Uma alternativa simples e eficiente para correção de recidivas após 15 anos de tratamento ortodôntico ­ relato de caso / A simple and efficient alternative for the correction of relapses after 15 years of orthodontic treatment ­ case report

Recidivas são frequentemente observadas após o tratamento ortodôntico e, com o objetivo de evitá-las e manter a estabilidade das posições dentárias após o tratamento, o uso de contenções superiores e inferiores é indicado. Entretanto, alguns pacientes não as usam de maneira correta, causando uma perda na estabilidade da posição dentária alcançada com o tratamento ortodôntico. Devido ao fato de os pacientes estarem mais preocupados com conforto e estética e o uso de alinhadores ortodônticos ser uma ferramenta viável para pequenas correções, o objetivo deste estudo foi descrever um caso clínico de correção de recidivas 15 anos após o fim do tratamento ortodôntico. As fotografias intraorais mostraram uma relação de má oclusão de Classe I com overjet e overbite satisfatórios, rotação do dente 23, extrusão do dente 11, desgaste incisal do dente 41 e apinhamento anteroinferior. Clinicamente, a paciente apresentava contato prematuro nos dentes 11 e 41 durante o movimento de protusão mandibular. O tratamento foi realizado com 4 alinhadores superiores e 10 alinhadores inferiores. Após este set de alinhadores, foram necessários mais 6 alinhadores inferiores, 2 por refinamento. Após 5 meses, a paciente apresentava boa oclusão, com guias laterais, protrusão sem interferência, além de alinhamento e nivelamento dentários. Esse caso clínico provou que o uso de alinhadores ortodônticos é eficiente em corrigir pequenas recidivas de tratamento ortodôntico.(AU)

Recurrences are frequently observed after orthodontics treatment, and in order to avoid them and keep the stability of dental positions after treatment, the use of maxillary and mandibular retainers are indicated. However, some patients do not use them properly causing the break of stability position obtained with the orthodontic treatment. As patients are more concerned with confort and esthetic and the use of clear aligners is a viable tool for small corrections, the aim of this study was to describe a case of relapse correction wich occurred after 15 years of orthodontic treatment with the use of clear aligners. The intraoral photographs showed a Class I maloclusion with satisfactory overjet and overbite, rotation of 23, extrusion of 11, incisal waste of 41, and mandibular anterior crowding, Clinically, the patient had premature contact with teeth 11 and 41 during protrusion movement. The entire treatment was done with 4 maxillary aligners and 10 mandibular aligners. After this set of aligners, it was necessary other 6 mandibular aligners, 2 per refinements. After 5 months, the patient presented good oclusion, with lateral guides, protrusion with no interferences, the teeth were aligned and leveled. This case report proved that clear aligners are efficient in correcting relapses.(AU)

Assessment of Long-Term Stability ofLeveling of theCurve of Spee after Orthodontic Treatment in Mesocephalic Patients -A Pilot Study

Objective:To assess the long-term stability of leveling the curve of Spee after at least 8 years post-treatment in patients with mesocephalic pattern. Material and Methods:Measuring the depth of the curve of Spee in 10 mesocephalic patients at the following times: T0 (before the beginning of orthodontic treatment), T1 (at the end of orthodontic treatment) and T2 (at least 8 years after orthodontic treatment). These measures were compared using paired t-test (significance level of 5%). The curve depths were calculated from the measures of the distances between the lower buccal cusp of the posterior teeth of each side to a reference surface, which was supported by 3 points of the lower cast. Results:The mean curve of Spee depth at T0 was 1.86 mm, 0.50 mm at T1 and 0.53 mm at T2. The mean correction of the curve of Spee depth was 1.36 mm (73.11%) and the average relapse was 0.03 mm (2.2%). No statistically significant differencebetween T1 and T2 values in left or right sides was found. On the other hand, significant differences among T0 and T1 and T0 and T2 values were found. Conclusion:The results suggest that there was no significant depth relapse of the curve of Spee and also that leveling the curve is a stable procedure after 8 years after treatment in mesocephalic patients still using mandibular fixed retainer. The values found when comparing the depth in T0 and T1 showed that the curve of Spee was leveled during orthodontic treatment

Mechanical properties of NiTi and CuNiTi wires used in orthodontic treatment. Part 2: Microscopic surface appraisal and metallurgical characteristics.

