الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
As conventional complete dentures have a clinical problem related to pain, inadequate retention and stability along with poor function, Implant-supported removable overdentures (ISRODs) have become a popular prosthodontic treatment option in recent years.
The implant-supported overdenture provides some advantages over the complete denture, such as decreasing rate of ridge resorption, refinement of retention and stability, increased comfort and chewing efficiency, as well as greater satisfaction and improved quality of life of the patient. few studies were conducted to evaluate the effect of application of soft liner on the stress induced in the supporting structures of two implants supported overdenture.
An acrylic model of edentulous mandible was fabricated, soft tissue was stimulated using Silicon rubber base material , Two implants fixtures were inserted (3.75mm diameter and 13mm length) placed in the canine region Of the right and left side, Two ball abutment were tightened to the implant fixture using the same hex tool provided by the same implant system., two over denture were constructed overdenture I (heat cured acrylic over denture) , overdenture II (lined by silicone based soft liner), the metal housings were transferred to the intaglio surface of the two overdentures, silicon soft liner applied on the intaglio surface of overdenture II. Sites of the acrylic model were prepared using fissure bur to receive the Gauges at the following areas (labial and lingual sides of each implant and the right,left posterior ridge). Gauges were bonded to their respective sites on the model. A Vertical load of 150N was applied to the mandibular right first molar and the lower two centrals in overdenture I&II The micro strain values readings at each position were measured in micro strain units from the multi-channel strain indicator. The results were tabulated to be statically analyzed.
An independent t-test was used to compare the micro strain values in each overdenture(I&II). On application of anterior load, a statistically significant difference was found between micro strain values in both dentures’ overdenture I and II where (p<0.001). The highest mean micro strain value was found in (overdenture I), while the lowest mean micro strain value was found in overdenture II. On application of posterior load, a statistically significant difference was found between micro strain values in both dentures Overdenture I and II where (p<0.001). The highest mean micro strain value was found in Overdenture I, while the lowest mean micro strain value was found in (Overdenture II).
Conclusion
Within the limitation of this study, it can be concluded that application of soft liners in implant supported overdenture may have a positive effect on reducing the stress induced in the supporting structures around dental implants.