Interventions
The following interventions were used in the study:(a) CPC+Zn: 0.075% cetylpyridinium chloride, 0.28% zinc lactate, 225 ppm fluoride (Colgate-Palmolive Company, São Paulo, Brazil);(b) CPC: 0.075% cetylpyridinium chloride, 225 ppm fluoride (Colgate-Palmolive Company, São Paulo, Brazil);(c) Negative control: distilled water.The volumes (20 mL) and rinsing times (once for 30 s) for the two test mouthwashes and for the negative control were as specified on the product label. Mouth washing was performed in the morning as the patient’s first oral hygiene procedure of the day. The participants were instructed not to perform toothbrushing or other oral hygiene procedures and were asked not to drink, eat, or chew gum after mouth washing and until the end of the experiment (for at least 60 min postrinsing). The patients were supervised by calibrated dentists to ensure compliance and to minimize experimental variations.