OBJECTIVE: This research aimed at comparing the qualitative chemical compositions and the surface morphology of fracture regions of eight types of Nickel/Titanium (NiTi) conventional wires, superelastic and heat-activated (GAC, TP, Ormco, Masel, Morelli and Unitek), to the wires with addition of copper (CuNiTi 27ºC and 35ºC, Ormco) after traction test. METHODS: The analyses were performed in a scanning electronic microscope (JEOL, model JSM-5800 LV) with EDS system of microanalysis (energy dispersive spectroscopy). RESULTS: The results showed that NiTi wires presented Ni and Ti as the main elements of the alloy with minimum differences in their composition. The CuNiTi wires, however, presented Ni and Ti with a significant percentage of copper (Cu). As for surface morphology, the wires that presented the lowest wire-surface roughness were the superelastic ones by Masel and Morelli, while those that presented the greatest wire-surface roughness were the CuNiTi 27ºC and 35ºC by Ormco, due to the presence of microcavity formed as a result of pulling out some particles, possibly of NiTi4. The fracture surfaces presented characteristics of ductile fracture, with presence of microcavities. The superelastic wires by GAC and the CuNiTi 27ºC and the heat-activated ones by Unitek presented the smallest microcavities and the lowest wire-surface roughness with regard to fracture, while the CuNiTi 35ºC wires presented inadequate wire-surface roughness in the fracture region. CONCLUSIONS: CuNiTi 35ºC wires did not present better morphologic characteristics in comparison to the other wires with regard to surfaces and fracture region.

Shear bond resistance and enamel surface comparison after the bonding and debonding of ceramic and metallic brackets.

OBJECTIVE: To evaluate, in vitro, the shear bond strength presented by three brands of polycrystalline ceramic brackets and one brand of metallic bracket; verify the adhesive remnant index (ARI) after the tests, and analyze, through scanning electron microscopy (SEM) the enamel surface topography after debonding, detecting the release of mineral particles. METHODS: Sixty bovine lower incisors were used. Three ceramic brackets (Allure®, InVu®, and Clarity®) and one metallic bracket (Geneus®) were bonded with Transbond XT®. Kruskal-Wallis's test (significance level set at 5%) was applied to the results of shear bond and ARI. Mann Whitney's test was performed to compare the pairs of brackets in relation to their ARI. Brown-Forsythe's test (significance level set at 5%) was applied to the results of enamel chemical composition. Comparisons between groups were made with Games-Howell's and the Post-hoc tests. RESULTS: No statistically significant difference was observed in relation to the shear bond strength loads. Clarity® brackets were the most affected in relation to the surface topography and to the release of mineral particles of enamel (calcium ions). CONCLUSIONS: With regard to the ARI, there was a prevalence of score 4 (40.4%). As for enamel surface topography, the Geneus® bracket was the only one which did not show superficial tissue loss. The InVu® and Clarity® ones showed cohesive fractures in 33.3% and the Allure® in 50%, the latter being the one that presented most fractures during removal.

Shear bond resistance and enamel surface comparison after the bonding and debonding of ceramic and metallic brackets

OBJECTIVE: To evaluate, in vitro, the shear bond strength presented by three brands of polycrystalline ceramic brackets and one brand of metallic bracket; verify the adhesive remnant index (ARI) after the tests, and analyze, through scanning electron microscopy (SEM) the enamel surface topography after debonding, detecting the release of mineral particles. METHODS: Sixty bovine lower incisors were used. Three ceramic brackets (Allure(r), InVu(r), and Clarity(r)) and one metallic bracket (Geneus(r)) were bonded with Transbond XT(r). Kruskal-Wallis's test (significance level set at 5%) was applied to the results of share bond and ARI. Mann Whitney's test was performed to compare the pairs of brackets in relation to their ARI. Brown-Forsythe's test (significance level set at 5%) was applied to the results of enamel chemical composition. Comparisons between groups were made with Games-Howell's and the Post-hoc tests. RESULTS: No statistically significant difference was observed in relation to the shear bond strength loads. Clarity(r) brackets were the most affected in relation to the surface topography and to the release of mineral particles of enamel (calcium ions). CONCLUSION: With regard to the ARI, there was a prevalence of score 4 (40.4%). As for enamel surface topography, the Geneus(r) bracket was the only one which did not show superficial tissue loss. The InVu(r) and Clarity(r) ones showed cohesive fractures in 33.3% and the Allure(r) in 50%, the latter being the one that presented most fractures during removal. .

