Associations between aging and second molar diseases in patients having adjacent impacted third molar extraction

There is limited evidence available regarding when the best time to extract impacted lower third molars (iLM3). Thus, the current study is aimed to examine the association between the age of patients during the time of extraction of their iLM3 and the sequelae of their adjacent second molar (LM2) in order to find a better time to remove iLM3. Retrospective cohort study was conducted with a total of 15,432 patients from ages 16–45 years old who had their first surgical extraction of iLM3. Statistical analysis was performed to evaluate variables in association with the sequalae of LM2. Adjusted odds ratios (AOR) were calculated to show the influence of the age of patients by multivariate regression model. Patients who had iLM3 extraction over 22 years of age had a significantly higher risk of having LM2 pulpal disease (AOR: from 2.84 in 23–25 age to 11.58 in >35 age). Significantly higher risk of having LM2 periodontal conditions was found in individuals over 31 years of age (AOR: 1.47 in 31–35 age, 1.90 in >35 age), with prior periodontitis (AOR: 1.97) or complicated odontectomy (AOR: 1.43). The risk of LM2 being extracted due to an untreatable condition was highest in patients more than 35 years old (AOR: 14.38). The age of patients having iLM3 extracted was independently associated with various LM2 sequelae. We suggest that patients can have their iLM3 extracted in their college/university age (19–22-year-old) to minimize complications on the adjacent LM2.