In Vitro Chewing Simulation Model Influence on the Adhesive-Tooth Structure Interface

Loss of hard dental tissues of the posterior teeth during caries removal represents an important issue for conservative dentistry. The use of direct dental biomaterials in this case have to satisfy the requirements of the restored area. The studies have shown higher values of chewing forces at the molar teeth level (20-120N) compared to other teeth [1,2]. Thus, for a long-term clinical success the dental biomaterials have to assure a good marginal sealing and a high resistance to thermal and mechanical stresses developed in the lateral zones of the oral cavity [3]. The aim of this study was carried out to assess the effect of an in vitro chewing simulation model on the adhesively-bonded resin composite restorations. Standardized extended proximal cavities were prepared and restored in forty five sound human third molars. Three in vitro aging methods: a chewing simulation model (mechanical cycling and periodontal ligament simulation) (MC+PDL), thermocycling (TC) and distilled water storage (WS), were used to test the marginal sealing behavior of two adhesive techniques (an adhesive-free flowable resin composite and a self-etch all-in-one adhesive system). A weight-controlled dual-axis chewing device (CS-4.2, SD Mechatronik, Germany) was used for mechanical testing (MC) of the samples. Significantly higher marginal leakage values were observed for the chewing simulation model (MC) compared to TC and WS groups (p<0.05). No statistical correlations were found with regard to aging methods for the tracer’s infiltration of the two adhesive techniques. The dual-axis chewing simulator (CS-4.2) due to its facile mechanical adjustment system may be used for different other in vitro aging models or simulated clinical settings.