Journal of Conservative Dentistry最新文献

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.

Background: Cleaning and shaping represent a vital step in the endodontic procedure. In routine endodontic therapy, the fracture of nickel-titanium (NiTi) instruments is a procedural problem creating a major obstacle to therapy.

Aim: This study examines the life span of one Neoendo Flex and ProTaper Next (PTN) rotary file using reciprocating motion and compares the time required by both file systems for canal preparation.

Materials and methods: One hundred maxillary permanent central incisors were selected. In that, fifty teeth are utilized in a reciprocating motion (RM) with the PTN file (n = 25) and Neoendo Flex file (n = 25). To check fractured resistance and the overall root canal preparation time, fifty more teeth are employed in continuous motion (CM) with canals prepared using PTN (n = 25) and Neoendo Flex (n = 25). All canals are prepared following the sequence of respective files. Later, the fracture mechanism of the files was inspected using a scanning electron microscope.

Results: In an RM motion, both PTN and Neoendo Flex files can be used in a minimum of 25 canals in single-rooted teeth. Statistical analysis using the Mann-Whitney U-test showed no significant difference in total time taken by PTN and Neoendo Flex in both motions.

Conclusion: Within the limitation of this study, the RM was found to be better than CM with less incidence of instrument fracture.

Background: Mature permanent teeth with irreversible pulpitis have traditionally been managed with pulpectomy. With advancements in pulp biology and dental materials, many clinicians are using vital pulp therapies like pulpotomy to manage such teeth. The current study was conducted to help clinicians in making decisions about case selection and choice of material for such cases.

Aim: This randomized clinical trial evaluated the outcome of complete pulpotomy, using mineral trioxide aggregate (MTA) and Biodentine, in permanent mandibular molars with symptomatic irreversible pulpitis (SIP).

Materials and methods: Fifty patients with moderate-to-severe pain in mandibular molars with SIP were included in this prospective, parallel, single-blind clinical trial. Coronal pulp was completely removed and hemostasis was achieved with a cotton pellet moistened with 2.5% sodium hypochlorite. Subsequently, the radicular orifices were randomly covered with MTA or Biodentine. All teeth were permanently restored with composite restoration at the same appointment. Clinical evaluation was performed at 1 week, 3 months, 6 months, 12 months, and 18 months and radiographic evaluation was done after 6 months, 12 months, and 18 months. Mann-Whitney U and Chi-square tests were utilized for statistical analysis.

Results: Success rates of MTA and Biodentine pulpotomy were 63.6% and 69.6%, respectively, with no significant difference between the two groups at any follow-up period (P > 0.05).

Conclusion: There were no significant differences in complete pulpotomy success rates between MTA and Biodentine over 18 months in mandibular molars with SIP.

Aim: Assessment of remineralizing agent's effect on laser and nonlaser bleached enamel surfaces subjected to erosion.

Materials and methods: In this study, 80 extracted human permanent anteriors were collected and divided into 4 groups with 20 teeth per sample. Enamel specimen of 3 mm × 3 mm were made using polyvinyl chloride rings and acrylic and randomly divided into four groups. Then the specimens were subjected to initial microhardness test using Vicker's hardness tester (AVK-CO, Mitutoyo, Japan). Two indentations were placed at 100 mm from one another in the center of all the samples. Bleaching with laser and without laser using hydrogen peroxide was performed followed by remineralization in the groups (Groups 1a and 2a) and then were subjected to erosion. The final hardness was measured using the above method used for initial microhardness.

Results: Microhardness in the remineralized groups showed least variation. The group in which laser bleaching was performed along with remineralization as compared with nonlaser bleaching group with remineralization showed improvement in microhardness but the data was not statistically significant. A significant difference was noted between the laser and remineralization group when compared with the groups in which no remineralization was done.

Conclusion: After bleaching the enamel surface is more prone to erosion, so to improve the microhardness of bleached enamel a remineralizing agent should be used. A combination of diode laser bleaching and remineralizing agents leads to improved microhardness of the bleached enamel thus proving this combination to be efficacious.

Aim: The aim of this study was to evaluate the effectiveness of ultrasonic activation of ethylenediaminetetraacetic acid (EDTA), maleic acid (MA), and fumaric acid (FA) in combination with sodium hypochlorite (NaOCl) on postendodontic treatment root fracture toughness.

