Hawaii with its groups of people of many different racial backgrounds and varied food habits, its unusually mild, even climate and the abnormally high percentage of tooth decay in some groups and the freedom from decay in others presents an opportunity for dental observation that is rather unusual. The good health organization on the sugar plantations and the conditioning of the children over many years to medical examinations are a great aid to any human study.
Tooth decay is the most prevalent disease in the world. It is present at all ages, in all races and has been present throughout history. The Iron Age skulls show immunity to tooth decay; the Bronze Age skulls show 37 per cent with decay and 11 per cent of all the teeth decayed or missing; the ancient Egyptians' skulls showed 51 per cent with decay, and 5 per cent of the teeth decayed or