bonding interface on fracture strength of the restored teeth, the fracture strengths of the various treatment groups were compared to that of intact teeth supplied with Dicor laminate veneers. In an experimental investigation using central and lateral incisors from sheep, it was found that fracture strength (16.6 +/- 4.2 MPa) equal to that of intact incisors (16.1 +/- 2.6 MPa) could be achieved using laminate veneers made of porcelain on fractured teeth whose crown fragments were reattached using a dentin bonding agent (5). In the present investigation, using the same experimental model but using cast ceramic (Dicor) laminate veneers, the fracture strength of the restored incisors was significantly increased (21.0 +/- 3.7 MPa), exceeding that of intact teeth. The fracture strength of intact teeth was also exceeded in veneered incisors which were initially restored with a conventional composite resin build-up (20.2 +/- 5.6 MPa). However, the greatest fracture strength (28.2 +/- 8.9 MPa) was achieved when a Dicor laminate veneer alone was used to restore the fractured incisal edge.(ABSTRACT TRUNCATED AT 250 WORDS)     

Critical appraisal: clinical considerations for restoring mandibular incisors with porcelain laminate veneers

Porcelain laminate veneers have been proven to be a successful treatment modality for maxillary incisors in clinical practice and in controlled clinical studies. However, the data in clinical studies on the success of veneers for restoring mandibular incisors are limited. Clinically, the successful restoration of mandibular incisors with porcelain laminate veneers is one of the more challenging procedures in all of esthetic restorative dentistry. Limited coronal dimensions, the small amount of enamel available for bonding (particularly in the cervical areas), materials and techniques for the bonding procedures, and the response of the tooth–veneer complex to forces generated during the incisal loading in both functional as well as parafunctional contacts must be considered as potential sources of success or failure.
This Critical Appraisal reviews three recent scientific articles to shed some light on these issues and, as in all research endeavors, leads the reader to identify additional areas of concern that might stimulate further scientific inquiry.
The first publication studied predictors for enamel thickness for mandibular incisors. The second examined bonding protocols for exposed dentin and suggested immediate dentin sealing. The third paper addressed fracture behavior of mandibular incisors restored with porcelain laminate veneers in vitro.     

Silk bonded replacements with porcelain veneers: a cosmetic alternative in dental treatment

A case in which the use of a silk bonded splint bridge was incorporated as a basis for porcelain veneer fabrication is discussed. The results of the treatment indicate that silk bonding may represent an acceptable conservative treatment alternative for patient care.     

下前牙瓷贴面修复三维有限元模型的建立

目的：建立下颌中切牙及其瓷贴面粘接修复的三维有限元模型,为前牙瓷贴面修复的生物力学分析奠定基础。方法：用Micro-CT扫描离体牙,Mi mi cs软件读取断层影像数据、数据分割、三维重建,Geo-magic软件精修,再运用Catia软件预备牙体并制作瓷贴面及粘接剂层,ANSYS workbench软件网格划分,最后进行有效性验证。结果：准确地建立含有瓷贴面、粘接剂、牙釉质、牙本质、髓腔的下颌中切牙三维有限元模型,网格划分后共计771788个单元,551587个节点。经收敛试验验证所得模型在力学和几何学方面与实体组织具有高度的相似性。应力云图可见Von-Mises应力主要集中于舌侧牙颈及唇侧肩台部,应力峰值发生在肩台偏近中处。结论：应用Micro-CT扫描结合逆向工程软件Mimics、Geomagic,及造型软件Catia,有限元分析软件ANSYS workbench建模的方法快捷可行、准确度高。     

Color characterization of porcelain veneers.

Porcelain veneers have become a popular treatment modality in recent years. A common problem associated with these restorations is the inability of the dentist to reproduce the polychromatic appearance of a natural tooth with a porcelain veneer. It is the purpose of this article to describe several methods that may be used to transform a monochromatic porcelain veneer into a polychromatic restoration that approaches the beauty of a natural tooth.     

Microleakage and shear bond strength of resin and porcelain veneers bonded to cast alloys.

Four resin veneering materials and four methods of retaining the veneer on metal castings were compared with metal ceramic restoration. Variations in microleakage were noted between the four resin materials retained by mechanical retention beads. When mechanical and chemical modes of a resin and porcelain veneer retention were compared, there was no microleakage with one mechanically and two chemically retained resin groups including one metal ceramic group. The resin materials tested understandably produced substantially lower shear bond strengths than the metal ceramic specimens. Higher shear bond strengths were recorded for the retentive beads than for the resins retained by three chemical bonding techniques. There was no direct correlation between microleakage and shear bond strength.