Impact of Calcium Hydroxide Particle Size on the Intracanal Medicament Penetration Efficacy

Calcium hydroxide (Ca (OH) 2 ) is an intracanal medicament used as a disinfectant in cases of tooth inflammation with ad dubia prognosis. The success of root canal treatment depends on the ability of intracanal medicaments to eliminate pathogenic bacteria present in the walls of narrow and complex root canals by releasing calcium and hydroxyl ions at the closest contacts. This study aimed to evaluate the effect of particle size on the ability to penetrate Ca (OH) 2 in the coronal, middle, and apical root canals. Fifteen mandibular premolars extracted for orthodontic and periodontal purposes were collected and cut to produce root canals with a length of 12 cm. The root canals were then prepared with a Protaper SX-F3 needle and irrigated using a solution of 2.5% NaOCl, NaCl, and 17% EDTA as lubrication at each needle change. Ca (OH) 2 with different particle sizes in paste form was manipulated with distilled water at a concentration of 0.8 g/mL then the paste was applied to the prepared tooth root canals and covered with a temporary filling. The samples were then stored in an incubator at 37 °C for 7 days. Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDX) was performed on the transverse surfaces of the coronal 1/3, middle 1/3 and apical 1/3 of the tooth. The maximum penetration depth was evaluated by measuring the maximum distance between the dentin canal wall and Ca (OH) 2 present in the dentinal tubules. In all three zones, the Ca (OH)₂ nanoparticles had a greater penetration depth than the Ca (OH)₂ nanoparticles (P<0.001). In both groups, the penetration depth increased from the apical to the coronal section. All differences in the penetration test ability of the Ca (OH)₂ nanoparticles and Ca (OH)₂ microparticles at all depths of the surface. Ca (OH)₂ nanoparticles penetrate deeper into the dentinal tubules than Ca (OH)₂ microparticles do.