Yuk! I can hear each mother silently say.
This discussion isn't about dog's saliva but it is interesting that studies have found dog's saliva is mildly antibacterial so when dog's groom their young or their own wounds it maybe that saliva has a role in helping kill harmful bacteria. There have also been studies that have demonstrated that children that grow up with a dog seem to have less allergies (It toughens them up!)
The cleansing result of our natural tendency to "lick wounds" is most likely largely due to the physical removal of debris from any wound, rather than more subtle antibacterial effects.
Saliva for humans - that is your own saliva - is very important in the health of your mouth.
Without saliva it is nearly impossible to stop people lossing their teeth due to decay.
Teeth Cleaning is important; Your diet is important; but neither of these can compensate for the protective qualities of your own saliva.
Saliva comes from a number of places in your mouth. Most of your saliva comes out in ducts under your tongue (70-75%) and the rest from a duct near your upper 6 year old molar. A small amount comes from tiny glands in your lips.
From the dentists viewpoint we are interested in: