北京乐山香港地区和日本儿童龋齿流行病学研究

调查了北京、四川乐山和香港３、６，１２和１５岁男女儿童的龋病流行情况，每组约６０人。将所得结果与日本国相同年龄组比较。结果表明，中国儿童乳牙患龋率高，城市高于农村，恒牙患龋率相对较低，乳牙和恒牙龋齿的治疗率均较低；香港儿童乳牙患龋率低于北京和乐山；日本儿童患龋率及治疗率均最高。

THE STATUS OF ERUPFION AND CARIES OF THE FIRST PERMANENT MOLAR IN CHILDHOOD

The first molar will play a key role in the formation of permanent dentition and also is easy to be caries. In this series, 7968 cases 4-6 yrs old children are investigated and the eruption and caries of first molar are analysed. The results are as follows: The eruption rate of first molar in 7968 cases 4-6 yrs old children is 22.13%. The mean number of molar erupted is 0.55+1.17. Both are in very signiflicant sexual difference. The eruption in girls is earlier than that in boys. The eruption rates are 1.01% in 4 yrs old group and 59.00% in 6 yrs old group. In the per centage of the molar erupted, (?) is 66.26% with symmetrical rate 69.31%, 6 is 33.74% with symmetrical rate 33.24%. The incidence rate of caries in 1763 cases 4-6 yrs old children with first molar erupted is 1.76% with dft 0.02±0.15. The dft in cases of caries is 1.26±0.63. There are two molars with caries of Degree IV in 5 yrs old group. The eruption and caries of the first molar in childhood are analysed. The importance of prevention dnd treatment of first permanent molar in childhood is indicated.

幼儿期正常乳牙列的表现与变化

作者测定并分析3～6岁幼儿的正常乳牙列,获得其长度、宽度、高度、复(牙合)和复盖的均值,在观察生长发育状况时有一定的参考价值。 总体观察幼儿期乳牙列的变化不大。复(牙合)、复盖随年龄增长而减少。有隙型牙列占93.86％,人均间隙数为8.49,灵长间隙占总间隙之35.58％,第一、二乳磨牙间间隙少见。末端平面中两侧近中型、近中—垂直型和两侧垂直型较多见。