Restoration of a Vital Tooth With Extensive Crown Destruction Using Glass Fiber and Polyethylene Fiber-reinforced Composite Resin: A Clinical Case.

Conservative restorative dentistry has been evolving in the last 25 years, focusing mainly on the development of direct restorative materials. Resin-based composites remain an excellent conservative alternative for restoration of teeth with extensive caries lesions. Over time, several strategies have been proposed to improve the mechanical properties of these composites so that they can adequately withstand masticatory forces. Glass fiber-reinforced resin-based composites and their use in situations where there is great loss of tooth structure have gained popularity due to their favorable mechanical properties. Combined techniques with polyethylene fibers can further enhance their clinical performance. This study presents a brief review of their most important qualities and potential use in direct restorative procedures. In addition, a clinical case is described where a vital tooth with extensive coronal destruction was restored using polyethylene fibers embedded in glass fiber-reinforced flowable resin under resin-based composite. The reinforcement of both the remaining tooth structure and the restoration with fibers is a valid treatment option since the network structure formed by the fiber reinforcement can increase the longevity of the direct composite restorations. There are few reports in the literature describing the use of a combined technique using polyethylene fibers embedded in glass fiber-reinforced flowable resin under resin-based composite. Thus, clinical follow-up of this case is required.

Limited Etching Time Increases Self-adhesive Resin Cement Adhesion to Enamel.

AIM: To evaluate the influence of different enamel etching times on the bond strength of two self-adhesive resin cements (RCs) with and without thermocycling (TMC). METHODS: One hundred twenty bovine teeth were used. Blocks of enamel (8×4×2mm) were obtained, polished, and randomly divided into two groups, according to the RC used: MaxCem Elite or RelyX U200. Groups were subdivided into four groups (n=16), according to the etching time: Control (0 seconds), 5 seconds, 10 seconds, and 20 seconds. Three RC cylinders (1-mm diameter) were built on each enamel block. The specimens were submitted to two storage conditions: 24 hours in distilled water or TMC (5000 cycles/5°C-55°C). Afterward, the specimens were submitted to the shear bond strength (SBS) test. The failure modes and adhesive interfaces were analyzed by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Data were analyzed with three-way analysis of variance (ANOVA) and Tukey test (α=0.05). RESULTS: Etching increased the SBS for both the RCs,especially forthe groups etched for 5 and 10 seconds. TMC affected negatively the SBS of the control groups (p<0.05). No resin tags were observed in control groups, and the formation of tags was time dependent. CONCLUSION: The 10 seconds etching time was more effective in increasing the enamel-resin bond strength. TMC negatively affected bond strength in specimens without acid etching.