OBJETIVO: avaliar, in vitro, a resistência ao cisalhamento apresentada por três marcas de braquetes ortodônticos cerâmicos policristalinos e uma marca de braquete metálico, verificando os índices de resina remanescentes (IRA) após os ensaios, e analisar, por meio de microscopia eletrônica de varredura, as topografias superficiais do esmalte após a descolagem, detectando o desprendimento de partículas minerais desse. MÉTODOS: foram utilizados 60 incisivos inferiores bovinos. Os braquetes cerâmicos (Allure, InVu e Clarity) e metálico (Geneus) foram colados utilizando-se o adesivo Transbond XT. Para os resultados referentes ao cisalhamento e ao IRA, foi utilizado o teste de Kruskal-Wallis, com nível de significância de 5%. A prova de Mann-Whtiney foi utilizada para comparar os diferentes tipos de braquetes aos pares, quanto ao IRA. Para a análise dos resultados referentes às composições químicas do esmalte, aplicou-se o teste de Brown-Forsythe, com significância de 5%. As comparações entre os grupos foram realizadas utilizando os testes Post Hoc e de Games-Hoewell. RESULTADOS: não foram observadas diferenças significativas quanto às cargas de cisalhamento. O Clarity foi o mais afetado em relação à topografia e ao desprendimento de partículas minerais do esmalte (íons Ca). CONCLUSÃO: em relação ao IRA, foi confirmada a prevalência do escore 4, com um percentual de 40,4%. Em relação à topografia superficial do esmalte, o Geneus foi o único que não apresentou perda de tecido . O InVu e o Clarity apresentaram fraturas coesivas de 33,3% de suas amostras, e o Allure de 50%, sendo o que mais fraturou durante a remoção. .

Mechanical properties of NiTi and CuNiTi wires used in orthodontic treatment. Part 2: Microscopic surface appraisal and metallurgical characteristics

OBJECTIVE: This research aimed at comparing the qualitative chemical compositions and the surface morphology of fracture regions of eight types of Nickel (Ni) Titanium (Ti) conventional wires, superelastic and heat-activated (GAC, TP, Ormco, Masel, Morelli and Unitek), to the wires with addition of copper (CuNiTi 27oC and 35oC, Ormco) after traction test. METHODS: The analyses were performed in a scanning electronic microscope (JEOL, model JSM-5800 LV) with EDS system of microanalysis (energy dispersive spectroscopy). RESULTS : The results showed that NiTi wires presented Ni and Ti as the main elements of the alloy with minimum differences in their composition. The CuNiTi wires, however, presented Ni and Ti with a significant percentage of copper (Cu). As for surface morphology, the wires that presented the lowest wire-surface roughness were the superelastic ones by Masel and Morelli, while those that presented the greatest wire-surface roughness were the CuNiTi 27oC and 35oC ones by Ormco, due to presence of microcavity formed as a result of pulling out some particles, possibly of NiTi. 4 The fracture surfaces presented characteristics of ductile fracture, with presence of microcavities. The superelastic wires by GAC and the CuNiTi 27oC and the heat-activated ones by Unitek presented the smallest microcavities and the lowest wire-surface roughness with regard to fracture, while the CuNiTi 35oC wires presented inadequate wire-surface roughness in the fracture region. CONCLUSION: CuNiTi 35oC wires did not present better morphologic characteristics in comparison to the other wires with regard to surfaces and fracture region. .

