Survival Rates and Bone and Soft Tissue Level Changes Around One-Piece Dental Implants Placed with a Flapless or Flap Protocol: 8.5-Year Results

The purpose of the current study was to determine the survival rates and to measure marginal bone changes and peri-implant conditions 8.5 years after placement of one-piece implants with an anodically oxidized surface (AOS). A total of 52 subjects who received a one-piece implant with an AOS using a flapless or flap protocol and completed a previous randomized clinical trial were contacted for a recall visit 8.5 years after implant placement (T8.5). Implant success and survival rates, probing pocket depth (PPD), presence of bleeding on probing (BoP), papilla level, and incidence of complications and peri-implant disease were assessed by a single, blinded examiner. A second blinded examiner evaluated marginal bone level changes. Results for 8.5 years were compared to those at the time of implant placement, implant loading (0.5 year), and 1 and 1.5 years follow-up. The results based on 28 patients who attended the follow-up visit (half had flapless and half a flap protocol) showed a 100% implant survival rate and a 96.4% implant success rate 8.5 years after implant placement using one-piece implants, with no difference in survival and success rates between the flapless and the flap protocol. During the same follow-up period, a significant increase in crestal bone height from 1.5 to 8.5 years was observed. Analysis suggested decreasing mean levels of bone loss with time (P .001). Moreover, there was 0.8 to 1.0 mm of bone loss through year 1.5, which decreased to 0.3 mm at 8.5 years (P .05). There was no statistically significant difference in PPD or BOP over time. Similar mean levels of PPD were found in flap and flapless groups (mean [SD] = 2.4 [0.3] and 2.2 [0.4] mm, respectively [P = .18]), as well as similar rates of BOP (22.8% vs 17.9%, respectively). Papilla levels increased during the first year after implant loading. However, there was little additional change between 1.5 and 8.5 years. A total of eight fractured porcelain crowns and three crown loosenings were reported. One-piece implants with an AOS showed high survival rates and stable marginal bone and periimplant soft tissue levels regardless of whether a flapless or flap protocol was used.