More difficult wisdom tooth extraction leads to greater swelling and pain in the first two days
In 45 patients, the difficulty of extracting an impacted lower wisdom tooth and the duration of the procedure were independent predictors of swelling, which peaked on the second day.
Difficulty and duration predict swelling
A prospective observational study published in the Swiss Dental Journal followed 45 patients who underwent surgical extraction of an impacted lower third molar from September to December 2025. The difficulty of the procedure was assessed preoperatively using a modified Pedersen index (low, medium, high). Swelling was measured using standardised linear facial measurements before the procedure and on the second and seventh days, while pain was assessed using a visual analogue scale on the first, second, and seventh days.
The procedure lasted on average 28.4 ± 8.6 minutes and significantly increased with difficulty. Swelling was greatest on the second day and significantly reduced by the seventh day. The difficulty of the procedure correlated with swelling on the second day (r = 0.52) and with pain on the first (r = 0.46) and second days (r = 0.41). Longer procedure duration was also associated with greater swelling and pain in the early period.
In a multivariate model, both the difficulty of the procedure (β = 0.42) and duration (β = 0.31) remained independent predictors of swelling, indicating that a prolonged procedure carries additional risk even when considering the inherent difficulty of the tooth's position.
Limitations
The sample size is small (45 patients), and the study is observational and from a single centre, so it does not establish causation nor can the results be directly generalised to other surgeons and techniques. Funding information is not provided in the abstract.
For your practice
- Use the Pedersen index preoperatively for patient discussions: for high difficulty, anticipate greater swelling, especially on the second day.
- Plan analgesia and swelling control for the first two days, when pain and swelling are most pronounced.
- For difficult positions, consider planning a technique that shortens the procedure, as duration is a separate predictor of swelling.