Relationship between breastfeeding duration and prevalence of posterior crossbite in the deciduous dentition.

INTRODUCTION: This cross-sectional retrospective epidemiologic study assessed the relationship between exclusive breastfeeding duration and the prevalence of posterior crossbite in the deciduous dentition. METHODS: Clinical examinations were performed in 1377 Brazilian children (690 boys, 687 girls), 3 to 6 years old, from 11 public schools in São Paulo, Brazil. Based on questionnaires answered by the parents, the children were classified into 4 groups according to the duration of exclusive breastfeeding: G1, never (119 subjects); G2, less than 6 months (720 subjects); G3, 6 to 12 months (312 subjects); and G4, more than 12 months (226 subjects). The statistical analyses included the chi-square test (P <0.05) and the odds ratio. RESULTS: The posterior crossbite was observed in 31.1%, 22.4%, 8.3%, and 2.2% of the children, in groups G1, G2, G3, and G4, respectively. The results showed a statistically significant relationship between exclusive breastfeeding duration and the prevalence of posterior crossbite. CONCLUSIONS: Children who were breastfed for more than 12 months had a 20-fold lower risk for the development of posterior crossbite compared with children who were never breastfed and a 5-fold lower risk compared with those breastfed between 6 and 12 months.

Bone scintigraphy as an adjunct for the diagnosis of oral diseases.

Bone scintigraphy is a very sensitive method for the detection of osteoblastic activity of the skeleton. The technique consists of imaging the uptake of bone-seeking radiopharmaceuticals, particularly technetium-99m labeled diphosphonates, in the mineral component of bone, which consists of hydroxyapatite crystals and calcium phosphate, as well as in the organic matrix such as collagen fibers. Plain radiographs, computed tomography, and magnetic resonance imaging are classified as structural imaging modalities, whereas bone scintigraphy is a functional method. In many cases, radionuclide imaging techniques are the only means by which early physiologic changes that are a direct result of biochemical alteration may be assessed, before significant bone mineral changes can be detected by other means. Since many oral diseases may cause metabolic changes in the oromaxillofacial complex, it would be of great value to use bone scintigraphy to evaluate more completely some conditions involving the bones in the region to formulate more appropriate treatment plans. Based upon the current literature, the authors discuss the possible applications of bone scintigraphy as a diagnostic and treatment planning adjunct for oral diseases. Bone scintigraphy has proven particularly useful in the study of malignant lesions and in the evaluation of vascularized bone grafts used for maxillofacial reconstructions.

Image quality in digital radiographic systems.

The aim of the present study was to evaluate the image quality of four direct digital radiographic systems. Radiographs were made of the maxillary central incisor and mandibular left molar regions of a dry skull, and an aluminum step-wedge. The X-ray generator operated at 10 mA. 60 and 70 kVp, and images were acquired with 3, 5, 8, 12, 24 and 48 exposure pulses. Six well-trained observers classified the images by means of scores from 1 to 3. Collected data were submitted to nonparametric statistical analysis using Fisher's exact test. Statistical analysis showed significant differences (p < 0.01) in image quality with the four systems. Based on the results, it was possible to conclude that: 1) all of the digital systems presented good performance in producing acceptable images for diagnosis, if the exposures of the step-wedge and the maxillary central incisor region were made at 5 pulses, as well as at 8 pulses for the mandibular left molar region, selecting 60 or 70kVp; 2) higher percentages of acceptable images were obtained with the administration of lower radiation doses in CCD-sensors (charge-coupled device); 3) the Storage Phosphor systems produced acceptable images at a large range of exposure settings, that included low, intermediate and high radiation doses.

Detection of vertical root fractures by cone-beam computerized tomography in endodontically treated teeth with fiber-resin and titanium posts: an in vitro study.

