الفهرس 
Problems in Kennedy class II distal extension casesOnly 14 pages are availabe for public view
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Abstract
This study was conducted to evaluate newly designed OT unilateral extra-coronal resilient attachments on the abutments and supporting structures, in tooth-tissue supported partial denture cases, by measuring bone height changes.
Sixteen patients with unilateral distal extension partially edentulous lower arches with last standing abutment 4 or 5 were selected in this study. The patients were divided into two groups:
group I: Eight patients were rehabilitated with a unilateral removable partial denture retained with a double OT Cap attachment where the last abutment was the second premolar.
group II: Eight patients were rehabilitated with a unilateral removable partial denture retained with a double OT Cap attachment where the last abutment was the first premolar.
The lower first and second premolars for group I and lower canine and first premolar for group II on the distal extension side were prepared with a deep chamfer finish line extend sub-gingivally to receive Ceramo-Metallic two-unit fixed crowns.
Impression was made in a pre-constructed special tray using heavy and light rubber base impression material. Wax pattern was constructed on the abutments. The plastic pattern of the double OT extra-coronal attachment was joined to the distal surface of the wax pattern of the lower second premolars for group I and lower first premolar for group II. Uni-Box (female part) was fit exactly on the attachment and flushed smoothly with abutment wax coping.
Spruing, investing, burnout and casting were carried out according to the manufacturer’s instruction. The casting was then finished and polished.
Porcelain was then fired to the metallic crowns. The veneered crowns with their attachments were properly seated on the abutment teeth and an impression was taken using rubber base impression material and poured in dental stone.
Wax pattern of the partial denture framework was made on the refractory cast then an indirect pick-up was done, the female portion of the extra-coronal attachments were attached to the wax pattern of the denture framework and were inserted into the male portions.
Cast procedures were completed and metallic framework was obtained. Casting, finishing and polishing of the metallic framework were done. The crowns-attachment assembly was finally cemented using resin cement.
Denture processing was carried out. The finished and polished denture was delivered to the patient after performing the needed occlusal adjustment.
They were evaluated radiographically by long cone parallel technique to determine bone height changes around abutments and distal extension ridge that support the newly designed unilateral attachment.
Data obtained from patients of both groups in this study were evaluated at the time of denture insertion then six, and twelve months later. The evaluation included bone height measurements around the natural abutments and the residual ridge of the distal extension area. The data was arranged tabulated, calculated and statistically analyzed.
The results obtained from this study showed that there was significant increase in bone resorption at distal aspect of 2nd abutment and distal extension ridge in both groups. There was also bone loss around the abutment teeth and on the residual ridge for all patients during the follow up period and there was significance difference between the two groups. However, group II shows higher bone loss around the abutments and distal extension part of the ridge than group I.