AbstructObjective: Sodium hypochlorite has been routinely delivered into the pulp canal via irrigation needle. The study aimed at to determine the advantage and disadvantage of apical extrusion of sodium hypochloride using monoject or hypodermic irrigation needle in root canal treatment. Materials and Methods: Eighty single rooted teeth with closed apices were used in this in vitro study to determine apical extrusion of sodium hypochlorite using the gel diffusion technique. Extracted human anterior teeth were used as study samples. Monoject (size 27G) and hypodermic (27G× ½, 0.40×13mm, Terumo Needle) irrigation needle were used. The highest concentration of 5.25% hypochlorite solution was used for irrigation. To standardize the time diffusion of the dye, the gel was photographed at exactly 20 minutes after the initial irrigation with sodium hypochlorite. Results: A total of 36 out of 40 (90%) teeth in the hypodermic needle group showed positive apical extrusion compared to 14 of 40 teeth (35%) in the monoject group regardless of apical size. The discoloration of agar was clearly obtained after the sample tooth had been irrigated with sodium hypochlorite indicating the sign of apical extrusion. It is therefore; recommend that monoject irrigation needle should be used by students regardless of costs during root canal treatment in the polyclinic or dental clinic due to its safety in order to prevent sodium hypochlorite accident. Conclusion: Monoject needle showed significantly less sodium hypochlorite extrusion compared to hypodermic needle

Background Recent research has explored volumetric assessment in three-dimensional (3D) imaging procedures for sexual dimorphism. The 3D techniques have enabled a more realistic, accurate, and non-invasive visualization of sex-related anatomical parameters, such as the size and shape of human teeth. Aim To perform sexual dimorphism based on dental tissue volumes of permanent left maxillary and mandibular canines in a Malaysian population. Methods A cross-sectional study was carried out on 220 post-mortem computed tomography (PMCT) scans of Malaysian subjects (114 males and 106 females) aged between 18 and 40 years old. The permanent left maxillary and mandibular canines were analysed based on the volume of their (I) enamel cap, (II) coronal dentine, and (III) root, as well as the combination between the three dental tissue volumes (DTV). 3D Slicer version 4.10.2 computer software was used to perform a semi-automated segmentation of the anatomic regions of interest of each tooth. Results The DTV of the permanent left maxillary and mandibular canines showed sexual dimorphism as the males presented larger DTV than females (p < 0.05). After binary logistic regression, the DTV revealed an overall sex classification rate of 60 to 74.1%. The DTV of the permanent left mandibular canine had more discriminant power to correctly classify males and females compared to the left maxillary canine. Conclusions The volumetric assessment of the dental tissues of the permanent left maxillary and mandibular canines could discriminate sex in the Malaysian population. Given the limited classification rate, this approach could act solely as a supplementary tool to existing sex estimation methods.