OBJECTIVE: The aim of this study was to assess the performance of 2 cone-beam computerized tomography (CBCT) systems for detecting vertical fractures in root-filled teeth with fiber-resin or titanium posts. STUDY DESIGN: CBCT images acquired with the use of Scanora 3D and i-CAT of roots with fiber-resin (n = 30) or titanium (n = 29) posts, before and after the induction of fractures, were assessed by 6 radiologists using Ondemand 3D software. Interobserver agreement was analyzed using kappa statistics. Sensitivity, specificity, accuracy, and positive and negative predictive values were compared with analysis of variance/Student-Newman-Keuls test. RESULTS: Interobserver agreement for fiber-resin posts ranged from 0.5 to 0.7 (Scanora 3D) and 0.35-0.76 (i-CAT). For titanium posts, ranged from 0.42 to 0.80 (Scanora 3D) and 0.31-0.73 (i-CAT). Higher sensitivity (0.85; P < .05) and negative predictive values (0.88; P < .001) were observed for i-CAT in roots with fiber-resin posts than with other combinations. CONCLUSIONS: The diagnostic performance for detecting vertical fractures was higher for roots with fiber-resin than with titanium posts.

Crown dimensions and proximal enamel thickness of mandibular second bicuspids.

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.

Breastfeeding and non-nutritive sucking patterns related to the prevalence of anterior open bite in primary dentition.

OBJECTIVE: Nutritional, immunological and psychological benefits of exclusive breastfeeding for the first 6 months of life are unequivocally recognized. However, mothers should also be aware of the importance of breastfeeding for promoting adequate oral development. This study evaluated the association between breastfeeding and non-nutritive sucking patterns and the prevalence of anterior open bite in primary dentition. MATERIAL AND METHODS: Infant feeding and non-nutritive sucking were investigated in a 3-6 year-old sample of 1,377 children, from São Paulo city, Brazil. Children were grouped according to breastfeeding duration: G1--non-breastfed, G2--shorter than 6 months, G3--interruption between 6 and 12 months, and G4--longer than 12 months. Three calibrated dentists performed clinical examinations and classified overbite into 3 categories: normal, anterior open bite and deep bite. Chi-square tests (p<0.05) with odds ratio (OR) calculation were used for intergroup comparisons. The impact of breastfeeding and non-nutritive sucking on the prevalence of anterior open bite was analyzed using binary logistic regression. RESULTS: The prevalence estimates of anterior open bite were: 31.9% (G1), 26.1% (G2), 22.1% (G3), and 6.2% (G4). G1 would have significantly more chances of having anterior open bite compared with G4; in the total sample (OR=7.1) and in the subgroup without history of non-nutritive sucking (OR=9.3). Prolonging breastfeeding for 12 months was associated with a 3.7 times lower chance of having anterior open bite. In each year of persistence with non-nutritive sucking habits, the chance of developing this malocclusion increased in 2.38 times. CONCLUSIONS: Breastfeeding and non-nutritive sucking durations demonstrated opposite effects on the prediction of anterior open bite. Non-breastfed children presented significantly greater chances of having anterior open bite compared with those who were breastfed for periods longer than 12 months, demonstrating the beneficial influence of breastfeeding on dental occlusion.

Mesiodistal width and proximal enamel thickness of maxillary first bicuspids.

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 (alpha = 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.

Family risk as adjunct for organizing the demand for oral health service in the Family Health Strategy / Risco familiar como elemento para organização da demanda em saúde bucal na Estratégia Saúde da Família

Introduction: One of the main problems of the public health services, in which the family oral health team is included, is access by users to dental treatment in primary care, with particular reference to caries disease. Objective: The aim of this study was to evaluate the relationship between family risk, for prioritization of home visits and oral health conditions, with a view to providing evidence about the first indicator for organizing the demand for oral health in the Family Health Strategy (FHS). Method: The application of family health is based on Form A of the primary care information database SIAB ("Sistema de Informação de Atenção Básica"), used for registering families with the FHS. Eleven dentists examined the oral health conditions of 1165 persons (608 from 12 to 19 years; and 557 from 35 to 44 years of age), classifying them into six codes from A to F. Multinomial logistic regression was used (α=0.05) to analyze the association between family risk variables and oral health situation. Result: There was significant association between family risk and presence of caries disease with treatment needs (OR: 2.08, p<0.0001). Conclusion: Persons who have family risk would have twice as much chance of presenting caries disease in comparison with those without risk, corroborating the relevance of this element in organizing the demand for oral health. .

