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

Introduction: Calcium hydroxide (CH) is one of the most common intracanal medications. Corticosteroids (CS) are used in endodontics because of their anti-inflammatory activity. This study aimed to evaluate the antimicrobial effect of CH+betamethasone and CH+saline against Enterococcus faecalis (E. faecalis) using agar diffusion test and measuring the microbial zone of inhibition (ZOI). Methods and Materials: Four plates containing Mueller-Hinton broth and E. faecalis culture media, were prepared. In each plate, 5 holes (5×3 mm) were created and a creamy mixture of CH+betamethasone was inserted into the holes (10 holes for each material). Two holes with ampicillin disks and two empty holes were used as negative and positive controls, respectively. Plates were incubated for 24 h and then the diameter of microbial ZOI was measured. The pH of each mixture was measured by pH meter. Data were analyzed using the Mann-Whitney U test. Results: The mean diameter of ZOI for CH+betamethasone and CH+saline was 3.4 and 3 mm, respectively. The difference was not significant (P=0.143). The pH was 12.5 for CH+saline and 12.3 CH+betamethasone, respectively. Conclusion: The mixture of CH+betamethasone had good antimicrobial effects against E. faecalis. Further studies are needed to confirm the value of this mixture in clinical settings.Keywords: Antimicrobial Activity; Betamethasone; Calcium Hydroxide; Enterococcus faecalis; Intracanal Medicatio

Dantrolene: A Selective Ryanodine Receptor Antagonist, Protects Against Pentylenetetrazole-Induced Seizure in Mice

Ryanodine receptor abnormalities has implicated in the generation and maintenance of seizure. Dantrolene, a selective ryanodine receptor antagonist, may be a potential drug for the prevention of seizure. Therefore, we aimed to clarify the protective effects of dantrolene against pentylenetetrazole seizure in mice. Male albino mice were received an intra-peritoneal injection of pentylenetetrazole (80 mg/kg) in seven separate groups (n=8). We used dantrolene (10,20 and 40 mg/kg), caffeine (200 mg/kg), dantrolene (40 mg/kg) + caffeine (200 mg/kg), diazepam (5 mg/kg as a positive control) and vehicle 30 minutes before the injection of pentylenetetrazole. Then, we registered the latency time of the first seizure, the severity of seizures and the incidence of seizure and death. Kruskal-Wallis test followed by Mann-Whitney and Fisher’s exact test were used to analyze the data. Dantrolene (10,20 and 40 mg/kg) significantly increased the latency time for the first seizure. Furthermore, dantrolene (20 and 40 mg/kg, but not 10 mg/kg) attenuated the severity of seizures in comparison to the vehicle group. Moreover, dantrolene only at the dose of 40 mg/kg prevented from tonic-clonic seizure and death in comparison to the vehicle group. In contrast, the addition of caffeine abolished the protective effects of dantrolene on the tonic-clonic seizure/death and inhibited the beneficial effects of dantrolene on the severity of pentylenetetrazol seizures. The acute dantrolene administration produced an anticonvulsant effect in the pentylenetetrazole-induced seizure. Moreover, caffeine prevented from dantrolene anticonvulsant effects. These results may imply about ryanodine receptors and intracellular calcium roles in the generation and control of pentylenetetrazole seizure