Investigating the Effect of Capsaicin Oral Solution in the Treatment of Burning Mouth in Patients: A Randomized Clinical Trial

Background Burning mouth syndrome is one of the most prevalent complications of the oral cavity with unclear etiology, which has led to offering inconclusive treatments. Due to limited studies on the effects of oral solution form of capsaicin on BMS, this study was conducted with the aim of investigating the effect of capsaicin in the treatment of burning mouth in patients. Methods In this double-blind clinical trial study, 22 eligible female patients suffering from burning mouth were randomly divided into 2 case and control groups. In the case group, subjects dissolved 10 drops of capsaicin oral solution in 1 tablespoon of water and swished 2 times a day for 1 minute in their mouth for 30 days. The same way of consumption was prescribed for the control group that used the placebo solution. Vitamin B and zinc supplements were also given to both groups. In both groups, the amount of burning mouth was assessed by visual analog scale, the amount of non-stimulating saliva was determined by Schirmer's test, and the amount of xerostomia and the quality of life were recorded by standard questionnaires on days 0 and 30 of the intervention. Results The findings of this research exhibited that the variables of burning mouth, xerostomia, amount of non-stimulating saliva, and quality of life in the capsaicin group show a significant difference before and after the intervention (p value < 0.05). However, there was no prominent difference between the capsaicin and placebo groups at day 30 regarding the 4 mentioned variables (p value > 0.05). Conclusions It was concluded that the use of 10 drops of capsaicin oral solution in one tablespoon of water twice a day for 30 days, along with the consumption of vitamin B and zinc supplements, cannot improve burning mouth sensation, non-stimulating saliva, xerostomia, and quality of life levels compared to placebo. Nonetheless, it was observed that in the capsaicin group, all the mentioned parameters were slightly improved after the intervention. Trial registration The study’s protocol followed the Declaration of Helsinki and was approved by the ethics committee of the Islamic Azad University Faculty of Dentistry, Tehran, Iran (IR.IAU.DENTAL.REC.1400.155) on 01/10/2022, and it was subscribed to the Iranian registry of clinical trials (IRCT20220117053748N1). The protocol of the study is available on https//irct.behdasht.gov.ir/trial/61360.