Minimally invasive flapless vs. flapped approach for single implant placement: a 2-year randomized controlled clinical trial

Purpose: The purpose of this 2-year randomized controlled clinical trial was to assess the differences in implant survival rates, soft tissue preservation, patient centered outcome and crestal bone changes applying the minimally invasive (MI) flapless approach for single implant placement compared to flapped implant surgery (FS). Materials and methods: Subjects eligible for this study were randomly assigned into two groups: MI or FS. Items of evaluation were the following: implant installation position, soft tissue healing, post-surgical pain, soft tissue outcome, marginal bone loss (MBL), and implant survival rate. Results: Forty subjects (14 women and 26 men, 20 in MI group and 20 in FS group with a mean of 39 +/- 13.2 years old) were included in the study. None of the implants demonstrated dehiscence or loss during the follow-up. Subjects in MI group showed significantly lower post-surgical pain and significantly less wound healing index scores at 1-week follow-up. The width of keratinized mucosa decreased from a mean of 4.2 +/- 1.6 mm pre-surgically to 3.7 +/- 1.1 mm at crown delivery but remained stable at 2-year follow-up in MI group. At every appointment in the study, no statistical significant difference of PD and MBL was found between the two groups. Conclusion: Compared with FS, single implants placed applying the MI technique in selected subjects showed advantages in improving patient comfort and decreasing post-implant placement soft tissue reaction. Meanwhile, implants with MI approach have the same level of MBL and high success rates as FS procedure at 2-year follow-up. The deduction of keratinized mucosa is very limited and the width of KM remained stable with MI approach at 2-year follow-up.