Força de contato proximal em restaurações posteriores de resina composta convencional e bulk fill - efeito do tipo de dente adjacente e da fadiga oclusal

Abstract

To measure the proximal contact force (N) and the proximal surface area in incremental and bulk fill class II composite resin restorations with implant molar teeth and with premolar adjacent teeth simulating periodontal ligament. The model was created with a typodont first molar teeth with two bilateral occlusal-proximal class II and adjacent teeth simulating an implant molar teeth (TitamaxCM, Neodent) and premolar simulating periodontal ligament. Two composite resin restorative technique: Inc-Z350, (Filtek Z350, 3M ESPE) inserted incrementally; Bulk-OPUS, (Opus Bulk Fill APS Regular, FGM) high viscosity bulk fill composite (n = 10). After restorative procedure, each sample was scanned using the s600 optical scanner system (Zirkonzahn GmbH, IT) generating a 3D dental surface, and radiographed using digital system (Dürr Dentall). The proximal contact force, CF(N) was measured using dental floss with microtensile machine (Microtensile ODEME, Luzerna, SC, Brazil). The samples were then submitted to fatigue mechanical cycling simulating 5 years of aging. All parameters were measured after the aging simulation. The x-rays were analyzed qualitative by two operators to blindly identifying the loss of continuity in contact. The 3D surface images were subtracted and the difference between initial and final scans were expressed in color graphics, and analyzed by two operators. Proximal contact force data were analyzed using two-way ANOVA in a split-plot arrangement followed by Tukey test. The CF with molar was significantly higher than with premolar, irrespective of composite resin or occlusal fatigue effect. Inc-Z350 showed similar contact force than Bulk-OPUS. The occlusal fatigue resulted in significant reduction on proximal contact force (P < 0.001), irrespective of region analyzed and restorative material used. Digital x-ray was not able to detect the alteration on the proximal contour after occlusal fatigue. No detection of wear within the sensitivity limit stipulated (0.3mm) was observed. Developed model for contact force test was efficient. The proximal with the molar was more effective than with premolar. The proximal contact decreased with simulated 5 years of occlusal fatigue. Bulk fill technique showed a similar behavior to incremental filling technique using conventional composite.