SPP1 and diabetes mellitus: In order to assess the usefulness of melatonin application as a potential therapeutic strategy in periodontal processes, a cross-sectional study was conducted, the objective of which was to determine the effect of topical application of melatonin on salivary concentrations of alkaline phosphatase, acid phosphatase, osteocalcin and osteopontin in patients with diabetes and periodontal disease and in a control group of healthy subjects.