Briguglio 2011.

Study characteristics
Methods	Study design: parallel‐group RCT Conducted in: Brazil (but researchers based in Italy)
Participants	Inclusion criteria: patients between the ages of 18 and 41 requiring extraction of mandibular third molars. Those with moderate impaction mesio‐angularly with a tilt degree more than 25° in relation to the second molar. Only impacted third molars with distil periodontal defects at the second molar with PPD ≥ 7 mm and CAL ≥ 6 mm were selected. Exclusion criteria: systemic disease, pregnancy, smoking, and medication (unspecified) Age: 18 to 45 years Number randomised: 45 Number evaluated: 45
Interventions	Laskin triangular flap versus Thibault and Parant modified envelope flap versus Laskin envelope flap Group A (n = 15): Laskin triangular flap Group B (n = 15): Thibault and Parant modified envelope flap Group C (n = 15): Laskin envelope flap All participants had a preoperative dental hygiene check, and procedures were performed under local anaesthetic. All participants given 1 g amoxicillin + sulbactam preoperation, and all used CHX mouthwash pre‐ and postoperation.
Outcomes	Short‐term complications (pain swelling and infection) and PPD and CAL at 3, 6, 12, and 24 months
Notes	Sample size calculation: not reported Gaetano Isola provided additional data on short‐term complications by e‐mail 7 March 2012.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: whilst the technique used in each case was randomly selected, the authors do not specify any further details on this allocation process
Allocation concealment (selection bias)	Unclear risk	Comment: no details of the allocation concealment provided
Blinding (performance bias and detection bias) patient	Unclear risk	Quote: "A clot of PRF, which was produced in a 10 ml tube, was enough to fill the socket of each patient." Comment: it is unclear if all participants had blood samples taken, or whether samples were only taken from participants in the PRF group. This could be a source of bias.
Blinding (performance bias and detection bias) assessor	Low risk	Quote: "all measurements were assessed by the same person (not the operating surgeon)" Comment: the assessor was blind to the allocations
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: all randomised participants were included until the end of the study
Selective reporting (reporting bias)	Low risk	All planned outcomes were reported on.
Other bias	High risk	Comment: some participants had unilateral extractions, whilst others had bilateral extractions. This could have influenced outcomes such as pain perception and trismus.