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Is the presence of the smear layer a limiting factor for root dentin permeability in primary teeth?
Fernanda Miori Pascon1, Kamila Rosamilia Kantovitz, Mario Alexandre Coelho Sinhoreti
1Piracicaba Dental School, University of Campinas, Piracicaba, São Paulo, Brazil.
Purpose:
The purpose of this study was to correlate the dye permeability to the morphological aspect (presence or absence of a smear layer) of the primary root dentin wall, using scanning electron microscopy, regarding the endodontic preparation and irrigation methods. The hypothesis evaluated was that there was a correlation between the dye permeability and the morphological aspect of the primary root dentin.
Methods:
A total of 112 extracted primary roots were distributed into the following groups: Dakin's liquid, Dakin+hydrogen peroxide; 2% chlorhexidine gel; and saline solution. Manual (MI) or Ultrasonic irrigation (UI) was performed. The roots were made impermeable, filled with dye (2% methylene blue), and longitudinally sectioned. The halves were divided in cervical, middle, and apical thirds for dye penetration measurement. The samples were observed under a scanning electron microscope. The data were submitted to linear regression analysis with a dummy variable (P<.05).
Results:
The data revealed a relationship between decreasing permeability and the presence of a smear layer on root canal dentin walls for MI in the middle third (P=.0147). Regarding UI, no statistically significant relation was observed (P>.05).
Conclusions:
The presence of a smear layer on root canal dentin walls was not a limiting factor to dye penetration in all groups except the middle third for manual irrigation.
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