M 102
(8) The mean eruption time and the order of eruption of permanent teeth of Chinese children of South China correspond quite closely to that of English children. Those teeth that erupt before the age of nine appear earlier among the English, while those that erupt after that age appear earlier among the Chinese. (See following table and chart.)
(9) Arrested caries affecting deciduous teeth is about twenty times more frequent than that affecting permanent teeth.
(10) The several observed types of hypoplasia on teeth are found to affect teeth less frequently among Chinese children than among English children in England. The ratios are about 1 to 7 for permanent teeth, and 1 to 3 for deciduous teeth.
(11) Salivary calculus around permanent teeth is found to be more common among children from Central China than among children in South China.
From this survey it is concluded that dental caries among Chinese children is prevalent beyond doubt. In order to improve the situation, preventive measures in ways of operative dental treatments, prophylaxis and dietetic adjustment should urgently be resorted to.
Table on time of eruption of permanent teeth.
Table showing the ages at which fifty per centum of the several types of teeth are found in any stage of eruption for both sexes together.
Type of tooth English Age in years Chinese Age in years 7|7 7.17 7.17- 6|6 6.10 ± .51 6.39 ± .55 3|3 6.23 ± .50 6.54± .35 5|5 ITI 6.36 .50 1|1 7.311 .49 6.92± .70 7.74.73 5|5 212 2|2 7.61 .53 8.03.87 2|2 8.59 .69 8.78.70 Type of Tooth 4|4 9.87.94 9.46± .84 3|3 212 3|3 313 2|2 10.35 .75 9.91 .83 4|4 10.61.94 10.19 .71 5|5 10.81±1.04 10.50 .94 קה English Chinese 5|5 313 3|3 11.51±1.09 10.71 .98 11.47 .82 10.87 .90 6|6 6166 8 77 7|7 11.69± .78 11.56± .63 Age in years. 12 13 14 7|7 12.20± .77 12.00± .73Page 465
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