Restor Dent Endod.  2015 Feb;40(1):44-49. 10.5395/rde.2015.40.1.44.

Calcium hydroxide dressing residues after different removal techniques affect the accuracy of Root-ZX apex locator

• Uzunoglu E
• Eymirli A
• Uyanik MO
• Calt S
• Nagas E

• KMID: 2316923
• DOI: http://doi.org/10.5395/rde.2015.40.1.44

Abstract

OBJECTIVES
This study compared the ability of several techniques to remove calcium hydroxide (CH) from the root canal and determined the influence of CH residues on the accuracy of the electronic apex locator.
MATERIALS AND METHODS
Root canals of 90 human maxillary lateral incisors with confirmed true working length (TWL) were prepared and filled with CH. The teeth were randomly assigned to one of the experimental groups according to the CH removal technique (n = 14): 0.9% saline; 0.9% saline + master apical file (MAF); 17% ethylenediamine tetraacetic acid (EDTA); 17% EDTA + MAF; 5.25% sodium hypochlorite (NaOCl); 5.25% NaOCl + MAF. Six teeth were used as negative control. After CH removal, the electronic working length was measured using Root-ZX (Morita Corp.) and compared with TWL to evaluate Root-ZX accuracy. All specimens were sectioned longitudinally, and the area of remaining CH (CH) and total canal area were measured using imaging software.
RESULTS
The EDTA + MAF and NaOCl + MAF groups showed better CH removal than other groups (p < 0.05). Root-ZX reliability to prevent overestimated working length to be > 85% within a tolerance of +/- 1.0 mm (p < 0.05). There was strong negative correlation between amount of CH residues and EAL accuracy (r = -0.800 for +/- 0.5 mm; r = -0.940 for +/- 1.0 mm).
CONCLUSIONS
The mechanical instrumentation improves the CH removal of irrigation solutions although none of the techniques removed the dressing completely. Residues of CH medication in root canals affected the accuracy of Root-ZX adversely.

Keyword

Apex locator; Calcium hydroxide; EDTA; Sodium hypochlorite

MeSH Terms

Bandages*
Calcium Hydroxide*
Dental Pulp Cavity
Edetic Acid
Humans
Incisor
Sodium Hypochlorite
Tooth
Calcium Hydroxide
Edetic Acid
Sodium Hypochlorite

Figure

• 

  Figure 1 Representative stereomicroscopic images. (a) Control group, Root canal is completely filled with calcium hydroxide (CH); (b) CH removed with 17% EDTA + MAF, Root canal is almost empty except apical section; (c) CH removed with 5.25% NaOCl, Less than half of the root canal is filled with CH.

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