Evaluation of Cytotoxic Effects of Various Endodontic Irrigation Solutions on the Survival of Stem Cell of Human Apical Papilla

Introduction: Root canal disinfection is an important step in regenerative endodontic treatments. An ideal irrigating solution must have high antimicrobial activity and minimum cytotoxicity. This study sought to assess the effect of some irrigating solutions on stem cells from the human apical papilla (SCAP) after different periods of exposure. Methods and Materials: Stem cells were isolated from immature, impacted mandibular third molars, transferred to 24-well plates, randomly divided into 6  experimental groups and exposed to BioPure MTAD Cleanser, QMix, 17% EDTA, 2% chlorhexidine (CHX), 5.25% sodium hypochlorite (NaOCl), sterile saline and untreated control group. Cytotoxicity of these solutions was assessed after 1, 5 and 15 min of exposure using the methyl thiazol tetrazolium (MTT) assay. Data were statistically analyzed using repeated measures ANOVA. Level of significance was set at 0.05. Results: The mean percentage of viable cells in all experimental groups was significantly different from the control and sterile saline groups at all the time points (P<0.0001). The mean percentage of viable cells significantly decreased over time in NaOCl, QMix, EDTA and MTAD groups, but no significant reduction was noted in CHX group. At all the time points the highest and the lowest cytotoxicity were seen in MTAD and normal saline groups, respectively. Cytotoxicity of the understudy materials from the highest to the lowest was as follows: MTAD>EDTA>QMax=NaOCl>CHX> sterile saline. Conclusion: Chlorhexidine had the lowest cytotoxicity compared to EDTA, MTAD, QMix and NaOCl and its cytotoxicity did not change over time compared to other solutions.Keywords: Apical Papilla; Cytotoxicity; Irrigating Solution; MTT Assay; Stem Cell

The effect of different irrigants and intra canal dressing on sinus tract closure

Introduction: Antimicrobial activity of irrigants and interappointment intracanal dressing is an important consideration in endodontics. The aim of this study was to evaluate the clinical efficacy of chemomechanical preparation of the necrotic canals with different irrigants and intra canal dressing in the control of root canal infection and sinus tract closure. Materials &Methods: In this study, 65 patients with sinus tract were treated. They were randomly divided into 4 groups. Sodium hypochlorite (NaOCl) and chlorhexidine (CHX) was used as the irrigation solutions in the group one and two, then the canals were filled. In group three, after irrigation with NaOCl, Ca (OH) 2/sterile Saline was used as intra canal medicament, and similar to group three Ca (OH) 2/CHX was used in group four after irrigating by CHX. After 7 days, the intra canal paste was removed and the canals were filled. The sinus tract closure was followed up within 7, 14, and 21-day intervals. The data were analyzed using Chi Square and Kruskal-Wallis statistical tests. Results: The highest mean time of sinus tract closure was for Ca (OH)2/sterile Saline and the lowest was for Ca(OH)2/CHX. The differences of sinus tract closure between group 2&4 (p=0.04), group 3&4 (p=0.004). Groups were statistically significant. Conclusion: It was concluded that Ca (OH)2/CHX paste as intra canal dressing has good clinical efficacy in the control of root canal infection and sinus tract closure

Antibacterial efficacy of lavandula officinalis extract, sodium hypochlorite and chlorhexidine gluconate solutions as root canal irrigations: A comparative analysis

Introduction: This in vitro study aimed to compare the antimicrobial effect of lavandula -0fficinalis extract, with sodium hypochlorite (NaOCL) and chlorhexidine gluconate (CHX), as root canal irrigants, on Enterococcus faecalis (EF). Materials &Methods: Seventy five extracted single-rooted premolars were selected. Root canals were prepared using rotary ProTaper system and were infected with the culture of E. faecalis. Specimens were randomly divided into five groups (n = 15), Group 1, 2: lavandula extracts (0.26 and 0.52 mg/mL), Group 3: 2.5%NaOCL, Group 4: 2%CHX, Group 5: Normal Saline. Irrigation was performed for each group for 5, 10 and 15 min. The viable bacteria obtained by collecting the canal dentin chips. Data analysis was performed with Kruskal-Wallis and Mann-Whitney u tests. Results: The mean number of viable bacteria was significantly reduced after 5 min exposure to lavandula solutions (p<0.05). A significant difference also existed between different times in the NaOCL group, being significant between 5 and 15 min (p<0.05), but there was no significant difference between different times in the CHX group. Comparison of the mean number of viable bacteria between different groups at different exposure times revealed that the difference between lavandula and NaOCL solutions with CHX was significant at 5 and 10 min (p<0.05), however, no statistically significant difference was observed between lavandula solutions and NaOCL. Conclusion: lavandula extract was effective in killing of EF. Further studies are necessary to fully understand its other properties such as tissue solubility, removal of smear layer and impact on dentin structure

Location of mental foramen in a southeast iranian population: a digital panoramic assessment

Introduction: Mental foramen is an important landmark in mandible and knowledge regarding the actual location of mental foramen is important in dentistry. Materials &Methods: A total of 1172 digital panoramic radiographs were evaluated for assessment of the location of the mental foramen. The location was classified into six groups in relation to the apices of the premolars and first molar. Results: In 957 of panoramic radiographs, fulfilling the inclusion criteria, the most common location of the mental foramen was at the apex of the mandibular second premolar. In 837 cases (87.5%), the mental foramen was located symmetrically on both sides of the mandible. Therefore, the apex of the second premolar was the most common symmetric location in both genders. Conclusion: The results showed that the most common location of the mental foramen in population of southeast Iran was at the apex of the second premolar