The Effects Of Dehiscence And Fenestration Before Orthodontic Treatment On External Apical Root Resorption(EARR)in Maxillary Incisors

Objective: The objective of this study was to investigate the effects of Dehiscence and Fenestration on External Apical Root Resorption(EARR)in maxillary incisors.Methods: 78 patients were selected for this study.We set Dehiscence,Fenestration,Gender,Extraction or non-extraction,Tooth Position,Initial age and Duration as independent variables and EARR as dependent variable.General statistical descriptions for these variables were made by mean,standard deviation and occurrence rates,etc.To make the data visualization and find more information,two heat maps were made by Hem I.Generalized estimation equation(GEE)analysis was performed to determine associations between EARR and independent variables.Results: The occurrence rates of dehiscence and fenestration in maxillary incisors were 14.77% and 10.74%,respectively.The average value of EARR was 1.09±0.87 mm in this study.Dehiscence,Tooth Position,Extraction,Initial age and Duration had significant correlations with EARR.The ratio of Exponent of B(Exp(B))was 1:1.643 for Dehiscence and Non-dehiscence.Meanwhile,Fenestration and Gender had no significant association with EARR.Conclusions: The amount of EARR at maxillary incisors in patients with dehiscence before orthodontic treatment might be less than that in patients without it and different incisors might have different contributions to it.However,the low value of Exp(B)for Dehiscence meant that there might be as well other unknown factors that were involved in this study.