A comparative evaluation of fracture resistance of endodontically treated teeth using four different intraorifice barriers: An in vitro study

Comparative evaluation of pericervical dentin preservation and fracture resistance of root canal-treated teeth with rotary endodontic file systems of different types of taper - An in vitro study

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.

Effect of Various Acid Solutions as an Aid in Removing the OrthoMTA-Based Root Canal Filling

The objectives of this study were to compare the effects of various acid solutions combined with ultrasonics as an aid to remove mineral trioxide aggregate (MTA)-based root canal filling and to assess their effect on the surface topography and microhardness of root canal dentin.

MATERIALS AND METHOD

Fifty human permanent single rooted and single canaled freshly extracted teeth were decoronated and sectioned apically to prepare the middle third of root sections of 5 mm length. The canals were prepared in a step-back manner. OrthoMTA was packed throughout the prepared canals. These root sections were incubated for one week and subsequently randomly allocated to five groups (n = 10) according to the OrthoMTA removal method: No treatment (NT); 5% glycolic acid + ultrasonics (5% GA+U); 10% glycolic acid + ultrasonics (10% GA+U); 10% citric acid + ultrasonics (10% CA+U); Distilled water + ultrasonics (DW+U). A 1 mm deep well was created within the coronal end of the set OrthoMTA. Wells were filled with each respective test solution and left for 5 min. Thereafter, further removal of OrthoMTA used a specific ultrasonic tip. Finally, the canals were flushed using 1 mL of the respective test solutions and activated with a Controlled Memory ultrasonic tip for two cycles of 20 s each followed by flushing with 1 mL of distilled water and paper point drying of the canals. Then, specimens were longitudinally split into two halves and examined under a scanning electron microscope (1000×) to assess the residual OrthoMTA and surface topography of root canal dentin. The Vickers surface microhardness of treated radicular dentin was measured using the HMV-2 microhardness tester.

RESULT

Data were analysed using one-way ANOVA followed by Tukey's post hoc test. Significant differences for residual OrthoMTA were observed between (10% GA+U) with (5% GA+U), (10% CA+U), (DW+U) and (NT) (p value < 0.01). In the context of microhardness, (5% GA+U) and (10% GA+U) showed statistically significant difference compared to (NT), (10% CA+U) and (DW+U) (p value < 0.01).

CONCLUSION

10% GA+U was superior to other tested groups in removing OrthoMTA, but it substantially reduced dentin microhardness.

Tooth Complications after Orthodontic Miniscrews Insertion

Orthodontic miniscrews (OM) are widely used in modern orthodontic clinical practice to improve skeletal anchorage and have a high safety profile. A complication at the time of OM insertion is tooth root perforation or periodontal ligament trauma. Rarely, OM injury can cause permanent damage, such as ankylosis, osteosclerosis, and loss of tooth vitality. The aim of this work was to analyze potential risks and dental complications associated with the use of OMs. A search of the PubMed, Cochrane, Web of Science, and Scopus databases was conducted without a time limit using the keywords "orthodontic mini-screw" and "dental damage", resulting in 99 studies. After screening and eligibility, including articles obtained through a citation search, 13 articles were selected. Four studies revealed accidental injuries caused by OM. Most of the damage was localized at the root level and resolved spontaneously with restorative cement formation after prompt removal of the OM, while the pain disappeared. In some cases, irreversible nerve damage, extensive lesions to the dentin-pulp complex, and refractory periapical periodontitis occurred, requiring endodontic and/or surgical treatment. The choice of insertion site was the most important element to be evaluated during the application of OMs.

Reinforcing the cervical dentin with bonded materials to improve fracture resistance of endodontically treated roots

Introduction:

Endodontic procedure leads to the loss of tooth structure resulting in fractures. Intraorifice barriers of bonded restorative materials placed in the cervical third of tooth may help in increasing fracture resistance.

Materials and Methods:

Human mandibular premolars (n = 75) underwent decoronation to adjust working length at 14 mm and prepared up to F3. They were obturated using gutta-percha and resin sealer AH-Plus and randomly divided into five groups (n = 15), Group 1: Control obturated with gutta-percha only. Groups 2, 3, 4, and 5 had placement of intraorifice barriers after the removal of 3 mm coronal gutta-percha such that Group 2: RMGI, Group 3: Self-adhering flowable composite, Group 4: Bulkfill Flowable Composite, and Group 5: mineral trioxide aggregate (MTA). Mounting of specimens was done in acrylic resin to expose coronal 3 mm and tested using the universal testing machine.

Results:

Group 1 (control) showed least fracture strength among all groups. Among those with intraorifice barriers, Group 2 Resin-modified glass ionomer cement showed maximum fracture resistance followed by Group 4 (Bulkfill composite) and Group 5 (self-adhering flowable composite) and least by Group 5 (MTA).

Conclusion:

The type of intraorifice barrier had a significant impact on root fracture resistance.