Clinical Assessment Of Inlay Retained Bridge Designs (Tub Shaped And Inlay Shaped) In Missing Posterior Teeth Cases.

The interest in partial coverage retainers such as inlays and onlays have increased drastically because these restorations are able to provide a more conservative option requiring minimal tissue removal thus preserving healthy tooth structure to a maximum extent. If patient rejects an implant treatment and enough sound tooth structure is available it would be desirable to restore a missing tooth with Inlay-Retained Fixed Partial Denture instead of full coverage retained one . The use of all-ceramic materials for inlays and onlays in restorative dentistry is becoming more popular , the proper selection of restorative materials, careful preparation design and adequate adhesion between tooth/restorative material interfaces considered important factor to prevent failures . Zirconia was introduced into dentistry in the 1990s.The high initial strength and fracture toughness of zirconia results from a physical property of partially stabilized zirconia known as transformation toughening. On the other hand, its white color, similar to the color of natural teeth and its ability to transmit light makes it useful in aesthetically important areas . Inlay Fixed Partial Denture restoration may have increased the risk of fracture due to the relative small size of restorations compared to the complete coverage restoration. An unfavorable distribution of stresses between the ceramic inlay and tooth structure may result in marginal deterioration around the inlay or its failure. The direction of forces on the occlusal surface of Inlay Fixed Partial Denture may lead to the phenomenon of submargination, ceramic fracture, wear at interface and postoperative hypersensitivity which remain a problem that require further investigation. One of the most important factors in the success and longevity of a restoration is to have an accurate marginal fit. Ideally, the cemented restoration should precisely meet the finish line of the prepared tooth. In reality, clinical perfection is challengi