Malocclusion and some functional recordings of the masticatory system in Swedish schoolchildren.

Four hundred and two children aged 7, 11 and 15 years answered a questionnaire and were clinically examined. Sixty per cent of the children had some form of occlusal anomaly. One fifth of 7-year-old children and 3 per cent of 11-year-old children were dummy- or finger-suckers and these children often had crossbite and frontal open bite. The mean maximal opening capacity was 49 mm in 7-year-old children and 53 mm and 57 mm respectively in the two oldest age-groups. The horizontal mobility was almost the same for 11- and 15-year-old children (about 10 mm) but slightly lower in the youngest children. The average distances between the retruded contact and intercuspal positions (RP and IP) antero-posteriorly, vertically and laterally were 0.6 mm, 0.5 mm and 0.3 mm respectively. Most of the children (60%) had a RP-IP displacement of 0.5-1.0 mm antero-posteriorly while 1% had dual bite. Children with postnormal occlusion had a large RP-IP distance antero-posteriorly and children with crossbite a lateral deviation more often than children without these occlusal anomalies. Fourteen per cent of 15-year-old children had dentine visible on at least one incisor. Children with deep bite had less worn teeth than other children.