Objectives:The present study was undertaken to evaluate the efficacy ofposterior implant supported distal extension removable partial overdenture in themanagement of patients with anteriorly displaced TMJ discs with reduction compared to conventional distal extension RPD.
Materials and Methods:8 patients with completely edentulous maxillary ridges opposing Kennedy class I mandibular partially edentulous ridges being already affected by anterior displaced TMJ discs with reduction were selected and  divided equally into two groups according to whether they would receive posterior implant or not. Conventional maxillary complete dentures were constructed for both groups. Mandibular RPD was constructed without implant underbeneath (group I) and with  implant underbeneath  (group II). For both groups, after the definitive partial denture insertion, anterior repositioning splint was constructed and the patients were instructed to wear it for a period of 3 months. Patients' evaluation was undertaken at 3 evaluation times: before denture insertion, 3 months after splint insertion, and 6 months later. MRI measurements of disc position were evaluated.
Results:For both groups there was significant increase in the relative value of TD at the second evaluation time indicating a more posterior disc position while at the third evaluation time, the relative value of TD was decreased significantly in group I and remained unchanged in group II. When comparing the two groups, there was non significant increase in the relative value of TD in group II compared to group I at the second and third evaluation times.
Conclusions:It could be concluded that the posterior implant supported bilateral distal extension removable partial overdenture preserves the TMJ disc in its normal relation in both short and longer term evaluations.