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Minimal invasive flap(flapless)technique appeared from the concept of periosteum preservation during implant placement was documented by many surgeons which this technique achieved their demands.When this technique was compared with conventional flap of their effect on bone resorption and remodeling around the implant, there was a controversy in the results due to different experimental conditions.The aim of this study was to compare the effect of flapless and full-thickness flap on crestal bone resorption and implant stability.Eleven implants were placed by flapless and also eleven implants were placed by full-thickness flap in split mouth design.Radiograph was taken and resonance frequency analysis (RFA) was done at implant placement at 6-week and 12-week intervals. Data was entered into SPSS software and analyzed using Wilcoxon Signed Ranks test.Results revealed no significant difference in crestal bone resorption and implant stability between both flaps at 6-week and 12-week intervals. In conclusion,results showed that crestal bone resorption and implant stability were not affected by periosteum disruption or preservation.

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