ORIGINAL PAPER
Assessment of impacted mandibular third molars and inferior alveolar canal contact: correlation with classification systems on cone-beam computed tomography
1
Faculty of Dentistry, Department of Oral and Maxillofacial Radiology, Istanbul University, Istanbul, Turkey
2
Faculty of Dentistry, Department of Oral and Maxillofacial Surgery, Istanbul University, Istanbul, Turkey
Submission date: 2026-02-06
Final revision date: 2026-03-16
Acceptance date: 2026-03-17
Publication date: 2026-09-17
Corresponding author
Sedef Ayşe Taşyapan
Faculty of Dentistry, Department of Oral and Maxillofacial Radiology, Istanbul University, Prof. Dr. Cavit Orhan Tütengil Sk. No: 4, Fatih, Istanbul, Turkey
Faculty of Dentistry, Department of Oral and Maxillofacial Radiology, Istanbul University, Prof. Dr. Cavit Orhan Tütengil Sk. No: 4, Fatih, Istanbul, Turkey
Pol J Radiol, 2026; 91(1): 444-454
KEYWORDS
TOPICS
ABSTRACT
Purpose:
This study analyzed the distribution patterns of impacted mandibular third molars (IMTMs) using the Winter and Pell & Gregory classification systems, which guide surgical planning and complication risk assessment. Additionally, the spatial relationship between IMTMs and the inferior alveolar canal (IAC) was evaluated with cone-beam computed tomography (CBCT) to enhance preoperative risk stratification.
Material and methods:
A total of 1594 IMTMs were retrospectively reviewed in patients with available panoramic and CBCT imaging. Angulation was classified according to Winter, while depth and ramus relation were categorized using Pell & Gregory. CBCT was used to assess IAC relationships. Associations between classifications and IAC contact were analyzed, and logistic regression identified independent risk factors.
Results:
Mesioangular impaction was most frequent (37.6%), and Class II Level B was the predominant Pell & Gregory type (29.6%). CBCT showed IAC contact in 83.5% of cases, most commonly superior and buccal. Logistic regression revealed horizontal impactions had significantly lower odds of contact (OR=0.57, p=0.005), while deep types such as Class III Level C strongly predicted contact (OR=10.22, p<0.001). A “between roots” IAC configuration, undetectable on panoramic radiographs, was noted in 7.5%.
Conclusions:
While Winter classification offers moderate predictive value, Pell & Gregory-particularly deeper and more posterior subtypes-correlates strongly with IAC involvement. Findings highlight the value of CBCT in high-risk IMTM cases to improve radiographic assessment of the canal–root relationship and surgical planning.
This study analyzed the distribution patterns of impacted mandibular third molars (IMTMs) using the Winter and Pell & Gregory classification systems, which guide surgical planning and complication risk assessment. Additionally, the spatial relationship between IMTMs and the inferior alveolar canal (IAC) was evaluated with cone-beam computed tomography (CBCT) to enhance preoperative risk stratification.
Material and methods:
A total of 1594 IMTMs were retrospectively reviewed in patients with available panoramic and CBCT imaging. Angulation was classified according to Winter, while depth and ramus relation were categorized using Pell & Gregory. CBCT was used to assess IAC relationships. Associations between classifications and IAC contact were analyzed, and logistic regression identified independent risk factors.
Results:
Mesioangular impaction was most frequent (37.6%), and Class II Level B was the predominant Pell & Gregory type (29.6%). CBCT showed IAC contact in 83.5% of cases, most commonly superior and buccal. Logistic regression revealed horizontal impactions had significantly lower odds of contact (OR=0.57, p=0.005), while deep types such as Class III Level C strongly predicted contact (OR=10.22, p<0.001). A “between roots” IAC configuration, undetectable on panoramic radiographs, was noted in 7.5%.
Conclusions:
While Winter classification offers moderate predictive value, Pell & Gregory-particularly deeper and more posterior subtypes-correlates strongly with IAC involvement. Findings highlight the value of CBCT in high-risk IMTM cases to improve radiographic assessment of the canal–root relationship and surgical planning.
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