Mandibular Atrophy and Its Impact on Overdenture Performance: Insights From a 5-Year Longitudinal Study

Background

The long-term influence of mandibular atrophy on masticatory function, patient-reported outcomes, and prosthetic maintenance in users of implant-retained overdentures remains unclear.

Objective

To assess the impact of mandibular bone atrophy on masticatory function, quality of life, patient satisfaction, and prosthetic maintenance over a five-year period.

Methods

Twenty-four fully edentulous patients were rehabilitated with mandibular overdentures retained by two narrow-diameter implants and divided into two groups according to mandibular bone height: atrophic mandible (AM) and non-atrophic mandible (NAM). Masticatory performance (MP) and swallowing threshold (ST) were assessed, while quality of life and satisfaction were evaluated using the Dental Impact on Daily Living (DIDL) questionnaire. Prosthetic maintenance events were recorded over 5 years. Multilevel mixed-effects regression evaluated temporal trends and group differences, and chi-square tests were used for prosthetic events.

Results

Four participants were lost to follow-up, resulting in 10 individuals per group at 5 years. The AM group showed significant reductions in MP_X50 (–9.66%; p = 0.00) and ST_X50 (–1.9%; p = 0.01); and increase in ST_ME5.6 (+43.32%; p = 0.01). The eating/chewing domain of the DIDL was significantly lower in the AM group (0.35 ± 0.72) compared to the NAM group (0.73 ± 0.47). Although overall prosthetic maintenance did not differ significantly, the AM group exhibited a higher frequency of Equator dislodgement (9.24%; p = 0.00) and attachment replacement (6.02%; p = 0.00).

Conclusion

Mandibular atrophy adversely affected masticatory function, patient-reported chewing satisfaction, and the frequency of specific prosthetic complications over 5 years.