The Impact of Coronal Flaring Files on Pericervical Dentin Thickness in Mandibular Molars.

INTRODUCTION: This study aimed to assess the influence of different coronal flaring files on dentin removal in mandibular teeth using cone-beam computed tomographic (CBCT) images. METHODS: CBCT images of 48 mandibular molar teeth were acquired and randomly divided into 2 main groups, with each main group further divided into 3 subgroups. In the first main group, root canal preparation was performed using TruNatomy (Dentsply Sirona, Ballaigues, Switzerland), ProTaper Gold (Dentsply Sirona), and One Curve (Micro-Mega, Besancon, France) files without the use of coronal flaring files. In the second main group, root canal preparation was performed using the same files with the use of coronal flaring files. After the completion of root canal preparation, a second set of CBCT images was obtained. Subsequently, the dentin removal and remaining critical dentin were assessed by measuring at 4 distinct points below the furcation level. Data were compared between groups using the Mann-Whitney U and Kruskal-Wallis tests with alpha set at 5%. RESULTS: The ProTaper Gold files demonstrated higher dentin removal compared with the TruNatomy files. In the no-flaring groups, the One Curve files exhibited greater dentin removal than the TruNatomy files at specific levels. The use of coronal flaring files generally did not significantly impact dentin removal, except for certain cases in the TruNatomy and ProTaper Gold groups. CONCLUSIONS: The TruNatomy instrument group was more effective in preserving pericervical dentin compared with the other instrument groups. Coronal flaring files can be confidently used to preserve critical dentin during root canal treatment.

Can ultrasonography be used to determine working length in endodontic treatment? An in vitro study.

This study was conducted to evaluate efficacy of ultrasonography (USG) in determining working length in in-vitro conditions. Twenty five access cavities of maxillary incisor teeth were opened and actual working lengths (AWL) were measured with dental operating microscope. The working length were then measured with an electronic apex locator and USG. USG and apex locator measurements were statistically analyzed using one sample t-test and compared with AWL. The mean AWL measurment was 20.68 mm. USG measured the working length slightly longer (21.09 mm) than the measurements of apex locator (20.64 mm). Statistical analysis showed that the USG method provided similar measurements to electronic apex locators and with no statistical difference with actual working length (P < .05). USG emerges as a promising method for working length measurement that allows simultaneous visualization of root tip anatomy in cases where electronic apex locators may be insufficient and there is buccal cortical bone loss.

Efficacy of glycolic acid for the removal of calcium hydroxide from simulated internal Resorption cavities.

OBJECTIVES: This study evaluated the efficacy of 5% and 10% glycolic acid solutions for the removal of calcium hydroxide medicament from artificial internal resorption cavities. MATERIALS AND METHODS: A total of 170 human maxillary premolars were selected and artificial internal resorption cavities were prepared using round burs and 37% orthophosphoric acid in the apical third of the root halves. Entire canal and resorption cavity were filled with calcium hydroxide paste. Then, the specimens were assigned to 2 control groups or ten experimental groups according to the irrigating solutions used for medicament removal with and without activation with ultrasonic energy as following: 5% glycolic acid, 10% glycolic acid, 17% EDTA, and 10% citric acid and distilled water. The resorption cavities were examined under different magnifications using stereomicroscopy and scanning electron microscopy (SEM). The calcium hydroxide remnants in the resorption cavity were scored by 2 evaluators using a 4-scoring scale. The data were analyzed with Kruskal-Wallis H tests with 5% significance threshold. RESULTS: There was no significant difference regarding the distribution of removal scores among non-activated solutions (P > 0.05). In activated groups, 10% glycolic acid irrigation removed significantly more amount of calcium hydroxide than EDTA and distilled water (P < 0.05). No significant difference was found between the efficacy of 10% glycolic and citric acid (P > 0.05). Citric acid, 5% glycolic acid, and EDTA showed similar removal scores (P > 0.05). Passive ultrasonic irrigation significantly improved calcium hydroxide removal scores in 10% glycolic acid, citric acid, and EDTA groups (P < 0.05). The SEM examination revealed that the specimens that were scored 0 are not entirely free of calcium hydroxide remnants. CONCLUSION: Concentration of 10% glycolic acid removed significantly more calcium hydroxide paste from resorption cavities than EDTA when used with passive ultrasonic irrigation. Although passive ultrasonic irrigation favored medicament removal in all irrigating solutions, complete elimination of medicament remnants was unattainable. CLINICAL RELEVANCE: This study showed the improved efficacy of ultrasonically activated 10% glycolic acid in removing the calcium hydroxide medicament from the internal resorption cavity.

Efficacy of XP-endo Finisher File in Removing Calcium Hydroxide from Simulated Internal Resorption Cavity.

INTRODUCTION: The aim of this study was to evaluate the effect of supplementary use of XP-endo Finisher file, passive ultrasonic activation (PUI), EndoActivator (EA), and CanalBrush (CB) on the removal of calcium hydroxide (CH) paste from simulated internal resorption cavities. METHODS: The root canals of 110 extracted single-rooted teeth with straight canals were prepared up to size 50. The specimens were split longitudinally, and standardized internal resorption cavities were prepared with burs. The cavities and root canals were filled with CH paste. The specimens were divided into 5 groups as follows: XP-endo Finisher, EA, PUI, CB, and syringe irrigation (SI). The root canals were irrigated with 5.25% NaOCl and 17% EDTA for 2 minutes, respectively. Apart from the SI group, both solutions were activated by using tested techniques for 1 minute. The quantity of CH remnants on resorption cavities was scored. Data were analyzed by using Kruskal-Wallis H and Mann-Whitney U tests. RESULTS: XP-endo Finisher and PUI removed significantly more CH than SI, EA, and CB (P < .05), showing no significant difference between them (P > .05). Differences among SI, EA, and CB were also non-significant (P > .05). CONCLUSIONS: None of the tested techniques render the simulated internal resorption cavities free of CH debris. XP-endo Finisher and PUI were superior to SI, CB, and EA.