Abstract: Objective To compare the shear bond strength and the adhesive remnant index of six orthodonticbonding agents in simulated oral environment in vitro. Methods Sixty healthy premolars were randomly divided into 6 groups.Then the brackets were bonded with six orthodontic bonding agents (A:3M Unitek Transbond XT; B:Xihubion no-mix orthodontic direct bonding system;C:Xihubiom no-mix light cure orthodontic bonding system;D:GC Fuji ORTHO LC;E:Medicept light cure orthodontic adhesive bonding system;F:Prime-Dent light cure orthodontic adhesive bonding system) strictly according to instructions.After 24 hours′ artificial saliva bath at 37 ℃, the shear strength of each group was tested with an universal dynamometer at 1 mm/min.The shear force values at which brackets fell off were recorded.The shear strength were worked out.SPSS 17.0 software was used to analyse the results.The adhesive remain index (ARI scoring) was recorded under a magnifier by 10 times.The results were dealt with by Kruskall-wallis H test. Results There was no significant differencein the bonding strength among group A,B,C,E (P>0.05).Though the bonding strength of D,F group was not significantly different (P>0.05),it was significantly less than A,B,C,E groups (P<0.05).ARI scores after Kruskall-wallis H test showed no significant differenceamong the six groups(P>0.05). Conclusions Although there are significant differences on the bonding strength ofthe six orthodontic bonding agents,all can be used in the orthodontic treatment.

Key words: orthodontic, Orthodontic adhesive, adhesive bond strength, ARI score.