Oral hygiene education based on bad breath can be more effective than other conventional educational methods because bad breath is considered a motivational tool for improving health-related behaviors. This study aimed to compare health education with different topics and compare their effects. In this study, students were randomly divided into three groups: oral hygiene education based on bad breath, traditional hygiene education based on caries and gum disease, and a control group (oral hygiene education only). The changed gingival index, plaque index, and bad breath were measured before the study, one month, and six months later. McNemar's test, Paired and independent t-test, and Wilcoxon tests were used to analyze the data. The study findings showed no significant improvement in the plaque index in the control groups at both follow-ups. At the one-month follow-up, the gingival index in the first group had a significant change compared to the other groups (P < 0.05). In terms of changes in bad breath, only in the first group, in both sexes, a decrease in the prevalence and severity of bad breath was observed compared to the beginning of the study (P < 0.01). According to the results of the present study, oral hygiene education based on bad breath was more effective, more lasting, and faster on students than traditional education and education alone.
