Histopathological comparative analysis of peri-implant soft tissue response after dental implant placement with flap and flapless surgical technique. Experimental study in pigs.

AIM: The aim of this study was comparing the effect of flapless vs. flap technique of implant placement on inflammation degree of peri-implant soft tissue, through histopathological analysis.

METHOD: The experiment was conducted on five domestic pigs. Nine weeks after tooth extraction, implants were installed. Each animal received six implants in mandible. According to split-mouth design, randomly one side was used for flapless technique using mini-incision, while on the other side, flap was raised. After 7, 14, 21, 28, and 90 days, the experimental animals were sacrificed. Samples for histopathological analyzes were taken from the buccal side of peri-implant mucosa next to the neck of implants, from three levels. The degree of inflammatory response in the peri-implant soft tissue was estimated through ordinal scores from 0 to 3.

RESULTS: In the flap group Score 3 indicating high degree of inflammation was present from day 7 to day 21, in contrast to flapless group where Score 3 was not recorded during the entire follow-up. Three months after implantation, there were no signs of inflammation neither around flap nor around flapless implants.

CONCLUSION: Flapless surgical implantation technique using mini-incision decreases peri-implant soft tissue inflammatory reaction compared with flap surgery.