Bonded molar tubes - An in vitro evaluation

This study aimed to evaluate the mean shear bond strength of molar tubes wi th micro-etched bases bonded with either a compomer (Ultra Band-Lok), a res in-modified glass ionomer cement QM Multi-Cure or Fuji Ortho LQ, or a light -cured resin adhesive (Transbond). The amount of adhesive remaining on the tooth surface following tube removal was assessed also. Finally, survival t ime of molar tubes bonded with each bonding agent was assessed following si mulated mechanical fatigue in a ball mill. A total of 120 extracted human t hird molars were collected and randomly divided into 4 test groups. Thirty teeth (20 to assess debonding force and 10 to assess survival time) were bo nded with each adhesive according to the manufacturers' instructions. Debon ding was carried out using, a Nene M3000 testing machine with a crosshead s peed of 0.5 mm/min. The mean shear bond strength of tubes bonded with Trans bond was significantly less than that of those bonded with 3M Multi-Cure (P =.0036) or Fuji Ortho LC (P <.0001). Tubes bonded with Ultra Band-Lok also had significantly lower mean shear bond strength than those bonded with Fu ji Ortho LC (P =.020). Distribution of adhesive remnant index scores only d iffered significantly between tubes bonded with 3M Multi-Cure or Transbond. Only 1 molar tube, bonded with Transbond, debonded in the ball mill at 5 h ours, but at 50 hours there was no significant difference in the survival t ime of tubes bonded with any of the bonding agents. Compomer or resin-modif ied glass ionomer cements appear to be viable alternatives to light-cured r esin adhesive for bonding molar tubes.