Welcome Tibor, the thick creamy colored liquid can be from a number of things like dry mouth, medications, an infection, like thrush, and so on, so if it doesn't go away, maybe see a doctor. The salivary glands basically shut down at night, reducing saliva production, and matters are worse with those that sleep with thier mouth open causing more dry mouth. Saliva kills bacteria in the mouth, and with this salivary loss it causes morning breath. Infections can also be an indication, and cause taste, appetite, eating, and breath problems. Radiation destroys thin saliva, not thick saliva, mainly produced by the parotid glands, the others produce a mixture of thin and thick, but modtly thin. The thick saliva can have a yellowish tinge to it.

http://www.oralcancerfoundation.org/complications/candida-infection.php

http://www.oralcancerfoundation.org/complications/xerostomia.php