Olaf Luck | PubMed Health

PubMed2004

Prevalence of malocclusions in the early mixed dentition and orthodontic treatment need.

Early interceptive treatment for the elimination of factors inhibiting dental arch development and mandibular and maxillary growth is applied varyingly by orthodontists, possibly because there is little scientific evidence that such interventions are of actual benefit. The aim of this study was to determine specific factors for treatment need in the early mixed dentition period in order to obtain basic data to support early intervention. The study was part of a larger survey of 8768 children aged between 6 and 17 years. From this sample, 1975 children aged between 6 and 8 years were used to estimate the prevalence of malocclusions using the Index of Orthodontic Treatment Need (IOTN) during the early mixed dentition period. The results showed that deep overbite and overjet, both more than 3.5 mm, were the most frequent discrepancies, affecting 46.2 and 37.5 per cent of patients, respectively. An anterior open bite was registered in 17.7 per cent, crossbite in 8.2 per cent, and a reverse overjet in 3.2 per cent. A tooth width to arch length discrepancy was recorded in 12 per cent of teeth in the upper arch and in 14.3 per cent in the lower arch. The proportion of children estimated using the Dental Health Component of the IOTN to have a great or very great treatment need (grades 4 and 5) was 26.2 per cent. The higher values of treatment need during the mixed dentition period may account for temporary changes in the dentition and for the discrepancy in overjet and overbite. These discrepancies will be compensated in part during mandibular growth and development of the dental arch. Nevertheless, the findings indicate the early development of progressive malocclusion symptoms which are evidenced in the IOTN and concur with the acronym 'MOCDO' hierarchy (missing, overjet, crossbite, displacement, overbite). This early formation of progressive symptoms inhibiting or disturbing mandibular or maxillary growth or the development of the normal dental arch, i.e. crossbite, reverse overjet and increased overjet with myofunctional disorders, should be treated at an early stage.

Adolescent↗

PubMed2003

Interocclusal clearance during speech and in mandibular rest position. A comparison between different measuring methods.

BACKGROUND AND AIM: The interocclusal clearance during speech and in mandibular rest position shows an interindividual variation and influences the stability of prosthodontic reconstruction or orthodontic therapy, especially in patients with deep bite or cover-bite. Exact determination of the vertical dimension, not always a simple matter in practice, is controversially discussed with respect to the methodology. The aim of the present investigation was to compare three methods for determining interocclusal clearance during speech and in mandibular rest position. PATIENTS AND METHODS: Extraoral manual registration and electronic registration were used to evaluate 33 malocclusion-free patients. The measurements were repeated to determine the reproducibility. For disturbance-free objectification, the freeway space, i.e. the interocclusal clearance in mandibular rest position, was also recorded cephalometrically. RESULTS: None of these registration methods displayed clear-cut superiority to the others. Electronic registration is very time-consuming and should be confined to special cases. Sources of error in manual registration are increased movement of the measuring points marked on the skin during mandibular movement and the free handling of dividers. CONCLUSIONS: This method can be used only in connection with mm. consonants. Speaking the word "Ohio" yielded excessively high values in all methods, so that this word has to be rejected as a speech sample. Cephalometric registration produced values with slight interindividual variations. In practice, however, this method is unsuitable for use with orthodontic patients because of the additional radiation exposure involved in producing an additional lateral cephalogram. For good reproducibility, practicing or frequent repeating of the measuring method prior to definitive measuring is essential.

Adult↗