The implementation of implant placement protocols and their short-term impact on marginal bone levels in the esthetic zone: a retrospective cohort study

PURPOSE: This study aimed to estimate the prevalence of International Team for Implantology (ITI)-defined implant placement and loading protocols in the maxillary anterior region. Secondary aims were to assess the impact of different ITI protocols on short-term peri-implant marginal bone levels and implant failure following prosthetic loading. METHODS: A retrospective chart review was conducted on 468 implants placed in partially edentulous patients at Tufts University School of Dental Medicine between 2014 and 2018. Implant placement was categorized into 4 groups: immediate placement following extraction; placement after 4-8 weeks; placement after 12-16 weeks; and placement after 6 months. Prosthetic loading was categorized into 3 groups: immediate loading within 1 week, loading between 1 week and 2 months, and loading after 2 months. Mesial and distal bone levels were measured on periapical radiographs at baseline after implant placement and at the final visit of a 12-month follow-up period using the AxiUm ruler tool, with adjustments for radiographic distortion. RESULTS: Most implants (53.2%) were placed at least 6 months post-extraction and loaded after more than 2 months. Additionally, 17.5% of implants were placed in fresh extraction sockets but loaded after more than 2 months. No significant differences in short-term marginal bone levels or implant failure were observed among ITI protocol groups. However, mesial and distal bone loss increased by 0.061 mm and 0.066 mm, respectively, for every 1-mm increase in implant length. Furthermore, Nobel implants exhibited significantly greater mesial bone loss (0.336 mm) and distal bone loss (0.262 mm) compared with Straumann implants. CONCLUSIONS: Although no significant differences were observed in short-term marginal bone levels and implant failure among protocols, the study suggested that implant length and brand might affect marginal bone loss, but further long-term studies are needed to draw more definitive conclusions and explore additional factors impacting implant success.