Introdução: Um dos principais problemas dos serviços públicos de saúde, em que a equipe de saúde bucal da família está inserida, é o acesso dos usuários ao tratamento odontológico na atenção primária, principalmente no que se refere à doença cárie. Objetivo: O objetivo deste estudo foi avaliar a relação entre risco familiar - para priorização de visitas domiciliares - e condições de saúde bucal, visando a prover evidência sobre o primeiro indicador para organização da demanda em saúde bucal, na Estratégia Saúde da Família (ESF). Método: A verificação do risco familiar baseou-se na ficha A do SIAB, utilizada para o cadastramento das famílias na ESF. Onze cirurgiões dentistas examinaram as condições de saúde bucal de 1165 pessoas (608 de 12 a 19 anos e 557 de 35 a 44 anos de idade), classificando-as em seis códigos de A a F. Empregou-se a regressão logística multinomial (α=0,05) para análise da associação entre as variáveis de risco familiar e a situação de saúde bucal. Resultado: Houve associação significativa entre risco familiar e presença da doença cárie com necessidade de tratamento (OR: 2,08; p<0,0001). Conclusão: As pessoas que possuem risco familiar teriam duas vezes mais chance de apresentar a doença cárie em comparação às sem risco, corroborando a relevância deste elemento na organização da demanda em saúde bucal. .

Tradução e adaptação brasileira do Questionnaire D'Alimentation / Brazilian translation and adaptation of theQuestionnaire D'Alimentation

RESUMO: Objetivo: traduzir o instrumento em língua francesa "Questionnaire D'Alimentation" para o português brasileiro e realizar a adaptação transcultural em adolescentes brasileiros. Métodos: a tradução foi realizada com base em protocolo que consistiu na tradução para o português brasileiro (por um professor formado em Letras e uma Cirurgiã Dentista fluentes em francês), tradução reversa para o francês (realizada por dois professores de francês), revisão por Comitê de especialistas (duas tradutoras, uma nativa e uma juramentada, e duas professoras universitárias, sendo uma Cirurgiã Dentista e uma Fonoaudióloga) e equivalência cultural (pré-teste). A versão utilizada no pré- teste consistiu de 26 questões com cinco respostas possíveis (5-Likert), distribuídas em cinco domínios (Alimentação- mastigação, Hábitos, Carnes, Frutas e Legumes). O pré-teste e teste-reteste foram realizados com uma amostra de 20 adolescentes (10 meninos/10 meninas) de escolas públicas de Piracicaba (Brasil). Nesta fase, a alternativa "não entendi" foi incluída a cada questão, a fim de identificar aquelas não compreendidas. A confiabilidade teste-reteste foi avaliada para cada domínio utilizando os coeficientes de correlação intra-classe (CCI). Resultados: no pré-teste, foi observada uma excelente compreensão do instrumento; no teste-reteste, os CCIs variaram entre 0,45-0,81 (moderada a excelente concordância). Conclusão: a versão em Português do Questionnaire D'Alimentationmostrou ser de fácil compreensão por parte dos adolescentes brasileiros e útil na avaliação da função mastigatória e dos distúrbios de alimentação e deglutição que podem alterar a ingestão de alimentos.

ABSTRACT: Purpose: to translate the French language instrument "Questionnaire D'Alimentation" to Brazilian Portuguese and culturally adapt it for adolescents. Methods: the translation was based on a protocol that consisted of translation to Brazilian Portuguese (by a professor with a Literary Arts degree and a Doctor of Dental Surgery, both fluent in French and Brazilian Portuguese); back-translation into French; revision by a Committee of specialists (two translators, one native and one sworn translator, and two university professors, one being a Doctor of Dental Surgery and a Speech Therapist) and cultural equivalence (pre-test). The version used in the pre-test consisted of 26 questions with five possible responses (5-Likert), distributed in five domains (Food-Mastication, Habits, Meats, Fruits and Vegetables). The pre-test and test-retest was performed with a sample of 20 adolescents (10 boys/10 girls) from public schools of Piracicaba (Brazil). At this stage, the alternative "I did not understand" was added to each question in order to identify those that were not understood. Test-retest reliability was assessed for each domain using intra-class correlation coefficients (ICCs). Results: in the pre-test, an excellent comprehension of the instrument was observed; in test-retest, ICCs ranged from 0.45 to 0.81 (moderate to excellent agreement). Conclusion: the Portuguese version of the Questionnaire D'Alimentationhas shown to be easy to understand by Brazilian adolescents and useful in the evaluation of the masticatory function and feeding or swallowing disorders that may affect food intake.

