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Operation time is independent associated with serious postoperative symptom in patients with mandibular third molar removal.

BACKGROUND
To investigate the association between operation time and serious postoperative symptom severity (PoSS) in patients following the surgical removal of mandibular third molar (M3M), independent of the degree of impaction.


METHODS
A retrospective hospital-based observational study was carried out at the Stomatology Hospital of Tianjin Medical University. The operation time was recorded and divided by quartiles (Q1-Q4). The primary outcome was PoSS. Clinical, demographic and radiologic variables were also recorded. A descriptive bivariate analysis was performed. Associations were analyzed using the adjusted multivariate logistic regression. The association between time and impaction status was also tested. Potential nonlinear associations were evaluated with the restricted cubic spline. P values of <0.05 were considered as statistically significant.


RESULTS
A total of 321 patients met our inclusion criteria (114 men and 207 women). The mean operation time was 16.0 minutes (range, 1.1 to 40.5 minutes). The odds ratio (OR) and 95% confidence interval (CI) were determined after multivariate adjustments for the risk of serious PoSS per 5-min incremental increase in operation time (OR 1.201, 95% CI, 1.005-1.434). The multivariable-adjusted ORs (95% CI) of PoSS across the categories of operation time were as follows: 1.00 (reference), 1.765 (0.770-4.045), 2.567 (1.047- 6.293), and 3.085 (1.180-8.064) (P for trend =0.027). The test of interaction effect was not significant (all P for interaction >0.05). No evidence of a nonlinear association was observed (P for nonlinearity=0.117).


CONCLUSIONS
Operation time was significantly and positively associated with a high risk of serious PoSS independent of impaction status in patients who underwent the surgical removal of M3M.