Comparative Evaluation of Debris Expulsion Beyond Apex During Re-root Canal Treatment by Utilizing Two Re-treatment Rotary Files and Two Reciprocating Files: An In-Vitro Study

AIM

This study aimed to assess and compare debris quality expelled beyond the apex during re-treatment using two reciprocating and two re-treatment rotary files.

MATERIALS AND METHODS

A total of 80 healthy human mandibular premolars excised for orthodontic therapy were selected. Distilled water was used to sterilize the teeth before they were preserved. The canals were widened and coronal access was created so that the F2 ProTaper universal system could be used. For the obturation, we utilized gutta-percha cones and AH plus sealant. All samples were cone-beam computed tomography (CBCT) recorded. Teeth were separated into four groups (n=20); Group 1: ProTaper re-treatment, Group 2: Mtwo re-treatment, Group 3: WaveOne gold, and Group 4: Reciproc. The re-instrumented process included collecting the extruded debris in Eppendorf tubes and then drying it off by evaporating the distilled water. The weight of the tube with debris was subtracted from the weight of the tube without debris to get the dry debris weight. Post-retreatment CBCT was recorded for all samples. Mean apical debris extrusion values were obtained, after which necessary statistical analysis was obtained using SPSS Statistics, version 21 (IBM Corp., Armonk, NY) to obtain the results. A one-way analysis of variance (ANOVA) and the student t-test were utilized for statistical analysis to compare the different experimental groups. Post-hoc Bonferroni tests were used to compare several groups.

RESULT

No statistical difference (p>0.05) was identified in the filler material that was left over across all groups. The reciprocating files discharged more material compared with re-treatment file systems.

CONCLUSION

The Reciproc files expelled more waste than WaveOne gold, ProTaper re-treatment, and Mtwo re-treatment file systems. Reciprocating file systems showed better cleaning efficiency compared to the re-treatment file systems.

Evaluating the Effect of NanoFilled Composite Restorations on the Wear Resistance of Posterior Teeth: An RCT

Background

Dental restorations play a crucial role in preserving the structural integrity and function of posterior teeth. However, wear resistance remains a significant concern for these restorations.

Materials and Methods

In this RCT, 120 participants with posterior tooth restoration needs were randomly assigned to two groups. Group A received conventional composite restorations, while Group B received NanoFilled Composite restorations. The restorations were placed according to standardized protocols. Wear resistance was assessed using a custom-designed chewing simulator, and the material wear was quantified using a profilometer. Patient-reported outcomes and clinical evaluations were also recorded at regular intervals over a 24-month follow-up period.

Results

The wear resistance of the NanoFilled Composite restorations (Group B) was significantly higher than that of the conventional composite restorations (Group A) after 24 months of follow-up (P < 0.05). Profilometer measurements revealed that Group B had an average wear depth of 0.15 mm, while Group A had an average wear depth of 0.25 mm. Patient-reported outcomes indicated higher satisfaction and comfort in Group B. Clinical evaluations also demonstrated that Group B restorations had better retention and marginal integrity.

Conclusion

This RCT demonstrates that NanoFilled Composite restorations exhibit superior wear resistance compared to conventional composite restorations when used in posterior teeth.

Effects of Blood Contamination and Decontamination Protocol on Reverse Torque Value of Abutment Screws in Dental Implants: An In Vitro Study

Background and Objective: Loosening of abutment screws in dental implants is a mechanical complication that affects prosthetic treatments and hence, patient satisfaction. Blood contamination of abutment screws may play a role in this phenomenon. However, only limited research attention has been given to this issue. In the present study, we determined the effect of blood contamination and decontamination protocol on the reverse torque value (RTV) of abutment screws. Materials and Methods: A questionnaire-based survey was sent to 210 implantologists requesting feedback on their attitude to the blood contamination issue and the decontamination protocols used. The survey responses were used in a selection of the decontamination solutions that were used in the subsequent in vitro study on the effects of blood decontamination protocol on the RTV of abutment screws. Thus, three study groups were used (n = 20 abutment screws in each group): Group 1 (control group; blood-contaminated screws); Group 2 (screws decontaminated with 5.25% sodium hypochlorite (NaOCl) solution); and Group 3 (screws decontaminated with normal saline solution (0.9%)). Then, each of the connections were subjected to thermocycling, and RTVs of the screw were measured using a digital torque meter. Intragroup and intergroup RTVs were analyzed for significance using analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) tests. Results: 48% of the implantologists responded to the survey; 80% of them were concerned with blood contamination in the implant connection, especially before abutment loading and 85% of them used either chlorhexidine solution or normal saline solution as the decontamination agent. The mean RTV for Group 2 screws (30.27 ± 2.8 N.cm) was significantly greater than that for Group 3 screws (26.02 ± 1.99 N.cm) which, in turn, was significantly greater than that for Group 1 screws (23.64 ± 1.84 N.cm). Conclusion: Decontamination of blood-covered connections using 5.25% NaOCl solution or normal saline solution restores the RTV of abutment screws. This finding may have clinical relevance in that the decontaminated screws may contribute to the low incidence of screw loosening and, ultimately, improved patient satisfaction.

