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Updated: Jan 9, 2026
Systematic Assessment of Mammalian Skull Specimens for Dental and Temporomandibular Joint Pathology
Published on: August 22, 2022
Prevalence and patterns of impacted third molars and their association with distal caries incidence in adjacent
Ahmed A Madfa1, Abdullah F Alshammari2, Basil B Alshammari3
1Department of Restorative Dental Science, College of Dentistry, University of Ha'il, Ha'il, Kingdom of Saudi Arabia. A.madfa@uoh.edu.sa.
Background:
Impacted third molars, particularly in the mandible, are commonly associated with complications such as pericoronitis, root resorption, and notably, distal caries in adjacent second molars. Despite this association, previous studies in Saudi Arabia have predominantly relied on two-dimensional imaging, which may underestimate diagnostic features. This study aimed to assess the prevalence and patterns of impacted third molars and their association with distal caries incidence in second molars using cone beam computed tomography (CBCT).
Methods:
A retrospective cross-sectional study was conducted from a leading dental center in Ha'il, Saudi Arabia, analysing 315 CBCT scans obtained between 2019 and 2024. The angulation, depth, and position of impacted third molars were classified using Winter's classification and the Pell and Gregory system. The presence of caries on adjacent second molars was recorded. Statistical analysis included Chi-square and Fisher's exact tests, with significance set at p ≤ 0.05.
Results:
Mesioangular impaction was most common in the mandibular arch, particularly among younger individuals (18-25 years). Class B and C impactions were prevalent in the lower molars, with deeper impactions more frequently observed in females and older individuals. Distal caries on mandibular second molars were significantly associated with mesioangular and horizontal impactions, particularly in the quadrant 4 CBCT imaging demonstrated a notable prevalence of distal caries, which appears higher than the rates reported in previous two-dimensional studies; however, direct intra-study comparison was not performed.
Conclusions:
Impacted mandibular third molars, especially those with mesioangular angulation and in deeper positions, pose a significant risk to adjacent second molars. While these findings highlight a potential role for early intervention, including prophylactic removal in selected high-risk cases, longitudinal and interventional studies are necessary to establish definitive clinical guidelines.
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