IADR Abstract Archives
Degradation of Adhesive Bond Strengths
Objectives: Study durability of adhesion to enamel and dentin using a conventional etch rinse (ER) adhesive system, self etching primers (SEP) that combine the primer with the acid, and self etching adhesives (SEA), that combine the three steps together. Methods: Z100 composite (3M) was bonded with the adhesives tested: one ER (Single Bond- 3M, SB), two SEP’s (Clearfil SE-Kuraray, SEPc and Mac Bond- Tokuyama, SEPm) and two SEA’s (Prompt-L-Pop- 3M, SEAp and One up Bond- Tokuyama, SEAo). To simulate aging we stored samples 1 day, 1 week, 1 month, 6 months and 18 months at 37°C in Hank’s balanced salt solution with 0.04% sodium azide. An average of 6 specimens per adhesive per time for each enamel and dentin were shear tested to failure at a crosshead speed of 5 mm/min, with a single plane lap shear testing apparatus. Data were analyzed with two-way ANOVA (treatment x time) and Tukey-Kramer tests at 95% confidence level. Failure mode was determined from SEM micrographs of the failed surface at 2 kX and analyzed with MANOVA statistical tests. Results: Shear Bond strength, MPa (St Dev) are shown in table below. Mean values with same superscript were not different (P>0.05). Lower case indicates comparison only in each material with time (columns) and uppercase indicates comparison between materials at each time (rows). 18-month results for dentin are separated because they were analyzed individually, since there was a 2-way interaction. Conclusions: Shear bond strength decreased for three adhesive systems (SB, SEPc, SEAp) after long-term storage only when dentin was used, suggesting that for long-term bond strength, the weak link is not the adhesive per se but the bonded layers created in dentin. Further investigation is warranted to understand the components of degradation within these layers. US DHHS/NIH/NIDCR Grant DE 09859. sofiaaol@oninet.pt. 