AIM: To investigate the associations between nutritive and non-nutritive sucking habits and the prevalence of anterior open bite, in children from Aragua-Venezuela and São Paulo-Brazil. METHODS: Seven calibrated examiners (κ = 0.89-1.0) performed clinical assessments in Venezuelans (N = 809) and Brazilians (N = 1,377) aged 3-6 years. Sucking habits were investigated using questionnaires answered by the mothers. Data were analyzed using logistic regression models (α = 0.05). RESULTS: Among 380 children with anterior open bite, 309 were Brazilians. Approximately 65% of Brazilians with pacifier-sucking habit lasting beyond 3 years of age had this malocclusion. Brazilians who prolonged pacifier and digit-sucking habits beyond 3 years of age have, respectively, 68.5 and 14.5 times more chances of presenting anterior open bite than children without sucking habits (p < 0.001). In Venezuelans with open bite, 37.7% had digit-sucking habits beyond 3 years of age, resulting in a high odds ratio (9.3; p < 0.001) when compared to children without this habit. No significant effect was found for bottle feeding. However, non-breastfed Venezuelan children or those breastfed for periods shorter than 6 months have a two-fold higher chance of presenting anterior open bite than children who were breastfed for longer periods, p = 0.008. CONCLUSIONS: Infant feeding had some effect on Venezuelan children, since insufficient breastfeeding was related to a higher prevalence of anterior open bite. Pacifier-sucking was more prevalent in Brazilians, corresponding to pronounced chances (8-68 times greater) of diagnosing anterior open bite in pacifier users compared to non-users. Among Venezuelans, on the other hand, digit-sucking effect surpassed that of pacifier use and was associated with far higher chances (6-9 times) for this malocclusion.

AIM: Knowledge of enamel thickness is relevant to perform stripping during orthodontic treatment. Thus, proximal enamel measurements of human permanent teeth were compared in this study. METHODS: The measurements were previously obtained on cut sections of mandibular central (n = 30) and lateral (n = 30) incisors, canines (n = 20), first (n = 40) and second (n = 40) premolars; maxillary central (n = 20) and lateral (n = 20) incisors, canines (n = 20), first (n = 40) and second (n = 42) premolars. Comparisons between thicknesses by arch side and proximal surface were carried out using Student's t-tests (α = 0.05). Teeth were compared according to the mesial and distal thicknesses by ANOVA and Tukey's test. RESULTS: No significant differences were found between right and left teeth. For the mesial surface, the mandibular second premolar presented the highest mean value (1.376 mm ± 0.198; p<0.001). The mandibular central incisor had the smallest thickness in relation to the other teeth (0.675 mm ± 0.144), although not significant compared with the mandibular lateral incisor and canine (0.734-0.781 mm). The mandibular second premolar also presented the higher distal thickness in relation to the others (1.450 mm ± 0.172), although not significant compared with the maxillary first premolar (1.322 mm ± 0.195). Mandibular incisors had the lowest means for distal thickness (0.872-0.879 mm), although not statistically different compared with maxillary incisors and mandibular canine (1.002-1.015 mm). Distal thickness was greater than mesial (p<0.001). CONCLUSIONS: Interproximal stripping should be less marked in incisors and mesial surfaces.

To achieve proper recontouring of anterior and posterior teeth, to obtain optimal morphology during enamel stripping, it is important to be aware of dental anatomy. This study aimed at evaluating crown dimensions and proximal enamel thickness in a sample of 40 extracted sound, human, mandibular, second bicuspids (20 right and 20 left). Mesiodistal, cervico-occlusal and buccolingual crown dimensions were measured using a digital caliper, accurate to 0.01 mm. Teeth were embedded in acrylic resin and cut along their long axes through the proximal surfaces to obtain 0.7 mm-thick central sections. Enamel thickness on the cut sections was measured using a perfilometer. Comparative analyses were carried out using the Student's-t test (α= 5%). The mean mesiodistal crown widths for right and left teeth were 7.79 mm (± 0.47) and 7.70 mm (± 0.51), respectively. Mean cervico-occlusal heights ranged from 8.31 mm (± 0.75) on the right to 8.38 mm (± 0.85) on the left teeth. The mean values for the buccolingual dimension were 8.67 mm (± 0.70) on the right and 8.65 mm (± 0.54) on the left teeth. The mean enamel thickness on the mesial surfaces ranged from 1.35 mm (± 0.22) to 1.40 mm (± 0.17), on the left and right sides, respectively. On the distal surfaces, the corresponding values were 1.44 mm (± 0.21) and 1.46 mm (± 0.12). No significant differences were found between measurements for right and left teeth. However, enamel thickness was significantly greater on the distal surfaces, compared with the mesial surfaces.

