THE FIT OF CAST AND PREMACHINED IMPLANT ABUTMENTS

Statement of problem. There is insufficient information regarding the adaptation of abutments to implants. Purpose. This study assessed the adaptation of premachined, cast, and laboratory modified premachined a butments to implants at two sites: abutment/implant interface and scre w to screw seat. Material and methods. Six combinations of abutments a nd implants were studied: CeraOne abutments joined to Nobel Biocare im plants; STR (Implant Innovations Inc.) abutments joined to 31 implants ; Cast UCLA (31) abutments subjected to porcelain firing cycles and jo ined to 31 implants; Cast UCLA abutments subjected to porcelain firing cycles and joined to Nobel Biocare implants; UCLA. premachined abutme nts cast with gold palladium alloy and subjected to porcelain firing c ycles (later joined to 31 implants); and UCLA premachined abutments jo ined to 31 implants. Each group contained five assemblies. Results. Th e adaptation of abutments to implants was closer and the amounts of co ntact larger for assemblies with premachined and laboratory modified p remachined abutments than for those with cast abutments. Conclusion. T he finishing of custom-made abutments requires further refinement.