Age-related differences in Mandibular third molars: Radiographic analysis of pathological conditions and impaction status

Objective: Although it is known that asymptomatic third molars rarely remain disease-free, few studies have examined the condition of the mandibular third molars in older individuals. This study aimed to examine the prevalence of erupted and impacted mandibular third molars according to age, along with the prevalence of associated pathological conditions, including dental caries and radiographically assessed periodontal bone loss. Methods: This retrospective study enrolled 2950 patients who visited our clinic for reasons other than extraction of mandibular third molars between June 2016 and March 2023. Clinical data (age, sex, impaction status, caries in the third molar and adjacent second molar, and periodontal bone loss of the adjacent second molar) and findings from panoramic radiographs were retrospectively analyzed. Results: Of the 5900 mandibular third molars, 2288 mandibular third molars were retained. Of these, 1311 sides (22.2%) had findings suggestive of caries or periodontal bone loss of the mandibular third molar. In patients aged 60 years or older, 465 mandibular third molars remained, accounting for 20.7% of the total 2246 mandibular third molars, and 224 (10.0%) mandibular third molars had erupted vertically and were functional. Furthermore, 169 (7.5%) mandibular third molars were impacted without caries or periodontal bone loss. Conclusions: The number of non-pathological impacted third molars was very low after the age of 60 years. Because impacted non-functioning third molars will likely need extraction at some point in life, it is preferable to do so at a time when extraction is less difficult and less likely to cause complications.