Saliva parameters
STERILE
To avoid the effect of the circadian rhythm, saliva was collected at the same time of day before and after the intervention, using a saliva collection kit (Salivette, Sarstedt, Germany) consisting of a centrifuge tube and sterile cotton. After rinsing the mouth with distilled water for 30 s, each participant, wearing rubber gloves, placed a sterile cotton swab in their mouth and chewed for 1 min at a mastication rate of 1 chew/s. The cotton swab, which absorbed saliva secreted in response to the chewing stimulus, was centrifuged (4 °C, 1,800 × 