ABSTRACT
Aims: The aim of this study was to evaluate and compare the pericervical dentin preservation and fracture resistance of root canal-treated teeth with rotary endodontic file systems of different types of taper. Subjects and Methods: Thirty-two single-rooted human-extracted premolars were used. They were mounted in wax, and preoperative cone-beam computed tomography (CBCT) scans were taken with 11 × 8 Field of view (FOV). The evaluation of the pericervical dentin thickness was done at the cementoenamel junction level. After pre-CBCT, the 32 samples were divided into four groups (n = 8) - Group A: fixed tapered hand files, Group B: variable regressive tapered TruNatomy, Group C: progressive tapered ProTaper Gold, and Group D: fixed tapered HyFlex EDM. Following instrumentation, postoperative CBCT scans were taken to evaluate pericervical dentin thickness. Obturation was done and access cavity was restored with composite. Fracture strength was checked for all the samples using "universal testing machine" until fracture, and calculated in newtons (N). Statistical Analysis Used: Student's t-test and ANOVA test, along with Tukey's post hoc analysis, were used for comparing mean values between the groups, and P < 0.05 was considered statistically significant. Results: The results of this study showed that there is no statistically significant difference in preserving pericervical dentin with file system of different types of taper and fracture resistance between the groups. Conclusions: Within the limitations of the study, it was concluded that different types of file taper systems used for root canal preparation have no significant effect on the preservation of pericervical dentin and fracture resistance of teeth.
ABSTRACT
BACKGROUND: Wettability of root canal sealers to the root canal wall plays a significant role in the attainment of a fluid-tight seal. AIMS: This study aimed to evaluate and compare the wettability of three different root canal sealers on the root canal walls after three different irrigant activation techniques using the contact angle meter. SUBJECTS AND METHODS: Thirty-six single-rooted mandibular premolars after decoronation and cleaning and shaping up to size #35 were randomly divided into three groups with 12 samples in each group (n = 12) based on the different activation techniques: Group I (passive irrigation with side-vented needle), Group II (manual dynamic agitation), and Group III (passive ultrasonic irrigation). Root segments were split longitudinally and were subdivided into three subgroups based on the root canal sealers tested with four samples in each subgroup (n = 4): Subgroup A (Tubliseal EWT), Subgroup B (AH Plus), and Subgroup C (Endosequence BC sealer). A controlled volume droplet of sealer was placed on each specimen and was subjected to the contact angle meter. STATISTICAL ANALYSIS: Data were statistically analyzed using the one-way ANOVA and Tukey's post hoc test at a significance level of 0.05 (P < 0.05). RESULTS: A statistically significant difference was seen among all the groups and subgroups with the highest contact angle value for Group III and Subgroup C and the least value for Group I and Subgroup A. CONCLUSIONS: Passive irrigation with side-vented needle and Tubli-Seal EWT showed better wettability on dentin.
ABSTRACT
AIMS: The purpose of this study was to evaluate the resistance to torsional failure and cyclic fatigue resistance of ProTaper Next (PTN), WaveOne, and Mtwo files in continuous and reciprocating motion. SETTINGS AND DESIGN: Randomized control trial in a tertiary care setting. SUBJECTS AND METHODS: A total of 10 new size 25.06 taper PTN X2, 25.06 taper Mtwo files, and 25.08 taper WaveOne primary files each was selected. A custom fabricated cyclic fatigue testing device with a 70° angle of curvature and 3 mm width; curvature starting at 6 mm from the tip was used. All instruments were rotated and reciprocated till fracture occurred and time till fracture of each instrument was recorded in seconds. For torsional failure testing 5 mm tip of each file was embedded in composite resin block and uniform torsional stresses (300 rpm, 2.0 Ncm) were applied repetitively by an endodontic motor with auto stop mode until file succumbed to torsional failure. Number of load applications leading to failure was recorded. STATISTICAL ANALYSIS USED: Data were analyzed using t-test for equality of means, Pearson correlation, and ANOVA test. RESULTS: All the files showed superior resistance to cyclic fatigue in reciprocating motion when compared with continuous rotation mode. WaveOne primary files displayed maximum resistance to cyclic fatigue both in continuous and reciprocating motion. WaveOne primary files also demonstrated maximum resistance to torsional failure followed by PTN with Mtwo files exhibiting least resistance. CONCLUSIONS: Operating files in reciprocating motion enhances their cyclic fatigue resistance. WaveOne files showed maximum resistance to cyclic fatigue and torsional failure due to their cross-sectional diameter coupled M-Wire technology.
