Effect of different pretreatment methods on dentin bond strength of a one-step self-etch adhesive.

AIM The aim of this in vitro study was to evaluate the shear bond strength of a one-step self-etch adhesive to dentin pretreated with phosphoric acid, air abrasion, or laser. METHODS AND MATERIALS Fifty-six extracted non-carious human mandibular molars were mounted and the occlusal surfaces ground with a mechanical grinder to obtain flat occlusal dentin surfaces. The teeth were randomly divided into four groups of 14 teeth according to the different dentin surface pretreatment methods: Group I--acid, Group II--laser, Group III--air abrasion, Group IV (control)--no surface treatment. After applying a one-step self-etch adhesive system, Futura Bond NR, cylinders of Z250 composite resin were bonded to the dentin surfaces by transparent gelatin capsules (2.5 mm diameter; 3 mm high) and then polymerized. All specimens were stored in distilled water at 37 masculineC for 24 hours. Shear bond testing was carried out using an Universal testing machine with a crosshead speed of 0.5 mm/sec. Data were analyzed using the Kruskal Wallis and Mann-Whitney tests at a significance level of 0.05. RESULTS The bond strength of air abrasion (Group III) and the control group (Group IV) were statistically higher than both the acid (Group I) and laser (Group II) pretreatments (p < 0.05). No statistically significant differences were found in shear bond strength between surfaces treated with air abrasion and the control group (p > 0.05). Surfaces pretreated with laser (Group II) resulted in the lowest bond strength which was not statistically different from those pretreated with acid (Group I) (p > 0.05). CONCLUSION Surfaces pretreated with acid and laser adversely affected the bond strength of a one-step self-etch adhesive, Futura Bond NR, while pretreatment with air abrasion had no effect on bond strength. CLINICAL SIGNIFICANCE The pretreatment of dentin surfaces prior to self-etch adhesive seems to be unnecessary and defeats the original purpose of these systems.