Use of Panoramic Radiographs in Localization of Maxillary Impacted Canines

Statement of Problem: In spite of low prevalence of maxillary canine impaction in population (1%-3%), its occurrence in orthodontic patients is nearly high sometimes reaching 23.5%. The exact determination of impacted canine location is of high importance for better access as well as correct force application. The purpose of this study was to determine the impacted maxillary canines location by orthopantomograph using Chaushu’s method in comparison with their real location which were determined by surgical exposure of the teeth. Sixty eight panoramic radiographs of patients with either unilateral or bilateral maxillary canine impaction were evaluated using Chaushu’s method. The available selected patients (14 males, 54 females) were treated orthodontically by force eruption of canines after surgical exposure. The mean age of the patients was 17 years. The largest mesiodistal width of 82 impacted canines as well as central incisors of the same side and also the contralateral side erupted canines were measured and evaluated using Chanchu’s technique for determining canine-incisor and canine-canine indexes (CII, CCI). Also these ratios were evaluated and compared for different horizontal and vertical positions of impacted canines. The mean of CII for palatally and bucally impacted canines were found to be 1.17 and 1.07 respectively which was statistically significant. Considering their vertical positions, it was revealed that CII was valid only in coronally positioned situation. In case of unilateral impaction, the CCI did not show to be statistically significant for buccal or palatal side. Evaluating the relation of impacted canine crown to the lateral incisor’s root, it was found that the palatally impacted canines were located more mesially than bucally impacted ones. Although panoramic radiography could show the buccal or palatal position of the impacted canines in coronally impaction situations, but due to the effect of their vertical position and also maxillary apical form on the radiographic magnification, use of other complementary radiographs for exact determination of impacted canine location seems to be necessary.