The Study Of The Shear Bond Strength With The Application Of Foil Mesh Base Brackets With Holes Bonded With GC Agent

Objective:The light curing adhesive strength of bracket will be affected by the curing depth.To increase the amount of light penetration and improve early bond strength of metal brackets,we have designed a kind of bracket base plate with through-holes.To provide guidance for the application of foil mesh base brackets with holes,this control study compared its immediate and ten to fifteen minutes shear bond strength and adhesive remnant index with foil mesh base brackets.Method:40 extracted human premolars were randomly and evenly divided into 4 groups(A1,A2,B1,B2).The teeth in group A1 and A2 were bonded with foil mesh base brackets from Hangzhou Xingchen 3B Dental Instrument&Material Co.,Ltd,while the same brackets in group B1 and B2 were each drilled three through holes on the base plate.All brackets were bonded with GC agent.The shear bond strength and adhesive remnant index of group A1 and group B1 were recorded by the universal test machine 1-2 min after the brackets were bonded.The relevant data in group A2 and B2 were recorded 10-15minutes later.The anti-shear bond strength were calculated,according to the area of the brackets base plate.Adhesive remnant index base were recorded after the brackets fell off.Result:1.Significant differences of shear bond strength were found between A1 and B1,A1 and A2.There were no significant differences between group A2 and B2,B1 and B2.2.The ARI scores of the brackets with holes were significantly lower than the traditional bracket both in 1 minute to 2 minutes and 10 to 15 minutes.This suggested that the bond strength can be significantly increased after making holes,compared with the traditional brackets,the fractures more often occurred in the interface between binder and enamel.Conclusion:1.The immediate shear bond strength was low,while the holes contributed to the high-level shear bond strength.2.Drilling three holes made no significant difference to bond strength compared with the traditional brackets at ten to fifteen minutes.It needs further research to meet the clinical needs.3.The longer after the GC agent was used,the greater shear bond strength we got.24-hour time span was recommended before the wire was ligated.4.When brackets are rebond with no need to change wires,we usually ligate immediately after bonding.It suggests to use the bracket with holes when bonding again.5.The ARI score of B1,B2 group was lower than group A1,A2,.This suggests that the bond strength is significantly enhanced after making holes.It also suggests to use the bracket with holes when bonding again.6.The location and number of holes may have an effect on the shear bond strength.To reach the clinical demand immediately,it needs further researches on the position and number of the drilling holes,and using 3D printing technology to make unified standardization of specimen to be more reliable in vitro experiment and clinical effect observation.Provide reliable theoretical basis for its popularization and application.