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Bone level changes at axial‐ and non‐axial‐positioned implants supporting fixed partial dentures. A 5‐year retrospective longitudinal study
Author(s) -
Koutouzis Theofilos,
Wennström Jan L.
Publication year - 2007
Publication title -
clinical oral implants research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.407
H-Index - 161
eISSN - 1600-0501
pISSN - 0905-7161
DOI - 10.1111/j.1600-0501.2007.01386.x
Subject(s) - implant , dentistry , orthodontics , protractor , medicine , radiography , materials science , surgery , mathematics , geometry
Abstract Aim: The aim of this study was to retrospectively analyze the potential influence of implant inclination on marginal bone loss at freestanding, implant‐supported, fixed partial dentures (FPDs) over a 5‐year period of functional loading. Material and methods: The material comprised 38 periodontally treated, partially dentate patients with a total of 42 free‐standing FPDs supported by implants of the Astra Tech System ® . Mesio‐distal inclination of the implants in relation to a vertical axis perpendicular to the occlusal plane was measured with a protractor on standardized photographs of the master cast. The two tail quartiles of the distribution of the implants with regard to the implant inclination were defined as axial ‐positioned (mean 2.4°; range 0–4°) and non‐axial ‐positioned implants (mean 17.1°; range 11–30°), respectively. For FPDs supported by two implants, both the mesial–distal and buccal–lingual inter‐implant inclination was measured. The primary outcome variable was change in peri‐implant bone level from the time of FPD placement to the 5‐year follow‐up examination. Comparison between axial‐ and non‐axial‐positioned implants was performed by the use of a Mann–Whitney U‐ test. Spearman's correlation analysis was used to analyze relationships between inter‐implant inclination (mesial–distal and buccal–lingual) and 5‐year bone level change on the FPD level. Results: The 5‐year mean bone level change amounted to 0.4 mm (SD 0.97) for the axial and 0.5 mm (0.95) for non‐axial‐positioned implants ( P >0.05). For the FPDs supported by two implants, the mean inter‐implant inclination was 9.2° (1–36°) in the mesial–distal direction and 6.7° (0–24°) in the buccal–lingual direction. Correlation analysis revealed lack of statistically significant correlation between inter‐implant inclination (mesial–distal and buccal–lingual) and 5‐year bone level change ( r =−0.19 and r =−0.32, respectively). Conclusion: The study failed to support the hypothesis that implant inclination has an effect on peri‐implant bone loss.