Microleakage in contemporary esthetic restorations following cyclic wet-dry storage

Objective: To compare the incidence of microleakage associated with contemporary esthetic restorative-adhesive systems following cyclic wet and dry storage as a representation to the dry mouth condition. Methods: Standardized cervical cavities in both buccal and lingual surfaces of 100 extracted human premolars were restored in 10 groups (n = 10 with 20 cavities) using 7 contemporary esthetic restoratives and 3 adhesive systems following their manufacturers’ instructions. Cavities in groups 1–3 were restored with self-adhesive restoratives; conventional glass-ionomer (GI) (Ketac Molar Aplicap), resin modified glass-ionomer (RMGI) (Vitremer) and self-adhesive flowable composite (SAFC) (Fusio Liquid Dentin). Conventional flowable (FC) (Filtek Z350 Flow), nano-hybrid (HC) (Filtek Z250 XT) and nano-filled (NC) (Filtek Z350 XT) methacrylate-based composites were used in conjunction with total-etch, 2-step adhesive (Adper Single Bond 2) to restore cavities in groups 4–6. The same restoratives were also used to restore cavities in groups 8–10 in the presence of self-etch, 1-step adhesive (Adper Easy One), while cavities in group 7 were restored with silorane-based composite (Filtek P90) together with its specific adhesive system. Five restored teeth from each group (10 cavities) were subjected to cyclic storage in wet and dry environment, each for 12 h/day and for a total period of 30 days, while the other 5 were tested with no cyclic storage to serve as control. Using dye penetration technique, the associated microleakage was then scored from 0 to 4 for all restorations according to the depth of dye penetration at both occlusal and gingival interfaces. The incidences of each score were recorded in percentages and the numerical microleakage data were statistically analyzed using Kruskal–Wallis and Mann–Whitney comparisons at α = 0.05 to stand on the significance of differences detected between groups. Results: All restorative systems showed incidences of microleakage before and following cyclic storage in wet and dry environment with no specific manner declared for any. Statistical analysis of the scored data revealed no difference between different restorative systems under no storage condition, however HC, S and FC in groups 5, 7 and 8 showed higher rates of microleakage when subjected to cyclic wet-dry storage (Mann–Whitney, P < 0.05). No significant effect of storage was declared on any of the tested restorative systems (Kruskal–Wallis, P > 0.05). For each restorative system, no significant difference (Kruskal–Wallis, P > 0.05) was recorded between microleakage values recorded at occlusal and gingival interfaces. Conclusion: Occlusal and gingival sealing ability of flowable resin composite bonded with self-etch, 1-step adhesive is the most affected following cyclic wet-dry storage. Selection of such restorative option accordingly is not suggested for patients suffering from dry mouth.