الفهرس 
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Abstract
To clinically evaluate the18-month adhesion durability of indirect resin composite inlays luted with three different resin cement strategies in MOD Class II restorations. In the laboratory section, evaluation of both microleakage and microtensile bond strength (µTBS) to dentin after specimens storage in distilled water and lactic acid. Materials and Methods: A randomized clinical trial was conducted following the protocol, 20 patients with three large cavities for each one that indicated for indirect MOD Class II restorations were enrolled in the study. Then, 60 indirect resin composite inlay restorations were placed and luted with three different resin cement strategies; an etch-and-rinse, self-etch and self-adhesive. Each resin cement was used for luting 20 inlay restorations. Immediatelly after placement, the restorations were finished and polished. Clinical evaluation was performed at baseline and at 6 monthly intervals after placement by two independent examiners using modified USPHS criteria. The changes in the USPHS parameters during the 18-month period were analyzed with Fredman test. The baseline scores were compared with those at the recall visits using Wilcoxon signed rank test, where the level of significance was set at p˂0.05. For microleakage and µTBS to dentin investigations, standardized MOD Class II cavities were prepared in 96 intact human molars and restored with indirect resin composite inlay restorations. The specimens for each test (n=48) were assigned into three sets (n=16) according to the luting resin cement used. Each set was subdivided into two equal subsets (n=8) relative to the storage media either distilled water or lactic acid. Half of the specimens of each subset was stored in each storage medium for 24h while the other half was stored for 168h (7days). Results : The outcome of the clinical trial showed that, there was no loss of restorations and no recurrent caries after 18-month for all luting cements groups. Both self-etch and self-adhesive resin cements exhibited minor differences between the evaluation periods regarding to marginal discoloration and marginal adaptation. At baseline, only 4 cases of etch&rinse resin cement group exhibited post-operative sensitivity which relieved after short time. Microleakage test results revealed that, there was significant difference (p<0.05) between the three resin cement strategies in each storage medium and storage time. Etch&rinse resin cement recorded the highest scores of dye penetration and self-etch resin cement showed the lowest scores. The outcome of µTBS to dentin evaluation showed that, SE samples stored in distilled water for 24h revealed the highest values. Etch&rinse samples stored in lactic acid for 168h showed the lowest values. Conclusion : All the three resin cement strategies tested, showed acceptable clinical performance after 18-month. While in the laboratory study, microleakage and µTBS showed good results with SE resin cement strategy.