الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
This study was carried out on five patients of completely edentulous maxillary arch against mandibular bilateral distal extension ridges, to evaluate the effect of implant retained tissue supported removable partial overdenture on alveolar bone height change of natural tooth adjacent to implant, implant marginal bone and distal extension ridge. For every patient, a temporary mandibular prosthesis was constructed. endosseous dental implant was mesial placed in intraforamenal area endosseous in the 1st premolar region, one on each side, of distal extension ridge. For delayed loading protocol, the temporary prosthesis relined with soft liner during the osseointegration period and the O-ring ball abutments were connected to the implants after 2nd stage surgery. Then a claspless overdenture constructed. Periodic digital periapical and panoramic radiographs were performed immediately before, and after 6 and 12 months of denture insertion to measure the crestal bone height changes. The results of this study revealed that:- 1. Alveolar bone height change was differing form individual to another along the interval period of study. 2. Along the interval period of study mandibular implant retained distal extension RPOD exhibit more bone resorption at distal end of extension ridge compared to mesial one. 3. Alveolar bone resorption at mesial part of ridge was increased significantly in 2nd 6 months than in the 1st one. 4. Mesial and distal crestal bone loss of implant abutment of RPOD was significantly increased in the 2nd 6 months compared to 1st 6 months. 5. After 12 month follow up, mandibular average alveolar bone resorption of tooth adjacent to the implant retained abutment with O-ring resilient attachment was significantly less than average crestal alveolar bone of either the implant or distal extension ridge. When comparing the later together it was not significantly less. 6. For implant mesially placed concept of mandibular distal extension partial overdenture average crestal implant bone resorption was significantly less than that found with the average distal extension alveolar ridge resorption after 1st 6 months follow up period. 7. Marginal bone loss that occurred in this study was within parameter of implant success, after 12m of loading. CONCLUSION: 1- Implant retained tissue-supported removable partial overdenture may be consider a treatment option to preserve the teeth adjacent to the mandibular distal extension edentulous ridge in order to be used as future abutment for removable partial denture. 2- The use of endosseous mesial placed implants with resilient attachment for removable partial overdenture may be the treatment planning of choice for preservation of the mesial part of the distal extension ridge from resorption. Recommendation: Relining of the implant retained tissue-supported removable partial overdenture (IRPOD) in the presence of spacer and change of the plastic O-ring when loss its resiliency is necessary to minimize implant and ridge resorption. This needs another investigation.