Chukwuneke 2008.

Study characteristics
Methods	Study design: parallel‐group, single‐blind RCT Conducted in: oral surgery department of University of Nigeria Teaching Hospital, Enugu, Nigeria
Participants	Inclusion criteria: patients who were willing to come for their follow‐up appointments, who were free from pain or any other inflammatory symptoms (swelling, hyperaemia, TMD), had impacted lower wisdom teeth, were not on medication that could interfere with healing, and did not smoke or have any systemic disease Exclusion criteria: pregnant or lactating females were excluded from the study Number randomised: 100 Number evaluated: 100
Interventions	Rubber tube (Penrose) drain versus no drain Group A (n = 50): sutures plus Penrose rubber drain placement for 72 h Group B (n = 50): sutures only postoperatively All participants received 2 g amoxicillin preoperatively, and procedures were performed under local anaesthesia. Follow‐up: 24 h, 72 h, and 5 days
Outcomes	Pain (0‐to‐10 VAS), swelling (horizontal and vertical guide with tape and reference points), and trismus (interincisal callipers). Evaluated at 24 h, 72 h, and 5 days postoperatively
Notes	Sample size calculation: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "...a prospective, randomised, single‐blind experimental study was undertaken" Comment: method of sequence generation not described
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding (performance bias and detection bias) patient	High risk	Participants could not have been blinded to the treatment group they were in, as they would have been aware of the presence of the Penrose rubber drain in their mouths. This is evidenced in the photographs.
Blinding (performance bias and detection bias) assessor	Unclear risk	There is no mention of assessor blinding other than "a prospective, randomised, single‐blind experimental study was undertaken". However, it is not clear to whom this single‐blinding refers.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No withdrawals
Selective reporting (reporting bias)	Low risk	All planned outcomes reported on.
Other bias	Unclear risk	The study accepted all impactions, but there was no report of measures to account for possible differing degrees of difficulty with the extractions. Whilst appropriate randomisation should result in groups with similar proportions of high‐risk patients, no baseline characteristics were reported in this trial. It is unclear whether these biases were avoided.