Purpose: To compare the clinical outcome of platform switching (PS) and regular platform (RP) implants in bilateral single molar replacements. Material and methods: This study was designed as a randomised, controlled, split-mouth trial. Eighteen patients, with bilaterally missing single molars had one site randomly assigned to a PS implant or a RP implant. A total of 36 implants were bilaterally installed. Both implants were loaded with screw retained temporary crowns 3 months after implant insertion and with screw retained definitive crowns 3 months later. Outcome measures were implant/crown failure, complications, radiographic marginal bone-level changes, pocket probing depth (PPD) and bleeding on probing (BOP). Clinical data were collected at baseline 6 and 12 months after implant placement. Results: No patients dropped out and no implant failed. No prosthetic or major biological complications were observed. One year after implant placement, mean marginal bone level was 0.93 ± 0.26 mm (95% CI 0.81 to 1.05) in RP group and 0.84 ± 0.23 mm (95% CI 0.73 to 0.95) in the PS group and no statistically significant differences between the two groups were observed (P = 0.18). Mean PPD and BOP values were, 6 and 12 months after implant placement, 2.74 ± 0.49 mm (95% CI 2.51 to 2.97) and 1.28 ± 0.75 (95% CI 0.93 to 1.63) in the RP group, and 2.70 ± 0.38 mm (95% CI 2.53 to 2.88) and 1.39 ± 0.78 (95% CI 1.03 to 1.75) in the PS group respectively, with no statistical differences between groups (P = 0.81 and P = 0.16, respectively). Conclusions: No statistically significant difference was observed between platform switched and non-platform switched implants. Keywords: abutment connection, dental implants, platform switching Conflict of interest statement: This study was not supported by any company and there is no conflict of interest.