Radiographic Evaluation of the Gap between Cemented Post and Remaining Gutta-Percha in Endodontically Treated Teeth Performed by Undergraduate Students: A Retrospective Cross-Sectional Study

The coronal seal in root canal-treated teeth may be compromised depending on the accuracy of post space preparation and post cementation along with remaining gutta-percha. Root canal treatment can be compromised by endotoxins released by the coronal bacteria as a result of microleakage. The study was conducted by undergraduate students to measure the gap between the cemented post and residual gutta-percha. In total, 217 endodontically treated teeth were evaluated with intraoral peri-apical radiographs. Based on the intraoral periapical radiographic examination in the CS-R4 program, Group I had no gap, Group II had a gap of >0 to 2 mm, and Group III had a gap of more than 2 mm between the end of the cemented post and the remaining gutta-percha. In total, 40% (n = 87) of the teeth had no gap, 59% (127) had a gap of >0 to 2 mm, and 1% (n = 3) had a gap of more than 2 mm between the cemented post end and remaining gutta. Chi square test revealed a significant difference in the gap between the post and remaining gutta-percha between males and females students (p < 0.001). In terms of the gap between the cemented post end and the residual gutta-percha, the root canal treated teeth with post and core by undergraduates were clinically acceptable.

Evaluating the Effect of Tideglusib-Loaded Bioactive Glass Nanoparticles as a Potential Dentine Regenerative Material

Dental pulp treatment is the least intrusive procedure currently available for preserving the vitality of the pulp. Several studies are underway to improve the bioactivity of pulp capping materials. Tideglusib isa potent anti-inflammatory, antioxidant, and a regenerative drug developed against Alzheimer’s disease and has been shown to be effective in the treatment of dental cavities. However, its bioactive properties encapsulated within the nanoparticles as a component of pulp capping material are largely unknown. In this study, tideglusib-loaded bioactive glass nanoparticles were synthesized (tideglusib-BgNPs) and mixed at various concentrations into the calcium silicate cement to testits physiomechanical and bioactivitiescompared with biodentine (control). The calcium silicate cement with 10wgt% tideglusib-BgNPs showed comparable physiomechanical properties to that of biodentine. Additionally, the assessment of cytotoxicity and bioactivity (cell proliferation, wound healing, and cell migration assays) showed increased bioactivity in terms of better wound healing, increased proliferation, and better migration of human dental pulp stem cells than biodentine. These findings suggest new opportunities to use tideglusib-BgNPs in pulp therapy.

Efficacy of Three Commercially Available Desensitizers in Reducing Post-Operative Sensitivity Following Composite Restorations: A Randomized Controlled Clinical Trial

One of the most widely used esthetic restorations in dentistry is composite. The widespread application of composites can be related to advancements in biomaterials. However, due to various factors, composites are commonly associated with dental sensitivity. Hence, the present study evaluates and compares the effectiveness of three desensitizing agents in reducing post-treatment sensitivity for Class I composite restoration. Eighty subjects with Class I cavities were selected according to the inclusion criteria, and a randomized, double-blind, controlled clinical trial was carried out. Twenty patients were randomly assigned to four groups: Group C (Control group), Group GL (Gluma group), Group SF (Shield Force Plus group), and Group TC (Telio CS group). The desensitizers were applied after Class 1 cavity preparation and acid etching in all the groups, except the Control group, and thereafter, composite restoration was completed in a conventional manner. Questionnaires were provided to all the participants to record the post-operative pain/sensitivity level according to the visual analogue scale (VAS) on intake of cold drinks, intake of hot drinks, and intake of sugar for different periods of time. Significant variation was observed between the three desensitizers for all three stimuli. However, no significant variations were seen with the various age groups and between the maxillary and the mandibular teeth at the different time periods. Group GL performed better than Group SF and Group TC. It can be proposed that the application of the desensitizers reduced the post-restorative sensitivity in the composite restorations and improved acceptance.

