Leknes 2005.

Methods	RCT, split‐mouth design, 2 treatment groups, 72 months' duration
Participants	20 individuals, 10 females, mean age 38.4 years, with 2 Miller Class I or II buccal gingival recessions of at least 3 mm. 11 individuals completed the study
Interventions	1. GTR (polylactic acid membrane ‐ Guidor) 2. CAF
Outcomes	GRC CALC KTC SCRC PCRC MRC (Automated controlled force probe and manual probe)
Notes	University/hospital‐based and membranes provided by Guidor AB Unpublished data were included following contact with author Data from earlier article (Amarante 2000) were reported as part of this trial
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Coin toss
Allocation concealment (selection bias)	Unclear risk	Method not reported
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Information not reported
Blinding of outcome assessment (detection bias) All outcomes	Low risk	All measurements were performed by 1 examiner not aware of the type of surgical procedure
Incomplete outcome data (attrition bias) All outcomes	Low risk	11 out of 20 subjects were available for the final evaluation (6 subjects rejected to complete the study and 3 moved to other part of Norway) Data are equally missing in both intervention groups (split‐mouth design), but reasons for these are both reported and balanced across groups, then important bias is not expected
Selective reporting (reporting bias)	Low risk	Evidence of selective reporting of outcomes was not detected
Other bias	Low risk	Evidence of other was not detected