IADR Abstract Archives

Micro-tensile Bond Strength of a Contemporary Total-etch and Self-etch Adhesive after in vivo Degradation

Long-term durability of the bond between tooth and restorative material is one of the most critical factors affecting the clinical performance of adhesive restorations. Objectives: The aim of the study was to evaluate the bonding effectiveness of a total-etch and a self-etch adhesive to dentin after 6-month in-vivo service, using a micro-tensile bond strength (µTBS) set-up and Fe-SEM. Methods: Class-I restorations were placed in 10 human caries-free third molars and pre-molars scheduled for extraction (approved by Committee for Medical Ethics, Warshaw University). The cavities were restored using either a three-step total-etch adhesive (OptiBond FL, Kerr) or a ‘mild’ two-step self-etch adhesive (Clearfil SE, Kuraray) along with one resin composite (Z100, 3M Espe). After 6 months of in-vivo service, the teeth were extracted and 2-4 µTBS samples were prepared from each restoration. Samples from in-vitro prepared restorations (stored for 24hr in water) served as controls. Results:

µTBS (MPa)	24 hr in-vitro	ptf/n*	6-month in-vivo	ptf/n*
OptiBond FL	30.7 ± 11.5	0/20	27.9 ± 15.2	2/19
Clearfil SE	28.3 ± 8.3	0/16	23.4 ± 7.6	0/12

*ptf/n = Pre-testing failures/ number of samples

Two-way ANOVA and Scheffe’s statistical analysis (p<0.05) revealed no significant bond degradation, nor any significant difference between both adhesives tested. The 2 pre-testing failures recorded for the OptiBond FL in-vivo group originated from upper third molars that were difficultly accessible, which consequently may have led to inaccurate adhesive application. Conclusions: In-vivo degradation up to 6 months seemed not to influence the µTBS of the tested total- and self-etch adhesive. Also Fe-SEM examination did not reveal distinct ultra-morphologic features of bond degradation.

This study was supported by a Visiting Scholar Program from IADR-CED.