Comparative study of dental arch width in plaster models, photocopies and digitized images.

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 (alpha = 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.

Effect of breast- and bottle-feeding duration on the age of pacifier use persistence.

This study evaluated the effect of breast- and bottle-feeding duration on the age of pacifier use persistence. Questionnaires (n = 723) with information on nutritive and nonnutritive sucking habits of children aged 3-6 years were assessed. The sample was divided according to breastfeeding duration: G1 - non-breastfed, G2 - up to 3 months, G3 - discontinued between 4 and 6 months, G4 - discontinued between 7 and 12 months, and G5 - longer than 12 months. The children were also assigned to 4 groups by age of pacifier use persistence, as well as by age of bottle-feeding persistence: no habits, up to 2 years, 3-4 years and 5-6 years. Associations between nutritive sucking habits and pacifier use were analyzed using logistic regression. The larger breastfeeding groups were G2 (37.9%) and G4 (19.4%). Many children discontinued pacifier use and bottle-feeding at 3-4 years of age (24.9% and 40.1%, respectively). Chances of non-breastfed children (G1) with prolonged pacifier-sucking habits, in the three age ranges, were progressively higher in comparison with group G4 (OR: 4.0-7.5, p < 0.01). When comparing bottle-fed with non bottle-fed children, the age range at which bottle-feeding had been discontinued was significantly associated with that of pacifier use cessation: up to 2 years (OR = 6.2), 3-4 years (OR = 7.6) and 5-6 years (OR = 27.0), p < 0.01. It may be suggested that breastfeeding duration has an inversely proportional effect on the age of pacifier use persistence. Bottle-fed children who use pacifiers tend to discontinue these habits at the same period.

Image quality in partially erased DenOptix storage phosphor plates.

This study aimed at investigating the effect of the partial erasing of DenOptix system storage phosphor plates on the image quality of digital radiographs. Standardized digital radiographs were acquired of a phantom mandible, using size 2 intraoral DenOptix storage phosphor plates (n = 10). Subsequently, the active areas of the plates were placed in a viewing box with a constant light intensity of 1,700 lux for 130 seconds to achieve complete erasing (control plate), as well as for 0, 5, 10, 15, 20, 25, 34, 66, and 98 seconds, to compose the experimental group of partially erased plates. The same exposure settings were repeated using the control and experimental plates, which were scanned at a resolution of 300 dpi. Five radiologists independently examined the pairs of digital radiographs obtained with the control and partially erased plates, in random order, and indicated the best image for oral diagnosis. Cochran-Mantel-Haenszels chi-square test, at a significance level of 5%, was used to compare the percentages of superior quality images in each combination of control and partially erased plates, subjectively assessed. No significant differences were found between radiographic images acquired with control and partially erased plates, except for the combination of 0 second (30%) versus 130 seconds (70%), p = 0.0047. It can be concluded that, under adequate light intensity conditions, erasing intraoral DenOptix storage phosphor plates may require time intervals of as little as 5 seconds.

In vitro induction of enamel subsurface demineralization for evaluation of diagnostic imaging methods.

The aim of this study was to investigate a model of inducing enamel subsurface demineralization for evaluating diagnostic imaging methods. Fifty sound teeth had their crowns coated with acid-resistant varnish, leaving a 7 mm(2) circular window of exposed enamel in one of the proximal surfaces. The specimens were assigned to 5 groups (4 experimental and the control) and were kept immersed in a buffer solution at pH 4.8, 50% saturated in relation to enamel, for 60, 75, 90 and 120 days, or were not exposed to the solution. Digital radiographs were taken, prior to and after each immersion period, and interpreted by a radiologist. For validation, the enamel was submitted to microhardness profiling. In addition, the solutions were analyzed for phosphorus (Pi) and calcium (Ca) concentrations. Microhardness data were evaluated using two-way ANOVA (p<0.05) and Tukey's test. Pi and Ca concentrations were compared using one-way ANOVA (alpha = 0.05). The performance of radiography was assessed by ROC analysis. The microhardness values for the control group ranged from 405 to 432 KHN. Of the 4 experimental groups, the 60-day group demonstrated the highest values (179-379 KHN) and the 120-day group, the lowest values (103-277 KHN). The lowest total concentrations of Pi and Ca (1.74 mM and 2.63 mM, respectively) were found in the solutions of the 60-day group, indicating the lowest rate of mineral loss, however, there was no significant difference among the other experimental groups. The performance for detecting images consistent with caries lesions was high (Az = 0.89). Therefore, this in vitro model of inducing demineralization may be considered suitable for research intended to evaluate imaging methods for the diagnosis of proximal caries lesions.

