Impact of 1% malic acid spray on the oral health-related quality of life of patients with xerostomia

Dry mouth sensation, also known as xerostomia, is a common clinical problem with an increasing prevalence. Although recent studies have reported promissory results of malic acid, none have evaluated the impact of malic acid on the oral health-related quality of life (OHRQoL) of patients with xerostomia. Thus, this study aimed to evaluate the impact of 1% malic acid, combined with fluoride and xylitol, on the OHRQoL of patients with xerostomia. We enrolled 70 patients and randomly allocated them into two groups: the intervention group (applied topical sialogogue with 1% malic acid) and the control group (applied a placebo). We assessed the OHRQoL and severity of xerostomia before and after treatment with the Spanish version of the Oral Health Impact Profile-14 questionnaire (OHIP-14sp) and a visual analogue scale (VAS), respectively. In addition, stimulated and non-stimulated salivary flow rates before and after treatments were also measured. In total, 60 patients completed the study. According to the VAS, both sprays significantly improved dry mouth sensation (P < 0.001). However, OHIP-14sp total scores decreased significantly in the intervention group from 20.8 ± 10.4 to 16.5 ± 9.5 (P < 0.001), indicating an improvement in the OHRQoL. No significant differences were observed in the control group (P > 0.05). Furthermore, non-stimulated salivary flow rates significantly increased in the intervention group from 0.25 ± 0.22 to 0.33 ± 0.33 mL/min (P < 0.001). Overall, this study demonstrated that malic acid improves the OHRQoL and dry mouth sensation in patients with xerostomia.