Orthodontic anomalies and differences in gnathometric variables in twins.

Actuality of gnathometric measurements by means of plaster casts persisting to the present days is stressed and the major research of the kind in twins mentioned. The study included 96 pairs of twins of both sexes (36 monozygotic and 60 dizygotic). Both qualitative and quantitative variables were evaluated and the results computer-processed.

[A comparative study of the craniofacial morphology of 2 ethnic groups].

The samples consisting of 200 latero-lateral cephalometric X-rays of examinees with nearly normal occlusion from Mainz are compared with homologous one from Zagreb. The purpose of the investigation was to point out the morphological differences in cranio-facial system. 19 variables were analysed by using essential statistic parameters and discriminative analysis.

[Photoocclusion as a complementary method in orthodontic diagnosis].

The sample consisted of 102 individuals, of which 30 were with normal occlusion, and the rest was classified in 6 groups of orthodontic anomalies. They were of both sexes, mean age was 16.8.

[3. L Cephalometer].

Authors present an original approach to the cephalometric measuring by obtaining absolute coordinates of the cephalometric points in a coordinate system fixed on the skull. An instrument especially constructed for that purpose is shown, and also the way of using it in vivo.

[Craniofacial dimensions in twins].

In order to estimate the role of the genetic and ecological factors in the craniofacial growth, study has been made on 36 monozygotic (MZ) and 31 dizygotic (DZ) twin pairs of the same sex. Standard anthropological instruments were used. The following dimensions were examined: the stature, Eu-Eu, G-Op, Zy-Zy, Go-Go, N-Gn and N-Pr.

[Characteristics of the palate and palatine folds in twins].

In a sample of 95 pairs of twins (36 mz and 59 dz) the traits were analysed which define the shape of the palate, the intensity, direction and ramification of the plicae palati, the intensity and location of the raphae palati mediana and the shape and size of the papila incisiva. The impressions of the palates were made with optosil and these models were photographed. The photographs were analysed.

[Measurement of orthodontic appliance force using prototype sensors].

In introductory remarks the most important biomechanical principles, which are relevant for the research, and conditions which must be satisfied presented in intraoral measuring of orthodontic forces were pointed out. First the aim of the research was defined, and then the investigation of mechanical properties of acrylics as a material for orthodontic appliances were carried out. The type of strain gauges, bonds and measuring system configurations, as well as measuring amplifiers and recording instruments were discussed.