Análise comparativa da adaptação marginal, infiltração microbiana e da citotoxicidade em ápices retrobturados com os cimentos Palacos-R e MTA

Abstract

The success of endodontic treatment is related to a proper cleaning, and a good seal of root canal system. Paraendodôntic surgery is a procedure that aims to solve problems that couldn't be solved by conventional endodontic treatment. These surgeries are performed by exposing and removing the root tips, making retrocavitations on the long axis of the root canals, and retrofilling with specific sealant materials Thus, the present work had the objective of performing a comparative study of MTA (Mineral Trioxide Aggregate) and Palacos-R (bone cement) cements in endodontic retrofillings through the evaluation of marginal adaptation, microbial infiltration and cytotoxicity. To evaluate the marginal adaptation and the sealing ability by the microbial infiltration method, 48 human permanent upper canines were selected, instrumented and obturated. The apicetomies for removal of the apical 3mm from the roots were performed using the diamond ultrasound tip CVD DENTUS 8.1117. The retroprepares were made with ultrasonic CVD DENTUS 6.1107-E diamond tips, 4mm deep. The 28 samples were retrobured with the Palacos-R (HERAEUS KULZER) cement and the gray MTA cement (ANGELUS), in a total of 14 specimens for each cement tested. The evaluation of the marginal adaptation was performed by scanning electron microscopy (SEM) with 8 teeth (4 for each retroburst cement). Sealing capacity was analyzed through bacterial infiltration assays with Enterococcus faecalis (ATCC 29212), with 10 teeth for the Palacos-R group, 10 teeth for the gray MTA group, 10 teeth for the positive control group and 10 teeth for the the negative control group. Cytotoxicity evaluation was performed with the eluates of the cements by the MTT test, with mouse gingival fibroblasts (L929 cells). The SEM analysis showed a better adaptation of the Palacos-R to the retroprepares than the gray MTA. Although Palacos-R had the lowest numerical rates of bacterial infiltration, there was no statistically significant difference between the two. The two cements did not demonstrate cytotoxic activity on L929 cells, however in the doubly concentrated extracts the Palacos-R cement was less cytotoxic than the gray MTA (P <0.0001). It was concluded that the Palacos-R presented a better marginal adaptation than the gray MTA to the SEM, that there was no difference between the Palacos-R and the MTA in terms of microbial infiltration and cytotoxicity, making it a promising retrofilling material to be used in Endodontics