The effect of interposed soft tissue grafts at second stage surgery on gingival and prosthetic appearance: a randomized, controlled, split-mouth, prospective clinical trial

Abstract Purpose: The aim of this clinical study was to evaluate the effect of interposed soft tissue grafts at second stage surgery on gingival and prosthetic appearance. Materials and Methods: Patients with bilaterally symmetrical implant positioning in the edentulous maxilla or in maxillary free-end situations received second-stage surgery using an apically repositioned flap three months after implant insertion. In the test group, soft tissue augmentation was performed using epithelial connective tissue grafts interposed between adjacent implants, while in the opposite control group the spaces between the implants remained open. All implants were restored with a screw-retained fixed bridge. The width of the horizontal and vertical keratinized gingiva as well as the ratio of white to pink ceramic of the bridges were evaluated in both groups. Results: With a follow-up of 36 months, 122 implants were inserted and 36 grafted and 36 non-grafted inter-implant spaces were examined. Postoperative healing was uneventful in all cases, in one case bleeding occured at the mucosal donor site. Throughout the study period, the test group consistently exhibited a significantly greater horizontal and vertical width of keratinized gingiva compared to the control group (p < 0.01). Likewise, the horizontal and vertical dimensions of the keratinized gingiva were significantly more preserved in the test group (p < 0.01). To achieving optimal pink-white aesthetics, in the control group, pink ceramic accounted for an average of 15.12% of the total height of the prosthetic restoration, while in the test group, the height of the pink ceramic averaged only 2.84%. Conclusions: The use of interposed epithelial-connective tissue grafts in combination with an apically repositioned flap during second-stage surgery significantly increases both the horizontal and vertical dimensions of keratinized gingiva compared to the apically repositioned flap alone. Furthermore, the augmented areas demonstrate significantly greater long-term horizontal and vertical tissue stability. The application of interposed soft tissue grafts significantly reduces the need for pink ceramic to achieve optimal pink-white aesthetics and thus reduces the total metal-ceramic volume of a fixed implant bridge.