Residual ridge and peri-implant outcomes in mandibular overdentures retained by four Locator versus four bar attachments: a 10-year retrospective analysis.

OBJECTIVES: To evaluate associations between attachment type (Locator vs. bar) and long-term residual ridge remodeling and clinical outcomes in patients with 4 inter-foraminal implants.

MATERIALS AND METHODS: Twenty-five edentulous patients were divided into 2 groups: Group I (n = 12) received Locator-retained overdentures (ODs), and Group II (n = 13) received bar-retained ODs. Posterior mandibular ridge resorption (PMandRR), anterior maxillary ridge resorption (AMaxRR), and crestal bone loss (CBL) were assessed using standardized panoramic and periapical radiographic techniques. Plaque index (PI), bleeding on probing (BOP), and probing depth (PD) were clinically recorded. All patients were followed for a minimum period of 10 years.

RESULTS: After 10 years, PMandRR was significantly lower in the Locator group (0.9 mm) compared to the bar group (1.6 mm) (p = 0.001). CBL was significantly higher in the Locator group (2.2 mm) versus the bar group (1.6 mm) (p = 0.0001). No significant difference was found in AMaxRR between groups (p = 0.428). PI, BOP, and PD showed no significant differences (p > 0.05).

CONCLUSIONS: Long-term patterns of posterior mandibular ridge remodeling and peri‑implant bone changes may be associated with the type of attachment system used. Both attachment systems demonstrated generally favorable long-term outcomes. Selection of attachment type may be considered on a patient-specific basis, balancing potential trade-offs between ridge preservation and crestal bone stability.

CLINICAL SIGNIFICANCE: Locator attachments may be preferred in cases of severe posterior ridge resorption, while bar attachments may benefit patients requiring enhanced peri‑implant bone stability.