Efficacy of final irrigation--a scanning electron microscopic evaluation.

Area of Science:

• Endodontics
• Dental Materials Science

Background:

• Effective cleaning and disinfection of the root canal system are crucial for successful endodontic treatment.
• The smear layer, a debris layer formed during instrumentation, can impede disinfection and healing.

Purpose of the Study:

• To compare the efficacy of three different final irrigation solutions in removing pulpal remnants and smear layer from root canals.
• To evaluate the cleanliness of root canal walls using scanning electron microscopy.

Main Methods:

• An in vitro study using extracted teeth.
• Root canals were instrumented using the step-back technique and irrigated with 1% sodium hypochlorite (NaOCl).
• Final irrigation protocols varied: Group I (1% NaOCl, 10% citric acid, distilled water), Group II (0.5% NaOCl, EDTA-T), Group III (5% NaOCl, 3% hydrogen peroxide (H2O2), 5% NaOCl).
• Scanning electron microscopy (SEM) was used to assess the number of open dentinal tubules.

Main Results:

• The cervical third of the root canals consistently showed the highest number of visible open dentinal tubules across all groups.
• No statistically significant difference in smear layer removal was observed between Group I (citric acid) and Group II (EDTA-T).
• Groups I and II demonstrated significantly less effective smear layer removal compared to Group III (NaOCl/H2O2).

Conclusions:

• A final irrigation regimen combining sodium hypochlorite and hydrogen peroxide is more effective in removing smear layer and pulpal remnants than solutions using citric acid or EDTA-T.
• The effectiveness of smear layer removal varies depending on the irrigation solution used.