Patel 2013.

Study characteristics
Methods	Trial design: randomised, parallel‐group trial Location: London, UK Number of centres: single centre, Clinical Investigation Centre, UCL Eastman Dental Institute, London, UK Recruitment period: 2006 to 2008 Funding source: the study was supported by a grant from the Institut Straumann AG, Basel, Switzerland
Participants	Inclusion criteria: age between 18 and 75 years; good general health; the presence of a hopeless tooth in the mandibular or the maxillary incisor, canine, or premolar region requiring extraction and would be suitable for replacement by a dental implant; the tooth to be extracted has at least 1 neighbouring tooth; the subject had voluntarily signed the informed consent Exclusion criteria: pregnancy or lactating period; chronic treatment with any medication known to affect oral status and bone turnover or contraindicate surgical treatment within 1 month of baseline visit; concomitant anticoagulant therapy; any known diseases (not including controlled diabetes mellitus); infections or recent surgical procedures within 30 days of study initiation; HIV or hepatitis; administration of any other investigational drug within 30 days of study initiation; limited mental capacity or language skills or suffering from a known psychological disorder; heavy smoking (> 10 cigarettes per day); uncontrolled or untreated periodontal disease; full‐mouth plaque level (FMPL) > 30% at the enrolment visit; severe bruxism; acute endodontic lesion in the test tooth or in the neighbouring areas; major part of the buccal or palatal osseous wall damaged or lost following tooth extraction Age at baseline: mean age 37.3 ± 11.4 years (20 to 58) Gender: M 6/F 21 Smokers: 3 Teeth extracted: non‐molar sites Number randomised (participants/sites): 30/30 Number evaluated (participants/sites): 25/25 (radiographic evaluation 24/24)
Interventions	Comparison: ARP (grafting material) versus ARP (grafting material) Test group: (n = 13 extraction sockets) synthetic bone substitute‐Straumann bone ceramic (SBC) (Straumann AG, Basel, Switzerland, granule size 400 μm to 1000 μm) + collagen barrier (Bio‐Gide, Geistlich, Basel, Switzerland) Control group: (n = 12 extraction sockets) deproteinised bovine bone mineral (DBBM) (Bio‐Oss, Geistlich Pharma AG, Basel, Switzerland) + collagen barrier (Bio‐Gide, Geistlich Pharma AG, Basel, Switzerland) Surgical technique: flap, no primary closure Type of socket: 4‐wall socket Duration of follow‐up: 8 months at implant placement (Mardas 2010); 12 months post‐loading (Patel 2013)
Outcomes	Width and height of alveolar ridge, probing pocket depth, gingival recession, implant survival, need for additional augmentation prior to implant placement Method of assessment: periodontal probe, standardised radiograph
Notes	Sample size calculation: reported The sample size was calculated based on previous literature and assumed difference in observed radiographic bone changes of 1 mm and standard deviation of 0.05 mm
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "The subjects were randomly assigned to the test or the control group by a computer‐generated table. A balanced randomly permuted block approach was used to prepare the randomisation tables in order to avoid unequal balance between the two treatments"
Allocation concealment (selection bias)	Unclear risk	It is not clear whether the randomised codes were enclosed in sequentially numbered, identical, opaque, and sealed envelopes
Blinding of outcome assessment (detection bias) All outcomes	Low risk	All the periodontal and surgical measurements were made by a single, blinded examiner
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	It is not clear whether the number and reasons of withdrawals had any impact on the results and how the authors managed the dropouts
Selective reporting (reporting bias)	Low risk	All outcomes appear to be reported
Other bias	Low risk	None detected