Influence of core-finishing intervals on tensile strength of cast posts-and-cores luted with zinc phosphate cement

Abstract

The core finishing of cast posts-and-cores after luting is routine in dental practice. However, the effects of the vibrations produced by the rotary cutting instruments over the luting cements are not welldocumented. This study evaluated the influence of the time intervals that elapsed between the cementation and the core-finishing procedures on the tensile strength of cast posts-and-cores luted with zinc phosphate cement. Forty-eight bovine incisor roots were selected, endodontically treated, and divided into four groups (n = 12): GA, control (without finishing); GB, GC, and GD, subjected to finishing at 20 minutes, 60 minutes, and 24 hours after cementation, respectively. Root canals were molded, and the resin patterns were cast in copper-aluminum alloy. Cast posts-and-cores were luted with zinc phosphate cement, and the corefinishing procedures were applied according to the groups. The tensile tests were performed at a crosshead speed of 0.5 mm/min for all groups, 24 hours after the core-finishing procedures. The data were subjected to one-way analysis of variance (ANOVA) and Tukey's test (α = 0.05). No significant differences were observed in the tensile strengths between the control and experimental groups, regardless of the time interval that elapsed between the luting and finishing steps. Within the limitations of the present study, it was demonstrated that the core-finishing procedures and time intervals that elapsed after luting did not appear to affect the retention of cast posts-and-cores when zinc phosphate cement was used.

Effect of the action of diamond burs with high speed on the tensile strength of cores cemented with zinc phosphate at different preparation times

“…Small variations must be considered in some factors such as room temperature, cement time and handling speed, time spent to be taken to the canal and core, pressure from the operator hand at the preparation time, among others, may have interfered in the results, since the other conditions had been fully satisfied Results similar to this study were found in the studies of Lund & Wilcox 14 , Rocha et al 15 , Domingos et al 16 , Iglesias 17 and Oliveira et al 18 , concluding that the preparation time after cementation does not interfere with the retention of cores cemented with zinc phosphate cement.…”

A Comparative Evaluation of Fracture Resistance of Endodontically Treated Teeth restored with Composite Resin Core using Two Different Designs of Prefabricated Metal Posts: An in vitro Study

“…9,10 For decades, zinc phosphate cement has been the gold standard for cementing cast post and cores, although resin luting agents have recently been studied as alternatives. 11 Many researchers use glass ionomer cement for cementing post. But, glass ionomer cement has several limitations and has been criticized by several authors, 12,13 whereas resin cement is more expensive and its bonding to the metallic post is questionable unless a primer is used for bonding.…”