[Study of perioral force exerted on the teeth in preadolescent children with anterior crossbite]

30 preadolescent children with anterior crossbite were selected for the present study. Among them 15 were male and 15 children were female. Their age ranged from 8 to 12 years. The mean age was 10. 8 years. Their perioral forces were measured in the areas as following: the labial and lingual sides of mandibular and maxillar central incisors, the first premolars and molars of both sides. After analysis of the results, some conclusions were drawn as the following, the distribution of the perioral force of bilateral arch was symmetric, and there were no significant differences between genders. The values of the perioral force in the premolar and molar area were the largest. When the children were in their nature head position, the perioral force values of labial side were larger than those on the lingual side. On the lingual side of mandibular incisors negative values were found. The perioral force correlated with malocclusion. The position of the teeth decides the value of the perioral force. It has been well concluded that the forces exerted on the teeth were not the only factor that influenced teeth position. There are also other factors influencing the teeth poison. This needs further study.