The Research Of Mesially Maxillary Impacted Canine-associated Incisor Root Resorption In Three-dimensional Space

[Objective]To identify characters for mesially maxillary impacted canines-associated incisor root resorption with cone-beam computed tomography(CBCT).[Methods]A total of 48 healthy patients with 56 maxillary mesial impacted canines were recuited for the study. The impacted maxillary canines were scanned by CBCT and then reconstructed by Mimics 17.0 software. Impacted canine subjects divided into two groups:bucally impacted canines(BIC) and palatally impacted canines(PIC).The variables and the severity of incisor resorption were assessed.[Results]Most patients were Class Ⅱ.The ratio between male and female was 1:2. When each variable was examined separately, the severe root resorption of incisor was associated with Angle’s classification(χ2=11.971, P=0.018), overbite(χ2=10.722, P=0.005) and dental follicles(χ2=10.382, P=0.006). The severe root resorption of incisors has a correlation with Angle’s classification(χ2=13.835, P=0.008),deciduous canines(χ2=7.778, P=0.020) and tooth position(χ2=6.9145 P=0.032) in BIC. And dental follicles (χ2=9.413, P=0.009),overjet(χ2=8.985, P=0.011), overbite(χ2=9.836, P=0.007) and the distance between the cusp tip of canings and the occlusion plane(χ2=8.598, P=0.014) in PIC.Overbite is related to the severe root resorption.[Conclusion]The root resorption of incisors should be carefully screened in female and Class II patiens. The severe incisor root resorption was associated with Angle’s classification,overbite and dental follicles. Overbite is related to the severe root resorption. In BIC, the severe incisor root resorption has a correlation with Angle’s classification, deciduous canines and the central incisors. In PIC, the severe incisor root resorption has a correlation with dental follicles, overjet and overbite.The distance between the cusp tip of canings and the occlusion plane in PIC is high risk for moderate arid severe root resorption.