Cytotoxicity Evaluation of Iranian Propolis and Calcium Hydroxide on Dental Pulp Fibroblasts

Abstract Background and aims. Since intracanal medicaments can affect the cell viability in periapical tissues, the aim of this study was to evaluate the effect of calcium hydroxide and propolis on pulp fibroblasts. Materials and methods. Two healthy third molars were used as a source to obtain fibroblasts. The fibroblasts were cultured and subjected to 1 mg/mL of propolis and calcium hydroxide. This experiment was performed in six replicates and cell viability was evaluated with MTT assay. Statistical analysis was performed by t-test. Results. Comparison of cell viability with the use of 1 mg/mL of calcium hydroxide and propolis showed that cells subjected to propolis were more viable when compared to calcium hydroxide (P < 0.05). Conclusion. In this study, calcium hydroxide reduced fibroblast viability, significantly more than Iranian propolis. Other properties should be evaluated before Iranian propolis could be indicated for use as intracanal medicament

Propolis: A New Alternative for Root Canal Disinfection

Introduction: This study evaluated and compared colony forming units (CFUs) and minimum inhibitory concentrations (MICs) of calcium hydroxide and propolis as intracanal medicaments.Materials and Methods: Eighty human single-root and caries-free teeth were selected and divided into five groups. Crowns were removed. Root canals were then prepared in a step-back manner. The samples were then inoculated by Enterococcus (E.) faecalis and incubated for 21 days. Intracanal medications were applied including, calcium hydroxide (n=20), propolis (n=20), and ethanol (n=20). Two groups of 10 teeth were also used as the positive and negative controls. Microbiological sampling was performed utilizing a piezo-reamer drill after one week of incubation. The samples were plated and CFUs were counted after 48 hours. MICs of calcium hydroxide and propolis were measured by serial dilution and agar dilution methods, respectively. The statistical tests of ANOVA and Duncan post-hoc were used to compare different medications.Results: MICs and CFUs of propolis were dramatically less than calcium hydroxide. The difference between the groups was statistically significant (P&lt;0.001).Conclusion: Our results reveal that propolis is an effective antimicrobial intracanal agent

Cytotoxicity of Triple Antibiotic Paste and Calcium Hydroxide against Cultured Human Dental Pulp Fibroblasts

Objective: In necrotic immature teeth, intra canal medicaments such as triple antibiotic paste (TAP) and calcium hydroxide (CH) are used for root canal disinfection and regeneration treatment. However, the effect of these medicaments on dental pulp fibroblasts has yet to be known. This study aimed to assess the cytotoxicity of CH and TAP against cultured human dental pulp fibroblasts (HDPFs) obtained from third molars.Methods: In this in vitro study, fibroblasts were obtained from the dental pulp of two third molars. Fibroblasts were exposed to 0.1, 1 and 10 mg/mL concentrations of TAP and CH. Six samples were prepared of each medicament and fibroblast viability was evaluated after 72 hours. Data were analyzed using one-way and two-way ANOVA (p&lt;0.001). The percentage of cell viability was calculated and the cytotoxicity of the medicament was categorized as severe (30%), moderate (30- 60%), mild (60-90%) and non-toxic (&gt;90%).Results: In TAP samples, only the 10 mg/mL concentration had a significant difference with the control group in terms of the percentage of cell viability and showed moderate cytotoxicity. In CH samples, the 1 and 10 mg/mL concentrations showed significant differences with the control group and were severely cytotoxic.Conclusion: Reduction in cell viability of fibroblasts by increase in concentration was significantly greater in CH compared to TAP group. Thus, in regeneration treatments, these medicaments must be used in concentrations with adequate therapeutic and insignificant adverse effects on fibroblasts

In vitro evaluation of the antibacterial effects of AH26 combined with two different antibiotics on Enterococcus faecalis

