Rosamma Joseph 2012.

Methods	Trial design: randomised, split‐mouth trial Location: Department of Periodontics, Government Dental College, Kozhikode, Kerala, India Number of centres: 1 Recruitment period: September 2009 to October 2010 Source of funding: not stated Ethical approval: Institutional Ethics Committee, Government Dental College, Kozhikode, in accordance with the Helsinki Declaration of 1975 as revised in 2000 Number of surgeons: 1
Participants	Inclusion criteria: patients had paired, contralateral interproximal infrabony defect with a probing PD > 6 mm, CAL loss > 5 mm, and an osseous defect depth estimated from radiographic evaluation as > 4 mm; were systemically healthy without a history of allergies; and had at least 2 mm of keratinized gingiva on the facial aspect of the selected tooth Exclusion criteria: haematological or immunological disorders; pregnancy or lactation; smoking or the use of other tobacco products; those taking drugs known to interfere with wound healing; had used antibiotics within the previous 1 year; had been treated for periodontitis during the previous 2 years; those with unacceptable oral hygiene (PI) after the re‐evaluation of phase I therapy; were not willing to sign an informed consent Age at baseline: mean = 29.47 + 7.65 years (range 17 to 44 years) Gender: F 9/M 6 Smokers: excluded Teeth treated: not reported Number randomised (participants/teeth): 15/30 Number evaluated (participants/teeth): 15/30
Interventions	Comparison: OFD + PRFm versus OFD alone Test group: OFD + PRFm (n = 15/15) Control group: OFD alone (n = 15/15) Surgical technique: test group was treated by placement of platelet‐rich fibrin matrix following OFD and control group was treated by OFD alone Follow‐up duration: 1 year
Outcomes	Clinical: PD, recession/enlargement, CAL, PI, modified GI Radiographic: the vertical dimension between the projection of the bone crest on the root surface (BCP) and the most coronal level along the root surface where the periodontal ligament space was considered to have a normal width (BoBD‐base of bone defect) was measured and designated as infrabony defect depth (IBD = BCP ‐ BoBD). The distance from the crest of remaining alveolar bone to CEJ was also recorded (CEJ‐BC) Other: a visual analogue scale (VAS1) was used to assess the patient experience with the 2 treatment modalities. Another visual analogue scale (VAS2) was designed and used to assess the initial soft tissue healing
Notes	Sample size calculation: reported Radiographs were taken with a bite block for ensuring reproducibility Comparability at baseline: yes, assessed Complications reported: yes Dropouts: reported, no dropouts
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Either right sided or maxillary defects were operated first and whether the site belonged to experimental or control group was determined by a simple lottery method by the toss of a coin" Comment: random sequence generation done correctly
Allocation concealment (selection bias)	Low risk	Quote: "The sites were divided into experimental and control groups at the time of periodontal surgery. Either right sided or maxillary defects were operated first and whether the site belonged to experimental or control group was determined by a simple lottery method by the toss of a coin" Comment: allocation concealment likely to have been done correctly
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	It is stated that the operator was blinded but no further information is provided on the exact method in which it was done
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "All radiographs were evaluated by a single examiner (RJ) who was masked to the treatment group to which a patient was assigned and also to whether the radiograph was taken at baseline or re‐evaluation" Comment: blinding of outcome assessment done correctly
Incomplete outcome data (attrition bias) All outcomes	Low risk	All enrolled patients completed the study
Selective reporting (reporting bias)	Low risk	All outcomes properly reported