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Biomedical subjects

S Helm

Publications and source records attributed to S Helm.

13 recordsLinked to original sources

Skeletal maturity in Danish schoolchildren assessed by the TW2 method.

Skeletal maturity was assessed from hand-wrist radiographs in a sample of 3,817 Danish schoolchildren aged 7 to 18 years using the new version of the bone-specific Tanner-Whitehouse scoring system, the TW2 method. In most of the age groups in both sexes the distributions of the bone maturity scores displayed marked departures from normality; percentiles for the scores were therefore counted from the raw data. On the average, over the total age range, the differences between the age equivalents (bone ages) for the fiftieth percentile and chronological age were close to zero in both sexes, indicating good agreement with the British standards. However, in the individual age groups, and in particular at adolescence, characteristic divergences from the standards occurred, apparently reflecting the developmental spurt.

Adolescent

Assessment of age-at-death from mandibular molar attrition in medieval Danes.

Stages of occlusal attrition of the permanent mandibular molars were recorded in 235 Danish medieval skulls, 52 of which were in various states of mixed dentition. For the first and second molar, ages at emergence and ages at occurrence of the earlier stages of attrition were estimated from the mixed dentitions, on the assumptions 1) that the age at eruption of a given number of permanent teeth was similar in medieval and contemporary Danish children, and 2) that the rate of attrition was similar for the first and second molars. Estimation of ages at occurrence of the later attrition stages and of the age at third molar emergence was based on percentage frequency distributions of the stages of attrition using reiterative calculating procedures. Third molar emergence was estimated at the early age of 14 years. It is argued that assessments of age-at death could be made fairly accurately for the age range 5-30 years, and with decreasing accuracy until about 40 years of age.

Adolescent

Prevalence of malocclusion in medieval and modern Danes contrasted.

A comparison was made of frequencies of anomalies of the dentition, occlusion, and space conditions for the permanent dentition in the skeletal remains of 278 medieval Danes and in 1258 contemporary Danes. The congenital anomalies of the dentition were equally common in the samples. Extreme maxillary overjet and distal molar occlusion, deep bite, and crowding were considerably less frequent in the Middle Ages. The frequencies of mesial molar occlusion and crossbite, but not that of midline displacement, were higher in the medieval sample, especially in the older subjects. It is suggested that the observed differences in malocclusion prevalence were related to exogenous factors, primarily the pronounced dental attrition.

Adolescent

Basic method for recording occlusal traits.

This article describes a basic method for the recording of malocclusion that has been developed jointly by the World Health Organization and the International Dental Federation. The method was developed and field-tested in the period 1969-78 and should provide investigators and health authorities with a common basis for assessing the prevalence of malocclusion in various parts of the world. It should also serve as a basic reference tool in the development of methods for assessing the need and demand for orthodontic treatment.

Dental Records

Intra-examiner reliability of epidemiologic registrations of malocclusion.

Intra-examiner consistency in the recording of single traits of malocclusion according to a previously described method was assessed by duplicate registrations on study models of 292 children. The level of agreement was expressed by the consistency ratio and the phi coefficient. A high level of consistency was obtained for most of the malocclusion traits, and it was concluded that the method employed is appropriate also for analyses of interrelations between these traits.

Adolescent

Timing of permanent tooth emergence in two Greenland Eskimo populations.

Mean times of emergence of the permanent teeth (except the first and third molars and mandibular central incisors) were studied cross-sectionally in an unmixed East Greenland population in 1957 and in present West Greenland Eskimo children. In spite of differences in racial and environmental conditions, practically no difference was found between the two samples in the timing of dental development in general, taking into account the average difference in emergence times of the individual teeth. Both samples showed advanced dental development in comparison with two unmixed Caucasoid and two unmixed Mongoloid populations. The mutual similarity in timing of tooth emergence between the East and West Greenland Eskimo children considerably greater than the similarity between each of the Eskimo samples and any of the other four populations.

Adolescent

Estimates of orthodontic treatment need in Danish schoolchildren.

Orthodontic treatment need has been assessed on the basis of complete orthodontic records in a random sample of 293 Danish children aged 13-17 years by a group of postgraduate orthodontic students and by three orthodontists. The estimates of treatment need ranged from 45% to 61%. Interexaminer agreement in pairs was observed in 77%-92% (mean 83%) of the cases. Uniformity in four individual assessments was reached in 69% of the cases: 38% were considered in need of treatment and 31% were considered not to present such need; conversely, 31% gave rise to disagreement. It is argued that, at present, the orthodontist's subjective estimate of treatment need probably constitutes a more realistic approach to the problem of assigning treatment priority than the various indices of malocclusion.

Adolescent