Influence of the extension of the anchorage surface of mandibular overdentures on patient's quality of life and satisfaction: 5-year follow-up of a randomized clinical trial

Aim: To evaluate the impact of extending the anchorage surface of mandibular overdentures on oral healthrelated quality of life (OHRQoL) and degree of satisfaction (SD) of edentulous patients. Materials and methods: Edentulous patients were randomly assigned to receive a mandibular overdenture with 2 interforaminal implants (Control) or, in addition, 2 extra-short (4-mm) implants distal to the mental foramen (Experimental), all splinted with a non-cantilevered bar. The Oral Health Impact Profile for Edentulous (OHIPEDENT) questionnaire and a Visual Analogue Scale (VAS) were used to measure OHRQoL and SD with treatment at 3- and 60-month follow-ups. Intraindividual comparisons at 3- and 60-months were analyzed using the Wilcoxon test. The Mann-Whitney U test was applied to compare different groups (Control vs. Experimental) at a significance level of 5 %. Results: The results for mandibular overdenture remained consistent during the 5-year follow-up period. However, the addition of implants in the posterior region to increase the anchorage surface (Experimental) had a smaller positive impact on the "Functional limitation" (p = 0.009), "Psychological disability" (p = 0.032) and "Overall score" (p = 0.036) dimensions of the OHIP-EDENT, as well as on the "Cleaning ability" domain (p = 0.018) of the VAS compared to the Control group. Conclusion: The addition of implants distally to the mental foramen to increase the anchorage surface did not significantly influence patient-centered outcomes when compared to the use of only 2 implants in an approach with anchorage limited to the interforaminal region. Clinical trial registration: The current study was not registered in a public database as required. It is important to note that the recommendation for registration was introduced by the Committee of Medical Journal Editors in 2017, while patient inclusion in the research began in 2016. Since the data in this manuscript covers a follow-up period of up to 5 years after surgical intervention, late registration was not possible. Clinical relevance: The addition of implants in the regions distal to the mental foramen, increasing the anchorage surface without cantilever, did not bring additional and significant patient-centered benefits compared to the installation of implants only in the interforaminal region.