Abstract
This study investigated the effect of water storage on nanoleakage depth and the pattern of cervical cavities bonded with different adhesives.
For nanoleakage depth evaluation, standardized cervical cavities (2 mm in diameter) were prepared on the buccal and lingual surfaces of 36 intact human premolars. Specimens were divided into three groups (n=12) according to the three adhesive systems used: an etch-and-rinse adhesive (SBMP, Adper Scotchbond Multi-Purpose, 3M ESPE) and two single-step self-etch adhesives; one was mild and acetone based (IB-iBond, Kulzer), while the other was strong water based (PL, Adper Prompt L-Pop, 3M ESPE). All cavities were restored using Filtek Z250 (3M ESPE) resin composite. For each adhesive, specimens (n=12 with 24 restored cavities) were subdivided into three subgroups (n=4 with eight cavities) according to the storage period before examination (24 hours, three or six months). Another duplicate of teeth was prepared in the same way for nanoleakage pattern evaluation. After storage, the specimens were placed in 50%W/V silver nitrate solution for 24 hours and immersed in a photo-developing solution for eight hours. Thereafter, the specimens were sectioned buccolingually, polished, and examined by scanning electron microscopy. For nanoleakage pattern, specimens were treated in the same way as for nanoleakage depth except that they were additionally immersed in 10% EDTA for five seconds after polishing. Silver penetration percentage was calculated to the total length of the tooth-restoration interface. Data were analyzed with two-way analysis of variance, Kruskal-Wallis, and post hoc tests.
After 24 hours, the least amount of nanoleakage depth was recorded for IB, while the highest was recorded for PL. For stored specimens, there was no significant difference among the nanoleakage depths of all adhesives. The tested adhesives recorded different nanoleakage patterns; however, there was an increase in the intensity and continuity of silver deposition by time.
After 24 hours, the nanoleakage depth/pattern varied with the type of adhesive used; however, after water storage, all adhesives performed equally.