Abstract
Background: The minimum standard treatment plan for the reconstruction of an edentulous mandible, according to York, is an
overdenture supported by two implants.
Objectives: The aims of this study were to evaluate and compare the clinical outcomes and peri-implant marginal bone loss around
implants in patients treated with mandibular overdentures supported by 1, 2, 3, 4, and 5 implants.
Materials and Methods: A total of 25 patients with amean age of 62.7 years old, who were treated with implant supportedmandibular
overdentures at Hamedan’s faculty of dentistry, were enrolled in this cross-sectional study. Among these patients, 6 had overdentures
supported by one implant, 9 had overdentures supported by two implants, 2 had overdentures supported by three implants, 5
had overdentures supported by 4 implants, and 3 had overdentures supported by 5 implants. The clinical and radiographic parameters
around the implants were assessed, including: probing depth, width of keratinized gingiva, bleeding on probing, peri-implant
inflammation, calculus formation, implant mobility, adverse events, and radiographic signs of peri-implant bone loss (distance between
the implant shoulder and the level of the mesial and distal proximal bone). The ANOVA and the Fisher’s Exact test were used
to evaluate the significant differences among the groups.
Results: None of the implants had loosened and no adverse events were seen around the implants. Additionally, the clinical variables
did not show significant correlation with the number of implants. Overall, the bone resorption showed an inverse and significant
relationship with the number of implants (P = 0.001).
Conclusions: With mandibular overdentures supported by 1, 2, 3, 4, and 5 implants, favorable clinical outcomes can be achieved.
However, when increasing the number of implants, marginal bone loss decreases. For example, the patients with five implants
showed less marginal bone loss than those with a lesser number of implants.