A longitudinal clinical comparison of plaque-induced inflammation between gingival and peri-implant soft tissues in...

Little information exists concerning the periimplant soft tissue response to plaque compared to the gingiva of the dentition. The purpose of this study was to compare this relative tissue response to plaque in humans over time.

Two hundred seventy-five (275) hydroxyapatite-coated implants were placed in the maxillae of 50 subjects followed by prosthetic rehabilitation. Baseline gingival (GI) and plaque (PI) index scores were obtained for all implants. Two to 4 teeth per subject were similarly measured, serving as controls. Measurements were repeated at 6-month intervals over 30-months. GI scores were evaluated relative to PI scores at 4 separate sites for each implant, to implant location within the oral cavity, and to length of time that each implant was in function.

The peri-implant mucosa demonstrated a significantly greater likelihood of having elevated GI scores relative to PI scores when compared to the gingiva (chi-square for combined PI scores of 0 and 1 = 85.0, df = 1, P <0.001; for combined P1 scores of 2 and 3 = 114.6, df = 1, P <0.001). A logistic generalized linear model confirmed the significance of these results (Student t for implant effect = 21.602). It further demonstrated significantly elevated GI scores for implant sites over time and for implants located in the posterior oral cavity.

The results indicate that maxillary peri-implant soft tissues are at increased risk for plaque-induced inflammation relative to the gingiva of the dentition. Hygiene recall standards and treatment regimens may require revisions to minimize peri-implantitis and prevent bone loss.