Influence of core-finishing intervals on tensile strength of cast posts-and-cores luted with zinc phosphate cement.
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 well-documented. 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 core-finishing 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.
Department of Occlusion, Fixed Prosthodontics and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, MG, Brazil.
Michele Andrea Lopes
MA
Iglesias
Gabriela Campos
GC
Mesquita
Analice Giovani
AG
Pereira
Lucas Costa de Medeiros
LC
Dantas
Luís Henrique Araújo
LH
Raposo
Carlos José
CJ
Soares
Adérito Soares da
AS
Mota
D000818:Animals; D002417:Cattle; D002484:Cementation / Q000379:methods; D016001:Confidence Intervals; D003762:Dental Instruments; D003775:Dental Polishing / Q000295:instrumentation* / Q000379:methods; D017268:Dental Prosthesis Retention; D008422:Materials Testing; D011176:Post and Core Technique; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D015036:Zinc Phosphate Cement / Q000737:chemistry*
D015036:Zinc Phosphate Cement