Summary of findings 7. Surgical drain versus no drain after the removal of mandibular wisdom teeth.

Drain versus no drain after the removal of mandibular wisdom teeth
Population: adults with mandibular third molars requiring removal Setting: oral surgery Intervention: drain (tube drain or gauze drain) Comparison: no drain
Outcomes	Illustrative comparative risks* (95% CI)		Relative effect (95% CI)	Number of participants (studies)	Certainty of the evidence (GRADE)
	Assumed risk	Corresponding risk
	No drain	Drain
Alveolar osteitis (up to 1‐week follow‐up)	Not reported
Wound infection (up to 1‐week follow‐up)	Not reported
Permanent altered tongue, chin, or lip sensation (more than 6 months)	Not reported
Adverse effects ‐ reactionary bleeding (up to 30 days)	Not reported
*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval
GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited; the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect.