den Hartog 2011.

Methods	Trial design: randomised, parallel group trial Location: Groningen, The Netherlands Number of centres: one (University of Groningen, The Netherlands) Recruitment period: January 2005 to February 2008 Funding source: study was funded by Nobel Biocare AB, Goteborg, Sweden (grant # 2004‐288)
Participants	Inclusion criteria: patients missing a maxillary single tooth from first to first premolars allowing the placement of a single implant at least 13 mm long and 3.5 mm wide with a minimal insertion torque of 45 Ncm Exclusion criteria: severe systemic conditions (ASA III), presence of periodontal disease, previous irradiation, smoking, presence of peri‐apical lesions or any other abnormalities in the maxillary anterior region, and missing tooth extracted less than 3 months before study start Age at baseline: immediate 38.4 (± 14.0); conventional 40.1 (± 14.4) Gender: immediate M9/F22; conventional M17/F14 Number randomised: 62 Number evaluated: 62
Interventions	Comparison: Immediate versus conventional loading Gp A (n = 31) Immediate loading: implants were restored within 24 hours with provisional non‐occluding acrylic crowns, replaced after 6 months by cemented or screw‐retained metal‐ceramic crowns Gp B (n = 31) Conventional loading implants were also restored after 3 months with provisional occluding acrylic crowns, replaced after 3 months by cemented or screw‐retained occluding metal‐ceramic crowns Nobel Replace Tapered Groovy (Nobel Biocare AB, Göteborg, Sweden) submerged TiUnite titanium screws were used Duration of follow‐up: 18 months
Outcomes	Crown and implant success, marginal bone levels, recession, various aesthetic indexes, patient satisfaction 1‐year data used for crown/implant success and 18 months form marginal bone level changes
Notes	Sample size calculation: paper states that "sample size was too small to demonstrate whether immediate loading was non‐inferior to conventional loading with respect to implant survival"
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Reported in the article: "A specifically designed locked computer software program was used to randomly assign patients to one of two study groups.... Randomization by minimization (Altman 1991) was used to balance possible prognostic variables between the treatment groups. Minimization was used for the variables age (<30 years, >31 <60 years, >60 years), location of the implant site (central or lateral incisor, canine or first premolar)and whether or not a pre‐implant augmentation procedure was indicated based on a clinical and diagnostic cast assessment"
Allocation concealment (selection bias)	Low risk	Reported in the article: "The allocation result was kept in a locked computer file that was not accessible for the examiner and the practitioners. The surgeon who inserted the implants was informed about the allocation on the day of surgery, before implant surgery was started"
Blinding of outcome assessment (detection bias) All outcomes	High risk	Reported in the article: "The examiner was blinded to the photographs and the radiographs taken at T6m and T18m. The radiographic examination could not be blinded to the radiographs collected after implant placement (baseline, T0), as the study group could be deduced from these radiographs.... The examiner was blinded for the protocol that was applied for a particular patient (for clinical measurements).....The examiner was blinded to the group allocation (for the aesthetic outcome assessment" Reviewer comment: "it was possible to take baseline radiograph not showing group allocation"
Incomplete outcome data (attrition bias) All outcomes	Low risk	All data presented
Selective reporting (reporting bias)	Low risk	All outcomes appear to be presented
Other bias	Low risk	None detected.