The Effect of Tongue Cleaning on Oral Malodor

Objectives: In a previous study, we showed that tongue coating (TC) is closely related to oral malodor. The aim of this study was to investigate the effect of tongue cleaning on oral malodor by analyzing data from a cross-sectional study.

Methods: The study population consisted of 157 patients from 18 to 59 years old with an average age of 42.5 ± 11.0 years old complaining of oral malodor and referred to the Clinic for Breath Odor, Tokushima University Hospital, Japan. By organoleptic measurement (OR), subjects were diagnosed as psychosomatic halitosis (OR0 and OR1) or genuine halitosis (OR2 to OR5). H₂S and CH₃SH in the mouth air were measured with a gas chromatograph system. TC accumulation was assessed by visual examination and subjects were categorized into four groups (TC1 to TC4) according to the criteria of Kojima. Full-mouth periodontal probing depth and the prevalence of teeth with bleeding on probing were recorded.

Results: There were significant relationships between TC status and parameters of halitosis in the study population. No significant relationship was found between TC and periodontal status. The subjects were divided into two groups, TC1/2 (slight) and TC3/4 (severe), and logistic regression analysis was performed using sex, age, the number of teeth, parameters of periodontal status, mouth cleaning habits (except for tongue cleaning) and smoking as explanatory variables. We found no positive significant relationship between TC accumulation and the variable used. The subjects with severe TC were divided into two groups whether they have habits of tongue cleaning or not. The group with tongue cleaning habits had significantly (p<0.05) lower concentrations of CH₃SH than that of the group without tongue cleaning habits.

Conclusion: This study showed that TC represents a major factor of genuine halitosis, and tongue cleaning may be an effective method for improving oral malodor.