Cephalometric assessment of human fetal head specimens.

BACKGROUND: Past investigations of prenatal craniofacial growth have largely relied on histological sections. Few studies have taken measurements on three-dimensional representations (3D reconstruction, 3D CT, postmortem) or varying depth levels (ultrasound), and we know of no craniofacial growth studies done on cleared-and-stained specimens of whole fetal heads. MATERIALS AND METHODS: This study comprised 14 human fetal head specimens cleared and stained with alizarin red and alcian blue. They had been stored in glycerol and represented weeks 8-12 of gestation, with crown-rump lengths ranging from 23-145 mm. These specimens were cephalometrically analyzed in norma frontalis and norma lateralis, which notably included the opportunity for side-to-side comparison. RESULTS: As the cranial membrane bones progressively approached each other, the orbits, maxilla, and mandible gradually grew wider. Likewise, the sagittal dimensions of the maxilla and mandible increased continuously and synchronically. We noted side-to-side differences ranging from 2-5 mm. Another notable finding concerned the inclination of the maxilla relative to the cranial base, which increased more on the right than on the left side. CONCLUSION: This is the first investigation presenting side-to-side comparative measurements of human fetal head specimens. Such measurements are essential in the quest toward validating the findings of other imaging techniques such as CT or MRI and-most importantly-intrauterine sonography.

The seven-year outcome of an early orthodontic treatment strategy.

The benefits of early orthodontic treatment are continuously discussed, but studies are few. We examined whether definite need for orthodontic treatment could be eliminated in public health care by systematically focusing on early intervention. One age cohort living in a rural Finnish municipality (N = 85) was regularly followed from ages 8 to 15 years, and persons with malocclusions were treated according to a pre-planned protocol. Treatment need was assessed according to the Dental Health Component (DHC) of the Index of Orthodontic Treatment Need, and treatment outcome by the Peer Assessment Rating Index (PAR). Fifty-two percent of the cohort received treatment, and definite treatment need decreased from 33% to 9%. In the treated group, the mean PAR score reduction was 63%, and 51% showed more than 70% improvement. The results suggest that an early treatment strategy may considerably reduce the need for orthodontic treatment in public health care with limited specialist resources.

Identification of cases requiring orthodontic treatment. A longitudinal study.

The present paper is a report on the second part of a longitudinal study dealing with the identification of children requiring orthodontic treatment. The series consisted of 200 children selected at random. The children were first examined at the age of 7 and next time at the age of 10. At the second examination 38% were found not to need any orthodontic treatment, while it was considered necessary to follow the occlusal development in 19%, and 43% were found to need treatment. The treatment need was urgent in 17%, moderate in 16% and slight in 10%. The re-examination of the untreated children at the age of 10 offered a possibility of checking the orthodontic prognosis made at the age of 7. It was concluded that only children showing cross bites and severe Class II malocclusions can reliably be selected for treatment at the age of 7. At this age misjudgements can be made with regard to dental arch crowding, open bite, deep bite, overjet and distal occlusion. Furthermore, it was concluded that a final decision concerning the need of orthodontic treatment cannot always be made even in 10-year-old children. The study will be continued by examinations at the ages of 12 and 14.

Need of orthodontic treatment in 7-year-old Finnish children.

The purpose of the investigation was to determine the need of orthodontic treatment in 7-year-old Finnish children. The series consisted of 200 Finnish children, 100 girls and 100 boys. With regard to the main lines of occlusion a close agreement was observed between the prevalence of malocclusion in this and other. Scandinavian series. The need of orthodontic treatment was assessed using a treatment scale for the age group concerned. No treatment was required in 42% of the children, while 23.5% were in immediate need of orthodontic treatment. In 34.5% it was considered necessary to follow the occlusal development.