Evaluation of Antibacterial Effects of Cold Atmospheric Plasma, Calcium Hydroxide, and Triple Antibiotic Paste on Enterococcus faecalis Biofilm in the Root Canal System: An In Vitro Study

Introduction: One of the essential factors in successful endodontic therapy is effective cleaning and disinfection of the root canal. This study aims to determine the effect of the cold plasma on the infected root canals with Enterococcus faecalis and compare its antibacterial effect with the conventional medicaments in vitro. Methods: 63 single-root teeth were extracted. Canals were cleaned and shaped. Ten teeth were selected as a negative control randomly. The rest of the teeth were incubated at 37°C for 21 days to form Enterococcus faecalis biofilm. The specimens were divided into five groups; 2 positive control groups of medicaments and plasma, 1 group treated with calcium hydroxide; 1 group treated with 10 mg/ml of TAP; 1 group treated helium/oxygen plasma. After treatment, F4 Pro-Taper rotary file was used to collect root canal microbial biofilms. Bacterial suspensions are serially diluted, and the percentage of growth reduction for each group was obtained by dividing the logarithm of CFU /mL of each group by CFU /mL of the control of the same group. Results: The CFU/mL of TAP and plasma-treated samples was significantly lower than the control groups; however, there were no significant differences between the control group and samples treated by calcium hydroxide. The most percentage of CFU reduction was in the TAP-treated group compared with plasma and calcium hydroxide-treated groups. Conclusion: The application of cold plasma effectively inhibits the growth of Enterococcus faecalis and reduces bacterial biofilm. Also, in the present study, 10 mg/ml of TAP caused the complete elimination of Enterococcus faecalis. Calcium hydroxide had the most negligible effect on Enterococcus faecalis biofilm elimination

In Vitro Cytotoxicity and Setting Time Assessment of Calcium-Enriched Mixture Cement, Retro Mineral Trioxide Aggregate and Mineral Trioxide Aggregate

Introduction: The present study sought to evaluate and compare biocompatibility and setting time of Retro mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) and Angelus MTA. Methods and Materials: CEM cement, Angelus MTA and Retro MTA were assessed in set and fresh states. Extracts transformed to each cavity of three 24-well plates in which 1×104 cell were seeded into each well 24 h earlier. All specimens were incubated in a humidified incubator with 5% CO2 at 37°C. Mosmann’s tetrazolium toxicity (MTT) assay was used to determine in vitro cytotoxicity on L929 mouse fibroblast cell line. Cell viability was determined at 1, 24, and 72 h after exposure. The initial setting time was measured by 113.4 g Gilmore needle testing. Then, final setting times were assessed by the 456.5 g Gilmore needle. Data comparisons were performed using the analysis of variance (ANOVA) and Tukey's post hoc test (α=0.05). Results: All groups in both forms indicated higher cell vitality compared to positive control group (P<0.001). After 24 h, the set Retro MTA showed better biocompatibility compared to set CEM and set Angelus MTA (P<0.001). Retro MTA showed significantly lower initial and final setting time compared to CEM and Angelus MTA (P<0.001). Conclusion: Our results indicated the good cell viability values of Retro MTA and relatively short period of setting time. It seems a promising alternative material in clinical situations where accelerated setting is required. However, more clinical and in vivo investigations are needed for a clear decision making.Keywords: Biocompatibility; Calcium-Enriched Mixture; Mineral Trioxide Aggregate; Retro MTA; Setting Tim

Comparative Evaluation of Canal Transportation and Centering Ratio in Curved Canals: A Study of Cone-beam Computed Tomography and Micro-computed Tomography

Introduction: This study aimed to compare the accuracy and agreement between cone-beam computed tomography (CBCT) and micro-computed tomography (micro-CT) in the assessment of canal transportation and centering ratio following root canal instrumentation with rotary files. Material and Methods: Twenty mesiobuccal canals of mandibular molars were prepared using the 2Shape sequential rotary system. CBCT and micro-CT scans were performed before and after instrumentation, and the magnitude of transportation and centering ratio were measured. The acceptable transportation was set at ≤0.15 mm. The accuracy and agreement between CBCT and micro-CT were calculated, and the intra-class correlation coefficient (ICC) and kappa coefficient were determined to assess the agreement between the two modalities. Statistical analyses were performed using repeated measures ANOVA. Results: Transportation was detected by both modalities at all distances from the apex after instrumentation. The agreement between CBCT and micro-CT in assessing canal transportation was observed in 80%, 85%, 75%, and 75% of specimens at 1-, 3-, 5-, and 7-mm from the apex, respectively. The ICC for transportation and centering ratio was much lower than 0.75, indicating poor agreement between the modalities. The kappa coefficient did not show acceptable agreement between the methods. Conclusions: CBCT and micro-CT demonstrated poor agreement in assessing canal transportation and centering ratio. Micro-CT remains the preferred modality for in vitro investigations, while CBCT should be limited to clinical settings

A Comparative Study of Dentoskeletal Changes Following Orthodontic Treatment with First Premolar Extraction in Long Face and Normal Patients

Introduction: The purpose of this study was to evaluate vertical facial and dental changes after orthodontic treatment with extraction of first four premolars, and to find whether long facial height could influence the treatment result. Methods: Fifty-six orthodontic patients with the minimum age of 15, whose treatment plan involved extracting four first premolars, participated in the study. The patients included 30 females and 27 males. Cephalometric measurements before and after treatment were compared using a paired T-test. Independent T-test was employed to compare post treatment changes for each parameter between normal and long face groups. The same analysis performed between male and female subjects. Results: Treatment changes revealed a significant increase in the vertical distance from the upper molar to palatal plane, the lower molar to mandibular plane and Menton to palatal plane in all groups. There was significantly more increase in most post-treatment linear measurements in males than in females, with the same direction in both genders. There were no significant differences between normal and long face in any measurement. Conclusion: All patients showed some extrusion of the molar teeth after extraction of the premolars. The difference between normal and long face groups was not significant

