Oral malodor measurement using a halimeter
Oral malodor values were measured using a halimeter (RH-17 K; Interscan Co., Chatsworth, CA). Subjects refrained from any oral activity, such as food intake, for at least 2 h pre-measurement. The subjects were instructed to close their mouths for 3 min (using only nasal breathing) before every measurement, followed by placing a straw, connected to the halimeter, 4-cm deep into their mouth. The measurement was performed automatically, and the mean value of three consecutive measurements was used for analysis [