## 4 Discussion  
Root resorption associated with an impacted maxillary canine can rapidly progress to threaten the vitality of the affected tooth. Hence, it is clinically important to diagnose and treat the condition as soon as it is noticed. Previously, the first study employing two-dimensional radiographic techniques noticed a prevalence of only 12% root resorption due to impacted canines [24]. Buccal and palatal canine impactions were more difficult and less reliable to diagnose with conventional two-dimensional techniques [25]. With the advancement in three-dimensional imaging like CBCT, more reliable information can be obtained than conventional methods. When directly comparing two- and three-dimensional imaging techniques on the same patients, [PERSON] et al. found more precise, detailed, and accurate management of an impacted canine with three-dimensional CBCT imaging [26]. CBCT is a low-cost and low radiation dose alternative to conventional computed tomography (CT), which has also been used to detect root resorption. Owing to its maximum spatial resolution, CBCT allows for the detection of root resorption of as low as 300-500 \(\upmu\)m [27]. Moreover, the high image quality of CBCT scan sets permits finer detection of root resorption than CT images [28]. Such is the superiority and convenience of CBCT that it has now become the imaging modality of choice for detecting root resorption associated with an impacted maxillary canine. CBCT being used more routinely in standard orthodontic care has invariably led to an increase in root resorption detection and prevalence rates in various populations. In this study of the Saudi population, at 74.3%, the lateral incisors were the most affected teeth with root resorption, followed by central incisors at 17.4%, first premolars at 7.3%, and first permanent molars at 0.9%. The findings of this study are in accordance with the results of other studies that have reported lateral incisors as the most affected tooth with root resorption associated with maxillary canine impaction [10,14,29]. A recent systematic review and meta-analysis conducted by [PERSON] et al. found a high prevalence of root resorption in the lateral incisor associated with contact with an impacted maxillary canine [19]. They reported that around 8.20%-89.61% lateral incisors, 1.19%-35.06% central incisors, and 4.48%-11.72% premolars were affected by root resorption associated with an impacted maxillary canine. This maximum incidence of root resorption is seen in lateral incisors that come into contact with the crown of the impacted canine. The physical pressure from the erupting canine can lead to activation of tooth-resorbing cells, odontoclasts, leading to the loss of cementum or dentine from the tooth surface, causing root resorption [13]. Nevertheless, resorption can occur in the central incisor, premolar, or even molar, depending on the immediate vicinity of the impacted canine [30]. Interestingly, no association has been found between the proximity or size of the dental follicle of the erupting maxillary canine with root resorption [6]. Root resorption can affect any level and surface of the tooth depending on the displacement of the maxillary canine. In this study, the apical one-third (63.2%) was the most involved level of root resorption, followed by the apical and middle one-third (12%). The least amount of root resorption was present in the aspect involving all three root levels, i.e., the apical, middle, and cervical one-third (3.2%). These findings agree with many other studies, including a recent systematic review and meta-analysis that reported that root resorption occurs most commonly in the apical one-third of the tooth associated with an impacted maxillary canine [19]. Clinically, the root resorption in the apical one-third region destroys less dentine than the middle or cervical region. Hence, the level of resorption can aid in accurate diagnosis and prove to be a prognostic factor for treating resorptions.