%0 Journal Article
%T pH and Antimicrobial Activity of Portland Cement Associated with Different Radiopacifying Agents
%A Juliane Maria Guerreiro-Tanomaru
%A Ana L¨ªvia G. Corn¨¦lio
%A Carolina Andolfatto
%A Loise P. Salles
%A M¨¢rio Tanomaru-Filho
%J ISRN Dentistry
%D 2012
%R 10.5402/2012/469019
%X Objective. The aim of this study was to evaluate the antimicrobial activity and pH changes induced by Portland cement (PC) alone and in association with radiopacifiers. Methods. The materials tested were pure PC, PC + bismuth oxide, PC + zirconium oxide, PC + calcium tungstate, and zinc oxide and eugenol cement (ZOE). Antimicrobial activity was evaluated by agar diffusion test using the following strains: Micrococcus luteus, Streptococcus mutans, Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans. After 24 hours of incubation at 37¡ãC, inhibition of bacterial growth was observed and measured. For pH analysis, material samples ( ) were placed in polyethylene tubes and immersed in 10£¿mL of distilled water. After 12, 24, 48, and 72 hours, the pH of the solutions was determined using a pH meter. Results. All microbial species were inhibited by the cements evaluated. All materials composed of PC with radiopacifying agents promoted pH increase similar to pure Portland cement. ZOE had the lowest pH values throughout all experimental periods. Conclusions. All Portland cement-based materials with the addition of different radiopacifiers (bismuth oxide, calcium tungstate, and zirconium oxide) presented antimicrobial activity and pH similar to pure Portland cement. 1. Introduction The ideal root-end filling material should present certain characteristics, such as ability to seal the root canal system, dimensional stability in the presence of humidity, and radiopacity. Equally important are its ability to induce repair, antimicrobial action, and biocompatibility. All these properties contribute towards the success of endodontic surgery [1]. Since its introduction as a root-end filling material in 1993, the clinical applications of mineral trioxide aggregate (MTA) have been expanded. Presently, MTA is also used as a reparative cement due to its alkaline pH [2]. The mechanism of action of MTA is similar to that of calcium hydroxide. However, the manipulation and insertion of this cement into retrograde preparations are extremely difficult. Yet another disadvantage of MTA is its high cost [3]. Several studies have evaluated Portland cement (PC) as an alternative to MTA [4, 5]. One of the limitations of PC is its low radiopacity, requiring addition of a radiopacifier prior to use. Bismuth oxide, the radiopacifying agent present in MTA, is not considered ideal by some authors. A number of studies have shown that this radiopacifier interferes with the mechanical stability of the cement by increasing its porosity [6] and also that it may negatively affect
%U http://www.hindawi.com/journals/isrn.dentistry/2012/469019/