Abstract
A clinico-statistical survey was performed in 1999 involving 7,000 children had visited the pediatric dental clinic of the Tsurumi University Dental Hospital during approximately 9 years from September 1987 to July 1996, and were the subjects. Among these 7,000 child patients, children who underwent treatment for malocclusion were investigated. The targets of the investigation were those cases diagnosed as having any kind of malocclusion, the difference in gender, the incidence of malocclusion, the number of the appliances used, and the time span of the treatment.
The results were as follows:
1) The number of cases diagnosed as having any kind of malocclusion and which underwent treatment was 1,192 (17.0%), and more girls (668) were treated than boys (524).
2) The most predominant malocclusion was anterior crossbite (32.5%), followed by space shortage (17.1%), upper anterior protrusion (14.4%), and inlocking (13.1%).
3) The percentage of the cases complaining of malocclusion at the first visit was 52.3%, with the highest percentage concerning anterior crossbite (61.7%).
4) The number of appliances used was 1,740. Among these 1,740 appliances, the most frequently used appliance was chin cap (27.1%), followed by lateral expansion appliance (15.6%), biteplate (15.0%), and multi-brackets appliance (14.4%).
5) The youngest average age using the appliance was 7 y 2 m for chin cap, followed by activator, and the oldest was 12 y 1 m for multi-brackets appliance.
6) The average time span to obtain acceptable occlusion from the start of treatment was longest for biteplate (1 y 10 m). Those for chin cap and habit breaker were longer than 1 year, whereas those of the other appliances were less than 1 year.
7) Three years two months of the average treatment time span was the longest, this being for chin cap, followed by biteplate. Those of the other appliances required between 1 year and 2 years.
