Effect of different orthodontic force values on tooth root resorption in rats with long-term drinking carbonated beverage

Objective:To study the effects of different orthodontic force values on the root resorption in rats with long-term drinking carbonated beverage.Methods:Twenty SD female rats(1 month old) were fed with 50 mL Coca-Cola each day.After 3 months,the rats were divided into the group A(0 g),group B(30 g),group C(50 g) and group D(80 g)according to the applying force value,and added orthodontic device in maxillary first molar.The BMD in rats at 0 d,21 d and 3 months of feeding Cola was measured.The maxillary first molar and near tissue were obtained after 21 days of operation,and detected using CBCT and stained using HE to observe the root absorption.The root resorption index was calculated by tissue section,and the number of osteoclasts was observed by TRAP staining.Results:With the increasing of feeding Cola time,the BMD in each group gradually decreased,the difference of which was statistically significant(P<0.05).At the same time-point,the difference of BMD between each group was not statistically significant(P>0.05).CBCT results showed that the root resorption in group D,group C and group B gradually decreased.The tooth root resorption index and number of osteoclasts in group D,group C and group B gradually decreased(P<0.01),the difference of those between group B and group A was not statistically significant(P>0.05).The bone remodeling in group B during orthodontic tooth movement is more active than that in group C and group D.Conclusions:The effect of 30 g force value on the root resorption in rats with long-term drinking carbonated beverage is the minimum,and the root resorption gradually increases with the increasing of force value.