Investigation of a Calcium Hydroxide Overflowing From Root Apex during Calcium Hydroxide Removal

Abstract

Calcium hydroxide has been widely used as intracanal medicament recently. However, removing calcium hydroxide accumulated in the apical foramen was difficult, and there is a risk of overflowing outside of the apical foramen during removing procedure. In this study, we investigated (1) the status of overflow from root apex foramen in each removal method using hand file or ultrasonic scaler, (2) possibility of reducing overflow in combination with citric acid solution or EDTA solution. Twenty-four maxillary premolar artificial teeth were performed root canal enlargement using K-fail until No.25 or No.30 size of thickness in each 12 teeth. After finishing root canal enlargement, calcium hydroxide was filled within root canal apex completely. Then calcium hydroxide was removed using ultrasonic scaler or hand file. Furthermore purified water, citric acid solution or EDTA solution was prepared as auxiliary agents respectively. After removing calcium hydroxide from each root canal was finished, the condition of calcium hydroxide overflowing from root apex was observed using stereomicroscope. Calcium hydroxide in the root canal was sufficiently removed from root canals in the groups using ultrasonic scaler. However slighted calcium hydroxide was remained around root apex in the groups using hand file. Overflow of calcium hydroxide to outside around root apex was observed both using ultrasonic scaler and hand file. The tendency of calcium hydroxide overflowing was higher in the case of using ultrasonic scaler than using hand file. In the groups of using hand file, no significant difference was observed for the different size of root canal enlargement, however overflow of calcium hydroxide was clearly higher in 30 size of root canal enlargement using ultrasonic scaler. The use of citric acid solution and EDTA solution as auxiliary agents showed that overflow of calcium hydroxide was decreased compared without using them. In particular, the decrease of overflowing was more clearly using citric acid solution than using EDTA solution. It is recommended that using hand file on removal apex areas of calcium hydroxide to reduce amount of overflowing and improve the removal efficiency. Moreover reducing the risk of calcium hydroxide overflowing are expected using citric acid solution or EDTA solution.