Prevalence of posterior crossbite among pacifier users: a study in the deciduous dentition.

The aim of this study was to evaluate the prevalence of posterior crossbite among children whose pacifier-sucking habit persisted until different ages. Children aged 3 to 6 years were randomly selected from public preschools in São Paulo, SP, Brazil. Their mothers were asked to complete a questionnaire on non-nutritive sucking behaviors. The sample consisted of 366 children assigned to 2 groups: control (n = 96) and pacifier users (n = 270). Pacifier users were further assigned to 3 subgroups, according to the age of habit persistence: P1 - until 2 years of age; P2 - between 2 and 4 years of age; and P3 - between 4 and 6 years of age. One dentist assessed the children for occlusal relationships through clinical examination. Associations between the age interval of habit discontinuation and the prevalence of posterior crossbite were analyzed using the chi-square test (p < 0.05). The prevalence of posterior crossbite was significantly higher among pacifier users (20.4%), compared to control children (5.2%), p < 0.01. Unilateral posterior crossbite was more prevalent than bilateral crossbite among pacifier users (9.8% versus 3.6%). Functional posterior crossbites were diagnosed in 3.1% of the control children and 7% of the pacifier users. The frequencies of posterior crossbite were notably high for children in the 3 pacifier subgroups, P1, P2, and P3, corresponding to 17.2%, 16.9%, and 27.3%, respectively. The high prevalence of posterior crossbite may be associated with pacifier-sucking habits that persisted after 2 years of age.

Orthodontic retainers: analysis of prescriptions sent to laboratories

OBJECTIVE: To investigate the most commonly fabricated orthodontic retainers. METHODS: Information on the type and amount of maxillary and mandibular retainers produced in a three-month period was collected from six laboratories in the cities of São Paulo, Mauá and Guarulhos - Brazil. The retainers were grouped according to the total production. For the maxillary arch, the groups were: 1S - Begg retainer, 2S - Hawley retainer, 3S - transpalatal arch retainer, 4S - buccal resin-arch retainer and 5S - vacuum-formed retainer, Planas appliance, bonded lingual retainer and V-loop bonded lingual retainer. The groups relative to the mandibular arch were: 1I - 3-3 bonded lingual retainer (canine to canine), 2I - Hawley retainer and V-loop bonded lingual retainer, 3I - Begg retainer, 4I - buccal resin-arch retainer, vacuum-formed retainer and Planas appliance. The data were presented in box plots. Groups were compared using the Student's-t test with Bonferroni correction. RESULTS: The average of maxillary appliances fabricated ranged from 189.5 (1S) to 3.95 (5S). There were significant differences between groups 1S versus 5S and 2S versus 5S (p < 0.0001). Mean values for the mandibular retainers ranged from 55.3 (1I) to 4.2 (4I). Significant difference was observed between groups 2I and 4I (p < 0.0001). CONCLUSIONS: For the maxillary arch, the most requested retainers were Begg and Hawley retainers. Regarding the mandibular arch, bonded lingual retainers and Hawley retainer were the most frequent ones.