A Case Report of Maxillary Second Molar with Two Palatal Root Canals and a Furcal Enamel Pearl

This case report presents an uncommon case of maxillary molar with two palatal root canals and an enamel pearl in the furcation area. The article discusses root canal complexities of maxillary second molars as well as possibility of coexisting anomalies in the region that makes radiographic interpretation difficult and compromises the success of endodontic treatment

Effect of Internal Bleaching on Discoloration Caused by 4 Different Materials: internal bleaching

Objectives In endodontics, mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM cement) are commonly used bioceramic materials. Regenerative endodontics often involves the use of double or triple antibiotic pastes (DAP or TAP), which are effective but may cause discoloration. This study aims to examine the effectiveness of internal bleaching in addressing discoloration caused by 4 different materials. Methods This in vitro study was conducted on 40 single-rooted anterior and premolar human teeth that did not have caries, restorations, obvious discoloration, or fractures and were extracted due to periodontal disease or orthodontic treatment. The teeth were randomly assigned to 4 groups (n=10). After root canal instrumentation, the baseline color of the specimens was measured using a spectrophotometer. After applying the aforementioned materials in the canals, access cavities were sealed with glass ionomer (GI), and the color of the specimens was measured again after 1 month to calculate color change (∆E). Internal bleaching was performed with 35% hydrogen peroxide 3 times within 3 weeks, and values were calculated at each time point. Data were analyzed using paired t-tests and 1-way analysis of variance (ANOVA). Results Clinically noticeable discoloration (∆E>3.7) occurred in the MTA Angelus (∆E=4.88) and TAP (∆E=17.3) groups. The ∆E of the TAP group was significantly higher than that of all other groups (P<0.05). The discoloration was borderline detectable in the CEM group (∆E=3.89) and clinically undetectable in the DAP group (∆E=2.02). Discoloration significantly improved after 3 rounds of bleaching in the TAP group (P<0.05), as well as after 2 rounds of bleaching in the MTA (P<0.05) and CEM (P<0.05) groups. In all groups, ∆E increased after each round of bleaching. Conclusion The CEM cement may yield better results with lower discoloration compared to MTA and exhibit a more favorable response to internal bleaching. For canal disinfection using antibiotic paste, DAP is a good alternative to TAP

The The Effect of Low-Level Laser Therapy on the Viability of Human Dental Pulp Stem Cells: Effect of LLL on the viability of DPSCs

Objectives: This study assessed the effect of low-level laser (LLL) irradiation on the viability of dental pulp stem cells (DPSCs). Materials and Methods: In this in vitro experimental study, human DPSCs were purchased from the cell bank of Iranian Genetic Resources and cultured in flasks containing Dulbecco's modified Eagle's medium supplemented with 20% fetal bovine serum (FBS) at 37°C, 5% CO2, and 95% humidity. The cells were stored in semi-confluent form, and the culture medium was refreshed every two days. The cells in the control group were not laser-irradiated. The cells in the experimental groups were irradiated with 660 and 808 nm diode lasers with 4.1 J/cm2 energy density. Cell viability was assessed at baseline and after 24, 48, and 72 hours using the methyl thiazolyl tetrazolium (MTT) assay. The effects of laser irradiation, laser wavelength, and time on the percentage of cell viability were analyzed by two-way ANOVA and Tukey's test. Results: The effects of laser irradiation and its wavelength (P=0.04), time of assessment (P<0.001), and the interaction effect of group and time (P=0.02) on cell viability were significant. Cell viability in 660 and 808 nm laser groups at 48 and 72 hours was higher than that of the control group; however, statistically, only the difference in cell viability between the 660 nm laser and control group at 72 hours was significant (P=0.03). Conclusion: Considering the optimal effect of diode laser irradiation (particularly 660 nm) on the viability of DPSCs, it may be suitable for relevant clinical applications

Correlation Between Pulp Sensibility Tests and Histologic Diagnosis

Introduction: Accurate diagnosis of dental pulp conditions plays a key role in selection of an appropriate treatment including conservative vital pulp therapy (treatable pulp) or root canal treatment (untreatable pulp). The purpose of this study was to assess the accuracy of sensibility tests and the correlation of pulp response to sensibility tests with histologic pulp condition. Material and Methods: Assessment of clinical signs and symptoms and sensibility test include thermal and electrical pulp tests were all performed for 65 permanent teeth. The normal pulp and reversible pulpitis were considered as treatable conditions while the irreversible pulpitis and necrosis ones were considered as untreatable condition. The teeth were then extracted and sectioned for histological analysis of dental pulp. Comparisons between histological treatable and untreatable pulp condition were performed with chi square analysis for sensibility test responses. Result: A significant difference was detected in the normal and a sharp lingered response to heat and cold tests with a marginally significant difference for no responses to cold test between two histological treatable and untreatable groups. There was significant difference in the negative response to electric pulp test (EPT) between histological groups. The kappa agreement between clinical and histological diagnosis of pulp condition was about 0.843(p<0.001).  The accuracy of cold and heat tests and EPT to detect treatable pulp or untreatable pulp states were 78% and 74% and 62% respectively. The sensibility tests diagnosed untreatable pulpitis with a higher probability (NPV=63%-67% -54%, PPV=83%-91% -95% for heat, cold and EPT respectively). Conclusion: Sensibility test results had a higher likelihood to diagnose pulpal disease or untreatable pulp conditions. The result demonstrated a good agreement between clinical and histological pulp diagnoses