This study aimed at evaluating measurements relative to the mesiodistal crown width and enamel thickness of maxillary first bicuspids. The sample consisted of 40 extracted sound bicuspids (20 right and 20 left), selected from white patients (mean age: 23.7 ± 4.2 years), who were treated orthodontically with tooth extraction at a private clinic in São Paulo, SP, Brazil. All teeth were embedded in acrylic resin and cut along their long axis through the proximal surfaces, parallel to the buccal side, to obtain 0.6-mm central sections. The mesiodistal crown width and proximal enamel thickness were measured using a stereoscopic microscope connected to a computer. Measurements for right and left teeth, as well as the mesial and distal enamel thicknesses in the total sample, were compared by the Wilcoxon test (α = 0.05). The mesiodistal crown width mean values found were 7.51 mm (± 0.54) on the right side and 7.53 mm (± 0.35) on the left side. The mean enamel thickness on the distal surfaces for both sides was 1.29 mm (right: s.d. = 0.12 and left: s.d. = 0.18). The mean values for the mesial surfaces were 1.08 mm (± 0.14) and 1.19 mm (± 0.25), on the right and the left sides, respectively. No significant differences were found between the crown measurements and enamel thicknesses on the left and right sides. However, enamel thickness was significantly greater on the distal surfaces. Reliable measurements of enamel thickness are useful to guide stripping, which may be an attractive alternative to tooth extraction because it allows the transverse arch dimension to be maintained.

The aim of this study was to comparatively assess dental arch width, in the canine and molar regions, by means of direct measurements from plaster models, photocopies and digitized images of the models. The sample consisted of 130 pairs of plaster models, photocopies and digitized images of the models of white patients (n = 65), both genders, with Class I and Class II Division 1 malocclusions, treated by standard Edgewise mechanics and extraction of the four first premolars. Maxillary and mandibular intercanine and intermolar widths were measured by a calibrated examiner, prior to and after orthodontic treatment, using the three modes of reproduction of the dental arches. Dispersion of the data relative to pre- and posttreatment intra-arch linear measurements (mm) was represented as box plots. The three measuring methods were compared by one-way ANOVA for repeated measurements (α = 0.05). Initial / final mean values varied as follows: 33.94 to 34.29 mm / 34.49 to 34.66 mm (maxillary intercanine width); 26.23 to 26.26 mm / 26.77 to 26.84 mm (mandibular intercanine width); 49.55 to 49.66 mm / 47.28 to 47.45 mm (maxillary intermolar width) and 43.28 to 43.41 mm / 40.29 to 40.46 mm (mandibular intermolar width). There were no statistically significant differences between mean dental arch widths estimated by the three studied methods, prior to and after orthodontic treatment. It may be concluded that photocopies and digitized images of the plaster models provided reliable reproductions of the dental arches for obtaining transversal intra-arch measurements.

OBJETIVO: verificar as prevalências dos diferentes tipos de relacionamentos ântero-posteriores entre os arcos dentários decíduos, bem como o possível dimorfismo sexual, em crianças nipo-brasileiras na faixa etária dos dois aos seis anos de idade. METODOLOGIA: foram avaliadas por inspeção visual 310 crianças nipo-brasileiras, matriculadas em 19 escolas do estado de São Paulo, sendo 154 do gênero masculino e 156 do feminino. Os resultados foram submetidos ao teste do qui-quadrado e revelaram ausência de dimorfismo sexual para a maioria dos relacionamentos analisados, permitindo apresentar os resultados conjuntamente para ambos os gêneros. RESULTADOS: as prevalências dos relacionamentos entre os segundos molares decíduos foram: 47,4% para o degrau mesial, 41,3% para o plano terminal reto, 5,5% para o degrau distal e 5,8% para os casos com assimetrias. Para os relacionamentos entre os caninos decíduos, conforme Foster e Hamilton, constataram-se prevalências de 77,4% para a Classe 1, 6,8% para a Classe 2, 6,8% para a Classe 3 e 9% para as relações assimétricas. Apenas a Classe 2 apresentou dimorfismo sexual, sendo de 3,9% para o feminino e de 9,7% para o masculino. Quanto à sobressaliência verificaram-se prevalências de 71,3% para a normal, 14,2% para a aumentada, 7,4% para a mordida cruzada anterior e 7,1% para a mordida topo-a-topo. RESULTADOS: concluiu-se que a maioria das crianças nipo-brasileiras avaliadas neste estudo, apresentaram um relacionamento ântero-posterior normal entre os arcos decíduos, merecendo atenção uma ligeira tendência para o desenvolvimento da Classe 3.

