The effect of cavity disinfectants on the micro-shear bond strength of dentin adhesives

This study was carried out to examine the effect of application of four different disinfecting agents on the micro-shear bond strength (μ-SBS) of an etch-and-rinse and self-etch adhesive systems.

One hundred flat dentin surfaces of human molars were produced by wet grinding the buccal surfaces. Specimens were randomly assigned to five groups according to the disinfectant used: Group I: Control (no disinfectant); Group II: 5.25% sodium hypochlorite based; Group III: 2% chlorhexidine based (Consepsis), Group IV: 0.1% benzalkoniumchloride based (Tubulicid red) and Group V: 3% doxycycline based (Biopure, MTAD). Specimens were bonded using either Adper Single Bond 2 or Clearfil S(3) Bond, which were employed according to the manufacturer's instructions. Resin composite microcylinders were bonded using Tygon(®) tubes for μ-SBS testing. The modes of failure were noted after visual examination using a binocular stereomicroscope at ×25 magnification. Failures were classified as adhesive, or mixed. μ-SBS results were analyzed using two-way ANOVA followed by Tukey's post-hoc test.

Dentin disinfectants tested significantly negated the bonding of Adper Single bond 2 and the groups were ranked; Group I > Group V = Group IV > Group II = Group III, meanwhile they enhanced significantly the μ-SBS values upon using Clearfil S(3) Bond and were ranked; Group II > Group III = Group IV = Group V > Group I. Most failures were adhesive with the Adper single bond adhesive system. Mixed modes of failure were evident with Clearfil S(3) bond.

The disinfectants tested should not be used with Adper Single Bond 2 when applied before the etching step, However they could be used safely prior to bonding with Clearfil S(3) Bond.