Researchers found that melatonin, a hormone created by the pineal gland, may be able to protect the oral cavity against free radicals produced by inflammatory diseases. Melatonin has strong antioxidant effects that can protect cells against inflammatory processes and oxidative damage.
"Patients with higher salivary and melatonin ratios had lower community periodontal index (CPI). CPI is the score used to assess periodontal status," said Pablo Galindo, DDS, Department of Oral Surgery, School of Dentistry, University of Granada, Spain. "This finding suggests that the melatonin may fight against infection and inflammation possibly due to its antioxidant, anti-aging and immunoenhancing ability."
Wow - they deduced this from measurements in only 55 people? Older people had more periodontal disease which correlated with having smaller salivary volume. So, it is not just melatonin that was low in these patients, but everything else in the saliva, including immunoglobulins, etc. How about the old adage that "correlation is not causation"?