Antimicrobial Activity of Calcium Hydroxide and Betamethasone on Enterococcus faecalis; An in vitro Assessment

Comparative Evaluation of the Effect of Six Different Low-Surface-Tension Vehicles on the Penetration of Modified Triple Antibiotic Paste in Dentinal Tubules: An In Vitro Study

Background Modified triple antibiotic paste (MTAP) helps in the elimination of microorganisms which is imperative for the success of endodontic therapy. The intracanal medicament powders must be mixed with vehicles for better handling and penetration in the root canals. The purpose of this study is to compare the effect of six low-surface-tension vehicles on the penetration of MTAP in dentinal tubules. Methodology The root apices of 60 single-rooted human mandibular premolars were resected to obtain 12mm length. After biomechanical preparation, intracanal medicaments were prepared by mixing with the six vehicles (Group 1- Bupivacaine, Group 2- Sodium ether lauryl sulfate, Group 3- Neosporin H, Group 4- Chlorhexidine gluconate, Group 5- Chitosan, and Group 6- Polyethylene glycol) with MTAP and Rhodamine B dye. Middle and apical transverse sections were scanned under a confocal laser scanning microscope. The data were statistically analyzed using the one-way ANOVA test and the level of significance was p<0.05. Results The maximum depth of penetration was seen in Group 2 (MTAP with sodium ether lauryl sulfate) followed by Group 5 (MTAP with chitosan), Group 4 (MTAP with chlorhexidine gluconate), Group 1 (MTAP with bupivacaine), and Group 6 (MTAP with polyethylene glycol), and the least penetration by Group 3 (MTAP with Neosporin H). The depth of penetration in the middle level was in the order of Group 2 followed by Group 4, Group 5, Group 3, Group 6, and Group 1. The depth of penetration in the apical level was in the order of Group 2 followed by Group 5, Group 1, Group 4, Group 6, and Group 3. The overall depth of penetration was significantly higher at the middle level than at the apical level. Conclusion Group sodium ether lauryl sulfate showed the maximum depth of penetration in both the middle and apical areas. The least depth of penetration in the middle area was seen in group bupivacaine and the apical area by group Neosporin H.

Efficacy of a Novel Rotary System in Reduction of Intracanal Bacteria: An in Vitro Study

Introduction:

This in vitro study aimed to assess the effectiveness of a single-file rotary system (OneShape) in reduction of intracanal bacteria.

Methods and Materials:

Eighty one single-rooted mandibular first premolars with single canals were used. Six samples were selected as aseptic control group. Seventy five remaining specimens were infected by Enterococcus faecalis and incubated for 72 h at 37^°C. Then they were randomly divided into three groups (n=25). In each group, cleaning and shaping procedures were done using either two conventional rotary systems (ProTaper and iRace), or the single-file system (OneShape). Microbial samples from the intracanal environment were taken by paper points in two steps, before and after instrumentation. Then, they were diluted and plated in blood agar. In order to compare bacterial reduction and turbidity, the Kruskal-Wallis test was used followed by the Chi-Square and Mann-Whitney tests for pairwise comparison. The level of significance was set at 0.05.

Results:

The control group didn’t show any bacterial growth. The pre- and post-instrumentation samples were significantly different between three groups (P=0.02). Hence, there was no significant differences between turbidity of samples (P>0.05).

Conclusion:

OneShape system is efficient in bacterial reduction. In this regard ProTaper is the most effective system in intracanal bacterial reduction followed by iRaCe and OneShape, respectively.

In Vitro Evaluation of Different Solvents for Retrieval of Mineral Trioxide Aggregate and Calcium-Enriched Mixture

Introduction:

The purpose of this study was to evaluate the effect of different solvents; carbonic acid (H₂CO₃), hydrochloric acid (HCl), chlorhexidine (CHX) and sodium hypochlorite (NaOCl) on the surface hardness of mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement.

Methods and Materials:

Plexiglass molds were prepared and filled with Angelus MTA or CEM cement and then exposed to 2% carbonic acid, 37% hydrochloric acid, 2% chlorhexidine, 5.25% sodium hypochlorite and normal saline at intervals of 1 and 21 days, respectively (n=4). Surface microhardness of all specimens was analyzed by a universal testing machine and an electron microscope for some selected samples. Data were analyzed using the three-way ANOVA. Subgroup analysis was performed by Student’s t-test, One-way ANOVA and Tukey’s tests. The level of significance was set at 0.05.

Results:

On the first day, all solvents and on 21^st day HCl, and H₂CO₃ were more effective in reducing the microhardness of MTA compared to CEM cement (P<0.05).

Conclusion:

The two experimental cements were differently affected by the solvents at specific time intervals. The solvents were more effective on MTA.