Mayury Kuramae

Jarabak 's cephalometric analysis of Brazilian black patients

The treatment of skeletal disharmonies presents better results when performed during the growth period. The physical changes that occur in every individual express growth, which is ruled by genetic, general and environmental factors. In order to identify such disharmonies and hence concentrate the clinical actions during treatment and influence facial growth, cephalometrics appears as a useful a diagnostic tool for identifying facial growth patterns or growth direction. Jarabaks cephalometric analysis is used to assess facial growth pattern of subjects with normal occlusion or malocclusions. The purpose of this study was to obtain mean values for cephalometric measurements from Jarabaks cephalometric analyses of black Brazilian subjects resident in the city of Piracicaba, São Paulo state, Brazil and vicinities, who presented Class I molar relationship with normal overjet and overbite, mild or no tooth crowding or spacing, and no history of orthodontic treatment. A sample of 37 stone plaster casts and 37 lateral teleradiographs from both male and female individuals aged 10 to 14 years was evaluated. Data were analyzed statistically by Students t-test at 5% significance level. There was no significant differences between genders. The cephalometric measurements obtained in this study were similar to the Jarabaks standards, except for S-N mean value in females (66.50 mm +/- 3.16), which was significantly lower than the standard.

Avaliação longitudinal de arcadas dentárias individualizadas com o método Borda WALA

INTRODUCTION: The form of mandibular arch is considered one of the main references among the diagnostic tools because the maintenance of this arch form and dimension is an important factor for stability of orthodontic treatment. OBJECTIVES: To evaluate the changes in mandibular intercanine and intermolar widths during orthodontic treatment and 3 years of posttreatment, in which the WALA ridge was used for individualization of the mandibular arch form. METHODS: Sample comprised of 20 patients (12 women and 8 men), with a mean age of 20.88 years. The dental casts of the initial, final and post-treatment evaluation were used for measurement of the intercanine and intermolar distances in the center of the buccal surface of the clinical crown and in the width of the WALA ridge. Data were analyzed by means of ANOVA test followed by Tukey test (p<0.05). RESULTS: Indicated that there was a statistically significant difference in intercanine and intermolar distances among the three stages evaluated. These distances increased significantly with treatment, and presented a reduction in the post-treatment period, however not reaching the initial values. CONCLUSIONS: The WALA ridge method used in this study for construction of the individualized diagrams and for measurement of the intercanine and intermolar distances was shown to be valuable, allowing the individualization of the dental arches and favoring the post-treatment stability.

Cephalometric evaluation of surgical mandibular advancement

The treatment of Class II adult individuals with mandibular deficiency has been the combination of orthodontic treatment and orthognathic surgery. Therefore, a study was conducted in which cephalometric analysis was used to evaluate the influence of dentoalveolar decompensation in Class II patients submitted to orthodontic and surgical treatment for mandibular advancement, by bilateral osteotomy of the mandibular ramus. A sample of 15 leukoderma adult female patients were selected and three cephalometric radiographs of each patient, taken before the orthodontic treatment, before surgery and after at least 6 months postoperatively, were analyzed in a total of 45 roentgenograms. The tracings were made by the manual method and the points were digitalized using software. The results showed that values of SNB increased from 75.6 to 78.6 degrees. The measures BNP and PGNP were reduced from -12.7 to -7.7 mm and -12.7 to -6.6 mm, respectively. For ANB there was a reduction of 3.23 degrees (from 8.1 degrees to 4.9 degrees). Likewise, the values of AOBO were diminished by 6.3 mm (from 7.6 to 1.3 mm), and in the values of OJ there was a reduction of 5.7 mm (from 9 to 3.3 mm). It was concluded that the pre-surgical orthodontic treatment promoted minimal and variable dental and skeletal changes in the final result. The surgical treatment caused significant skeletal changes, especially in the measurements related to the mandible (SNB, BNP, PGNP and SNPM) or indirectly to it (ANB, AOBO and OJ).

In vitro evaluation of flexural strength of different brands of expansion screws

Objective: The objective of this study was to compare the flexural strength of the stems of three maxillary expanders screws of Morelli, Forestadent and Dentaurum brands. Methods: The sample consisted of nine expander screws (totalizing of 36 stems), three from each brand, all stainless steel and 12 mm of expansion capacity. The stems of the expander screws were cut with cutting pliers close to the weld region with screw body, then fixed in a universal testing machine Instron 4411 for tests of bending resistance of three points. The ultimate strength in kgF exerted by the machine to bend the stem of the 5 mm screw was recorded and the flexural strength was calculated using a mathematical formula. During the flexural strength test it was verified the modulus of elasticity of the stems by means of Bluehill 2 software. The flexural strength data were subjected to ANOVA with one criterion and Tukey’s test, with significance level of 5%. Results: Forestadent screw brand showed the greatest bending strength, significantly higher than Dentaurum. Morelli showed the lowest resistance. Conclusion: The flexural strength of the screws varied according to the brand. Forestadent screw showed the greatest resistance and Morelli the lowest. All the three screws were found adequate for use in procedures for rapid maxillary expansion.

Knoop hardness of enamel and shear bond strength of brackets bonded with composite resin with and without fluoride

OBJETIVO: o proposito deste estudo foi avaliar a dureza Knoop do esmalte, resistencia ao cisalhamento e padrao de falha (adesiva; interface braquete/resina; e mista) apos a colagem e descolagem de braquetes, utilizando uma resina composta com fluor (Ortho Lite Cure, Ortho Source®) e uma sem fluor (Orthobond, Morelli®). METODOS: fragmentos (6mm x 6mm) de 40 coroas de incisivos bovinos foram embutidos em resina acrilica autopolimerizavel. A dureza Knoop foi avaliada antes e apos a colagem dos braquetes metalicos. Os corpos de prova foram divididos em dois grupos: resina com fluor (Ortho Lite Cure, Ortho Source®) e resina sem fluor (Orthobond, Morelli®). Apos a colagem, os corpos de prova foram submetidos ao ciclo de desmineralizacao e remineralizacao durante 14 dias, e submetidos ao ensaio de resistencia ao cisalhamento em maquina universal de ensaios EMIC, com velocidade de 0,5mm/min. RESULTADOS: o ensaio de resistencia de uniao mostrou que nao houve diferenca significativa entre os grupos. Apos o processo de desmineralizacao e remineralizacao, os corpos de prova colados com a resina composta com fluor apresentaram maior dureza, comparados aos colados com resina sem fluor. Para ambos os grupos houve predominância de falhas na interface resina/braquete. CONCLUSAO: os corpos de prova colados com a resina composta com fluor apresentaram maior microdureza apos os processos de desmineralizacao e remineralizacao, comparados aos colados com resina composta sem fluor, porem sem diferenca para a resistencia de uniao ao cisalhamento.