Introduction: To prevent growth of residual bacteria, it has been proposed that sealers and filling materials should have antibacterial properties. The aim of this study was to evaluate the antibacterial effects of AH26 sealer combined with two different antibiotics on Enterococcus faecalis. Materials and methods: In this in vitro study, the antimicrobial effects of amoxicillin and minocycline which were added separately to AH26 sealer were evaluated on Enterococcus faecalis. In group 1, 25% amoxicillin with AH26 sealer, in group 2, 25% minocycline with AH26 sealer, in group 3, pure AH26 sealer, and in group 4, distilled water were used. The samples were placed in agar plates inoculated with Enterococcus faecalis. All the plates were incubated for 7 days at 37°C under anaerobic condition, and zones of growth inhibition were measured in millimeters at 24-, 48-, 72- and 7-day intervals. Data were analyzed using 2-way repeated measures ANOVA and multiple comparisons were made by Tukey tests (α=0.05). Results: The results showed that adding antibiotics at 25% concentrations to AH26 sealer created significantly larger zones of growth inhibition compared to the sealer alone (p value < 0.05). In groups 1 and 2, there were significant differences in zones of growth inhibition with an increase in incubation period from 14 to 72 hours; however, there were no significant differences between 72- hour and 1-week intervals. The maximum antibacterial activity was observed in the amoxicillin group. Conclusion: Mixing AH26 sealer with amoxicillin and minocycline significantly increases the antibacterial property of the sealer against Enterococcus faecalis

Fracture strength of mesiobuccal roots following canal preparation via hand and rotary instrumentation: An in vitro study

INTRODUCTION: The aim of this in vitro study was to compare the effect of hand and rotary instruments on fracture strength of tooth roots.MATERIALS & METHODS: Thirty two teeth were randomly divided into two experimental groups of 15 each and one negative control group with two samples. In group 1, step-back technique with conventional stainless steel K-files was used, and in group 2, instrumentation was performed using rotary Ni-Ti Hero642. Samples in control group did not received cleaning or shaping after access cavity preparation. After obturating each canal, tip of the spreader was locked within canal. The required force for root fracture was measured using Instron testing machine. Recorded data was statistically analyzed using t-test.RESULTS: The mean and standard deviation force required for vertical root fracture were 50.33±19.1 and 63.1±25.46 N for hand and rotary groups respectively. However, no significant difference was found between experimental groups.CONCLUSION: The results indicate that the manual technique did not lower fracture strength of obturated roots in comparison with the rotary preparation technique

Comparison of coronal microleakage of resin modified glass ionomer and composite resin as intra-orifice barriers in internal bleaching

Introduction: Internal bleaching is a treatment option for wightening endodontically treated discolored teeth. Cervical resorption is one of the side effects of this method. The aim of this study was to compare the sealing ability of resin composite and light-cured resin modified glass ionomer (RMGI) as intra-orifice barriers in internal bleaching. Materials &Methods: In this study, 34 single-canal anterior teeth were used. All samples were endodontically prepared and divided into two experimental groups (n=12) and two control groups (n=5). In the experimental groups, Gutta-percha was removed up to 3 mm below the cemento enamel junction (CEJ). RMGI and composite resin was placed over gutta-percha in the experimental groups up to the level of CEJ. After 24-hours incubation period, the bleaching agent (a mixture of sodium perborate and 30% hydrogen peroxide) was placed in the access cavities. The bleaching agents were replaced every 3 days over 9 days. Then, the access cavity was filled with 2% methylene blue for 48 hours. All samples were longitudinally sectioned and the dye penetration range was evaluated using stereomicroscope. Data was statistically analyzed by using T-student test and variance analysis. Results: The microleakage in RMGI group was 0.945mm and in composite resin group was 0.641mm. Statistically, no significant difference was observed in microleakage between the experimental groups (p=0.121). Conclusion: Both materials can be applied as the intra-orifice barriers for internal bleaching

Comparison of Endodontic Medicaments on Bond Strength of Fiber Post to Root Dentin Using Resin Cement.

