Effectiveness of root canal debris removal using passive ultrasound irrigation with chlorhexidine digluconate or sodium hypochlorite individually or in combination as irrigants.

AIM The aim of this in vitro study was to evaluate the cleaning capacity of different auxiliary chemical substances energized with ultrasound in radicular dentin using morphologic analysis. METHODS AND MATERIALS Twenty-eight single-canal, mandibular incisors were prepared with the Hero 642 canal preparation system following the sequence: 25/12, 30/06, 35/02, and 40/02, 1 mm from the apex. The specimens were then divided into four groups of seven teeth. During biomechanical preparation the teeth were irrigated with 2 ml of distilled water between files. Each group of specimens (n=7) received a final irrigation with 100 ml of the following irrigants that were activated with ultrasound for 3 minutes: Group 1- distilled water; Group 2- 0.2% chlorhexidine digluconate (CHX); Group 3- 2.5% sodium hypochlorite (NaOCl); and Group 4-the filtrate obtained after combining 0.2% CHX and 2.5% NaOCl. The apical portions of the root canals from each group were then submitted to histological processing and analyzed using optical microscopy. RESULTS Results showed statistical differences between the groups (p<0.01). Groups 1 and 2 (distilled water and 0.2% CHX respectively) were statistically similar in terms of a greater amount of debris, whereas 2.5% NaOCl and the filtrate were more efficient in removal of debris. CONCLUSION There is no additional benefit in terms of debris removal from root canal walls by irrigating with the filtrate obtained from the combination of NaOCl and CHX when compared to using NaOCl alone. CLINICAL SIGNIFICANCE The findings of this study suggest the time and expense of preparing and using a combination of NaOCl and CHX is not warranted compared to using NaOCl alone for root canal irrigation.