Peri-implant bone alterations in relation to inter-unit distances. A 3-year retrospective study

Area of Science:

• Dental Implantology
• Oral and Maxillofacial Surgery
• Biomaterials Science

Background:

• Assessing bone topography changes around dental implants is crucial for long-term prosthesis success.
• Understanding the influence of implant positioning on bone levels is vital for predictable outcomes in implant-supported fixed partial prostheses.

Purpose of the Study:

• To evaluate longitudinal radiographic bone topography alterations at proximal sites of three-unit implant-supported fixed partial prostheses.
• To investigate the relationship between vertical and horizontal inter-unit distances and bone level changes over the first 3 years post-installation.

Main Methods:

• Retrospective study of 28 patients with 35 three-unit implant-supported fixed partial prostheses.
• Radiographic assessment of bone levels at implant installation, 1-year, and 3-year follow-ups.
• Multiple regression analyses to identify factors influencing peri-implant and periodontal bone level changes.

Main Results:

• Mean bone loss of 0.5 mm at implants and 0.4 mm at teeth in tooth/implant units over 3 years, with no significant explanatory factors identified.
• Peri-implant bone loss of 0.6-0.7 mm in implant/implant units was significantly influenced by vertical inter-implant distance, baseline bone level differences, and opposed implant surface bone changes.
• Apical displacement of inter-implant bone crest was negatively associated with horizontal inter-implant distance.

Conclusions:

• Vertical and horizontal differences in implant positioning can influence bone alterations in the inter-implant area within the first 3 years of loading.
• No significant relationships were found for bone changes at the proximal area between implants and neighboring teeth.
• Implant positioning parameters are critical considerations for inter-implant bone stability in fixed partial prostheses.