The purpose of this study was to compare retention and release periods. of the rigid Dolder bar (Cendres & Metaux SA., Switzerland), resilient Dolder bar (Cendres & Metaux SA., Switzerland), Round bar (Cendres & Metaux SA., Switzerland), Hader bar (3i Implant Innovations Co., USA), and Dal-Ro attachment (3i Implant Innovations Co., USA) on an implant-retained overdenture model. Dislodging tensile forces were applied to the denture with the attachment in two directions simulating function: vertical and oblique. Each model was attached to an Universial Testing Machine (cross-head speed 50.8 mm/minute) and retention and release periods were measured. The data of retention and release periods for each attachment was statistically processed by Statistical Package of Social Science (SPSS).
The obtained results were as follows:
1.. When subjected to dislodging forces in vertical direction, the Dal-R.o attachment and the rigid Dolder bar were the most retentive and the Round bar was the next most retentive. The Hader bar and the resilient Dolder bar were the least retentive.
2. When subjected to dislodging forces in oblique direction, the Dal-Ro attachment was the most retentive and the Round bar and the rigid Dolder bar were the next most retentive. The Hader bar and the resilient Dolder bar were the least retentive.
3. When subjected to dislodging forces in vertical direction, the Hader bar, the resilient Dolder bar, and the Round bar had the fastest release period and the Dal-Ro attachment and the rigid Dolder bar had the slowest release period.
4. When subjected to dislodging forces in oblique direction, the Hader bar had the fastest release period and the resilient Dolder bar had the next fastest release period. The rigid Dolder bar, the Round bar, and the Dal-Ro attachment had the slowest release period.
|