The long-term outcomes of maxillary implant-supported overdentures: A retrospective study

This study examined the survival rate of implants and maxillary implant-supported overdentures (MIS-ODs) and identified the frequency of maintenance needs as well as technical and biological complications associated with MIS-ODs.

This retrospective cohort study included 86 patients who received 86 MIS-ODs between 1982 and 2023 in a university setting. Data analyses were performed to determine the survival rate of implants and MIS-ODs, as well as the frequency of maintenance events and complications (technical and biological). The survival proportion of MIS-ODs was estimated, and prognostic factors were analyzed using Cox regression analyses (p < 0.05).

The median follow-up time for MIS-ODs in this study was 39.0 months (interquartile range [IQR]: 15.0-84.3). Among 86 MIS-ODs, 45.3% had non-splinted attachments and 54.7% had splinted attachments; 9.3% of prostheses were supported by 2 to 3 implants, 59.3% by 4 implants, and 31.4% by more than 4 implants. The most common maintenance intervention was adjustment of the prosthesis intaglio surface. Technical complications occurred in nearly 60% of cases, with inadequate prosthesis retention being the most frequently reported issue. The most prevalent biological complication was peri-implant mucositis. Lastly, 27.9% of prostheses (24 cases) required a new prosthesis after a median survival time of 58.5 months (IQR: 16.0-79.0) due to acrylic tooth wear, implant loss, fabrication errors, and suboptimal retention.

Within the limitations of this study, MIS-OD survival is independent of the prosthesis design characteristics. However, certain technical and biological complications can affect the survival of MIS-ODs.