Resumo

RODRIGUES, Vanilde Rocha. Effect of the action of diamond burs with high speed on the tensile strength of cores cemented with zinc phosphate at different preparation times. RGO, Rev. gaúch. odontol. (Online) [online]. 2015, vol.63, n.4, pp. 405-410. ISSN 1981-8637.

Objective To know the finishing effect, in order to be able to safely proceed with the cores preparation in the daily clinic, without compromising the prosthetic restoration longevity. Methods This study used 48 human single-rooted premolars, which after the section of its crowns, were endodontically treated, and its root canal prepared 8 mm deep to receive cores casting in cobalt-chrome alloy. Cementing was made with zinc phosphate and the tensile test performed at different preparation times: G1 - without re-preparation after cementation (control); G2 - re-prepared 24 hours after cementation, and G3 - re-prepared 15 minutes after cementation. Results Statistical analysis showed no significant difference in the tensile strength values in the different groups (p = 0.233), in other words, the core re-preparation 15 minutes or 24 hours after the cementation caused no significant reduction in tensile strength between the core and the root remaining when using the zinc phosphate cement. Conclusion The metallic core re-preparation cast 15 minutes or 24 hours after cementation caused no significant reduction in tensile strength between the cast metallic core and the root remaining, although in absolute values there was an important difference.

Palavras-chave : Cementing film.; Core re-preparation.; Post and core.; Posts retention.; Zinc phosphate cement..