Influência da limpeza mecânica com e sem o uso do microscópio operatório na resistência adesiva intrarradicular / Influence of mechanical cleaning with and without the use of the operating microscope in intraradicular adhesive strength

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

10/02/2012

RESUMO

In endodontic treatment, there is an imperative need to restore the tooth, reestablishing its functions, since there is always a risk of recontamination of the root canal system and fractures. These risks are higher when there is loss of dental structure, requiring intraradicular posts to hold the restoration procedures in place. For the definitive and immediate restoration of these teeth, adhesive bonding of fiberglass posts is a good option. However, adhesion to the root dentin presents some difficulties due to its morphological characteristics, such as reduced number of dentinal tubules, lower diameter of dentinal tubules, high C factor, distance from light source, and residues from restoring substances and materials used during the endodontic treatment. The objective of this study is, therefore, to evaluate whether mechanical cleaning of dentinal walls of the post space, whether under microscopy or not, is able to improve bond strength between the fiber post and the root dentin. The roots of 45 bovine incisive teeth were endodontically treated, irrigated with 5.25% sodium hypochlorite and restored with Pulp Canal Sealer¿. For Group 1 (G1), the control group, the post space was prepared in 10mm, with heated instrument, and cleaning was carried out using microapplicator and 70% alcohol, Gates Glidden #5 and White Post DC2© burs, with abundant irrigation with physiological saline solution (NaCl). After identical preparation for Group 2 (G2), gentle superficial cleaning was carried out using a sequence of long round # 4, 2 and 1 burs (HL), controlled speed of 500 rotations per minute (rpm) and torque of 0.8 Newton (N), cleaning using microapplicator and 70% alcohol, followed by irrigation with NaCl. Group 3 (G3) was prepared in the same way as G2, with the exception that the superficial cleaning with round burs was carried out under microscope, with a magnification of eight times. After adhesive bonding of White Post DC2© fiberglass posts using self-etching adhesive Clearfil¿ SE Bond and dual RelyX¿ ARC dual core resin cement, two 1mm thick sections were obtained from each third (cervical, middle, apical) and then submitted to the push-out test. The results in megapascal were analyzed through the Kruskal-Wallis nonparametric tests (p<0.05) and the Student-Newman-Keuls test (p<0.05). G3 presented the highest bond strength (2,37MPa) compared to G1 (0,95MPa) and G2 (1,04MPa), which, in turn, presented similar results. It is concluded that mechanical cleaning the dentinal walls of the post space with the superficial and gentle use round burs (HL) at 500 rpm, under surgical microscope with magnification of eight times (G3), showed the highest bond strength between the fiberglass post and the root dentin.

ASSUNTO(S)

endodontia dentina endodontics dentin

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