The effect of saliva contamination on shear bond strength of orthodontic brackets when using a self-etching primer
QI Juan,MAO Jing.Department of Stomatology, TongJi Hospital of HuaZhong Science and Technology University,Wuhan 430030,China
Objective:The purpose of this study was to assess the effect of saliva contamination on the shear bond strength of orthodontic brackets using a new self-etching primer. Method:The samples were divided into four groups according to four different enamel surface conditions: Group A: dry; Group B: saliva contamination before priming; Group C: saliva contamination after priming, and Group D: saliva contamination before and after priming. Stainless steel brackets were bonded in each test group with a light-cured composite resin (TransbondXT 3M).The shear bond strength and the adhesive remnant index (ARI) were determined in the first 30 minutes after bonding.Result:The shear bond strengths of the four groups were significantly different(F=11.89,P0.05). Group D, the most contaminated, had a significantly lower shear bond strength(4.6286±1.6883 MPa) than either the control group(8.7548±1.9153MPa) or the groups where contamination occurred either before(7.8951±1.9692MPa) or after(6.9010±1.5162 MPa) the application of the primer. No significant differences in ARI scores were found among the four groups. Conclusion:The new self-etching primer can maintain adequate shear bond strength if contamination occurs either before or after the application of the primer. On the other hand, contamination both before and after the application of the primer significantly reduced the shear bond strength of orthodontic brackets.