Is the presence of the smear layer a limiting factor for root dentin permeability in primary teeth?
OBJECTIVE
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.
Pascon
Fernanda Miori
FM
Piracicaba Dental School, University of Campinas, Piracicaba, São Paulo, Brazil.
Kantovitz
Kamila Rosamilia
KR
Sinhoreti
Mario Alexandre Coelho
MA
Puppin-Rontani
Regina Maria
RM
D002710:Chlorhexidine; D004396:Coloring Agents; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D003806:Dentin Permeability; D004338:Drug Combinations; D006801:Humans; D006861:Hydrogen Peroxide; D016014:Linear Models; D008751:Methylene Blue; D008855:Microscopy, Electron, Scanning; D012388:Root Canal Irrigants; D018915:Root Canal Preparation / Q000379:methods; D016369:Smear Layer; D017693:Sodium Bicarbonate; D012973:Sodium Hypochlorite; D014094:Tooth, Deciduous / Q000033:anatomy & histology*; D014465:Ultrasonics
D004396:Coloring Agents; D004338:Drug Combinations; D012388:Root Canal Irrigants; C069467:modified Dakin's solution; D017693:Sodium Bicarbonate; D006861:Hydrogen Peroxide; D012973:Sodium Hypochlorite; D002710:Chlorhexidine; D008751:Methylene Blue