Aim: This study aimed to evaluate the influence of tooth -implant supported telescopic partial overdentures with cervical clearance on the supporting structures of unilateral distal extension removable partial dentures.
Materials and methods: Twelve male partially edentulous patients exhibiting lower Kennedy class II (lost second premolar and molar teeth on one side) opposed by completely edentulous maxilla were selected. Single unilateral implant was placed in the edentulous first molar area of the distal extension ridge. Patients were rehabilitated by Maxillary complete dentures and mandibular tooth-implant retained telescopic partial overdentures. Patients were randomly divided by using closed envelope into two equal groups; according to the design of telescopic crown. Group I; patients received cervically relieved telescopic crowns, (cervical clearance), and Group II; patients received telescopic crowns with no relief between primary and secondary copings, (precise fit). Measuring probing depth, and radiographic changes in marginal bone height of the abutments, and crestal bone height of the residual ridge, were evaluated at 3, 6, 9 and 12 months after denture insertion.
Results: Statistical analysis revealed a significant increase in the means of the measured abutments probing depth, change in alveolar bone height of the abutments, and crestal bone height of the residual ridge (mm) during the follow up time intervals in both group I (cervical clearance) and group II (precise fit). Abutments having telescopic crowns with precise fit showed significantly higher probing depth and change in alveolar bone height compared to those with cervical clearance. There was no statistically significant difference in the change in crestal bone height between the two studied groups at the end of the study period.
Conclusions: Telescopic retainers with cervical clearance are recommended for unilateral partial dentures compared to those with precise fit as they have a lowest destructive effect on the change in probing depth and height of the marginal bone of the abutments. However, the change in the crestal bone height was not significantly affected by the design of the telescopic retainers.