Heterogeneous trajectories of oral frailty and their determinants in older patients receiving dental implants: a longitudinal study

ObjectiveTo describe distinct trajectory patterns of oral frailty after implant-supported prosthesis delivery in older patients and to identify associated factors.MethodsThis prospective longitudinal cohort study consecutively enrolled 211 older patients who completed implant-supported prosthesis delivery at Nantong Stomatological Hospital and Haoting Dental Clinic between January 1 and April 30, 2025. Oral frailty was assessed using the adapted seven-item version of the Oral Frailty Index-8 (OFI-8, 7-item version; score range 0–9) at baseline (T0, prosthesis delivery) and at 3, 6, 9, and 12 months post-delivery (T1–T4). Distinct trajectories were identified using latent class growth modeling (LCGM). Multivariable multinomial logistic regression was used to analyze factors associated with trajectory membership.ResultsThree distinct oral frailty trajectories were identified: (1) Rapid Improvement-Stable Pattern (Class 1, n = 90, 42.7%), characterized by a sharp decline in OFI-8 scores immediately after prosthesis delivery followed by sustained low levels; (2) Gradual Improvement-Plateau Pattern (Class 2, n = 74, 35.1%), showing a gradual decline followed by a plateau; and (3) Persistent High-Risk Pattern (Class 3, n = 47, 22.2%), with scores remaining elevated throughout the 12-month observation period. Multivariable multinomial logistic regression analysis revealed that age (aOR = 1.12, 95% CI: 1.04–1.21), number of medications (aOR = 1.25, 95% CI: 1.05–1.49), and number of missing teeth (aOR = 1.09, 95% CI: 1.02–1.16) were independently associated with membership in Class 3. Bootstrap validation supported the robustness of the model. None of these variables showed statistical significance in distinguishing Class 2 from Class 1.ConclusionOral frailty trajectories in older patients with dental implants are heterogeneous. Older age, polypharmacy, and a greater number of missing teeth were independently associated with membership in the persistent high-risk trajectory, suggesting that these factors may help identify patients requiring prioritized follow-up.