Effect of Resin Coating on Adhesion of Composite Crown Restoration

Objectives: The purpose of our study was to evaluate the durability of resin coating technique on adhesion and adaptation of indirect composite restorations. Method: Recently extracted non carious, human mandibular molars stored in water at 4°C water were used in this study. Full crown preparation was done on each tooth with slightly rounded internal line angles. Crown margin was designed bellow cervical line. The prepared teeth were randomly divided in two equal groups; experimental group (GI), which received resin coating and the control group (G2) without resin coating. For GI, low viscosity microfilled resin (RZ-II, Sun Medical Co. Kyoto, Japan) was applied on the dentin surface and cured according to the manufacture's instructions and composite crown (Estenia, Kuraray Medical Co, Tokyo, Japan) was bonded using chemical cured resin cement, Chemiace II (Sun Medical Co. Kyoto, Japan). For G2, prepared teeth were directly bonded using Chemiace II. After 1 day storage in 37°C water, the micro-tensile bond strengths (µTBS) were measured at crosshead speed of 1mm/mn. The data were analyzed using one way ANOVA & Fisher's PLSD test. The adhesive interface between composite resin crown and abutment tooth was observed by Scanning Electron Microscope (SEM). Results: The µTBS (Mean ± SD MPa) of resin coated group was significantly higher than the control group. No significant differences were detected between axial and occlusal wall for both coated and non coated group. Resin coated specimens showed fewer gaps at the adhesive interface compared with that of the control specimens.

Conclusions: It can be said that resin-coating technique can provide better bonding adaptation than the conventional method.