OBJETIVO: objetivou-se nessa pesquisa comparar as composições químicas qualitativas e as morfologias das superfícies e das regiões de fratura, após ensaios de tração, de oito tipos de fios de NiTi superelásticos e termoativados convencionais (GAC, TP, Ormco, Masel, Morelli e Unitek) aos fios com adição de cobre (CuNiTi 27°C e 35°C, da Ormco). MÉTODOS: as análises foram realizadas em microscópio eletrônico de varredura (JEOL, modelo JSM-5800 LV) com sistema de microanálise EDS (energy dispersive spectroscopy). RESULTADOS: os resultados mostraram que os fios de NiTi ensaiados apresentaram Ni e Ti como os principais elementos da liga, com diferenças mínimas em suas composições. Os fios de CuNiTi, por sua vez, apresentaram Ni e Ti, com percentual significativo de cobre (Cu). Em relação às morfologias das superfícies, os fios que apresentaram os melhores acabamentos foram os superelásticos da Masel e Morelli, e os que apresentaram os piores acabamentos foram os de CuNiTi 27°C e 35°C, da Ormco, graças à presença de microcavidades formadas devido ao arrancamento de partículas, possivelmente de NiTi 4 . As superfícies de fratura apresentaram características de fratura dúctil, com a presença de microcavidades. Os fios superelásticos da GAC e de CuNiTi 27°C, bem como os termoativados da Unitek, apresentaram as menores microcavidades e os melhores acabamentos à fratura, enquanto os fios de CuNiTi 35° apresentaram acabamentos inadequados das regiões de fratura. CONCLUSÃO: os fios de CuNiTi 35°C não apresentaram características morfológicas mais adequadas das superfícies e das regiões de fratura em relação aos demais fios. .

Clinical evaluation of dental alignment and leveling with three different types of orthodontic wires.

INTRODUCTION: A wide variety of orthodontic wires made of different alloys is available to be used in orthodontic practice and may produce different clinical responses during tooth movement. OBJECTIVE: This research evaluated the alignment and leveling of lower dental arches after the use of three types of orthodontic wires. METHODS: A sample of 36 patients was randomly divided into 3 groups: stainless steel, multistranded steel and superelastic nickel-titanium, according to the first leveling arches used. In order to observe differences in tooth position and axial inclination of the lower incisors, all patients had lateral cephalometric radiographs taken before the insertion of the first arches and 2 months later. The irregularity index and the curve of Spee were measured, compared between groups and considered influential on the proclination of incisors during the initial phase of alignment and leveling. The Reflex microscope was used to measure the irregularity index, whereas the ANOVA analysis of variance was used to verify differences between groups with regard to the degree of dental alignment and leveling. RESULTS: There were significant differences between groups only at T2 for the irregularity index. CONCLUSIONS: The NiTi and multistranded steel wires showed greater aligning capacity when compared with stainless steel wires.

Prototype of a new tip developed to be coupled to dental light-curing units for optimizing bonding of orthodontic brackets and accessories.

OBJECTIVE: Development of a new device to be coupled to light-curing units for bonding orthodontic brackets and accessories, and test its efficacy in an in vitro mechanical trial. The inner surface of the device is mirrored and is based on physical concepts of light refraction and reflection. The main advantage of such device is the reduced clinical time needed for bonding and the low possibility of contamination during the process. METHODS: One hundred and twenty specimens were used for testing the shear bond strength of brackets bonded with the device. The Adhesive Remnant Index (ARI) was also determined. The sample was divided into 2 groups. In group 1 a halogen light-curing unit was used while in group 2 a led light-curing unit was used. Each group was then subdivided. In subgroups H1 and L1, a conventional light guide rod was used while in subgroups H2 and L2 bonding was performed with the mirrored device coupled to the tip of the guide light rod. RESULTS: The values obtained for the shear bond strength and the ARI in the subgroups were compared. Results showed that there was no statistically significant difference for the shear strength (p > 0.05) and the ARI (p > 0.05) between the subgroups. CONCLUSIONS: The tests of mechanical trials and the ARI analysis showed that the new device fulfilled the requirements for bonding orthodontic accessories, and that the time for bonding was reduced to half, being necessary only one light exposure.

Clinical evaluation of dental alignment and leveling with three different types of orthodontic wires

INTRODUCTION: A wide variety of orthodontic wires made of different alloys is available to be used in orthodontic practice and may produce different clinical responses during tooth movement. OBJECTIVE: This research evaluated the alignment and leveling of lower dental arches after the use of three types of orthodontic wires. METHODS: A sample of 36 patients was randomly divided into 3 groups: stainless steel, multistranded steel and superelastic nickel-titanium, according to the first leveling arches used. In order to observe differences in tooth position and axial inclination of the lower incisors, all patients had lateral cephalometric radiographs taken before the insertion of the first arches and 2 months later. The irregularity index and the curve of Spee were measured, compared between groups and considered influential on the proclination of incisors during the initial phase of alignment and leveling. The Reflex microscope was used to measure the irregularity index, whereas the ANOVA analysis of variance was used to verify differences between groups with regard to the degree of dental alignment and leveling. RESULTS: There were significant differences between groups only at T2 for the irregularity index. CONCLUSION: The NiTi and multistranded steel wires showed greater aligning capacity when compared with stainless steel wires.

