Refo'a 2011.

Study characteristics
Methods	Study design: parallel‐group RCT Conducted in: Tehran, Iran Number of centres: 1 Recruitment period: not stated
Participants	Inclusion criteria: patients aged 20 to 25 years with wholly bone‐impacted mandibular third molar with mesioangular inclination and willing to participate in study Exclusion criteria: systemic medical conditions, smoking, inflammation in the oral cavity, history of drug use Number randomised: 32 Number evaluated: unclear
Interventions	Primary versus secondary wound closure Group A (n = 16): triangular flap was raised, teeth were extracted and following saline irrigation flaps were repositioned and sutured completely using 0.5‐inch round cutting needle with 3.0 silk suture Group B (n = 16): triangular flap was raised, teeth were extracted and following saline irrigation flaps were repositioned and 5 to 6 mm of distil extension to second molars was kept open, while other parts of the flap were repositioned and sutured All surgical procedures were performed by the same surgeon under local anaesthetic. All participants received amoxicillin and ibuprofen and used CHX mouth rinse twice daily postoperatively.
Outcomes	Pain VAS (0 to 5), swelling, and trismus after 3 days
Notes	No sample size calculation reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quotes: "...randomly divided into two quantitatively equal groups using a computer generated random number table…. The groups were equalised regarding gender"
Allocation concealment (selection bias)	Low risk	The surgeon was unaware of the type of closure until suturing.
Blinding (performance bias and detection bias) patient	Unclear risk	Not specifically mentioned
Blinding (performance bias and detection bias) assessor	High risk	Blinding of outcome assessment not mentioned. Participants self assessed pain, and it is unclear if lack of blinding would have introduced a risk of bias.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Numbers of participants included in the outcome evaluation not stated.
Selective reporting (reporting bias)	High risk	Pain, swelling, and trismus were planned outcomes in the methods section. Data for swelling and trismus not reported, only graph without estimates of variance and P values for difference.
Other bias	Low risk	No other sources of bias identified.