Felice 2009b.

Methods	1‐year post‐loading follow‐up randomised, parallel group study including 2 groups. There were no withdrawals.
Participants	Patients having residual bone above the mandibular canal of between 4.5 to 11 mm and a width of at least 5 mm. Adults treated at the Oral and Maxilofacial Surgery Unit, S. Filippo Nieri Hospital, Rome, Italy. Patients were excluded if they had general contraindications to implant surgery, irradiation, chemotherapy, immunosuppressive therapy, or amino‐bisphosphonates in the previous 5 years, poor oral hygiene and motivation, uncontrolled diabetes, pregnant or lactating, previously subjected to reconstructive procedures of the posterior mandible, active periodontal disease, and mucosal disease such as lichen planus, in the areas to be treated. 23 patients enrolled, 13 in the onlay group and 10 in the inlay group.
Interventions	Autogenous inlay versus onlay bone grafts harvested from the iliac crest to vertically augment deficient posterior mandibles. Patients were grafted with a 2‐stage approach: a monocortical bone block was either interposed between the basal bone and an osteotomised segment raised coronally without flap elevation at the lingual side to preserve blood supply or placed as an onlay. Grafts were fixed with titanium miniplates or miniscrews (Gebrüder Martin GmbH & Co, Tuttlingen, Germany). The grafted areas were covered with resorbable barriers (Bio‐Gide®, Geistlich Pharma AG). All augmentation procedures were performed under general anaesthesia. Patients were instructed not to wear removable prostheses for 1 month after the augmentation procedure. After 3 to 4 months miniplates/screws were removed and 2 dental implants were placed and left submerged for 4 months. Dental implants of several brands were used (Biomet 3i and XiVe Dentsply‐Friadent implants for the inlay group and Astra Tech, Biolok and Alpha Bio implants for the onlay group). All patients were rehabilitated with screw‐retained acrylic partial provisional prostheses for 4 to 5 months until definitive screw‐retained prostheses were delivered.
Outcomes	Prosthesis and implant failure, complications, bone gain, and perimplant marginal bone loss.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Article: No information presented. Author's reply: "Toss of a coin".
Allocation concealment (selection bias)	Low risk	Article: "The surgeons were blind to the group assignment until the surgical procedure". Author's reply: "The surgeon was informed about the intervention after the patient was anaesthetised".
Blinding (performance bias and detection bias) All outcomes	Low risk	Article: No information presented. Author's reply: "Independent outcome assessor could understand which intervention was delivered, however they were completely blinded after implant placement". It is judged as adequate.
Incomplete outcome data (attrition bias) All outcomes	Low risk	In the article, data of 20 patients were presented. However, after our query about how they ended up having 10 patients in each group by tossing a coin, which is quite unlikely to happen, the author replied that there were actually 23 patients enrolled, but they excluded data of 3 patients from 1 group to balance the numbers. After our request, they gave us the complete data.
Selective reporting (reporting bias)	Low risk
Other bias	Unclear risk	Different types of implants were used. It is unclear if this could have influenced the results.