Study of optimal conditions for growth and osteogenic differentiation of dental pulp stem cells based on glucose and serum content

Dental pulp stem cells (DPSCs) have shown promising characteristics in terms of their proliferation and osteogenic differentiation potential, which could be of greater benefit in regenerative dentistry. However, obstacles remain in the in vitro cultivation of DPSCs, which significantly affect their growth and differentiating ability. Therefore in this study, we demonstrated the growth and osteogenic differentiation of DPSCs in the presence of media containing different combinations of serum and glucose to get an optimized combination of both. DPSCs were cultured in media containing combinations of low glucose (LG), low serum (LS), high glucose (HG), and high serum (HS). The proliferation and osteogenic differentiation were assessed in DPSCs cultured with these different combinations of culture conditions. High glucose high serum condition significantly inhibited the proliferation of DPSCs and also affected their clonogenic potential, as evidenced by colony-forming units. Irrespective of the serum content, high glucose in the media also decreased the osteogenic potential of DPSCs confirmed by functional staining, and downregulation of osteogenesis-related genes. High glucose content in the culture media affects the growth and differentiation potential of the DPSCs. Hence, the culture conditions for the DPSCs should be reconsidered to utilize their maximum potential.

Complete Obturation-Cold Lateral Condensation vs. Thermoplastic Techniques: A Systematic Review of Micro-CT Studies

To prevent re-infection and provide a hermetic seal of the root canal system, an endodontist must aim to produce a void-free obturation. This review aimed to compare the completeness of root canal obturation between the two most prevalent methods-cold lateral condensation and warm gutta-percha techniques-using micro-CT (PROSPERO reg no. 249815).

MATERIALS AND METHODS

A search of Scopus, Embase, PubMed (Medline via PubMed), and Web of Science databases was done without any time restriction according to the PRISMA protocol. Articles that compared both techniques and were published in English were included. Data was extracted and the risk of bias was assessed using an adapted tool based on previous studies.

RESULTS

A total of 141 studies were identified by the search. Following the screening and selection of articles, 9 studies were included for review. Data was extracted manually and tabulated. Most studies had a moderate risk of bias. None determined operator skill in both methods before comparison. The data extracted from the included studies suggests that both techniques produce voids in the obturation. The thermoplasticized gutta-percha techniques may result in fewer voids compared to cold lateral condensation.

CONCLUSION

Considering the limitations of the included studies, it was concluded that neither technique could completely obturate the root canal. Thermoplasticized gutta-percha techniques showed better outcomes despite a possible learning bias in favor of cold lateral condensation. Establishing operator skills before comparison may help reduce this bias.

Efficacy of Desensitizers in Reducing Post-preparation Sensitivity Prior to a Fixed Dental Prosthesis: A Randomized Controlled Clinical Trial

Aims:

The aim of this article is to evaluate and compare the effectiveness of Gluma, Shield Force Plus, and Telio CS desensitizers, in reducing pre- and post-cementation sensitivity for complete coverage restorations.

Materials and Methods:

The study was a double-blind, randomized, controlled clinical trial in which 56 patients requiring posterior three-unit fixed partial dentures were randomly assigned to four groups, each group with 14 patients (n = 14): Group C (Control group), Group GL (Gluma group), Group SF (Shield Force Plus group), and Group TC (Telio CS group). In the desensitizer groups, desensitizer application was performed following the manufacturer’s directions immediately after tooth preparation (first visit), before metal restoration try-in (second visit, 2 weeks after the first visit), and before final cementation (third visit, 2 weeks after the second visit). Sensitivity levels were scored and evaluated using a visual analog scale (VAS), using cold test and electric pulp test (EPT) during the three visits before the cementation, and then over the phone 2 weeks after the final cementation. The data were statistically analyzed using one-way analysis of variance (ANOVA) followed by post-hoc Bonferroni and unpaired t-tests.

