Kumar 2016.

Study characteristics
Methods	Study design: split‐mouth RCT Conducted in: India
Participants	Inclusion criteria: systemically healthy people between 18 to 50 years with bilaterally completely impacted mandibular third molars indicated for surgical removal Exclusion criteria: medical conditions that can complicate surgical extraction, obesity (body mass index ≥ 30 kg/m2), current smokers, pregnant or lactating females, those taking oral contraceptive drugs, and those under any antibiotic coverage Age: 18 to 50 years Participants: 30 participants/60 teeth
Interventions	Tube drainage versus no tube Control group (n = 30): primary closure was accomplished using 3‐0 silk suture Experimental group (n = 30): tube drain was sutured by a circumferential suture tethered with the buccal flap through the releasing incision
Outcomes	Pain scale: no pain‐slight pain‐mild‐severe‐very severe Swelling: mean of horizontal and vertical measurements Maximum interincisal opening in millimetres
Notes	Sample size calculation: reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "left and right mandibular quadrants of each individual were randomly allocated by means of a tossing coin into two groups, test (with tube drain, n=30) and control (without tube drain, n=30)" Comment: a coin‐tossing technique was used
Allocation concealment (selection bias)	Unclear risk	Comment: no concealment methods described
Blinding (performance bias and detection bias) patient	Unclear risk	Quote: "The eligible individuals were informed of the nature, possible risks, and benefits of their participation in the study and a written informed consent was obtained from each participant." Comment: it is unclear how much detail was given to participants, but it is likely that they would know which side a tube drain was placed as it was in situ for 3 days
Blinding (performance bias and detection bias) assessor	Unclear risk	Comment: blinding of the assessor not mentioned
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: no dropouts mentioned
Selective reporting (reporting bias)	Low risk	Comment: planned outcomes reported
Other bias	Unclear risk	Quote: "Following the complete resolution of post‐operative sequelae the second surgical procedure of other side with tube drain was carried out in the same patient." Comment: wash‐out period not specified. Any potential carry‐over effect was not analysed.