A scanning electron microscopic study of dentinal erosion by final irrigation with EDTA and NaOCl solutions.
OBJECTIVE
The purpose of this in vitro study was to examine dentinal erosion caused by final irrigation with EDTA and NaOCl.


METHODS
Twenty-five single-rooted human teeth were instrumented with rotary nickel-titanium Series 29 Profile Instruments. The teeth were divided into five groups and subjected to final irrigation as follows: group A, irrigated with 6% NaOCl (3 mL) for 2 min; group B, 15% EDTA (3 mL) for 1 min; group C, 15% EDTA (3 mL) for 1 min, followed by 6% NaOCl (3 mL) for 2 min; group D, 15% EDTA (3 mL) for 3 min and group E, 15% EDTA (3 mL) for 3 min, followed by 6% NaOCl (3 mL) for 2 min. Photomicrographs of dentinal walls were produced using a scanning electron microscope (3000 x) at 1, 3 and 6 mm from the apex. The amount of debris and dentinal tubule diameter were evaluated, and values were statistically analysed using one-way ANOVA and Fisher's PLSD test.


RESULTS
When the root canal was irrigated with 15% EDTA alone, the dentine had a smooth and plane appearance, and dentinal tubule orifices were regular and separated. When the root canal was irrigated with EDTA followed by NaOCL the dentine was eroded and the dentinal tubule orifices were irregular and rough. Dentinal tubule diameter increased to 3.43 +/- 0.23 microm in group C and to 3.93 +/- 0.44 microm in group E. Significant differences were observed between groups B and C, and between groups D and E (P < 0.05). However, more debris was removed by irrigation with EDTA followed by NaOCl than with EDTA alone (P < 0.05).


CONCLUSIONS
Final irrigation with 6% NaOCl accelerates dentinal erosion following treatment with 15% EDTA.
Niu
W
W
Pulp Biology and Endodontics, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. niu.endo@tmd.ac.jp
Yoshioka
T
T
Kobayashi
C
C
Suda
H
H
D000704:Analysis of Variance; D002614:Chelating Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D003722:Dental Alloys; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D004202:Disinfectants / Q000008:administration & dosage / Q000627:therapeutic use*; D004338:Drug Combinations; D004492:Edetic Acid / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D009532:Nickel; D012388:Root Canal Irrigants / Q000627:therapeutic use*; D018915:Root Canal Preparation / Q000295:instrumentation; D012973:Sodium Hypochlorite / Q000008:administration & dosage / Q000627:therapeutic use*; D013223:Statistics as Topic; D007507:Therapeutic Irrigation; D013997:Time Factors; D014025:Titanium; D019227:Tooth Apex / Q000187:drug effects / Q000648:ultrastructure
D002614:Chelating Agents; D003722:Dental Alloys; D004202:Disinfectants; D004338:Drug Combinations; D012388:Root Canal Irrigants; C040654:titanium nickelide; D009532:Nickel; D004492:Edetic Acid; D014025:Titanium; D012973:Sodium Hypochlorite