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The aim of this study was to examine the change in the occlusal plane inclination that takes place during craniofacial growth relative to various facio-cranial reference lines, as well as to find possible differences in means between sexes, to determine if there were correlations among variables, and to find out which of the parameters were the most reliable in determining the occlusal plane inclination. The investigation was carried out on 192 lateral radiographs of subjects divided into five age groups. The radiographs were traced and six angular roentgencephalometric variables were analysed by using different reference lines: cranial base (OLNS), Frankfort horizontal (OLFH), maxillary base (OLPL), mandibular base (OLML), anterior face height (OLNM) and posterior face height (OLSGO). It could be concluded that the change in occlusal plane inclination shows anterior rotation (left profile) during growth. The most significant change of the occlusal plane inclination was found using variables OLPL, OLFH and OLNS. There were no significant differences according to sex. Small but significant correlations were found between all investigated variables, except OLML.

In contemporary orthodontic treatment, the extraction of a premolar is frequently indicated, followed by canine retraction with bodily movement. The main problem is how to prevent the mesial movement of first molars (loss of anchorage) and loss of the space obtained by extraction. The aim of the study was to evaluate the anchorage capacity of posterior teeth using SW (straight wire) appliances after extraction of first premolars and to determine Goshgarian transpalatal arch as anchorage reinforcement. All experiments were recorded by video-camera, and the analogue signal has been digitized and saved on PC. Computer animation visualised the direction and the amount of tooth movement. Very significant loss of anchorage was found (in the control experiment), when molars and premolars were reinforced. No significant difference between the active and non-active transpalatal arch has been perceived in the sense of lateral anchorage stabilization.

Estimation of the inclination of the occlusal plane and its spatial orientation during the insertion of plaster casts in the articulators space, and control during the clinical phase of the prosthetic work, is one of the key problems in dental prosthetics. The aim of this investigation was to compare the relations of the basic roentgencephalometric parameters applied and to determine their reliability. Five angular variables were analysed: OP-MdP, OP-PP, OP-CP, OP-FP and OP-SNP, on a sample of 86 radiographs of subjects with almost normal occlusion by applying basic statistical parameters and the correlation's analysis. The results gave mean values of the investigated variables with estimation of their variability and level of mutual correlation, which can be used when determining individual inclination of the occlusal plane. Parameters FP and SNP showed significant stability and reliability which can be successfully applied in prosthodontics.

The aim of this study was to establish prevalence of hypodontia in the twin sample and to assess the degree of its heritability. A study was performed in a sample of 96 twin pairs, 38 pairs being monozygotic (MZ) and 58 pairs dizygotic (DZ), from north-west Croatia. The sample included 25.82% of all twins born in the region during a ten-year period. The twin zygosity was determined according to the WHO recommendations (1996). A revised Holzinger's index (Hc') according to Allen was applied to calculate the degree of heritability. Hypodontia was found in 22 out of the total of 192 twins analyzed (11.5%). Among 96 pairs of twins, hypodontia was observed in 17 pairs (7 MZ and 10 DZ pairs). Among the MZ, 4 pairs were found to be concordant for hypodontia, among the DZ one pair only. The heritability index was 0825. A prevalence of hypodontia in twins observed in this study is significantly higher than in the general population. A high index of heritability (Hc' = 0.825) points to a high genetic determination.

Correlation between the cranial base flexure with the sagital and vertical positions of both jaws has been analysed on 180 radiographs of eugnathic probands and 256 radiographs of patients with various malocclusion forms. Radiographs were analysed by conventional cephalometric procedures determining maxillar rotation, mandibular rotation, sagittal position of the maxilla, sagittal position of the mandible, and cranial base flexure. A significant correlation between the degree of cranial base flexure and facial prognathism was found. The correlation coefficients were higher in eugnathic probands than in those with malocclusions. Regression analysis defined three basic types of sagittal bimaxillar relations: orthognatism, retrognatism and prognatism.

Data on the dynamics of craniofacial growth, obtained by simple non-invasive measurements, are scarce in comparison with those collected by cephalometric methods. The aim of this study was to measure a number of craniofacial parameters, and to evaluate their changes during transition from the deciduous to the permanent dentition. A sample of 61 subjects (32 boys and 29 girls) were followed longitudinally by annual examination from an initial mean age of 4.7 years to a final mean age of 11.8 years. Conventional anthropometric instruments were employed to measure six craniofacial variables: G-Op, Eu-Eu, Zy-Zy, Go-Go, N-Gn and N-Pr. The data were analysed using basic summary statistics and a longitudinal regression model. A difference between males and females was found for all variables during the study period. During the transition from deciduous to mixed dentition (4.7-7.5 years), the cranial breadth and length (Eu-Eu and G-Op) decreased followed by an increase during the mixed dentition. All other parameters showed a continuous increase, which was highest for the variables defining facial height.

Earlier research in craniofacial morphology of the inhabitants of Mainz (Germany) and Zagreb (Croatia), who represent the populations of wider areas, have shown some roentgen-cephalometric differences. The aim of this study is to determine the craniofacial morphologic differences of these populations in three dimensions. The sample consists of 200 adult examinees, male and female respectively, inhabiting the mentioned areas. The sample has been chosen so that the examinees with prominent craniofacial anomalies have been excluded. Twenty three craniofacial parameters with the usual anthropometric instruments have been measured. The data have been processed by using elementary descriptive statistics and discriminant analysis. The results have shown that in Mainz examinees longer and narrower heads and higher faces in comparison with Zagreb examinees, predominate. Significant differences in forehead widths and bipupilar distances have been found.