INTRODUÇÃO: uma grande variedade de fios ortodônticos, compostos por diferentes ligas, está disponível para utilização ortodôntica, podendo gerar respostas clínicas diversas, durante a movimentação dentária. OBJETIVO: este trabalho visa a avaliar o alinhamento e nivelamento das arcadas dentárias inferiores, após a utilização de três tipos de fios ortodônticos. MÉTODOS: uma amostra de 36 pacientes foi aleatoriamente dividida em três grupos, de acordo com os primeiros arcos utilizados para o alinhamento e nivelamento: aço inoxidável convencional, aço multifilamentado e de níquel-titânio superelástico. Para se avaliar as diferenças relacionadas ao posicionamento dentário e inclinação axial dos incisivos inferiores, foram obtidas radiografias cefalométricas de perfil, de todos os pacientes, em duas fases do tratamento: antes da inserção dos primeiros arcos e dois meses após a inserção dos mesmos. O índice de irregularidade dentária (IID) e a profundidade inicial de curva de Spee, fatores influentes sobre a projeção de incisivos durante a fase inicial de alinhamento e nivelamento, foram avaliados e comparados intra- e intergrupos. Para a medição do IID, foi utilizado o Reflex Microscope, possibilitando a mensuração do grau de alinhamento e nivelamento dentário em terceira dimensão. A análise de variância (ANOVA) foi utilizada para se avaliar as diferenças intergrupos em relação ao grau de alinhamento e nivelamento dentário. RESULTADOS: diferenças estatisticamente significativas intergrupos somente foram encontradas em T2, em relação ao índice de irregularidade dentária, já que os fios de NiTi e aço multifilamentado apresentaram maior capacidade de alinhamento do que os fios de aço inoxidável convencionais.

Prototype of a new tip developed to be coupled to dental light-curing units for optimizing bonding of orthodontic brackets and accessories

OBJECTIVE: development of a new device to be coupled to light-curing units for bonding orthodontic brackets and accessories, and test its efficacy in an in vitro mechanical trial. The inner surface of the device is mirrored and is based on physical concepts of light refraction and reflection. The main advantage of such device is the reduced clinical time needed for bonding and the low possibility of contamination during the process. METHODS: One hundred and twenty specimens were used for testing the shear bond strength of brackets bonded with the device. The Adhesive Remnant Index (ARI) was also determined. The sample was divided into 2 groups. In group 1 a halogen light-curing unit was used while in group 2 a led light-curing unit was used. Each group was then subdivided. In subgroups H1 and L1, a conventional light guide rod was used while in subgroups H2 and L2 bonding was performed with the mirrored device coupled to the tip of the guide light rod. RESULTS: The values obtained for the shear bond strength and the ARI in the subgroups were compared. Results showed that there was no statistically significant difference for the shear strength (p > 0.05) and the ARI (p > 0.05) between the subgroups. CONCLUSION: The tests of mechanical trials and the ARI analysis showed that the new device fulfilled the requirements for bonding orthodontic accessories, and that the time for bonding was reduced to half, being necessary only one light exposure.

OBJETIVO: desenvolver uma nova ponteira para ser acoplada aos aparelhos fotopolimerizadores utilizados para colagem de braquetes e acessórios ortodônticos, e testar sua da efetividade em ensaio mecânico in vitro. A ponteira é espelhada na superfície interna e baseia-se em conceitos físicos de refração e reflexão de luz. Apresenta como principal vantagem o menor tempo clínico durante o procedimento de colagem, reduzindo a possibilidade de contaminação durante o processo. MÉTODOS: por meio de ensaio de resistência ao cisalhamento e determinação do índice remanescente de adesivo (IRA), testou-se a ponteira desenvolvida em 120 corpos de prova. A amostra foi dividia em dois grupos. No grupo 1, foi utilizado aparelho fotopolimerizador de fonte de luz halógena e, no grupo 2, fonte de LED. Cada grupo foi subdividido. Nos subgrupos H1 e L1, utilizou-se a ponteira convencional. Nos subgrupos H2 e L2 a colagem foi feita utilizando a ponteira desenvolvida para a polimerização do material de colagem. RESULTADOS: os valores dos testes de cisalhamento e IRA para os subgrupos foram comparados entre si. Os resultados mostraram que não houve diferença estatisticamente significativa para o ensaio de resistência ao cisalhamento (p > 0,05) nem para o IRA (p > 0,05) entre os subgrupos. CONCLUSÃO: os testes de ensaio mecânico, assim como a análise do IRA, mostraram que a nova ponteira desenvolvida cumpriu os requisitos necessários à colagem dos acessórios ortodônticos, e que o tempo de colagem foi reduzido pela metade, sendo necessária uma só incidência.

