Marginal bone changes around platform-switched conical connection implants placed 1 or 2 mm subcrestally: A...

Area of Science:

• Dental Implantology
• Periodontology
• Biomaterials Science

Background:

• Early marginal bone modifications around dental implants are crucial for long-term success.
• Platform-switched implants with conical connections are designed to mitigate bone loss.
• Subcrestal placement is a common surgical technique, but optimal depth is debated.

Purpose of the Study:

• To analyze early marginal bone modifications around platform-switched implants with conical connections.
• To compare bone levels when implants are placed 1 mm versus 2 mm subcrestally.
• To evaluate the effect of subcrestal placement depth on peri-implant bone levels after one year of loading.

Main Methods:

• A crossover randomized controlled trial was conducted with partially edentulous patients.
• Two platform-switched implants with conical connections were placed: one 2 mm (Test) and one 1 mm (Control) subcrestally.
• Radiographs were taken at implant placement, prosthesis delivery, and 1 year post-loading to measure peri-implant bone level (PBL) reduction.

Main Results:

• No significant difference in mean PBL reduction was observed between Test (0.49 ± 0.32 mm) and Control (0.46 ± 0.35 mm) implants after 1 year (p=0.66).
• A history of periodontitis significantly correlated with increased PBL reduction.
• While no Test implants showed exposed surfaces, 11.8% of Control implants had PBL below the implant platform at 1 year.

Conclusions:

• One-year prosthetic loading revealed no significant differences in marginal bone changes between 1 mm and 2 mm subcrestal implant placements.
• 2 mm subcrestal placement resulted in deeper implant positioning without exposing the implant surface.
• Deeper subcrestal placement may offer a preventive effect against peri-implant pathology.