Are There Differences in the Causes and Complications of Mandibular Third Molar Extraction in Older Patients Compared to Younger Patients?

Background: Although most impacted third molars (ITMs) are extracted in the teens and early 20s, some undergo extractions after their 40s. It is unclear whether the reasons for extraction, the degree of impaction, and complications differ in patients in an older age group compared with a younger age group. Purpose: The purpose of this study was to measure the association between age and 1) reason for extraction and 2) postoperative complications. Study Design, Setting, Sample: This was a retrospective cohort study of patients who had undergone surgical extraction of at least one mandibular ITM at a single institution. We excluded 1) age under 20 years, 2) follow-up period of less than 1 week, and 3) tooth extraction under general anesthesia. Predictor Variable: The primary predictor variable was age, classified into 3 groups (20s:20-29; 30s:30-39; over 40s: 40 and greater). Main Outcome Variable(s): The primary outcome variables were the reason for extraction (prophylactic or symptomatic) and the presence of complications. The secondary outcome variable was type of complication (postoperative infection, dry socket, neurosensory disturbance, presenting pain over 1 month, retained root requiring secondary treatment). Covariates: The covariates were sex, laterality of ITM, and difficulty of extraction as measured by the difficulty index, a measure based on depth, orientation, and ramus relationship/space available, with a higher score indicating greater difficulty. Analyses: chi(2) test was performed to analyze the association of categorical outcome variables and covariates. Level of statistical significance was set at P < .05. Results: Of a total of 831 eligible subjects, there were 555 (66.8%), 159 (19.1%), and 117 (14.1%) in the 20s, 30s, and over 40s age groups, respectively. The percentage of symptomatic extraction of ITM was significantly higher in the over-40 age group compared with the 20s group (92.3 vs 69.4%, (P < .001). Complication rate also significantly differed between over 40s group and the 20s group (7.7 vs 1.8%, P < .001). Difficulty index and indications for ITM extraction were significantly different between groups (P < .001). Conclusion and Relevance: Symptoms, difficulty, and complications related to ITM increase at over 40 years of age. This should be taken into consideration during the joint clinical decision-making process with patients with ITM.