Mechanical properties of NiTi and CuNiTi shape-memory wires used in orthodontic treatment. Part 1: stress-strain tests.

OBJECTIVE: This research aimed to compare, through traction tests, eight types of superelastic and heat-activated NiTi archwires, by six trade companies (GAC, TP, Ormco, Masel, Morelli and Unitek) to those with addition of copper (CuNiTi 27°C and 35°C, Ormco). METHODS: The tests were performed in an EMIC mechanical testing machine, model DL10000, capacity of 10 tons, at the Military Institute of Engineering (IME). RESULTS: The results showed that, generally, heat-activated NiTi archwires presented slighter deactivation loadings in relation to the superelastic ones. Among the archwires that presented deactivation loadings biologically more adequate are the heat-activated by GAC and by Unitek. Among the superelastic NiTi, the CuNiTi 27°C by Ormco were the ones that presented slighter deactivation loadings, being statistically (ANOVA) similar to the ones presented by the heat-activated NiTi archwires from Unitek. When compared the CuNiTi 27°C and 35°C archwires, it was observed that the 27°C presented deactivation forces of, nearly, ⅓ of the presented by the 35°C. CONCLUSIONS: It was concluded that the CuNiTi 35°C archwires presented deactivation loadings biologically less favorable in relation to the other heat-activated NiTi archwires, associated to lower percentage of deformation, on the constant baselines of deactivation, showing less adequate mechanical behavior under traction, in relation to the other archwires.

Mechanical properties of NiTi and CuNiTi shape-memory wires used in orthodontic treatment. Part 1: stress-strain tests

OBJECTIVE: This research aimed to compare, through traction tests, eight types of superelastic and heat-activated NiTi archwires, by six trade companies (GAC, TP, Ormco, Masel, Morelli and Unitek) to those with addition of copper (CuNiTi 27ºC and 35ºC, Ormco). METHODS: The tests were performed in an EMIC mechanical testing machine, model DL10000, capacity of 10 tons, at the Military Institute of Engineering (IME). RESULTS: The results showed that, generally, heat-activated NiTi archwires presented slighter deactivation loadings in relation to superelastic. Among the archwires that presented deactivation loadings biologically more adequate are the heat-activated by GAC and by Unitek. Among the superelastic NiTi, the CuNiTi 27ºC by Ormco were the ones that presented slighter deactivation loadings, being statistically (ANOVA) similar, to the ones presented by the heat-activated NiTi archwires by Unitek. When compared the CuNiTi 27ºC and 35ºC archwires, it was observed that the 27ºC presented deactivation forces of, nearly, ⅓ of the presented by the 35ºC. CONCLUSION: It was concluded that the CuNiTi 35ºC archwires presented deactivation loadings biologically less favorable in relation to the other heat-activated NiTi archwires, associated to lower percentage of deformation, on the constant baselines of deactivation, showing less adequate mechanical behavior, under traction, in relation to the other archwires.

OBJETIVO: o objetivo dessa pesquisa foi comparar, por meio de ensaios de tração, oito tipos de fios de NiTi superelásticos e termoativados, de seis empresas comerciais (GAC, TP, Ormco, Masel, Morelli e Unitek) àqueles com adição de cobre (CuNiTi 27ºC e 35ºC, da ORMCO). MÉTODOS: os ensaios foram realizados em máquina de ensaios mecânicos, da marca EMIC, modelo DL10000, de 10 toneladas de capacidade, no Instituto Militar de Engenharia (IME). RESULTADOS: os resultados mostraram que, de forma geral, os fios de NiTi termoativados apresentaram cargas mais suaves de desativação que os superelásticos. Entre os fios que apresentaram as cargas de desativação biologicamente mais adequadas, estão os termoativados da GAC e da Unitek. Entre os fios de NiTi superelásticos, os de CuNiTi 27ºC da Ormco foram os que apresentaram as cargas mais suaves de desativação, sendo estatisticamente semelhantes (ANOVA) às apresentadas pelos fios de NiTi termoativados da Unitek. Quando comparados os fios de CuNiTi 27ºC aos de 35ºC, observou-se que os primeiros apresentaram forças de desativação de, aproximadamente, ⅓ das apresentadas pelos últimos. CONCLUSÃO: conclui-se que os fios de CuNiTi 35ºC apresentaram cargas de desativação biologicamente menos favoráveis em relação aos demais fios de NiTi termoativados, sendo associadas a percentuais inferiores de deformação, nos patamares constantes de desativação, demonstrando comportamento mecânico, sob tração, menos adequado em relação aos demais fios.

