The mean age of the 90sG was eight years and five months ± 13 months. These subjects were born between 19, and they presented Class I (37), Class II (61), and Class III (2) malocclusions. The 1990s group (90sG) with 100 subjects (52 boys and 48 girls) derived from patients observed at the same department between 19. The 50sG exhibited 43 subjects with Class I, 47 with Class II, and 10 with Class III malocclusions.

The mean age of the 50sG was seven years and 11 months ± eight months. The 1950s group (50sG) with 100 subjects (52 boys and 48 girls) derived from the records of patients who were first observed at the Department of Orthodontics of the University of Florence, Italy, in the 1960s. 1) of two modern samples living in the same geographic area and separated by almost 35 years: a group of subjects born in the 1950s and another group born in the 1990s, in order to investigate the biological bases of malocclusions. The aim of this study is to compare the dental arch dimensions and the degree of occlusal tooth wear in the mixed dentition ( Fig. Dental interferences, forced guidance of the mandible and an incorrect position in both the sagittal or transverse planes can result in a lack of physiological changes in the dental arches. The decrease in masticatory performance caused by the widespread use of processed food could be responsible for inadequate wear of deciduous teeth along with underdeveloped jaws. 2, 3 Changes in dietary habits 4 and a greater prevalence of respiratory pathologies in the last decades 6 were held responsible for a progressive increase in the prevalence of malocclusions. Modifications of the environment surely have a major role in causing a severe increase in the prevalence of malocclusions. Differences were reported also in groups of the same century separated by almost 30 years. 4 Secular trends in occlusal patterns were reported in several populations between ancient and modern subjects. A dramatic difference is demonstrated in individuals with a similar genetic pool in the change from a sociotechnologically preindustrial situation to another influenced by industrialisation. These observations were the basis to indicate malocclusion as a 'disease of civilisation'. 1Ī high prevalence of malocclusion was reported in many contemporary cohorts while populations living in primitive conditions were often described with good dental alignment and with an almost correct occlusion. Malocclusion includes the malposition of individual teeth, discrepancies between tooth and jaw size and malrelations of the dental arches in the sagittal, transverse, and vertical dimensions. The comparison of abrasion showed significant differences between the two groups for all examined teeth which appeared to be more abraded in the 1950s group.Ĭonclusions This association can partially explain the greater risk of developing malocclusions in contemporary children compared with children living 35 years before. Posterior transverse interarch discrepancy was significantly minor in girls of the 1990s. Results The results show that both boys and girls of the 1990s showed significantly smaller maxillary intermolar width when compared with the 1950s. Groups were compared using a nonparametric test (Mann-Whitney U-test) for independent samples (P <0.05). The available anterior space in both arches and the posterior and anterior transverse dimensions were calculated. The evaluation of tooth wear scores and measurements for posterior and anterior arch segments, intermolar and intercanine width, and mesiodistal size of incisors were taken. Methods Dental casts of a group of subjects born between 19 were compared with subjects born between 19. Aim The objective of this study was to compare the degree of tooth wear in posterior deciduous teeth and the dental arch dimensions in the mixed dentition in two modern samples living in the same geographic area and separated by almost 35 years.

Maria franz teeth