 Secretion at rest varies authors 0,05ml min 0,4ml min. The mouth dryness is defined by a total salivary flow rate below 0.1 unstimulated - 0,1ml min 0.16 ml min. The salivary potential of hydrogen pH varies between 6.5 and 8.5. Decreased salivary flow will cause a decrease in pH and promote the degradation of the oral health status. 