Microleakage of occlusoproximal adhesive restorations, effect of dentin moisture after acid etching

The aim of this study was to evaluate the effect of dentin moisture after acid-etching on marginal sealing in occluso-proximal composite restorations.

Ninety occluso-proximal preparations were made in posterior teeth with gingival margin in dentin. Prepared teeth were divided in 3 groups (N=30) according to the type of solvent of adhesive (ethanol/water=SB, Single Bond 3M ESPE, acetone=PB, Prime & Bond NT Dentsply, and ethanol=OP, OptiBond Solo Plus, Kerr). And 3 subgroups (N=10) according to the types of treatment of the cavity after rinsing the acid etchant ( 1) cavity air-dried for 10 s at a distance of 1 cm; 2) cavity blot-dried with slightly moist cotton pellets; 3) cavity with visible excess of water). Hybrid composite was applied in four increments. After 24 hours, teeth were thermocycled (500 cycles, 30 s, 5 to 55 masculineC) and immersed in 0.5% basic fucsin for 4 hours. The teeth were cleaned, dried and sectioned. The microleakage extent was analyzed with a 0-5 scale in dentin margin. Enamel margins were verified for presence or absence of microleakage. Data were submitted to Kruskal Wallis test (P<0.05).

The median of microleakage scores in dentin margins were: SB_a=1, SB_b=0, SB_c=1, PB_a=1, PB_b=1, PB_c=2, OP_a=0, OP_b=1, OP_c=1. Considering bonding systems, PB provided more microleakage than SB and OP (P=0.0316). In groups where cavity had visible excess of water there was higher microleakage degree than the dry cavity subgroups (P=0.048). In enamel margins, median was 0 for all groups.

Better marginal sealing is obtained in dentin margins of occluso-proximal cavities when they are air-dried or blot-dried with cotton pellets after acid-etching.