An Experimental Study On Frictional Resistance Between Different Preadjusted Brackets And Archwires In The Buccal Segments Under Artificial Saliva Condition

Objective : To study the frictional resistance in the buccal segment between 4 kinds of preadjusted domestic and imported brackets coupled with 4 different archwires, at different times under artificial saliva condition . Methods: According to orthogonal experiment design, the static and dynamic friction of different combinations of 4 kinds of preadjusted brackets ( 2 domestic brackets and 2 imported brackets ) and 4 archwires ( 2 stainless steel round wires and 2 stainless steel rectangular wires ) were tested simulating archwires sliding in the buccal segments at 4 different times (0 ,15,30,45 days ) under artificial saliva condition at 370C; The optimal combination of archwire,brackets and time was searched by regnession analysis . Results : Under artificial saliva condition bracket , archwire and time were all important factors to the static and dynamic frictional resistance ( P< 0.05 ). The static and dynamic frictional resistance of combinations of 3M Roth bracket and all archwires were significantly higher than that of other 3 preadjusted brackets . The static and dynamic frictional resistance of combinations of 3M MBT bracket and all archwires was the smallest.The combinations of 0.018 inch stainless steel round wire and all brackets produced significantly the lowest static and dynamic frictional resistance than that of other archwires . The 0.019× 0.025 inch stainless steel rectangular wire produced the highest static and dynamic frictional resistance combined with all preadjusted brackets combinations . There were no significant differences of frictional resistance between 0.020 inch stainless steel round wire and 0.019× 0.025 inch stainless steel rectangular wire. The static and dynamic frictional resistance of combinations of archwires and brackets was highest at the 15th day and was smallest at the 30th day under artificial saliva condition at 370C .As for static frictional resistance , the optimal combination of archwire , brackets and time was : 3M MBT bracket, 0.018 inch stainless steel round wire and at the 30th day under artificial saliva condition and at 370C ; As for dynamic frictional resistance , the optimal combination of archwire brackets and time was : 3M MBT bracket, 0.019× 0.025 inch stainless steel rectangular wire ,at the 0 day under artificial saliva condition and at 370C . Conclusions: 1 Bracket , archwire and time all were effective factor of frictional resistance.2 MBT brackets and bucall tubes were more favorable to sliding mechanics compared with other brackets and bucall tubes in this study. 3 0.018 inch stainless steel round wire produced the smallest frictional resistance with all preadjusted brackets combinations .4. As for times ,the highest frictional resistance emerged at the 15th day while the lowest frictional resistance exhibited at the 30th day under artificial saliva condition and at 370C.5. As for static frictional resistance , the optimal combination of archwire, brackets and time was : 3M MBT bracket, 0.018 inch stainless steel round wire and at the 30th day under artificial saliva condition; As for dynamic frictional resistance , the optimal combination of archwire , brackets and time was : 3M MBT bracket, 0.019× 0.025 inch stainless steel rectangular wire and at the 0 day under artificial saliva condition .