Root resorption is a variable to be considered in induced tooth movement (ITM). It is related to root morphology and alveolar bone crest, and also to the types of forces exerted by mechanotherapy. This histometric study evaluated the predominance of root resorption among roots of different dimensions, following ITM with different types of forces and at different time intervals. The study was conducted on 54 rats divided into three groups, according to the type of force: continuous (CF), continuous interrupted (CIF) and intermittent (IF), at periods of 5, 7 and 9 days. The percentage of resorption between mesiobuccal roots of larger dimension and intermediate roots of smaller dimension was assessed. The evaluations were performed on the AxioVision software, and the non-parametric analysis of variance for repeated measures in independent groups was further applied, consisting of a scheme of two factors, and complemented by the Dunn test at a significance level of 5%. The intermediate roots presented a higher percentage of resorption, which was gradual at the periods evaluated for the three types of forces, but mainly for CF. Comparing the intermediate roots with the mesiobuccal roots, there was a statistically significant difference (p < 0.05) in the CF group at day 7 and day 9, and in the FI group, at day 9. The intragroup analysis evidenced a statistically significant difference (p < 0.05) between the 5th and the 9th day for the intermediate root in the CF group. The intergroup analysis did not reveal any statistically significant difference (p > 0.05) in individually analyzed roots.

This study evaluated whether periodontal ligament (PL) thickness varied with root size and examined the possible influence of this variation on orthodontic mechanics. Measurements were taken of the maxillary left first molar in 54 male Wistar rats. Mean mesial and distal PL thicknesses were compared between the intermediate buccal and mesiobuccal roots using paired Student's t-tests with a 5% significance level. Mean values differed significantly between roots (p < 2.2 × 10-16). PL thickness in rats is directly proportional to root dimensions.

INTRODUÇÃO: é possível definir a morfologia facial e o padrão de crescimento em idade precoce, a partir da dentadura decídua completa. OBJETIVOS: frente à escassez de trabalhos na literatura pertinente ao assunto, a presente pesquisa explora o diagnóstico epidemiológico da face no estágio de dentadura decídua. METODOLOGIA: a amostra foi composta por 2.009 crianças de etnia brasileira, de ambos os gêneros, entre 3 e 6 anos de idade, no período de dentadura decídua completa, de 20 pré-escolas do município de Bauru/SP. RESULTADOS E CONCLUSÕES: baseando-se nos resultados obtidos no levantamento epidemiológico, foi encontrado - na análise em norma lateral - predomínio de crianças Padrão I (63,22%) em relação ao Padrão II (33,10%) e Padrão III (3,68%), não havendo diferenças estatisticamente significativas quanto ao gênero. Na análise em norma frontal, houve predomínio do tipo mesofacial (64,56%) em relação ao dolicofacial (21,90%) e braquifacial (13,54%), sendo que a proporção do tipo braquifacial nas meninas foi significativamente superior em relação aos meninos. Na distribuição dos tipos faciais frontais dentro dos padrões faciais sagitais ficou evidenciada uma manifestação mais freqüente do tipo dolicofacial dentro dos Padrões II e III, sendo encontrado dimorfismo quanto ao gênero, notadamente no Padrão I, onde houve maior manifestação do tipo braquifacial e menor manifestação do dolicofacial no gênero feminino.

INTRODUCTION: It is possible to define the facial morphology and growth pattern in early ages, starting from mature deciduous dentition. AIM: Due to the lack of studies about this issue in the deciduous dentition, the current paper aims to present the epidemiologic diagnosis of the face in this stage of the occlusal development. METHODS: The sample was comprised of 2,009 Brazilian children aged between 3 and 6 years, all in the deciduous dentition, from 20 schools in Bauru/SP. RESULTS AND CONCLUSIONS: Based on results of epidemiologic study, the lateral norm analysis showed a prevalence of 63.22% of Pattern I children in relation to Pattern II (33.10%) and to Pattern III (3.68%), without statistically significant differences as to gender. In the frontal analysis, the mesofacial type was predominant (64.56%) in relation to dolichofacial (21.90%) and to brachyfacial types (13.54%), the last being predominant in girls. When the frontal type was related to the sagittal pattern, it was noticed that the dolichofacial type was more frequent in Patterns II and III. In Pattern I the brachyfacial type was more frequent and the dolichofacial type was less frequent in females.

Até que ponto o crescimento mandibular pode ser realmente influenciado pelos aparelhos ortopédicos de reposicionamento anterior, ainda permanece indecifrável. Mas a lógica leva a crer que se existe alguma chance de potencializar o deslocamento anterior da mandíbula, ela será mais certa quando se utiliza aparelhos de avanço contínuo. O presente artigo discorre sobre os protocolos de tratamento precoce e tardio para a correção da deficiência mandibular com o aparelho Herbst.

The question as to what extent mandibular growth may be influenced by orthopedic appliances remains unanswered. However, it seems reasonable to believe that the use of continuous forces potentialize the anterior displacement of the mandible. The current paper describes the early and late protocols of treatment of the mandibular deficiency with the Herbst appliance.