Salivary melatonin is depleted in patients with dental caries due to the elevated oxidative stress

To determine salivary melatonin and malondialdehyde levels in individuals with and without dental caries.

Saliva samples were collected in a fasting state from patients with active dental caries (n ​= ​16) and patients without dental caries (n ​= ​16). Melatonin was measured in the samples using a commercially available ELISA kit and malondialdehyde was assayed using a standardized spectrophotometric method.

The salivary melatonin levels were significantly lower (p ​< ​0.01) in patients with active dental caries than patients without dental caries, while the salivary malondialdehyde values were significantly higher (p ​< ​0.01) in patients with active dental caries than patients without dental caries. The binary logistic regression analysis revealed a negative correlation (-0.513) between the salivary melatonin and malondialdehyde levels which was statistically significant (p ​< ​0.042) in the patient group with active dental caries, while no such relationship could be demonstrated in the patient group without dental caries.

Melatonin depletion and augmented malondialdehyde levels potentially indicate that the endogenous melatonin has been utilized to counter the oxidative stress-induced during the initiation and progression of dental caries. Further research could explore the potential use of exogenous melatonin supplementation as a preventive and therapeutic measure for dental caries.