Dental cements: Bioactivity, bond strength and demineralization progression around restorations

PURPOSE: To evaluate demineralization progression around indirect restorations placed with various cements using swept-source optical coherence tomography (OCT) and microshear bond strength (MSBS) to enamel and dentin. METHODS: Resin inlays in cervical preparations (4×2 mm) were luted with two glass ionomer luting cements, Fuji I (FI) and RelyX Luting Cement (RL) and two adhesive cements, Adshield RM (AD) and RelyX Unicem 2 (UC). After 7-day artificial saliva incubation and 10,000 thermal cycles, specimens were demineralized (pH 4.5). Lesion progression at enamel and dentin margins was measured on OCT images after 1, 3 and 5 weeks demineralization (n= 8). RESULTS: Repeated-measures ANOVA showed that demineralization period, cement type, and their interaction had a significant effect on lesion size in both substrates (P< 0.001). Enamel lesion progression was slower in RL, FI and AD, and was significantly different from UC and control (P< 0.001). RL dentin lesions were significantly different from FI and AD lesions (P< 0.05), which in turn were significantly different than UC and control lesions (P< 0.001). MSBS means of AD and UC were significantly higher than those of FI and RL (P< 0.001). CLINICAL SIGNIFICANCE: A bioactive cement combining bioavailable calcium, functional monomer and glass-ionomer formulations showed better lesion progression inhibition around restorations than the adhesive resin cement, and higher bond strength than the resin-modified and conventional glass-ionomer cements.