Retrievability of Intracanal Medicament from Root Canals: An In-vitro CBCT Volumetric Analysis

Introduction: The complete removal of Calcium Hydroxide {Ca(OH)2 } using various techniques remains a challenge in root canal therapy. One of the most commonly used methods for removing calcium hydroxide is by using a Master Apical File (MAF) along with sodium hypochlorite and Ethylenediaminetetracetic Acid (EDTA). Various new modalities, like Canal Brush, NaviTip and file systems, have emerged to tackle the residual calcium hydroxide in the canal; but none of these methods have been able to completely remove it from the canal. Aim: To evaluate and compare the efficacy of H-files, NaviTip FX and Canal Brushes in removing calcium hydroxide intracanal medicament from root canals. Materials and Methods: This in-vitro study was carried out in the Department of Conservative Dentistry and Endodontics at KM Shah Dental College and Hospital, Vadodara, Gujarat, India, from December 2023 to March 2024. To standardise the length at 14 mm, 30 mandibular premolar teeth (n=30) with a single root were decoronated at the Cementoenamel Junction (CEJ). The working length was determined, followed by the cleaning and shaping of all specimens using ProTaper Rotary Files. Intracanal medicament (Metapex) was placed and the canals were sealed with Glass Ionomer Cement (GIC). The specimens were then placed at 37±1ºC and 100% relative humidity for 30 days. The medicament was subsequently removed by three different protocols: H-file, NaviTip FX and Canal Brush (n=10 each). The residual volumes in the mesial, distal and apical thirds were assessed, referring to the volume of medicament left in the canal, which was measured using Cone-beam Computed Tomography (CBCT). The recorded variables were analysed using one-way Analysis of Variance (ANOVA) post-hoc tests (p<0.05). Results: The Canal Brush removed the maximum amount of Metapex in the apical third (0.108) of the roots of the premolars, followed by NaviTip FX and then H-file. In the middle third of the root, NaviTip FX removed more Metapex than the Canal Brush, followed by H-files. A comparison of retrieval between and within the groups it showed that none of the techniques were capable of removing all the Metapex from the specimens, with p>0.05. Conclusion: The present study demonstrated that the Canal Brush showed superior results in retrieving Metapex from the apical third of the root and the distal side (middle third), whereas NaviTip FX removed more Metapex from the mesial side (middle third) of the root, but H-file exhibited the least efficacy in the retrieval of Metapex. Total removal of calcium hydroxide from the entire canal is not possible regardless of the technique used.