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Biomedical subjects

Luc Dermaut

Publications and source records attributed to Luc Dermaut.

5 recordsLinked to original sources
PubMed2004

Has hypodontia increased in Caucasians during the 20th century? A meta-analysis.

It has been claimed that agenesis of permanent teeth has increased over the years. The present study tested this hypothesis in Caucasians. Published data on the prevalence of children with one or more congenitally missing permanent teeth were selected on the basis of strictly imposed criteria. Using a meta-analysis, the data were evaluated and presented chronologically. Furthermore, the selected publications were checked for differences in the prevalence of agenesis between the male and female populations. Finally, information on the occurrence of upper and lower premolars as well as upper incisor agenesis was collected and calculated as a percentage of the total number of congenitally missing teeth. From 42 studies on this subject, 19 were selected based upon six stringently applied criteria. Chronological classification of the percentage of children with congenital absence of one or more permanent teeth revealed relatively higher percentages since 1957. Fourteen out of the selected studies presented data on sex distribution. In all but one publication girls tended to have a slightly higher occurrence of missing teeth compared with boys of the same age. The second lower premolars were most often agenetic, whereas missing upper laterals occurred almost equally as agenesis of the upper second premolars. The considered period of time is too short and the available data too limited to describe a possible trend in the human dentition. However, this meta-analysis seems to confirm that hypodontia has been diagnosed more often in recent studies.

Age Factors↗
PubMed2004

Unilateral posterior crossbite and chin deviation: is there a correlation?

A retrospective study evaluating the clinical discernment of chin deviations in general, and especially in relation to unilateral posterior crossbite (UPXB), was carried out to determine whether (1) there is a correlation between UPXB and clinically discernible chin deviation, (2) there are differences between the judgement of professional dental observers and laymen, (3) visual assessment of chin deviation compares well with computer-assisted assessment and (4) how large a chin deviation should be before it is noticed. The experimental group consisted of 72 patients (30 males and 42 females, average age 14.5 years) with a UPXB. A control group of 72 subjects without a UPXB was matched for age and sex. In addition, one computer-designed face was added with chin deviations of 0, 2, 4, 6 and 8 mm to the left. The full-face slides of all subjects were shown twice, with an interval of 2 weeks, to an audience of seven orthodontists, ten dental students and five laymen judging by eye. A computer-assisted assessment was carried out by one observer, in order to create a standardized comparison to visual scoring. Inter-observer examination of visual scoring showed moderate agreement (kappa = 0.48). When comparing the computer-assisted and visual scores, the intra-class correlation coefficient (ICC) was 0.87. There were no major differences between professional observers and laymen, although the latter gave significantly more responses in the direction opposite to the crossbite. In 70.3 per cent (on average) of the subjects with a crossbite, a deviation in the same direction as the crossbite was noticed visually. The majority of the observers observed a chin deviation of at least 4 mm.

Adolescent↗
PubMed2003

The value of the centre of rotation in initial and longitudinal tooth and bone displacement.

Force application on teeth and bone structures results in orthodontic and orthopaedic movements. The effect of force application during different time intervals (initial and longitudinal displacements) can be evaluated by describing the displacement vectors or by constructing the centres of rotation of the displacements. The aim of this investigation was to review different experimental studies to compare the position of the centre of rotation (CR) with the displacement vectors of the object (tooth or bone) after force application. The results indicate that the measuring procedure and the use of the CR to describe the displacement are very sensitive: a large discrepancy in the position of the CR does not necessarily lead to a major change in the displacement vector of the object. Displacement vectors seem to be more appropriate in describing both initial and longitudinal tooth or bone displacements.

Alveolar Process↗
PubMed2002

Long-term stability of the leveling of the curve of Spee.

The aim of the study was to investigate whether the orthodontic leveling of the curve of Spee is a treatment procedure with a stable result on a long-term basis. Measurements were made on the plaster casts of 149 orthodontically treated patients (57 males and 92 females). The mean age before treatment was 12.8 years (range, 8-25 years). Study casts were taken before treatment (T1), at the completion of orthodontic therapy (T2), and 6.7 years (mean) posttreatment (T3). Inclusion criteria were no extractions, all Angle classifications except Class III malocclusions, and all permanent teeth fully erupted except second and third molars. The curve of Spee and the irregularity index were measured on standardized digital photographs of the casts. Overjet and overbite were assessed with a ruler. Changes in the curve of Spee were correlated with changes in irregularity index, overjet, and overbite from T1 to T3. The following results were noted: (1) leveling of the curve of Spee is a relatively stable treatment procedure compared with a return of incisor crowding and deepening of the bite; (2) neither the initial depth of the curve of Spee nor the initial irregularity index is an indicator for the amount of relapse; (3) the amount of leveling is not correlated with the relapse of the 4 tested parameters (curve of Spee, irregularity index, overjet, and overbite); and (4) there is a mild correlation between the relapse of the curve of Spee and the relapse of the irregularity index, overjet, and overbite. According to the results of the study, leveling the curve of Spee during orthodontic treatment seems to be very stable on a long-term basis; it was weakly correlated with the other variables tested.

Adolescent↗