Evaluation of proximal enamel thickness and crown measurements in maxillary first premolars

Estimating enamel thickness and planning the resultant optimal morphology of premolars aresubstantial steps before interproximal stripping. Aim: To analyze proximal enamel thickness andcrown measurements in maxillary premolars. Methods: The mesiodistal, buccolingual andcervico-occlusal measurements of 40 human maxillary first premolars (20 right, 20 left) wereregistered with a digital caliper. The teeth were embedded in acrylic resin and sectioned mesiodistallyat the level of the contact areas to obtain 1 mm-thick central sections. Enamel thickness on theproximal surfaces was measured using a perfilometer. Measurements were compared by theStudent’s t-test (α = 0.05). Results: The mean enamel thickness on the mesial surface was 1.22mm for the right (± 0.17) and left (± 0.18) sides. On the distal surface, the corresponding valueswere 1.28 mm (± 0.19) on the right side and 1.39 mm (± 0.17) on the left side. Mean values, inmillimeters, for the mesiodistal, buccolingual and cervico-occlusal measurements on both sidesranged from 7.03 (± 0.43) to 7.07 (± 0.48), 9.59 (± 0.48) to 9.65 (± 0.58) and 8.65 (± 0.66) to8.85 (± 0.65), respectively. There were no significant differences between right and left teeth.However, enamel thickness was significantly greater (p<0.05) on the distal surface. Conclusions:In maxillary first premolars, considering the greater thickness of distal enamel, interproximalstripping during orthodontic treatment may be more pronounced on this surface. The greatestmean value was observed for the buccolingual crown measurement, followed by the cervicoocclusaland mesiodistal dimensions.

Breastfeeding and non-nutritive sucking patterns related to the prevalence of anterior open bite in primary dentition

OBJECTIVE: Nutritional, immunological and psychological benefts of exclusive breastfeeding for the frst 6 months of life are unequivocally recognized. However, mothers should also be aware of the importance of breastfeeding for promoting adequate oral development. This study evaluated the association between breastfeeding and non-nutritive sucking patterns and the prevalence of anterior open bite in primary dentition. MATERIAL AND METHODS: Infant feeding and non-nutritive sucking were investigated in a 3-6 year-old sample of 1,377 children, from São Paulo city, Brazil. Children were grouped according to breastfeeding duration: G1 - non-breastfed, G2 - shorter than 6 months, G3 - interruption between 6 and 12 months, and G4 - longer than 12 months. Three calibrated dentists performed clinical examinations and classifed overbite into 3 categories: normal, anterior open bite and deep bite. Chi-square tests (p<0.05) with odds ratio (OR) calculation were used for intergroup comparisons. The impact of breastfeeding and non-nutritive sucking on the prevalence of anterior open bite was analyzed using binary logistic regression. RESULTS: The prevalence estimates of anterior open bite were: 31.9 percent (G1), 26.1 percent (G2), 22.1 percent (G3), and 6.2 percent (G4). G1 would have signifcantly more chances of having anterior open bite compared with G4; in the total sample (OR=7.1) and in the subgroup without history of non-nutritive sucking (OR=9.3). Prolonging breastfeeding for 12 months was associated with a 3.7 times lower chance of having anterior open bite. In each year of persistence with non-nutritive sucking habits, the chance of developing this malocclusion increased in 2.38 times. CONCLUSIONS: Breastfeeding and non-nutritive sucking durations demonstrated opposite effects on the prediction of anterior open bite. Non-breastfed children presented signifcantly greater chances of having anterior open bite compared with those who were breastfed for periods longer than 12 months, demonstrating the benefcial infuence of breastfeeding on dental occlusion.

Crown dimensions and proximal enamel thickness of mandibular second bicuspids

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 percent). 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.

Assessment of enamel demineralization using conventional, digital, and digitized radiography.

This experimental research aimed at evaluating the accuracy of enamel demineralization detection using conventional, digital, and digitized radiographs, as well as to compare radiographs and logarithmically contrast-enhanced subtraction images. Enamel subsurface demineralization was induced on one of the approximal surfaces of 49 sound third molars. Standardized radiographs of the teeth were taken prior to and after the demineralization phase with three digital systems--CygnusRay MPS, DenOptix and DIGORA--and InSight film. Three radiologists interpreted the pairs of conventional, digital, and digitized radiographs in two different occasions. Logarithmically contrast-enhanced subtraction images were examined by a fourth radiologist only once. Radiographic diagnosis was validated by cross-sectional microhardness profiling in the test areas of the approximal surfaces. Accuracy was estimated by Receiver Operating Characteristic (ROC) analysis. Chi-square test, at a significance level of 5%, was used to compare the areas under the ROC curves (A(z)) calculated for the different imaging modalities. Concerning the radiographs, the DenOptix system (A(z) = 0.91) and conventional radiographs (A(z) = 0.90) presented the highest accuracy values compared with the other three radiographic modalities. However, logarithmically contrast-enhanced subtraction images (A(z) = 0.98) were significantly more accurate than conventional, digital, and digitized radiographs (p = 0.0000). It can be concluded that the DenOptix system and conventional radiographs provide better performance for diagnosing enamel subsurface demineralization. Logarithmic subtraction significantly improves radiographic detection.

