OBJECTIVE: To analyse marginal bone level changes at implants placed using high-speed drilling (800 rpm) with irrigation versus low-speed drilling (150 rpm) without irrigation. Peri-implant soft-tissue parameters were assessed and the influence of bone density and vertical dimensions of supracrestal soft tissue on marginal bone level changes was evaluated. MATERIAL AND METHODS: Patients with a single posterior edentulous area were included in a randomized parallel single-blinded clinical trial. The study groups were: high-speed drilling with irrigation (CG:control group) and low-speed drilling without irrigation (TG:test group). Marginal bone level changes were measured using parallelized periapical radiographs during 12-months. Probing depth, bleeding on probing, plaque index, buccal keratinized mucosa, suppuration and recession were measured. The mean total bone density was evaluated in Hounsfield Units. Mann-Whitney U-test for non-parametric variables and t-test for parametric variables were employed. RESULTS: A total of 66 patients were included (33 per group). The implant success rate was 100% for both groups according to Misch classification. No statistically significant differences were found regarding marginal bone loss (CG: -0.03 (0.17)
TG: -0.01 (0.05)), bone remodeling (CG: 0.81 (0.64)
TG: 0.86 (0.54)), or peri-implant soft tissue parameters (p >
0.05). Bone density showed no significant correlation with the peri-implant bone and soft-tissue changes. The vertical supracrestal soft tissue was inversely correlated to peri-implant bone remodeling. CONCLUSIONS: Within the limits, high-speed drilling with irrigation and low-speed drilling without irrigation had no statistically significant influence on the peri-implant marginal bone and soft tissue changes during 12 months of follow-up. These variables were not significantly influenced by bone density. TRIAL REGISTRATION: Unique identification number: NCT05286866.