Mandibular overdenture with a single implant in the canine region (c-SIMO): a feasibility study

The aim of this multi-center pilot study was to assess the viability and feasibility of a novel treatment concept - the canine-positioned single implant mandibular overdenture (c-SIMO), with the single implant placed on the patient's preferred chewing side instead of the midline.

Participants received a single implant in the canine region of their preferred chewing side, based on an Asymmetry Index observed during mastication. The pre-existing mandibular denture was transformed into a c-SIMO on a spherical attachment. The primary outcome was oral health-related quality of life (OHRQoL), measured with GOHAI and OHIP-EDENT. Secondary outcomes included denture satisfaction index (DSI), chewing efficiency (CE), maximum bite force (MBF), implant survival and success, and prosthetic maintenance. Data analysis included descriptive statistics and bivariate comparison tests.

Fifteen participants received the c-SIMO treatment (mean age: 69.9 ± 7.0). Implant success and survival rates were 100% at 1 year. Patient-reported outcome measures improved significantly compared to pre-treatment values (OHIP-EDENT: p = 0.001; DSI: p = 0.001; GOHAI: p = 0.002). Masticatory outcomes also improved significantly (CE: p = 0.001; overall MBF: p = 0.005). Post-implant, MBF was significantly higher in the ipsilateral side compared to the contralateral side at 2 weeks (p = 0.019) and 3 months (p = 0.015), but no longer at T3 (p = 0.730). Common prosthodontic events included denture base adjustments (n = 17) and matrix activation (n = 9).

This pilot study concludes that c-SIMO is a promising treatment option, and a potential alternative to the single midline implant overdenture.

The novel treatment concept of a canine-positioned single implant mandibular overdenture could be a viable treatment alternative to the midline positioning.