Intracanal medicament removal revisited: A volumetric cone beam computed tomography analysis of four techniques

Microorganisms in the root canal are the primary cause of pulpal and periapical disease. Although chemomechanical preparation reduces microbial load, complex canal anatomy hinders complete disinfection, necessitating intracanal medicaments like calcium hydroxide. However, residual medicament can compromise sealer penetration, dentin bonding, and increase apical microleakage, making its complete removal crucial. Techniques such as needle irrigation, sonic activation, passive ultrasonic irrigation, and XP-Endo Finisher have been proposed to improve their removal, while cone beam computed tomography (CBCT) enables accurate 3D assessment of residual materials.

The aim of this study was to evaluate and compare the effectiveness of these four techniques in removing calcium hydroxide from root canals, using CBCT for volumetric analysis.

Sixty-four extracted human single-rooted premolars were collected and stored according to OSHA guidelines. The teeth were decoronated, and canals were prepared using a standardized chemomechanical protocol. Calcium hydroxide paste was placed as an intracanal medicament, and the samples were stored at 37°C and 100% relative humidity for 1 week. A pre-retrieval CBCT scan was obtained to assess the initial medicament volume. Specimens were randomly divided into four groups (n = 16) based on the removal technique: sonic activation, XP-Endo Finisher, passive ultrasonic irrigation and conventional needle irrigation. Following medicament removal using these four techniques, postretrieval CBCT scans were performed, and volumetric analysis was conducted using imaging software to quantify residual calcium hydroxide.

Data were analyzed using IBM SPSS; intergroup comparisons used analysis of variance/Kruskal-Wallis and pre-post changes used paired tests, with significance set at P < 0.05.

XP-Endo Finisher showed the highest reduction (95.3%), followed by passive ultrasonic irrigation (92.4%) and sonic activation (88.6%), with no significant differences (P > 0.05). Needle irrigation was least effective (74.6%), leaving significantly more residual Ca (OH) ₂ (P < 0.001).

All techniques reduced calcium hydroxide, with the XP- Endo-finisher being the most effective, while needle irrigation was the least effective.