The effect of metal alloys and surface treatment on the retention of cast post: An in vitro study

The main objectives of this study were to determine the effect of different metal alloy posts with different surface treatments cemented within their prepared post canal spaces with two luting agents on the tensile strength of cast posts. Ninety sound upper permanent canines were collected; the anatomical crown were removed about (1) mm above the Cemento-Enamel Junction, Preparation of post space Was made by using slow speed straight hand piece fixed onto swiveled arm of the Surveyor direct acrylic pattern is made and undergoes a casting procedure immediately. The samples were divided into (3) groups thirty in each; first group was casted with MAX-white A alloy, second group with CB Blando (72) alloy and the third group with Palliag M alloy. Three surface treatment procedures for each group were done. Ten samples in each, first group was sandblasted with (100)m aluminum oxide andsecondone was sandblasted with (50) maluminum oxide and the third one receive no surfacetreatment and considered as a control group. Then each of these three groups were further subdivided randomly into two subgroups, (5) samples for each according to the type of luting agent used for cementation of the posts. First subgroup was cemented with zinc phosphate cement, the second subgroup was cemented by adhesive resin luting cement (Aureocem). A tensile strength tester was used to test the tensile strength. The results showed that there was no significant difference in the mean tensile strength among different alloys used and surface treatment with (100) m aluminum oxide procedure, produced the highest tensile strength when it is used in combination with resin cement. Examination of the type of failure after tensile test showed that most of the samples cemented with resin cement failed adhesively at resin-dentin interface. While for samples that were cemented with zinc phosphate most of failure were cohesive within the cement followed by failure at the metal cement interfac