Effects of Reducing Agents on Birefringence Dentin Collagen after Use of Different Endodontic Auxiliary Chemical Substances

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• 作者：Danna Mota Moreira ; DDS ; MSc^&lowast ; ; Judith Pessoa de Andrade Feitosa ; PhD^&dagger ; ; S&eacute ; rgio Roberto Peres Line ; PhD^&Dagger ; ; Alexandre Augusto Zaia ; PhD^&lowast ; ; ^{zaia@fop.unicamp.br" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Auxiliary chemical solutions ; birefringence ; collagen ; reducing agents
• 刊名：Journal of Endodontics
• 出版年：2011
• 出版时间：October 2011
• 年：2011
• 卷：37
• 期：10
• 页码：1406-1411
• 全文大小：1147 K

文摘

The aim of this study was to evaluate the effect of 10% ascorbic acid or 10% sodium ascorbate on organic matrix collagen of bovine dentin root canal walls after irrigation with 5.25% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid (EDTA), or 0.9% sodium chloride.

c_2">Methods

Eighty bovine incisors were randomly divided into 8 groups (n = 10): group 1, 0.9% sodium chloride (control); group 2, 5.25% NaOCl + 17% EDTA (NaOCl + EDTA); group 3, 5.25% NaOCl + 17% EDTA + 10% ascorbic acid (NaOCl + EDTA + AA); group 4, 5.25% NaOCl + 17% EDTA + 10% sodium ascorbate (NaOCl + EDTA + SA); group 5, 5.25% NaOCl (NaOCl); group 6, 17% EDTA; group 7, 10% ascorbic acid (AA); and group 8, 10% sodium ascorbate (SA). Teeth were chemomechanically prepared, submitted to histologic processing, and stained with Sirius Red dye to be analyzed under polarized light microscopy. Absorbance assay was also performed to confirm the loss of collagen.

c_3">Results

NaOCl + EDTA and NaOCl groups presented a significantly different birefringence pattern compared with the control group (m>Pm> < .05). The measurement of the optical retardations of NaOCl + EDTA + SA indicated that this group was not statistically different from the control group. Although the measurement of the optical retardations of NaOCl + EDTA + AA was statistically different from the control group, the results were significantly higher than for NaOCl + EDTA. The birefringence of EDTA, AA, and SA groups was not statistically different from that of control group. The absorbance assay of NaOCl + EDTA and NaOCl groups confirmed the loss of collagen (m>Pm> < .05).

c_4">Conclusions

It is possible to conclude that 5.25% NaOCl, whether associated or not with 17% EDTA, causes birefringence alterations and loss of dentin collagen. These alterations reduced the ability of Sirius Red to bind with collagen fiber molecules. The reductions in the optical retardation values could be reversed by the application of either 10% ascorbic acid or 10% sodium ascorbate after 5.25% sodium hypochlorite and 17% EDTA irrigation.