Comparison of the effect of licorice extract gel and 0.2% chlorhexidine mouthwash on the amount of Streptococcus mutans in saliva: a clinical trial

Abstract

Background: In recent years, the use of plant extracts in modern medicine has increased. Licorice plant is one of these medicinal plants that is widely used in the field of dentistry and oral diseases. The aim of this study was to compare the effect of licorice extract gel and 0.2% chlorhexidine mouthwash on the reduction of Streptococcus mutans in saliva in the form of a clinical trial. Materials and methods: After the steps of separating the extract from it, licorice extract was prepared in the form of oral gel. The prepared gel (100 µg/mL) was sterilized by gamma rays. Ten patients were included in the study based on the above entry and exit criteria and were divided into two intervention and control groups using the randomization method of coin toss (tap and line). Licorice extract gel was used in the intervention group and 0.2% chlorhexidine mouthwash was used in the control group. Patients were asked to rinse their mouths with the given gel for 1 minute every day for 1 week. Sampling of saliva was in two stages: one stage before starting to consume the formulations (extract and mouthwash) and the second sampling at the end of one week after consuming the formulations. Then the prepared saliva samples were sent to the microbiology laboratory of Tabriz University of Medical Sciences to count the colonies. SPSS version 25 software was used for data analysis. A value less than 0.05 was considered significant. Results: The results showed that the microbial density of patients decreased significantly after using chlorhexidine (P<0.0001). Also, the results showed that the microbial density of patients decreased significantly after using licorice gel (P<0.0001). Comparing the reduction of microbial density in two groups showed that the microbial density of patients after using licorice gel was not significantly different from the microbial density of patients after using chlorhexidine (P=0.39). This means that both substances have acted similarly. That is, licorice gel has been able to create antimicrobial effects equal to chlorhexidine. Conclusion: Due to the appropriate antimicrobial property of licorice extract gel on Streptococcus mutans bacteria, various oral formulations can be prepared from this substance to prevent or treat oral and dental diseases.