Physiological causes of odor.

The most frequent causes physiological halitosis is caused by or arising directly into the oral cavity. An investigation by Sulser indicates that more than half of the sample of the study is offensive breath during certain hours in a day.
Hunger may be associated with the breath and smells of the mouth, this relates to the retention that can occur in the mouth because of the low activity of chewing, plus a factor associated with increased odor Oral systemic changes are of the age as well as the daily cycle of normal metabolic activity .