Micro Leakage at Resin Composite-Tooth Interface Utilizing Unicem Cement, Various Adhesive Systems and A Recent Resin composite (In-Vitro Study)

Abstract

Introduction Marginal seal is one of the most important factors for successful restorations, trials to reach the dream of increasing bonding between resin composite and hard tooth tissue and overcome polymerization shrinkage associated with using composites as direct or indirect techniques. The use of different etching and bonding protocols and / or the use of base material considered to be real step to increase bonding, also changing the nature of resin help to solve this problem to a limit Objectives The aim of this study is to compare microleakage scores at composite-unicem cement interface using different etching and bonding protocols and various resin- based formulations. Materials and methods A total of 72 freshly extracted human molars were used in this study. One type of resin cement was used as a base which is Rely X U200, 37% phosphoric acid etching gel for pre-etching of dentin, Three types of bonding systems were used, Bond-1 primer/adhesive, Tetric N-Bond and Bond 1 SF S. Three types of resin composite were used, A micro-rod fiber reinforced hybrid composite, Inten-S low shrinkage composite and Filtektm Z250XT Nano hybrid resin composite. The teeth were divided into three main groups (24 teeth each) according to the type of adhesive system used. Each group was further subdivided into three subgroups (8 teeth each) according to different resin formulation (N=8). After restorations, all the teeth were immersed in 1% methylene blue for six hours then facio-lingually sectioned into two halves. Micro-leakage was examined and evaluated under stereo-microscope at x30 magnification at occlusal and gingival margins of restoration and results were statistically analyzed using paired samples t test. Results A high statistically significant difference was observed (0.003) between groups having the same adhesive system (etch and rinse unfilled primer adhesive) but different resin composite materials (micro-rod (fiber) Nulite f and Nano hybrid Z250resin composite). Another high significant difference was seen between groups having the same adhesive system (bond I SF) and different resin materials (low shrinkage Inten-S and Nano hybrid Z250resin composite). A low statistically significant difference was observed between groups which had the same resin material (low shrinkage Inten-s resin composite) and different adhesive systems (etch and rinse unfilled primer adhesive and bond 1SF), Another low statistically significant difference was seen between groups having the same low shrinkage inten-S resin composite with self-etch Nano filled tetric N. Bond adhesive system and self-etch bond 1SF. Conclusions the use of combination of Unicem Relay X as base (liner) and low shrinkag