Characteristics of impacted mandibular third molar-related lesions.

Objectives: This study identifies factors for differential diagnosis among lesions by retrospectively comparing panoramic and cone-beam computed tomography images and analyzing the characteristics of lesions associated with impacted mandibular third molars (IMTs).

Materials and methods: A retrospective cohort study was conducted in patients who simultaneously underwent IMT extraction surgery and related benign tumor resection or cyst enucleation at our institution from 2017 to 2021. To compare the characteristics of each group, two comparative analyses were conducted. The first comparison considered the most frequently observed lesions associated with IMTs: dentigerous cysts, odontogenic keratocysts (OKCs), and ameloblastoma. The second comparison involved placing dentigerous cysts, which have a relatively low recurrence rate, into group A and placing OKC, ameloblastoma, and odontogenic myxoma, which have high recurrence rates, into group B.

Results: Significant differences in the size of the lesion were found in the order of ameloblastoma, OKC, and dentigerous cyst (P <0.05). The buccolingual width of ameloblastoma differed significantly from that of the other groups, with no significant difference observed between the OKCs and dentigerous cysts (P=0.083).

Conclusion: Patient age and lesion size differed significantly among lesion types associated with IMTs, with younger age and larger lesions for OKCs and odontogenic tumors. OKCs are likely to have a larger mesiodistal width than dentigerous cysts. The buccolingual width of ameloblastomas was larger than those of dentigerous cysts and OKCs.