The effects of sandblasting on the bond strength of molar attachments--an in vitro study.

This study evaluated the effect of sandblasting foil mesh molar tube bases on the shear bond strength obtained when bonding to first molar teeth. Fifty-two recently extracted first molar teeth were etched with 35 per cent phosphoric acid gel for 30 seconds. Twenty-six sandblasted 'A' Company molar tube attachments and 26 non-sandblasted attachments were then bonded to the teeth using Phase II orthodontic bonding resin. After storage in water for 24 hours at 37 degrees C, the specimens were debonded in a direction parallel to the buccal surface. Survival analysis using the Weibull function revealed that for a 90 per cent probability of survival, the predicted bond strengths for sandblasted and non-sandblasted bases were 1.76 and 1.66 MPa, respectively. For larger shear stresses, the probabilities of bond survival with sandblasted molar tubes were greater than with non-sandblasted molar tubes although the differences were small, which may be explained by the large proportion of bond failures which occurred at the resin to enamel interface in both groups. It was concluded that sandblasting foil mesh bases is likely to provide only a minimal improvement in clinical performance when bonding to molar teeth.