STATEMENT OF THE PROBLEM Endodontic irrigants and medicaments may affect the bond strength of intracanal posts to root dentin. PURPOSE The aim of this study was to compare the effect of calcium hydroxide (Ca(OH)2) and 2% chlorhexidine gel (CHX) on bond strength of fiber post cemented with resin cement to root dentin. MATERIALS AND METHOD This in vitro experimental study was conducted on 36 mandibular premolars. Canals were prepared using the step back technique. After root canal irrigation, the teeth were divided into three groups of 12. Ca(OH)2 paste and CHX gel were used as intracanal medicaments in the first and second groups respectively. No intracanal medicament was used in the third group (control group). Access cavities were then sealed and the teeth were incubated for one week. The root canals were then filled using gutta percha and AH26 sealer and the teeth were incubated for 72 hours. Tooth crowns were then cut at the level of the cementoenamel junction and intracanal posts were placed. The teeth were mounted in auto-polymerizing acrylic resin, and incubated for one week .They were then sectioned into 1.5mm thick slices from their coronal surface using a fully automated cutting machine, and subjected to push-out test until failure. The load at debonding was recorded and data were analyzed using one-way ANOVA, post-hoc test and t-test. The coronal margin of the root was at the level of the surface of acrylic resin in the mold. RESULTS The mean bond strength was 4.45 MPa in the Ca(OH)2, 2.45 MPa in the CHX and 2.48 MPa in the control group. The difference in this regard was statistically significant among groups (p= 0.04). The Ca(OH)2 group had significant differences with the CHX and control groups (p= 0.03 and p= 0.02, respectively). The difference between the CHX and control groups was not significant (p= 0.974). CONCLUSION Based on the results, Ca(OH)2 increased the bond strength of fiber post to root dentin but 2% CHX had no effect on bond strength

Long-term pH Alterations in the Periradicular Area Following the Application of Calcium Hydroxide and MTA

Statement of the Problem: A rise in pH and the presence of calcium ions play an important role in prevention or management of external root resorption. Purpose: This study assessed the long-term pH alterations in the periradicular area following the application of calcium hydroxide (CH) and mineral trioxide aggregate (MTA) intracanal medicaments. Materials and Method: This in vitro, experimental study evaluated 45 single-canal extracted human teeth. After decoronation and root canal instrumentation, defects (3×3×1mm) were created in the middle third of the roots. Following smear layer removal, the root surface (except for the defect) was sealed with nail varnish. Five teeth served as negative controls and were filled with distilled water. The remaining 40 teeth were randomly divided into two groups (n=20) for application of MTA and CH as intr-acanal medicaments. Periapical radiographs were obtained to ensure optimal quality of obturation. After coronal sealing with glass ionomer, the teeth were incubated at 37°C, and their pH was measured at 1 and 2 weeks, and 1 and 3 months, using a pH-meter. Data were analyzed using one-way ANOVA, Tukey’s test and Bonferroni adjustment. Results: The mean pH was significantly higher in CH group at 1 and 2 weeks (p< 0.01) but no difference was noted at 1 and 3 months (p= 0.52). The mean pH in both groups was significantly higher at 2 weeks compared with other time points (p< 0.05). Conclusion: CH may be preferred for use in the first weeks following the initiation of root resorption to provide a high pH. MTA can be later applied to maintain the high pH for a longer period of time without the need for medicament exchange

The Mediating Role of Perceived Social Support in the Relationship between Cognitive Emotion Regulation Strategies and Corona Disease Anxiety

The aim of this study was to investigate the relationship between cognitive emotion regulation strategies and Corona disease anxiety mediated by social support. The research design was descriptive - correlational and the statistical population included all students studying at Shiraz University in the academic year 1399-1400, of which 293 were selected by convenience sampling. They responded to Alipour et al.'s Corona Disease Anxiety Scale, Zimet et al.'s Multidimensional Perceived Social Support Scale and the short form of Garnefski and Kraaij 's Cognitive Emotion Regulation Questionnaire. The results showed that there was a significant negative correlation between adaptive strategies of cognitive emotion regulation with corona disease anxiety and a significant positive correlation between maladaptive strategies of cognitive emotion regulation and corona disease anxiety. Also, cognitive emotion regulation strategies had a significant relationship with corona anxiety both directly and indirectly through social support. The goodness-of-fit indices also indicated the good fit of the proposed model. These results, in addition to explaining the role of cognitive emotion regulation strategies in the occurrence of anxiety, emphasize the importance of paying attention to these strategies, especially strengthening adaptive strategies along with providing social support

Effect of triple Antibiotic paste and 2% chlorhexidine gel on shear bond strength of composite resin to dentin; an in vitro study

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