Clinical and Radiographic Assessment of Peri-Implant Tissue in Posterior Areas with and Without the Need for Guided Bone Regeneration

Background: Dental implants are increasingly used in resorbed alveolar ridges, and the success of implants inserted concomitantly with guided bone regeneration (GBR) needs to be evaluated. Objectives: This study aimed to clinically and radiographically assess the peri-implant tissues in the posteriormaxilla andmandible in cases in which dehiscence or fenestration occurred at the time of implant surgery and treated with GBR (simultaneously with implant placement in one session). A comparison was also made between the above-mentioned patients and controls in which implants were placed in intact bone (entire length of implant in bone). Patients and Methods: This study was conducted on ۱۲ patients as cases who received ۱۷ standard implants (dehiscence or fenestration occurred after placement of ۴ mm diameter standard implants and GBR was performed) and ۱۰ patients as the control group (those who received ۱۷ standard implants, ۴ mm in diameter and ۱۰ mm in length, in adequate bone). Periapical (PA) radiographs were obtained in the first ۲۴ hours post-surgery. Radiographs were repeated at one month, at the time of loading (two months postsurgery), and at three and six months after loading to assess marginal bone loss. To assess the peri-implant soft tissue, thickness and width of the keratinized gingiva were evaluated. Data were analyzed using t-test and repeated measures analysis of variance. The level of significance was set to P = ۰.۰۵. Results: The difference in distance from the bone crest to the implant shoulder between the two groups of cases and controls was significant at the following time points: baseline and ۲ months post-surgery (P = ۰.۰۰۰), baseline and ۶ months after loading (P = ۰.۰۱), ۲ months post-surgery and ۳ months after loading (P = ۰.۰۰), and ۲ months post-surgery and ۶ months after loading (P = ۰.۰۰). Changes in the width of the keratinized gingiva were not significant in the two groups of cases and controls at ۲ months postsurgery (P = ۰.۸۷) or at ۶ months after loading compared with the baseline preoperative values (P = ۰.۴۷). Changes in the thickness of the keratinized gingiva were not significant in the case or control group at ۲ months post-surgery (P = ۰.۹۷) or at ۶ months after loading compared with the baseline preoperative values (P = ۰.۲۵). Conclusions: Changes in the marginal bone level were greater when implants were placed concomitantly with GBR. No significant difference was noted in terms of changes in width or thickness of the keratinized gingiva between the two groups.