Evaluation of the friction force generated by monocristalyne and policristalyne ceramic brackets in sliding mechanics.

OBJECTIVE: To evaluate and compare "in vitro" the maximum friction force generated by three types of esthetic brackets, two types of polycrystalline conventional ceramic brackets (20/40 and InVu) and one type of sapphire monocrystalline bracket (Radiance) in dry and artificial saliva wet settings. Also, to evaluate the influence exerted by artificial saliva on the friction forces of those brackets. METHODS: Tests were performed in dry and artificial saliva wet setting (Oral Balance) by using an EMIC DL 10000 testing machine, simulating a 2 mm slide of 0.019 x 0.025-in rectangular stainless steel wires over the pre-angulated and pre-torqued (right superior canine, Roth prescription, slot 0.022 x 0.030-in) brackets (n = 18 for each bracket). In order to compare groups in dry and wet settings, the ANOVA was used. For comparisons related to the dry versus wet setting, the student t test was used for each group. RESULTS: The results showed that in the absence of saliva the Radiance monocrystalline brackets showed the highest friction coefficients, followed by the 20/40 and the InVu polycrystalline brackets. In tests with artificial saliva, the Radiance and the 20/40 brackets had statistically similar friction coefficients and both were greater than that presented by the InVu brackets. The artificial saliva did not change the maximum friction force of the Radiance brackets, but, for the others (20/40 and InVu), an increase of friction was observed in its presence. CONCLUSION: The InVu brackets showed, in the absence and in the presence of saliva, the lowest friction coefficient.

Apical root resorption: the dark side of the root.

INTRODUCTION: The diagnosis of apical root resorption is usually based on routine radiographs. However, these methods are limited because the images reflect the superimposition of the whole root structure and can lead to underestimation of the extent of apical root resorption. In this study, we aimed to determine the lengths of the labial and lingual surfaces of incisors with apical root resorption and compare them with the longest radicular length obtained on sagittal images of cone-beam computed tomography, and to create a qualitative visual scale of the different patterns of apical root resorption. METHODS: Eighty-two incisors with apical root resorption from 25 patients had their labial and lingual root surfaces and the longest radicular lengths determined in the sagittal plane and compared. Five orthodontists, at 2 times, classified the images of each incisor according to a visual scale developed by the authors. RESULTS: There was no significant difference between the labial and lingual surfaces; however, the longest radicular length was significantly greater than the shortest surface length. The visual scale showed intraobserver agreement of 0.615 and interobserver agreements of 0.74 and 0.52 at both times, respectively. CONCLUSIONS: The difference between the longest and shortest root lengths suggests that radiographic superimposition underestimates the extent of the resorption lesion. The proposed visual scale showed a frequency of agreement above 65% and a coefficient of reproducibility varying from moderate to substantial.

Evaluation of the friction force generated by monocristalyne and policristalyne ceramic brackets in sliding mechanics

