Comparison between panoramic radiography and CBCT imaging on the diagnosis of second molar external root resorption associated with an impacted mandibular third molar: two case reports Submit Manuscript | http://medcraveonline.com
IntroductionThird molar impaction is a usual condition found at the dental practice. Occasionally, it is necessary to remove the tooth in order to avoid other problems such as pericoronitis, swelling, odontogenic cysts or tumors, bone loss and external root resorption (ERR) of the adjacent second molar.1 However, the decision of extracting or maintaining a third molar is controversial.2 If an impacted third molar is not extracted after a certain stage of its formation, it may contribute to second molar ERR.1 According to Tsesis et al. 3 ERR is a pathological process that occurs at the permanent tooth outer surface and it may be induced by pulpal infection or periodontal inflammation related causes, or pressure associated with orthodontic movements, impacted tooth or pathoses. Periapical and panoramic radiographies (PR) are the standard imaging modalities for determining third molar characteristics. These imaging exams are readily available and dental professionals are acquainted with images interpretation. However, they are two-dimensional images, thus impairing a more detailed analysis of the region. Additionally, panoramic radiographies (PR) present a certain degree of distortion. 4 The limitation generated by the absence of a third dimension resulted in methods that do not inform precisely the actual location of the third molar, its anatomy or its relationship with adjacent structures. 4 Cone beam computed tomography (CBCT) imaging allows a tridimensional evaluation of teeth and their adjacent anatomical structures, 4 resulting in a detailed visualization of the third molar as well as its neighboring structures, and subsequently, a meticulous diagnosis of ERR. CBCT is widely recommended for third molar surgical removal planning. 4 Among the advantages of this imaging modality, some authors mention spatial resolution, multiplanar reconstruction simultaneous analyses and structures superimposition avoidance.5 Hence, the aim of this study was to report two cases of mandibular impacted third molar associated with second molar external root resorption, comparing panoramic radiography and CBCT imaging.
Case reportsCase 1: A 24 year-old Caucasian male patient was submitted to a follow-up PR nine months after the extraction of tooth 38. The radiologist observed a severely inclined, mesialized and impacted 48. Its roots were contiguous to the mandibular canal roof and it was possible to recognize a severe dilaceration at the mesial root apex. Tooth 47 was endodontically treated and an overlap was noted between 48 crown and dental follicle, and 47 distal root ( Figure 1A). Tooth 48 was recommended for extraction and a CBCT was requested for planning the surgical intervention. The patient was submitted to a CBCT exam with the following characteristics: field of view (FOV) 5.0 cm by 5.5 cm, v...