Peri-Implant Gingival Healing Following Platform-Switched Abutment Delivery

Objectives: Platform-switching concept is based on the use of small-diameter abutment compared to the platform diameter of the implant, thus, moving away the connective tissue inflammatory infiltrate from the bone crest. The purpose of this study is to investigate early changes in soft tissue related clinical parameters following platform-switched abutment delivery.
Methods: Non-smokers with a need of two dental implants in different quadrants were recruited in this randomized clinical trial. The platform-switched (test) and -matched (control) implants were placed randomly in 2 different quadrants. Two-stage surgical placement protocol was used with traditional healing time for osseointegration. Correspondent healing abutments were connected to the implant fixture at the uncovery. The probing depth (PD), modified sulcus bleeding index (mBI), modified plaque index (mPI), and peri-implant crevicular fluid (PICF) were taken at 1-, 2-, 4-, and 6-week after implant uncovery. A small piece of peri-implant keratinized mucosa (approximate 1x2mm) was collected around the abutments at implant uncovery and at 6-week. Clinical measurements were analyzed by paired T-test.
Results: Eighteen subjects were recruited with 11 completed required follow-up period for this ongoing study. Preliminary data analysis revealed no statistically significant differences in both mPI and PICF volume between 2 groups at any time points (p > 0.05). However, PD and mBI in test group were significantly lower than those in control group (p≤0.05) at each time point examined. Data analysis on soft tissue gene expression is pending
Conclusions: Within the limits of this study, platform-switched implants and their correspondent healing abutments may have more favorable peri-implant soft tissue healing than the platform-matched ones by shallow PDs and less mBI.