Conduct of the study
STRIX, xerostomia, bristle hardness
XEROSTOMIA, CAVITY
The participants were randomly divided into two groups by a simple randomization using the envelope method in a 1:1 ratio by one of the authors (MF): wiping and mouthwashing groups.Before brushing, medical interviews and oral examinations were conducted, and TCI, xerostomia, and pre-brushing saliva samples were collected. Saliva samples were collected by placing a filter paper under the tongue of the participant for 5–10 s to absorb the saliva accumulated in the oral cavity and moistened at least 10 mm from the tip of the filter paper. The patients were brushed by two trained dental hygienists. The toothbrush used had a 10 mm wide × 20 mm head, normal bristle hardness, a flat-cut brushing surface, and a straight grip (STRIX DESIGN, Inc., Tokyo, Japan). The sponge brush used for cleaning was bale-shaped with a cut-like, uneven treatment on the scrubbing surface, 18 mm in diameter, 18 mm in length, and 150 mm in total length including the handle. The scrubbing method was used for brushing. The dental hygienist first brushed the participant's upper jaw from the buccal molars to the anterior teeth, then the palatal side of the maxilla, and finally the mandible in the same order for approximately 3 min.After brushing, the participants were instructed to leave saliva in the oral cavity without swallowing or spitting it out and not to rinse their mouths. A second saliva sample was collected in the manner described above. Subsequently, according to the assigned oral care technique group, the wiping group wiped the buccal and lingual (palatal) mucosal surfaces of the dentition for approximately 2 min using a sponge brush. Two paper cups filled with water were used for wiping. The sponge brush that had been used to wipe the oral cavity was rinsed with one cup, and the other was used to rinse the sponge brush again, adjusting the water content. In the mouthwashing group, the participants were instructed to swish around the mouth with up to one paper cup of tap water (about 180 mL), so that the water was distributed throughout the mouth and on the right and left buccal sides. They then spit out the mouthwash solution. A third sample was collected after wiping or washing the mouth. Bacterial counts in the saliva were determined using real-time PCR, as described above.