A comparison of facial form in three Western European male groups

<p>Comparison of lateral skull radiographs of male subjects, aged 10 and 15 years, with Class I incisor relation, drawn from Belfast, Glasgow and Stockholm, showed a marked similarity in shape and size at both ages between the Celtic groups.</p> <p>The Swedes showed significant differences from the other groups, their jaws and teeth being more prognathic and their horizontal linear facial dimensions being larger.</p> <p>By means of Stepwise Discriminant Analysis it was possible to correctly classify 80 per cent of the Swedish subjects at each age and of the combined Celtic group, 70 per cent at 10 years and 82 per cent at 15 years.</p&gt

Modifications dimensionnelles de l'arcade dentaire au cours des traitements de Classe III par régulateur de fonction

Les moulages dentaires de dix-huit cas de malocclusion de Classe III, traités par le régulateur de fonction de type III (FR III), sont mesurés et comparés avec ceux d'un groupe témoin traité par appareils amovibles maxillaires et dispositifs Edgewise pour les mêmes malocclusions. Les modifications moyennes enregistrées pendant le traitement sont cliniquement peu importantes dans les deux groupes et sont caractérisées par une expansion de l'arcade maxillaire et une contraction de l'arcade mandibulaire. Le groupe FR III montre une augmentation significativement plus importante de l'expansion au niveau de la largeur intermolaire et une augmentation significativement moins importante de la flèche d'arcade maxillaire (P<0,05), par comparaison au groupe témoin. Le manque de coopération et les différences de conception des écrans vestibulaires semblent expliquer que l'on obtienne moins d'expansion avec le FR III comparé avec les études précédentes portant sur le FR II

The variability of some craniofacial dimensions

The variability of eight linear and five angular dimensions measured on 124 lateral skull radiographs of 10-year-old boys was assessed by means of Bartlett's test for homogeneity of variances and Pitman's test for the comparison of correlated standard deviations. The linear dimensions which demonstrated the greatest variability within the four constituent Angle classes (N = 31) were mandibular body length, total cranial base length, total mandibular length and lower face height. The dimensions which demonstrated the least intra-group but greatest inter-group variability were maxillary length and Angle SNB. The Class II division 2 group exhibited the greatest variation in skeletal morphology; it is therefore postulated that its etiology is mainly dentoalveolar and soft tissue in origin

Maxillary retention: is longer better?

Two different maxillary retention regimes were compared to ascertain if differences in posttreatment relapse existed. The patient pool was derived from subjects being treated at two orthodontic departments in the west of Scotland. Group 1 (20 patients) followed a 6 month regime using removable upper Hawley retainers for a period of 3 months full time and 3 months nights only. Group 2 (18 patients) followed a 1 year regime of 6 months full time and 6 months nights only. The results revealed that maxillary incisor alignment, as determined by Little's irregularity index, had relapsed by an average of 50 per cent of the end of retention value 3 months out of retention in Group 1 but only 23 per cent in Group 2. Although the actual mean values for relapse were 0.77 and 0.23 mm, respectively, seven subjects in Group 1 showed relapse of more than 3 mm as compared with only one in Group 2. This suggests that retaining a case for 1 year rather than 6 months is clinically beneficial

Maxillary retention: is longer better?

Two different maxillary retention regimes were compared to ascertain if differences in posttreatment relapse existed. The patient pool was derived from subjects being treated at two orthodontic departments in the west of Scotland. Group 1 (20 patients) followed a 6 month regime using removable upper Hawley retainers for a period of 3 months full time and 3 months nights only. Group 2 (18 patients) followed a 1 year regime of 6 months full time and 6 months nights only. The results revealed that maxillary incisor alignment, as determined by Little's irregularity index, had relapsed by an average of 50 per cent of the end of retention value 3 months out of retention in Group 1 but only 23 per cent in Group 2. Although the actual mean values for relapse were 0.77 and 0.23 mm, respectively, seven subjects in Group 1 showed relapse of more than 3 mm as compared with only one in Group 2. This suggests that retaining a case for 1 year rather than 6 months is clinically beneficial

A comparison of facial form in three Western European male groups

Comparison of lateral skull radiographs of male subjects, aged 10 and 15 years, with Class I incisor relation, drawn from Belfast, Glasgow and Stockholm, showed a marked similarity in shape and size at both ages between the Celtic groups. The Swedes showed significant differences from the other groups, their jaws and teeth being more prognathic and their horizontal linear facial dimensions being larger. By means of Stepwise Discriminant Analysis it was possible to correctly classify 80 per cent of the Swedish subjects at each age and of the combined Celtic group, 70 per cent at 10 years and 82 per cent at 15 years.</p

Development of three-dimensional imaging system for analysis of facial change

The objective of this report is to present facial changes produced by the Twin Block appliance in three-dimensional visual and numerical formats. Using a C3D system, stereophotogrammetric records were made of two children with Class II division 1 malocclusions prescribed treatment with a Twin Block appliance. Three-dimensional images of their faces were captured. Comparison of specified regions of the three-dimensional images was made using landmark identification and superimpositions. In addition to obvious visual evidence, numerical data in the form of surface area measurements were also generated. The three-dimensional, C3D, system, provides a flexible imaging tool which should become increasingly useful as more improvements are made