AIM: the purpose of this cross-sectional study was to verify the prevalences of different types of anteroposterior relationships between deciduous dental arches and its possible sexual dimorphism, in Japanese-Brazilian children from 2 to 6 years of age. METHODS: a total of 310 Japanese-Brazilian children from 19 schools in São Paulo, Brazil, comprising 154 males and 156 females, were examined by visual inspection. The qui-square statistical test was applied to evaluate the data, and the results revealed no statistically significant sexual dimorphism for the majority of types of anteroposterior relationship. Therefore, the results for both genders were grouped together. RESULTS: the prevalences of anteroposterior relationships between deciduous second molars were: mesial step, 47.4%; flush terminal plane, 41.3%; distal step, 5.5% and asymmetric cases, 5.8%. The prevalences of anteroposterior relationship of deciduous canines were: Class 1, 77.4%; Class 2, 6.8%; Class 3, 6.8% and asymmetric cases, 9%. Only Class 2 revealed sexual dimorphism: 3.9% for female and 9.7% for male. The prevalences of overjet, were: normal, 71.3%; increased, 14.2%; anterior cross-bite, 7.4% and edge-to-edge bite, 7.1%. CONCLUSION: it was concluded that the majority of Japanese-Brazilian children evaluated in this study showed normal anteriorposterior relationship between dental arches, with a slightly tendency for the development of Class 3.

OBJETIVO: avaliar as possíveis diferenças nas dimensões transversais dos arcos dentários superiores e inferiores entre jovens com oclusão normal e má oclusão de Classe II, 1ª divisão. METODOLOGIA: foram avaliados 170 pares de modelos em gesso de jovens brasileiros leucodermas, com dentadura permanente, sendo 76 com oclusão normal (41 do gênero feminino e 35 do masculino) e média de idade de 13 anos e 6 meses e 94 com má oclusão de Classe II, 1ª divisão (58 do gênero feminino e 36 do masculino) e média de idade de 13 anos e 9 meses. Este grupo com má oclusão foi dividido em duas categorias: Classe II sem apinhamento e Classe II com apinhamento. Compararam-se as distâncias intercaninos, interprimeiros pré-molares e intermolares, em ambos os arcos dentários. RESULTADOS: em relação ao grupo com oclusão normal, os jovens do gênero masculino evidenciaram as seguintes diferenças estatisticamente significantes: 1) distância intercaninos inferiores maior para o grupo com Classe II sem apinhamento; 2) distância interprimeiros pré-molares superiores menor para o grupo com Classe II sem apinhamento e 3) distâncias interprimeiros pré-molares e intermolares, superiores e inferiores, menores para o grupo com Classe II com apinhamento. Por sua vez, o gênero feminino evidenciou: 1) distâncias interprimeiros pré-molares e intermolares superiores menores para o grupo com Classe II sem apinhamento e 2) distâncias interprimeiros pré-molares e intermolares, superiores e inferiores, menores para o grupo com Classe II com apinhamento. CONCLUSÃO: de um modo geral, os jovens com má oclusão de Classe II, 1ª divisão, apresentaram uma tendência para deficiência transversal posterior dos arcos dentários, principalmente no grupo com apinhamento.

AIM: to evaluate possible differences of the upper and lower dental arches widths among youths with normal occlusion and Class II, division 1, malocclusion. METHODS: the evaluation was conducted on 170 pairs of dental casts of white Brazilian youths, with permanent dentition, 76 with normal occlusion (41 females and 35 males) at the mean age of 13 years and 6 months and 94 with Class II, division 1, malocclusion (58 females and 36 males) at the mean age of 13 years and 9 months. The group with malocclusion was divided into two categories: Class II without dental crowding and Class II with dental crowding. A comparison was made between the intercanine, inter first premolar and intermolar widths of both dental arches. RESULTS: with regard to normal occlusion group and statistically significant differences, male subjects presented: 1) larger intercanine lower width in the group with Class II without crowding; 2) smaller upper inter first premolar width in the group with Class II without crowding and 3) smaller upper and lower inter first premolar and intermolar widths in the group with Class II with crowding. In turn, the females have revealed: 1) smaller upper inter first premolar and intermolar widths in the group with Class II without crowding and 2) smaller upper and lower inter first premolar and intermolar widths in the group with Class II with crowding. CONCLUSION: generally, the subjects with Class II, Division 1 malocclusion have presented a tendency to a posterior deficiency of dental arches widths, especially in the group with crowding.