The Study Of Maxillary Canine Impaction And Root Resorption Of Adjacent In Three-dimensional Space

Objective To localize impacted maxillary canine and to observe the root resorption ofadjacent incisor in3dimensions using cone beam computed tomography (CBCT).Methods Sixty-three patients of impacted maxillary canines were scanned by CBCT.The three-dimensional images of impacted maxillary canines were obtained by multiplanarreconstructions (MPR) to observe the location of impacted canines. The cusp tip of eachimpacted canine was located and in digitized Dolphin3D imaging and to set the X，Y，Zplanes, after viewing sagittal, coronal,and axial views. While observing the extent resorptionimpacted maxillary canine of adjacent incisor root.Results1. The mesial-palatal canine impactions account for56.94%(n=41) of the totaland mesial-labial canine impactions account for33.33%(n=24) of the total. In the sagittalview, measure distance impacted maxillary canines from the X plane is25.20～40.30mm, theaverage distance was32.40mm;In the coronal view,90.28%(n=65) were mesial impactions, toY-plane distance was7.50to13.60mm, the average degree was10.80mm,9.72%(n=7) weredistal impactions, to Y-plane distance was10.40to15.10mm, The average distance was12.40mm; In the axial view,61.11%(n=44) were palatal impactions, to Z-plane distance was4.60to10.9mm, the average distance was8.90mm;38.89%(n=28) were buccal impactions, toZ-plane distance was3.50to11.80mm, the average distance was9.70mm.2. Compared with the first and the second measurement of impacted maxillary caninesshow that no statistically significant difference.3. The percentage of lateral incisors resorption34.7%was higher than that of centralincisors resorption19.4%, and there was statistically significance (χ2=4.26, p<0.05). The extents of incisor resorption were mainly mild resorption and moderate resorption, mildresorption accounted for53.8%(n=21) and moderate resorption counted for35.9%(n=14).4. The adjacent incisors of mesial canines root resorption rate is60%much higher thandistal, root resorption rate difference was statistically significant(χ2=9.16，P=0.002，P＜0.05).The adjacent incisors of labial canines root resorption rate of32%, and adjacent incisors ofpalate canines t root resorption rate of68%, the difference between the rates of root resorption(χ2=8.95，P=0.03，P＜0.05).Conclusion1. The most frequent location of impacted canines was mesial, palatal.2. Using cone beam computed tomography in three-dimensional space to evaluate theposition of canines is reliability and repeatability.3. Adjacent incisors root resorption of maxillary canines commonly found in the lateralincisor and primarily mild and moderate absorption.4. The type of mesial, palatal canines’ easier cause root resorption of adjacent incisors.