[ comparative study on the tensile strength of 3 luting cements: zinc phosphate, gloss ionomer and core maxII in the retention of custom posts [research]]

ABSTRACT

Post retention in endodontically treated teeth is an important factor in post-core technique. One of the factors effective in post retention is the type of applied luting cement. The goal of this study was to compare the tensile strength of 3 luting cemnts zinc phosphate, glass ionomer and Core max II in the retention of custom posts. In this study, 33 extracted maxillary central incisors, of the similar dimensions, were selected and divided into three groups randomly. All the teeth crowns were cut at 2 mm above CEJ. Following standard 2 root canal therapy, 2/3 of the canal space was enlarged with pizo reamer No 2 and 3. The length of posts were 12 mm. Acrylic resin patterns, of the same dimensions, were made for all samples. In order to do the tensile strength test, a hole with the diameter of 2 mm was prepared on the crown of each tooth. Castings were fabricated using silver cast alloy, Then each group was cemented with one of the studied cements. Following cementation, the tensile strength of posts was measured using the instron testing machine. In order to analyze the data, using SPSS software, one-way variance analysis test was used and for parried comparisons t-student test was used [P=0.05]. No statistically significant differences were found in the tensile strength of glass ionomer [29.11 kg] and zinc phosphate [29.19kg] [P=0.97], whereas both of these cements showed significantly higher tensile strength than Core maxII [11-56Kg] [P=0.000]. It is concluded that the retention of posts luted with glass ionomer and zinc phosphate are higher than Core max II