Tissue stability of implants placed in fresh extraction sockets: A 5-year prospective single-cohort study

Background: Several materials have been used for ridge preservation after tooth extraction. This 5-year prospective single-cohort study is aimed at evaluating the success rate, marginal bone level (MBL), soft tissue stability, and subjective patient evaluation of implants placed in fresh extraction sockets with the use of a flapless technique and a xenograft to treat the peri-implant bone defect. Methods: Patients requiring a single implant in fresh extraction sockets were selected. After flapless extraction and implant insertion, the peri-implant bone defect was grafted with porcine bone. Collagen membrane was used to stabilize the graft. Four months later, a second surgery and prosthetic procedures were performed. Clinical parameters (width of keratinized gingiva [WKG], facial soft tissue level [FST], papilla index, plaque index, and bleeding on probing) were measured, and periapical radiographs were taken at the time of implant placement (baseline) and then at 1, 3, and 5 years thereafter. Image analysis software was applied to measure changes in the marginal bone level (DMBL). Additionally, patient satisfaction regarding the implant treatment was evaluated. All analyses were collected and measured by an independent, trained observer. Together with descriptive statistics, for each of the outcome variables, pairwise comparisons were performed using the Wilcoxon signed-rank test for matched samples. The level of statistical significance was set at 0.01 for all analyses. Results: Forty-seven consecutive patients were treated, with an implant survival rate at 5 years of 95.7%. DMBL showed statistically significant differences: mean values were -0.68 – 0.39, -0.94 – 0.44, and -1.08 – 0.43 mm at the 1, 3, and 5-year follow-up, respectively. Changes in WKG (DWKG) and FST (DFST) decreased from the 1-year point of the survey (0.80 – 0.79 and 0.71 – 0.73 mm for DWKG and DFST, respectively) to the last follow-up check at 5 years (0.67 – 0.74 and 0.56 – 0.69 mm for DWKG and DFST, respectively), with no significant differences. The papilla indexes showed significant differences among the baseline and all the other time points. Concerning patient satisfaction, at the last survey time point, 74% – 11.8% of patients were satisfied regarding the overall implant treatment, 73.0% – 11.1% gave a favorable opinion regarding the appearance of the peri-implant soft tissues, and 80.5% – 11.3% judged positively the finished appearance of the implant crown. No significant differences were obtained among the three follow-up times. Conclusions: The data of the present study suggest that the placement of a dental implant by means of a flapless technique in a fresh extraction socket filled with slowly resorbable graft biomaterial and with a delayed prosthetic restoration shows positive final esthetic outcomes. At the 5-year point of the survey, the changes in the bone level were minimal. Moreover, both midfacial tissue and the papillae maintained the early increase recorded before the first year of the follow-up.