Smear layer dissolution by peracetic acid of low concentration.
OBJECTIVE
To test the effect of a noncaustic concentration of peracetic acid (PAA) in a standardized smear layer model.


METHODS
The smear layer dissolution kinetics of 0.5% PAA on human dentine were compared to those of 2.25% PAA and 17% ethylenediaminetetraacetic acid (EDTA) solutions. Coronal dentine discs were prepared from six human maxillary molars. A standardized smear layer was produced on the pulpal side of each disc. The smear layer-covered surface was divided into three similar areas and then exposed to one of the three solutions tested. Co-site image sequences (around 40, 500 ×) of the specific areas were obtained after four cumulative demineralisation times (15, 30, 60 and 180 s). An image processing and analysis sequence measured sets of images, providing data of area fraction (AF, dentine-free area in % of total analysis area). A general linear model for repeated measures was used to verify the influence of time and solution type over the change in AF from baseline (ΔAF).


RESULTS
Overall, EDTA and 2.25% PAA produced higher ΔAF values than the 0.5% PAA solution (P < 0.05). No significant difference was observed in ΔAF between 15 s and 30 s (P > 0.05). After 60 s of etching, all tested solutions produced similar ΔAF (P > 0.05), whereas at 180 s, ΔAF of both EDTA and 2.25% PAA continued to increase (P > 0.05).


CONCLUSIONS
After 60 s of contact, the 0.5% PAA solution dissolved smear layer as well as 2.25% PAA and 17% EDTA.
Veiga de Almeida University (UVA), Rio de Janeiro, Brazil. endogus@gmail.com
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De-Deus
E M
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Souza
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Marins
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Reis
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Paciornik
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Zehnder
D003646:Debridement / Q000379:methods; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000648:ultrastructure; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D003808:Dentin Solubility / Q000187:drug effects; D004202:Disinfectants / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004492:Edetic Acid / Q000494:pharmacology; D006801:Humans; D016014:Linear Models; D010463:Peracetic Acid / Q000494:pharmacology*; D012388:Root Canal Irrigants / Q000494:pharmacology*; D018915:Root Canal Preparation / Q000379:methods*; D016369:Smear Layer; D013499:Surface Properties; D013997:Time Factors
D004202:Disinfectants; D012388:Root Canal Irrigants; D004492:Edetic Acid; D010463:Peracetic Acid