الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 169 |  |  |
| | | from | 169 | | |
Abstract
Purpose: This comparative study was conducted to compare between two different design concepts of four implant assisted complete mandibular overdenture regarding the residual alveolar bone height changes. Materials and methods: Ten healthy completely edentulous male patients were selected for this study. For each patient, a conventional complete denture was constructed and delivered, then followed up weekly for one month for correction of any complaints. Each mandibular denture was duplicated to be used as a radiographic stent, then the CBCT surgical guide template was printed according to each design concept of 4-implant overdenture. The CBCT surgical guide templates were used for installing the implants according to flapless surgical technique followed by delayed loading. According to the two design concepts of the 4-implant overdenture used in this study, the patients were randomly classified into two equal groups: group [A]had two vertical canine implants with two axial 1st molar short implants (short design concept), and group [B]had two vertical canine implants with two distally inclined premolar implants (inclined design concept). Radiographic evaluations were performed immediately (T0), 6 months (T6), and 12 months (T12) respectively after picking up of the ball attachments. Result: The result of this study showed that the residual bone resorption in the two groups after one year of loading was within the accepted limits (less than 0.7mm). Also, these results showed a significant decrease in bone resorption in both groups during the 2nd 6 month after loading. When comparing between the two groups, a statistically significant higher ridge resorption was found in group B during the first six months whereas in the second six months, the difference was insignificant. Conclusion: from the results of this study, it could be concluded that: 1- In regard to the accepted limits of residual alveolar bone loss, the two design concepts with either 1st molar short implant or premolar distally inclined implant can be used for assisting the mandibular complete overdentures. 2- The posterior short implant concept can be considered more favorable design than inclined implant concept when designing the 4-implant assisted mandibular complete overdenture, regarding the preservation of alveolar bone height.