Developmental stability reflects the ability of a genotype to develop in the same way under varying environmental conditions. Deviations from developmental stability, arising from disruptive effects of environmental and genetic stresses, can be measured in terms of fluctuating asymmetry, a particularly sensitive indicator of the ability to cope with these stresses during ontogeny. In an inbred Adriatic island population, we expected dental arch fluctuating asymmetry 1) to be higher than in an outbred sample from the same island, and 2) within this population, to increase with the level of inbreeding. Due to environmental stress, we also expected to find higher fluctuating asymmetry in the outbred island population than in an urban reference group from the same country. The material consisted of 506 dental casts of 253 children from 1) the island of Hvar, and 2) Zagreb, Croatia. Three-dimensional coordinates of 26 landmarks spanning the arches were digitized. The analysis partitioned the asymmetry of arch forms into components for directional and fluctuating bilateral asymmetry, using the appropriate Procrustes method (geometric morphometrics). The results corroborated the hypotheses. Fluctuating asymmetry was found to be higher on the island than in Zagreb in all groups and in both jaws, and increased significantly with endogamy level in the lower jaw. There was no significant directional asymmetry in the Zagreb sample and likewise none in the upper jaws of the outbred island group, but significant directional asymmetry in both jaws of the inbred population and also in the lower jaws of the outbred island group. These results suggest an environmental as well as a genetic influence on dental arch asymmetry. Although the lower jaws expressed these two stresses almost additively, the upper jaws appeared to be better buffered. The role of directional asymmetry as a potential indicator of craniofacial developmental instability clearly merits further attention.

No abstract

The prevalence of malocclusion was studied on the Hvar island, Croatia. This island is characterized by high rates of endogamy, inbreeding and reproductive isolation. The sample for this study comprised 224 children, 126 males and 98 females from all schools on the island of Hvar (20.2 per cent of the total public school population). The sample was selected according to age, sex distribution, and demographic characteristics. The Angle Classes, overjet, overbite, crowding, spacing, and the type of anterior bite were examined. Class I buccal relationship was found in 47.3 per cent of the subjects, Class II in 45.1 per cent, and Class III in 5.4 per cent. Normal overjet was the most frequent finding (69.9 per cent). Normal overbite was seen in 42.5 per cent, deep in 49.1 per cent, and very deep in 2.7 per cent of the cases. Open bite was diagnosed in seven subjects (3.1 per cent) and edge-to-edge bite in six (2.7 per cent). The frequency of crowding was 57.1 per cent, normal relationships were observed in 34.9 per cent, and spacing in 8 per cent. The results of this investigation showed that the inhabitants of Hvar, who are characterized by a high rate of inbreeding and traditional diet, have more Class II malocclusions, deep bites, and midline shifts than the general Croatian population but not higher than other modern urbanized groups. Since the lack of chewing stress in this population cannot be considered as the main explanation for the above phenomenon, the genetic influence on the development of these occlusal traits in the inbred population of Hvar requires further investigation.

ObjectivesDespite variation in lifestyle and environment, first signs of human facial aging show between the ages of 20–30 years. It is a cumulative process of changes in the skin, soft tissue, and skeleton of the face. As quantifications of facial aging in living humans are still scarce, we set out to study age‐related changes in three‐dimensional facial shape using geometric morphometrics.Materials and methodsWe collected surface scans of 88 human faces (aged 26–90 years) from the coastal town Split (Croatia) and neighboring islands. Based on a geometric morphometric analysis of 585 measurement points (landmarks and semilandmarks), we modeled sex‐specific trajectories of average facial aging.ResultsAge‐related facial shape change was similar in both sexes until around age 50, at which time the female aging trajectory turned sharply. The overall magnitude of facial shape change (aging rate) was higher in women than men, especially in early postmenopause. Aging was generally associated with a flatter face, sagged soft tissue (“broken” jawline), deeper nasolabial folds, smaller visible areas of the eyes, thinner lips, and longer nose and ears. In postmenopausal women, facial aging was best predicted by the years since last menstruation and mainly attributable to bone resorption in the mandible.DiscussionWith high spatial and temporal resolution, we were able to extract a shared facial aging pattern in women and men, and its divergence after menopause. This fully quantitative three‐dimensional analysis of human facial aging may not only find applications in forensic and ancient human facial reconstructions, but shall include lifestyle and endocrinological measures, and also reach out to studies of social perception.

No abstract