Avaliação comparativa do espaçamento anterior em nipo-brasileiros e leucodermas, na dentição decídua / Comparative assessment of anterior spacing in Japanese-Brazilian and white children in the primary dentition

OBJETIVO: avaliar comparativamente a prevalência das características de espaçamento anterior em nipo-brasileiros e leucodermas, na dentição decídua. MÉTODOS: duas amostras de crianças com 2 a 6 anos de idade foram selecionadas: 405 nipo-brasileiros de 36 escolas do estado de São Paulo e 510 leucodermas de 11 instituições públicas da cidade de São Paulo. As variantes oclusais foram classificadas em quatro categorias, nas arcadas superior e inferior: espaçamento generalizado; somente espaços primatas; ausência de espaços; e apinhamento. Foi aplicada regressão logística para análise do efeito dos fatores idade, sexo e grupo étnico sobre a prevalência das características oclusais (α = 0,05). RESULTADOS: em nipo-brasileiros, o espaçamento generalizado foi a característica mais prevalente nas arcadas superior (46,2 por cento) e inferior (53,3 por cento). A frequência dos espaços primatas foi maior na arcada superior (28,2 por cento versus 15,3 por cento). Para a ausência de espaços (21,7-26,4 por cento) e o apinhamento (4,0-4,9 por cento), a variação entre as arcadas foi relativamente pequena. Em leucodermas, a ausência de espaços e a presença exclusiva dos primatas evidenciaram distribuição similar à observada nos nipo-brasileiros. O espaçamento generalizado foi diagnosticado em aproximadamente 50 por cento das arcadas. A prevalência de apinhamento foi maior na arcada inferior (12,8 por cento versus 3,9 por cento). O único modelo de regressão logística que apresentou algum fator significativo foi o ajustado para a prevalência de apinhamento. Apenas o fator racial foi significativo (p < 0,001). CONCLUSÃO: sugere-se que as características de espaçamento anterior, na dentição decídua, não estariam condicionadas à idade ou ao sexo. Contudo, leucodermas teriam chances 2,8 vezes maiores de apresentar apinhamento na arcada inferior, em comparação aos nipo-brasileiros.

OBJECTIVE: To carry out a comparative evaluation of the prevalence of anterior spacing characteristics in Japanese-Brazilian and white children in primary dentition. METHODS: Two selected samples of children aged 2-6 years were: 405 Japanese-Brazilians from 36 schools in the State of São Paulo and 510 white children from 11 public institutions in São Paulo city. The spacing features in the maxillary and mandibular arches were assigned to four categories: generalized spacing; only primate spaces; no spacing; and crowding. Logistic regression was used to analyze the effect of age, gender and ethnic group on the prevalence of the occlusal characteristics (α=0.05). RESULTS: In Japanese-Brazilians, generalized spacing was the most prevalent trait in the maxillary (46.2 percent) and mandibular (53.3 percent) arches. The frequency of primate spaces was higher in the maxillary arch (28.2 percent versus 15.3 percent). Concerning no spacing (21.7-26.4 percent) and crowding (4.0-4.9 percent), the variation between arches was relatively small. In white children, no spacing and exclusive presence of primate spaces showed distributions similar to that observed in Japanese-Brazilians. Generalized spacing was diagnosed in approximately 50 percent of the arches. Crowding prevalence was higher in the mandibular arch (12.8 percent versus 3.9 percent). The regression model adjusted for crowding prevalence was the only significant one. Only racial factor was significant (p<0.001). CONCLUSION: It may be suggested that anterior spacing features in primary dentition would not be influenced by age or gender. Nevertheless, white children would have 2.8 times more chances of presenting crowding in the mandibular arch, in comparison with Japanese-Brazilians.