Comparative Study Of Three Bonding Materials In Bonding Attachments Of Removable Thermoplastic Appliances

Objective:To evaluate the operation time,bonding strength,placement accuracy and wear resistance of three types of bonding materials（Filtek TMZ350XT nano universal composite resin,Filtek TMZ350XT flowable composite resin and Sonic Fill ultrasonic composite resin）in bonding attachments of removable thermoplastic appliance and to provide reference for orthodontists to select appropriate materials in bonding attachments.Methods:A total of 129 healthy mandibular premolars were collected,and 69were randomly selected and divided into group A1,B1and C1,with 23 teeth in each group.The remaining 60 teeth were divided into group A2,B2 and C2,with 20 teeth in each group.3M Adper Single Bond2 adhesive and Filtek^TMZ350 XT nano universal composite resin were used in group A1,A2 to bond attachments.3M Adper Single Bond2 adhesive and Filtek^TMZ350 XT flowable composite resin were used in group B1,B2.Optibond S adhesive and Sonic Fill ultrasonic composite resin were used in group C1,C2.The operation time required for bonding attachments of groups A1,B1and C1 was recorded.20 samples were randomly chosen from each group and were tested in shear strength.The shear strength was tested with an universal dynamometer a speed of 1mm/min.The shear force values at which attachments fell off were recorded.The shear strength were worked out.The other samples were used to observe the interface with scanning electronmicroscope.The placement accuracy was tested in group A2,B2,C2 by measuring the volume change of 3D designed attachments and the attachments after actual bonding.The specimens were prepared with Filtek^TMZ350 XT nano universal composite resin,Filtek ^TMZ350 XT flowable composite resin and Sonic Fill ultrasonic composite resin.10mm in diameter,2mm in height specimens were made for abrasion resistance.The specimens were fixed in a ball-on-disc wear testing machine,artificial saliva as abrasion media（50N loading force,10000 cycles）.The volume loss was recorded.Results:The operation time of group B1,C1 was shorter than that of group A1（P<0.05）;The shear strength of group C1 was stronger than that of group A1 and B1（P<0.05）;Under scanning electron microscope,the bonding degree of Z350XT universal resin group and Sonic Fill ultrasonic resin group with enamel was better than Z350XT fluid resin group;The volume change of 3D designed attachments and the attachments after actual bonding of group C2 was less than that of group A2,B2（P<0.05）;The wear volume loss of Sonic Fill ultrasonic resin and Z350XT universal resin was less than Z350XT fluid resin（P<0.05）.Conclusion:Attachment made of Sonic Fill ultrasonic has short operation time,strong bonding strength,good placement accuracy and well wear resistance,so it can provide an experimental basis for the selection of attachment materials clinically.