A medico-dental survey of 920 Australian school and pre-school children —in the northwestern area of N.S.W. and at Hammondville, near Sydney —indicated that 97.5 percent of the children, five years of age and over, had caries. Statistical analysis of the data support the following conclusions :
(1) The greater the lack of oral hygiene, the greater the incidence of caries.
(2) Freedom from caries is associated with low intake of sweets ; rampant caries, with high intake ; there are more carious surfaces when consumption of sweets is high than when low. (3) In rachitic children, teeth that commence calcification during the period of rickets are not different, in susceptibility to caries, from the corresponding teeth of non-rachitic children. (4) Incidence of caries in teeth of children who show hypoplastic defects, in at least one tooth in each case, is not different from that in normal teeth.
A survey of oral conditions in 1,976 natives of New Guinea showed that 2.5 percent had caries. The incidence of odontoclasia (a peculiar type of hypoplastic defect occurring mainly in temporary teeth), in children under six years of age, was 22.4 percent—an average of 6.6 odontoclastic teeth per affected child. Statistical analysis of the data suggested that there is much less caries among the natives living on the coast, where sea food is obtainable, than among those living inland. Incidence of caries in the various inland districts was practically the same throughout.
References: Den. J. Aus., 7, 707, 1935; 10, 339, 1938.