Efficacy of different irrigants in the removal of calcium hydroxide from root canals.
OBJECTIVE
To compare the efficacy of different solutions (1% sodium hypochlorite, 10% citric acid and 20% EDTA) in the removal of calcium hydroxide from root canals.


METHODS
One hundred single-rooted maxillary incisors were prepared to size 50 and split longitudinally. Two standardized grooves were cut into the apical and coronal part of the root canal dentine and filled with calcium hydroxide. The reassembled teeth were irrigated with a syringe and a size 30 needle using the following irrigants: (i) 20% EDTA, (ii) 10% citric acid, (iii) 1% NaOCl, (iv) 10% citric acid + 1% NaOCl, (v) 20% EDTA + 1% NaOCl and (vi) water (control). Volume of irrigant was 20 mL in each group, and irrigation time was 5 min. Evaluation of cleanliness of the blinded specimens was performed by two calibrated observers under a microscope with 30x magnification using a four-grade scoring system as described by van der Sluis et al. (2007). Statistical evaluation was performed using a SAS-macro for non-parametric multifactorial analysis (P < 0.05).


RESULTS
The best results were found for irrigation with EDTA and citric acid, whereas NaOCl and water showed the least effect. The combinations of irrigants did not result in improvement in terms of cleanliness.


CONCLUSIONS
None of the irrigants nor their respective combinations were able to completely remove the calcium hydroxide. Chelating agents such as citric acid and EDTA showed the best results. The combination of chelators and NaOCl did not result in significant improvement of calcium hydroxide removal.
Department of Preventive Dentistry, Periodontology and Cariology, University of Göttingen, Göttingen, Germany. troedig@med.uni-goettingen.de
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T
Rödig
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S
Vogel
A
A
Zapf
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M
Hülsmann
D002126:Calcium Hydroxide; D019343:Citric Acid / Q000737:chemistry / Q000627:therapeutic use; D004492:Edetic Acid / Q000737:chemistry / Q000627:therapeutic use; D006801:Humans; D007180:Incisor; D008437:Maxilla; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants / Q000737:chemistry / Q000627:therapeutic use*; D018915:Root Canal Preparation / Q000379:methods; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000737:chemistry / Q000627:therapeutic use
D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D019343:Citric Acid; D004492:Edetic Acid; D012973:Sodium Hypochlorite; D002126:Calcium Hydroxide