الفهرس 
COVEROnly 14 pages are availabe for public view
 |  | from | 152 |  |  |
| | | from | 152 | | |
Abstract
This study was conducted to evaluate and compare the effect of OT and Reverse OT extracoronal resilient attachments on the abutments supporting structures, in tooth-tissue supported Kennedy class I partial denture cases, by measuring bone height changes.
Twenty one male and female patients exhibiting mandibular bilateral free end saddles were selected for this study. The selected patients were randomly divided in to three equal groups:
Group A: For group A patients, conventional removable partial dentures retained by RPA clasps were constructed.
Group B: For group B patients, removable partial dentures retained by extracoronal attachments (OT CAP attachments) and lingual bar as major connector were constructed.
Group C: For group C patients, removable partial dentures retained by extracoronal attachments (OT Reverse/3 attachments) and lingual bar as major connector were constructed.
The effect of each retainer on the denture supporting structures was evaluated by measuring:
1- Crestal bone height changes around the abutment teeth.
2- Changes in alveolar bone height of the residual ridge.
Periapical radiographs were made following the long cone parallel technique for evaluating bone height changes around the abutments and on the residual ridges, 15 mm distal to the abutments.
All the collected data at time of denture insertion and every six months for 18 months were arranged, tabulated and statistically analyzed.
The results obtained from this study showed that, there was significant bone loss around the abutment teeth and on the residual ridge for all patients during the follow up period.
Patients rehabilitated with RPDs retained by OT extracoronal attachment showed the least amount of crestal bone loss around the abutments, while patients receiving clasp retained RPDs showed the greatest bone loss around the abutments.
Patients rehabilitated with reverse OT extracoronal attachment showed the highest amount of crestal bone loss of the residual ridge 15 mm from the distal abutment followed by patients with OT attachments, while patients rehabilitated with the clasp retained RPDs showed the least amount of crestal bone loss of the residual ridge 15 mm from the distal abutment.