Research Article Radiographic Position of Impacted Mandibular Third Molars and Their Association with Pathological Conditions Zahra Haddad, 1 Mansour Khorasani, 2 Mahin Bakhshi , 3 Maryam Tofangchiha , 4 and Zeynab shalli 5 1 Dental Faculty, Qazvin University of Medical Sciences, Qazvin, Iran 2 Department of Oral & Maxillofacial Surgery. Dental Faculty, Tehran University of Medical Sciences, Tehran, Iran 3 Department of Oral Medicine, Dental Faculty, Shahid Beheshti University of Medical Sciences, Tehran, Iran 4 Department of Oral and Maxillofacial Radiology, Dental Caries Prevention Research Center, Qazvin University of Medical Sciences, Qazvin, Iran 5 Department of Orthodontics, Dental Faculty, Qazvin University of Medical Sciences, Qazvin, Iran Correspondence should be addressed to Maryam Tofangchiha; mtofangchiha@qums.ac.ir Received 2 August 2020; Revised 13 December 2020; Accepted 28 February 2021; Published 24 March 2021 Academic Editor: Boonlert Kukiattrakoon Copyright©2021ZahraHaddadetal.isisanopenaccessarticledistributedundertheCreativeCommonsAttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Objectives. is study aimed to assess the radiographic position of impacted mandibular third molars (IMTMs) and their as- sociation with pathological conditions. MaterialsandMethods. e impaction depth, relationship with ramus, and angulation of 1600 IMTMs and their association with 2 nd molar distal caries and root resorption, pathological conditions, and proximity to the mandibular canal were evaluated on panoramic radiographs. e IMTM position was determined based on the depth of im- paction according to the Pell and Gregory classification, relationship with ramus according to the Pell and Gregory classification, and angulation according to the Winter’s classification. e classical and Bayesian logistic regressions were applied to analyze the effect of IMTM position on the associated complications using the odds ratio (OR) and 95% confidence interval (credible interval for Bayesian models). Two-tailed P value < 0.05 was considered statistically significant. Results. Of 1600 IMTMs evaluated in this study, 195 (12.2%), 252 (15.8%), and 119 (7.4%) had caused second molar distal caries, secondmolar root resorption, and pathological lesions, respectively, and 872 (54.5%) had contact with the mandibular canal. Impaction angulation was a risk factor for second molar distal caries (maximum OR � 5.01, 95% CI: 3.12–8.18). Changed angulation and greater impaction depth were the risk factors for second molar root resorption (minimum OR � 1.64, 95% CI: 0.58–4.02). Decreased distance between the ramus and distal side of the second molar was a risk factor for associated pathological lesions (minimum OR � 2.73, 95% CI: 1.79–4.25). Mesioangular and horizontal angulations and greater impaction depth were the risk factors for contact with the mandibular canal (maximum OR � 3.44, 95% CI: 2.6–4.57 and minimum OR � 1.3, 95% CI: 094–1.8). Conclusions. e frequency of complications associated with IMTMs was low, but considerable. e occurrence of these conditions might be affected by the impaction position. us, regular follow-ups are recommended in order to be able to surgically intervene when the first signs of pathologies arise. 1. Introduction Mandibular third molars are the most commonly impacted teeth, which are usually impacted due to different reasons. e two major causes of impaction include (I) failure of tooth rotation from the horizontal to mesioangular and vertical position and (II) space shortage for eruption [1]. Impacted mandibular third molars (IMTMs) can cause various pathological complications such as pericoronitis, periodontal disease, distal caries, bone loss, root resorption of the adjacent teeth, odontogenic cysts and tumors, jaw fractures, and infections [1–13]. ird molar surgery is among the most common surgical procedures worldwide. is surgical procedure may be in- dicated for the following purposes: (I) to treat the symp- tomatic pathologies related to impaction, (II) to prevent future pathological conditions, or (III) for non-pathological reasons, e.g., prior to orthognathic surgery, orthodontic Hindawi International Journal of Dentistry Volume 2021, Article ID 8841297, 11 pages https://doi.org/10.1155/2021/8841297