Content area
Full text
ABSTRACT:
Aim: Computer-aided design/computer-aided manufacturing (CAD/CAM) technology is gaining popularity in dentistry, and more recently, used to fabricate custom post-and cores (PC) for endodontically treated teeth. The purpose of this study was to evaluate the overall retention of conventional cast gold post-and-cores compared to CAD/CAM fabricated printed, milled titanium post-and-core and milled zirconia post-and-cores based on load, time of dislodgement '. Results: Pull out test revealed higher retention values for (CPTPC) and (CMTPC) among the groups. When compared to (CMZPC), conventional (CCGPC) revealed significantly better retention values .Cohesive failure was observed with groups I, II and IV. However, group III revealed a mixed type of failure. Keywords- High flexural strength, ASTM (American Society of Testing and Materials)
INTRODUCTION
Cast post-and-core (CPC) is commonly used to restore endodontically treated teeth with extensive coronal structural loss. Retention of CPC is a fundamental factor influencing definitive restoration longevity and success. Length, shape, diameter, and post surface, as well as the type of cement used, are associated factors that may affect CPC retention and stability. Custom CPC is documented to have superior adaptation and fit to the radicular post space walls when compared to prefabricated post2.
Moreover, gold alloy creates a layer of chromium oxide that resists tarnish. Custom-made PC has been reported with some disadvantages, for example, most abutments break at a point beyond the half distance of the root length due to its high stiffness. If these teeth abutments fracture, usually they are unrestorable3. Custom-made PC has also been reported to be fabricated out of zirconia to overcome esthetic limitation associated with metal CPC.
This has been made possible due to the following properties of zirconia; high flexural strength, high fracture toughness, chemical stability, biocompatibility, favourable optical properties, greater toughness and maximum adaptability to the canal and appropriate esthetic characteristics. However, the use of zirconia PC to restore endodontically treated teeth has limitations. In relation to its rigidity,zirconia posts cause more catastrophic root fractures than fiber posts. Also, the surface of zirconia posts does not bond to resin composite materials, leading to an inferior post retention4. Another limitation of zirconia PC is the difficulty in retrievability when endodontic retreatment is required. Titanium has gained wide acceptance in dentistry due to its biocompatibility, excellent corrosion resistance, reduced...