Results:

One-way ANOVA revealed significant differences between the four groups. The post-hoc Bonferroni tests showed a significant decrease in the mean cold test scores from the first to third visit, with a p-value <0.001 for the GL, SF, and TS groups. The mean EPT scores also decreased significantly from the first to third visit (p< 0.001) for the GL and SF groups, whereas p = 0.023 for the TS group. Most of the subjects did not complain of any sensitivity post-cementation, except for one patient in Group TS.

Conclusion:

All three desensitizers were found to be effective in reducing pre- and post-cementation dentin sensitivity, as indicated by the consistent reduction in VAS scores throughout the visits.

Efficacy of photodynamic therapy, photobiomodulation and antimicrobial agent on the shear bond strength of composite restorations to hypomineralized teeth

PURPOSE

The aim of this study was to investigate the adhesive bond strength and fracture analysis of resin based restorations to carious dentin of hypomineralized molars (HMs) after disinfecting with photodynamic therapy (PDT), Nd:YAG and chlorhexidine (CHX).

MATERIALS AND METHODS

Sixty carious HM molars were investigated. After removal of all carious infected tissue, the cavities were condition with methylene blue initiated PDT, a 1064 nm wavelength Nd:YAG laser or 2.0% CHX gel. Non-carious dentin from HM was used as a control without performing any disinfection or conditioning technique. All samples were bonded using a one-step one-coat adhesive bond over the dentin surface, packed with composite and light cured. All specimens were subjected to thermocycling at 5°C and 60°C with a dwell time of 30 s for 10,000 cycles. Bonded specimens were placed on a universal testing machine with a flat loading head. The debonded surface were viewed under light optical microscope to estimate the type of failure including adhesive, cohesive, and admixed.

RESULTS

The highest mean SBS was seen in the non-carious HM (control group). The mean score for control group was 17.64 ± 2.96 MPa. The lowest bond strength value was displayed for Group-PDT (11.37 ± 3.66 MPa) and Group-Nd:YAG (12.69 ± 2.45 MPa). Affected dentin disinfected with the Group-CHX (15.71 ± 3.04 MPa) bonded with composite showed statistically significantly higher SBS values compared to the laser groups (p < 0.05). No statistically significant difference was noted with specimens disinfected with PDT and Nd:YAG laser showed comparable SBS scores (p > 0.05). Fracture analysis showed equal incidence of adhesive and cohesive failures in control group and Group-CHX. Moreover, a significant number of failures in group-PDT were related to adhesive. Whereas in group 4, admixed type failures were common.

CONCLUSION

Caries infected hypomineralized teeth demonstrated lower bond strength values compared to non-carious hypomineralized teeth. Adhesive bond strength of hypomineralized teeth was highest with chlorhexidine compared to other laser treatment strategies.

Comparison of Sagittal Condylar Guidance Determined by Panoramic Radiographs to the One Determined by Conventional Methods Using Lateral Interocclusal Records in the Saudi Arabian Population

Objectives

The objectives of this study were to determine the condylar guidance by the conventional method using interocclusal records and by panoramic radiographs in healthy dentate patients and to compare the values obtained from panoramic radiographs with the values obtained by a conventional method.

Materials and Methods

Thirty healthy dentulous subjects of either sex with an age range of 20-40 years visiting Jazan University, College of Dentistry, Dental Clinics for replacement of missing teeth or crowns, were selected according to the inclusion criteria. Maxillary and mandibular casts were obtained and mounted on Whipmix 2240 articulator. Right and left lateral interocclusal records were then made in patients by base plate wax (Dentsply truwax baseplate). This record was transferred to articulator, and condylar values were determined. In all the cases, articulator was programmed. Left and right condylar values were also measured on digital radiographs and readings were recorded. Condylar guidance readings obtained from interocclusal records and those obtained from panoramic radiographic images were compared and analyzed statistically using the t-test.

Results

The condylar guidance values obtained from the interocclusal record method for both left and right sides were less when compared to the values obtained from tracing the panoramic radiographs (radiographic method). The difference in values of both the methods was highly significant.

Conclusion

Although a significant amount of correlation was found between the two methods, better radiographic techniques should be further investigated.