The mandibular angle, an important roentgenocephalometric parameter, undergoes marked changes during growth and development. The dynamics of alterations of the entire mandibular angle and its two segments was studied in a sample of 200 roentgenograms of eugnathic subjects divided into homologous age groups at 10-year scale intervals to the adult age. For each age group, three roentgenocephalometric variables were statistically processed. Results, presented numerically and graphically, led to a conclusion that the size of the mandibular angle and its superior segment decreased considerably in a defined period of time. A decrease in the values of all variables was clearly seen in both adolescence and postadolescence.

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. For most parameters evaluated, statistical processing revealed a markedly higher compatibility in monozygotes than in dizygotes. This held particularly true for types and severity of anomalies as well as for all qualitative variables, with the exception of over bite, overjet, class and class severity. The maxilla-related variables were shown to be highly genetically determined, which might be explained by the dynamics of mandibular movements and, possibly, a stronger effect of external factors on its growth and development.

A skin projection of the orbitale as palpated through soft tissues was designated on the left cheek of 22 subjects. The nasion, orbitale and cephalostat nasion direction medium were plotted on transparent paper after teleroentgenography. Mutually parallel lines were drawn through the points, the line obtained on the construction of the nasion direction medium used as a basic one. Distances between the lines were measured and results statistically processed. Transfer of the model into the articulatory region by means of the orbitale and buccal arch nasion direction appeared not to orientate reliably the model according to reference planes of the head. Our results are consistent with literature data available.

The study was carried out in two age-matched groups of patients from two different periods of time. The aim of the study was to determine whether any craniofacial system alterations attributable to the influence of secular trend had occurred during a defined period of time. Four basic craniofacial variables, from which the craniofacial indices were derived, were measured. The findings were statistically processed by the basic parameter evaluation and testing of differences of arithmetical means of the same variables between the two study groups. The results showed the following alterations to have occurred during a 13-year period due to the secular trend effects: cranial indices decreased, mostly by a significant cranial length increase (g-op); and facial indices decreased, mostly by a facial height decrease (n-gn).

In this study, teleroentgenocephalograms of 34 subjects with at least 20 natural teeth were used. Correlation between the angle formed by linking the PORION-NASION-SPINA NASALIS ANTERIOR (PONANS angle) points and the angle made by Frankfort horizontal and occlusion plane was studied. The coefficient of correlation was 0.1263. It is considered that there is no correlation if the coefficient of correlation is less than 0.5. Thus, there was no correlation in the study sample, which is consistent with the results reported by Karkazis and Polyzois, but in disagreement with those published by Monteith. In our sample, the occlusion plane could not be oriented in the articulatory space or in toothless mouth by means of the method proposed by Monteith.

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. The results show the differences in the anterior face height, the lower border mandible inclination, the interincisal angle as well as the degree of face convexity. The average examinee from Zagreb, in comparison with the same one from Mainz, shows smaller anterior face height, the marked mandibular basal line inclination in the sense of the anterior rotation, the higher interincisal angle as well as smaller facial convexity.

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. The results indicate a significant genetic determination of the shape of the palate and the papilla incisiva and of the direction of the plicae palati. The analysed traits give the greatest values to the Hc index of inheritance.

The aims of the study were: --to determine sagittal differences in the position and inclination of incisors in defined orthodontic anomalies as compared to eugnathic occlusion; --to assess the importance of variable interrelationships for the evaluation of incisor orientation; and --to describe the distribution of compatibility of all linear and angular assessments of incisor orientation studied in relation to both jaws, direction of deviation and type of malocclusion. A sample of 436 roentgenograms taken in subjects of both sexes aged 10-18 years (180 with eugnathic occlusion and 256 with orthodontic anomalies) were analyzed. Five dentoalveolar variables were observed. Use of the 3 degrees = 1 mm principle allowed the inclination and position of incisors to be compared. The following conclusions were reached: --as compared to eugnathic subjects, dentoalveolar variables were changed in defined orthodontic malocclusions with clear differentiation according to type of anomaly; --a significant relationship was found for most variables used to assess the position and inclination of incisors; --a complete compatibility between the position and inclination was recorded in 16.7% and 15.7% of cases in the maxilla and mandible, respectively; --compatibility between the inclination and position was highest in subjects with eugnathic occlusion; and --inclination and position of incisors may be mutually independent or even contradirectional in one and the same subject, necessitating separate analytical evaluation.

Eight linear variables have been analysed in a sample of 200 persons with normal occlusion. Selected variables define the cranial base, basal planes of both jaws, anterior face height, upper and lower segment of the anterior face height, posterior face height and mandibular height. Particular aim of this investigation was to establish the differences according to age and sex, to describe the correlations as well as to define the proportional relations among the selected linear variables. From the results obtained the following conclusions were drawn: All variables increased by growing up; the greatest increase was found in posterior face height, and the smallest in cranial base length, The highest correlation was found between variables defining both facial heights. Index defining proportion between posterior and anterior face height (65.4) showed a horizontal growth tendency in the population investigated.