Mandibular Overdentures Retained by 1 or 2 Implants: a 5-year Randomized Clinical Trial on Implant Stability and Peri-implant Outcomes

Overview

Journal Clin Oral Investig

Specialty Dentistry

Date 2024 Sep 15

PMID 39279004

Authors

Claudio Rodrigues Leles

Gabriela Pereira de Resende

Nilva de Oliveira Martins

Lays Noleto Nascimento

Nadia Lago Costa

Murali Srinivasan

Martin Schimmel

Affiliations

Soon will be listed here.

Abstract

Aim: This is a report of the 5-year results of a two-group parallel randomized clinical trial comparing longitudinal implant stability, and clinical and radiographic peri-implant outcomes of mandibular overdentures retained by one (1-IOD group) or two (2-IOD group) implants.

Methods: All participants received 4.1 mm diameter tissue-level implants (Straumann Standard Plus - SLActive, Institut Straumann AG), installed in the mandible midline (1-IOD; n = 23) or the lateral incisor-canine area bilaterally (2-IOD; n = 24), and loaded after 3 weeks. Implant Stability Quotient (ISQ) was measured using a resonance frequency device (Osstell Mentor, Integration Diagnostics) at implant placement, after three weeks (loading), and at the 6-month, 1-, 3-, and 5-year follow-ups. Marginal bone loss and clinical implant outcomes (plaque, calculus, suppuration and bleeding) were assessed periodically up to 5 years after loading.

Results: Only minor changes in marginal bone level were observed after 5 years (mean = 0.37; SD = 0.44 mm), and satisfactory and stable peri-implant parameters were observed throughout the 5-year follow-up. No significant differences between groups were found. Overall, the mean primary implant stability was considered high (> 70) for the two groups (1-IOD = 78.1 ± 4.5; 2-IOD = 78.0 ± 5.8). No noticeable changes were observed between implant insertion and loading. A marked increase was observed from insertion to the 6-month follow-up - the mean difference for the 1-IOD group was + 5.5 ± 5.5 (Effect size = 1.00), while for the 2-IOD group, the mean difference was + 6.0 ± 5.6 (Effect size = 1.08). No relevant changes were observed throughout the follow-up periods up to 5 years. Linear mixed-effect model regression showed no influence of the bone-related variables (p > 0.05) and the number of implants (p = 0.087), and a significant effect of the time variable (p < 0.001).

Conclusion: Satisfactory peri-implant outcomes and stable secondary stability suggest good clinical performance and successful long-term osseointegration of the implants for single and two-implant mandibular overdentures. Using a single implant to retain a mandibular overdenture does not seem to result in detrimental implant loading over the five years of overdenture use.

Clinical Relevance: This study corroborates the use of a single implant to retain a mandibular denture.

Citing Articles

Carbon fiber-reinforced PEEK as a framework material for single implant-retained mandibular overdentures.

Borges G, Mesquita M, Matias L, Barbin T, Machado L, Ricardo Barao V Braz Oral Res. 2025; 39:e018.

PMID: 39936717 PMC: 11808703. DOI: 10.1590/1807-3107bor-2025.vol39.018.

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