Materials and methods: Forty single-rooted mandibular premolars were sectioned below the cementoenamel junction and were kept on average 14 mm long. With the exception of eight randomly selected teeth acting as a negative control group (Group I/nonprepared), the rest were prepared till F3. Thirty-two specimens were randomly placed into four groups equally and then irrigated using the final irrigation protocols. Saline and NaOCl were used to irrigate Group II, 17% EDTA and NaOCl were used to irrigate Group III, 7% MA and NaOCl were used to irrigate Group IV, and 0.7% FA and NaOCl were used to irrigate Group V. The irrigants were ultrasonically activated in every group. The root canals were obturated with gutta-percha and AH Plus sealer. The roots were embedded along the long axis in the self-curing acrylic blocks along with polyvinyl siloxane, leaving the coronal 2 mm of the root exposed. The specimens were tested using a universal testing machine.

Statistical analysis: The Post hoc Tamhane's and one-way ANOVA tests were applied to examine the data.

Results: The result of the study revealed that 0.7% FA (598.09 N) provided better root fracture resistance than EDTA (428.07 N) and MA (511.87 N).

Conclusion: The conclusion derived from the study was that 0.7% FA provided better fracture resistance of endodontically treated teeth when compared to 17% EDTA and 7% MA.

Aim: The aim of this study was to assess and compare the influence of the presence of full-coverage crown on the obturation material removal efficiency of different retreatment file systems.

Materials and methods: Sixty extracted, human, maxillary premolars were accessed, instrumented, and obturated with gutta-percha and AH Plus sealer. The samples were scanned with cone-beam computed tomography and volume of obturating material was measured using ITK-SNAP volumetric software. Samples were divided (n = 30) into with and without all metal full-coverage crown groups. Each group was then subdivided into three subgroups (n = 10) based on retreatment file used (ProTaper URS, HyFlex Remover, and NeoEndo). The volume of remnants of obturating material was remeasured by image segmentation using ITK-SNAP volumetric software. One-way analysis of variance, followed by the Tukey's post hoc test, was used for data analysis, with a significance level of 5%.

Results: A significant difference in percentage remnant of obturating material after retreatment file was observed on overall comparison between with (29.84%) and without crown (21.79%) groups (P < 0.05). Each file system removed significantly more obturating material in without crown samples than with crown samples (P < 0.05). The percentage remnant of obturating material after retreatment file use was as follows: ProTaper URS > NeoEndo retreatment file > HyFlex Remover. All file systems showed significantly different (P < 0.05) efficiency in removal of obturating material.

Conclusions: None of the retreatment file systems were able to remove obturating material completely. The presence of full-coverage crown negatively impacted the efficiency of retreatment files for the removal of obturating material. HyFlex Remover performed better than NeoEndo which was better than ProTaper URS.

Aim: The aim of this study was to evaluate the homogeneity and quality of different obturating systems using cone-beam computed tomography (CBCT).

Materials and methods: One hundred and twenty extracted maxillary and mandibular molars were included in this study which was decoronated first and then dissected into palatal and distal roots. After working length determination, all the roots were biomechanically prepared with ProTaper universal system. The prepared roots were evaluated using CBCT, and volumetric analysis was done. Samples were then randomly divided into three groups corresponding to the obturation method used - cold lateral compaction technique, single-cone technique, and BeeFill 2 in 1 system. After obturation, CBCT imaging and volumetric analyses were performed again to compare and analyze the amount of volume of obturation in different obturating techniques. To standardize the volume, pre-and postobturation images were superimposed. To avoid errors, for each section, measurements were repeated three times and the means were calculated.

Statistical analysis used: The data were statistically analyzed using one-way analysis of variance, followed by post hoc test.

Results: Results showed a statistically significant difference of the single cone with lateral compaction and the BeeFill system (P < 0.001). Maximum volume of obturating material was found in BeeFill at all levels - Coronal, middle, and apical, followed by cold lateral compaction and single-cone technique (P < 0.001).

Conclusion: It could be concluded that the thermoplasticized obturating technique can be a better choice for obturation rather than the single cone and lateral compaction technique.