Vol. 77 No. 02 (2022): The South African Dental Journal

Medical and Dental Hydrology
Hydrothermalism refers to the water / steam manifestations seen on the ground as a result of
waters welling up from the deep underground areas. Due to their heated origins, they usually contain a number of dissolved minerals and algae. Their physical and chemical properties have long been revered and valued for their many purported therapeutic effects. The father of Medicine, Hippocrates may have been one of the first to study the healing properties of water. However, it took many centuries for medical hydrology to become recognised as a branch of medicine, and only in1986 was it officially accepted by the World Health Organisation as a complementary tool1. Dentistry too has embraced hydrology by supporting the valuable role of water fluoridation plays in tooth and bone development, prevention of dental caries, and possible remineralisation of enamel. In the early 1940’s, the US Public Health Service appointed a dentist, Dr. H.T. Dean, to carry out research into the possible link between water fluoride levels and tooth staining. He undertook a series of epidemiological investigations, culminating in his famous “21-City Study”. The results published in 1942, showed that mottling of the teeth was rare at fluoride levels below 1ppm, while at the same time there was evidence of a caries preventive effect at 1ppm. Numerous other studies followed and in 1945, Grand Rapids, Michigan,
became the first town in the world to institute artificially fluoridated water. This treasured landmark and tourist attraction has been described as “An ethereal icy blue heaven, where white steam rises up from the vibrant water, closed in by black snow-capped rocks”. Its geothermal waters originate 1.2 miles below the surface where freshwater and seawater combine at extreme temperatures, and pick up many therapeutic minerals and algae that account for its healing reputation and brilliant blue colouring.