Beveled and Non-beveled Enamel Margin Microleakage Utilizing Various Bonding Systems

Objectives: To investigate the amount of microleakage in beveled and non-beveled proximal cavosurface margins utilizing various types of adhesive bonding systems. Methods: Two proximal slot preparations, each having one beveled and one non-beveled proximal margin, were cut in each of fifty extracted human teeth (n=100). The teeth were divided into five equal groups. A separate acid-conditioning step was required in two groups: AB (AllBond2, Bisco) and PB (Prime&Bond NT, Caulk). The remaining groups contained self-etching adhesive resins: OS (One-Step Plus/Tyrian SPE, Bisco), XN (Xeno III, Caulk) and IB (iBond, Heraeus Kulzer). All specimens were restored with Universal Supreme (3M) hybrid resin composite, thermocycled (500 cycles, 5º-23º-47ºC) and stained with 50% silver-nitrate solution. Proximal surfaces were abraded with a 400-grit diamond cup grinder in 0.25 mm increments, which were digitally imaged (12.5X; Olympus-SZX12). Percent microleakage values were calculated by measuring microleakage lengths and wall lengths (micrometers) for beveled and non-beveled walls using IPLab software (Scanalytics, Inc.). Products were compared using repeated-measures ANOVA and SNK post hoc tests (p=0.05) within each proximal margin type. Results:

	Non-beveled		Beveled
Bonding Agent	Mean % microleakage ± STD	SNK groups	Mean % microleakage ± STD	SNK groups
AB	16.62±14.19	A	8.72±14.09	A
IB	51.64±9.79	B	35.07±13.33	B
OS	55.98±15.60	B	19.34±11.56	A
PB	22.99±15.99	A	8.86±6.56	A
XN	47.30±7.32	B	42.42±10.69	B

Conclusions: Beveled walls in products AB, PB and OS were associated with less mean percent microleakage (p < 0.05) than XN and IB. Products AB and PB exhibited less mean percent microleakage (p < 0.05) than XN, IB and OS in non-beveled enamel proximal walls. This study was funded by the Native American Center for Excellence, University of Oklahoma Health Sciences Center.