Study schedule and test product
teeth
ADVERSE EVENTS, CAVITY, RECRUITMENT
The subjects visited the dental clinic at the time of recruitment (6 weeks before the start of the study), received an explanation about the details of the study, and gave consent. Saliva was collected for initial stratification according to the Shannon index, and laboratory tests in the oral cavity were performed. On Day 0 of the study, the tongue coating was evaluated to calculate TCI, and then samples of the saliva and tongue coating were collected. Scaling with an ultrasonic scaler (Solfy F; J. MORITA MFG. CORP.) and polishing with a polishing brush (Prophy brush ratch flat; Sakaki L&E Wise Co., Ltd.) and rubber cup (Prophy cup ratch 4 wave; EGUERU Inc.) were performed by the dental hygienist on all subjects as professional oral care. Subjects randomized to the CPC spray group were given the GUM/Mouth and Throat Sterilization Spray (Sunstar Inc.). On Day 1 after the start of the study, saliva and tongue‐coating samples were collected immediately after waking (see details of sampling methods below). After saliva and tongue coating sampling, subjects in the CPC spray group were administered four puffs (approximately 0.36 mL each) of the CPC spray to the tongue dorsum four times a day; three times after each meal of breakfast, lunch and dinner, and one time before sleeping. The subjects continued to perform their daily oral care routine. For example, if individuals in the CPC spray group typically brush their teeth after a meal or before sleeping, they use the CPC spray after brushing without rinsing their mouth with water immediately after use. The group without CPC spray was determined as the control group. After 1 week, samples of the saliva and tongue coating were collected at home from the subjects, similar to Day 1. After 3 weeks, saliva and tongue coating samples were collected at the dental clinic and the TCI was evaluated. Moreover, the subjects were requested to record the use of CPC spray and brushing of teeth, and the date, status of use of CPC spray, status of brushing of teeth, status of use of other oral care products such as mouthwash, status of taking the drug, and any unpleasant sensations and adverse events.