الفهرس 
Palatal Coverage
Evaluation of Retention in Implant OverdentureOnly 14 pages are availabe for public view
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Abstract
Purpose: The aim of this study was to detect the effect of accelerating
aging on retention, release period and wear of the clips in a bar retained
maxillary implant overdenture.
Material and methods: Four implants were placed in two maxillary
edentulous epoxy models. One model had two bar attachments with two
clips overdenture while the other model had three bar attachments with three
clips in the overdenture. Retention, release period and wear of the clips were
checked before applying insertion removal cycles. Retention was measured
using universal testing machine after 540 cycles (6 month) and 1080 cycles
(1 year) of insertion removal on a chewing simulator, and the clips were
observed under the microscope using scanning electron microscope.
Results: There was a significant difference in retention and release period
between the two bars and three bars implant retained maxillary overdentures.
A significant difference was also seen in each group after accelerated aging.
Scanning electron microscope of the clips revealed surface changes and wear
after 540 and 1080 insertion removal cycles.
Conclusion: Three bar implant retained overdenture had higher retention
values than two bar. Retention loss occurred in both groups after the
insertion removal cycles. Release period value was lower in two bar
overdenture than three bar overdenture. Minor cracks and surface
irregularities were seen in Scanning electron microscope of clips after 540
cycles while numerous horizontal vertical and oblique scratches were
detected after 1080 cycles.