OBJECTIVE: To evaluate and compare "in vitro" the maximum friction force generated by three types of esthetic brackets, two types of polycrystalline conventional ceramic brackets (20/40 and InVu) and one type of sapphire monocrystalline bracket (Radiance) in dry and artificial saliva wet settings. Also, to evaluate the influence exerted by artificial saliva on the friction forces of those brackets. METHODS: Tests were performed in dry and artificial saliva wet setting (Oral Balance) by using an EMIC DL 10000 testing machine, simulating a 2 mm slide of 0.019 x 0.025-in rectangular stainless steel wires over the pre-angulated and pre-torqued (right superior canine, Roth prescription, slot 0.022 x 0.030-in) brackets (n = 18 for each bracket). In order to compare groups in dry and wet settings, the ANOVA was used. For comparisons related to the dry versus wet setting, the student t test was used for each group. RESULTS: The results showed that in the absence of saliva the Radiance monocrystalline brackets showed the highest friction coefficients, followed by the 20/40 and the InVu polycrystalline brackets. In tests with artificial saliva, the Radiance and the 20/40 brackets had statistically similar friction coefficients and both were greater than that presented by the InVu brackets. The artificial saliva did not change the maximum friction force of the Radiance brackets, but, for the others (20/40 and InVu), an increase of friction was observed in its presence. CONCLUSION: The InVu brackets showed, in the absence and in the presence of saliva, the lowest friction coefficient.

OBJETIVO: avaliar e comparar in vitro as cargas máximas de atrito geradas por três tipos de braquetes estéticos, sendo dois deles cerâmicos policristalinos convencionais (20/40 e InVu) e um monocristalino de safira (Radiance), em ambientes seco e umedecido por saliva artificial. Também avaliar a influência exercida pela saliva artificial sobre as cargas de atrito dos referidos braquetes. MÉTODOS: os ensaios foram realizados em ambiente seco e em ambiente umedecido com saliva artificial em gel (Oral Balance), utilizando uma máquina de ensaios mecânicos (EMIC, modelo DL10000), simulando um deslizamento de 2mm de fios retangulares 0,019" x 0,025" de aço sobre os braquetes (n = 18, para cada braquete), pré-angulados e pré-torqueados (canino superior direito prescrição Roth, slot 0,022" x 0,030"). Para comparação entre os braquetes, em ambiente seco ou umedecido, utilizou-se a análise de variância; e para a comparação dos braquetes em ambiente seco e umedecido, utilizou-se o teste t para amostras independentes. RESULTADOS: os resultados obtidos indicaram que, na ausência de saliva, os braquetes monocristalinos Radiance demonstraram o maior coeficiente de atrito, seguidos pelos braquetes policristalinos 20/40 e InVu. Nos ensaios realizados em ambiente umedecido, os braquetes Radiance e 20/40 apresentaram coeficientes de atrito estatisticamente semelhantes, e superiores ao apresentado pelos braquetes InVu. A saliva artificial não promoveu alterações na força máxima de atrito para os braquetes Radiance; todavia, para os demais (20/40 e InVu), promoveu aumento significativo nos coeficientes de atrito. CONCLUSÃO: os braquetes InVu apresentaram, tanto nos ensaios realizados na ausência, quanto na presença de saliva, os menores coeficientes de atrito, entre os braquetes ensaiados.

The role of orthodontic tooth movement in bone and root mineral density: a study of patients submitted and not submitted to orthodontic treatment.

BACKGROUND: Orthodontic force application to the teeth is responsible for a series of biological responses in the bone and dentin, which lead to some alterations of the mineral density of the tissues. Our objective was determine, through cone-beam computed tomography (CBCT), the mineral density of the apical third of the roots of the upper central incisors and of the periapical bone portion surrounding these teeth, in patients submitted to orthodontic treated and untreated individuals. MATERIAL/METHODS: 30 untreated individuals and 15 treated ones (treatment cessation at least 1 year before the study) underwent CBCT. Mineral density was assessed in the apical third of the root of the upper central incisors and in the alveolar bone in the periapical region of these teeth. In order to reduce CBCT-related mineral density variability, we standardized the cone-beam tomography device, the image-acquisition settings and the field of view positioning and size. Student's t test was used for the analyses. RESULTS: bone mineral density (BMD) and root mineral density (RMD), in Hounsfield Units, were 674.84 and 1282.26 for the untreated group and 630.28 and 1370.29 for the treated group, respectively. The differences between the group means were statistically significant for RMD (p<0.05). CONCLUSIONS: untreated individuals had a significant lower mean RMD in comparison with those submitted to orthodontic treatment.

Estudo dos Determinantes Cefalométricos da Relação ÂnteroPosterior Maxilomandibular em Amostra de Oclusão Normal / Study of Cephalometric Measurements of Maxillomandibular Anteroposterior Relationship in a Sample of Normal Occlusion Patients

Objetivo: Comparar os valores das medidas utilizadas na análise da relação ântero-posterior maxilomandibular (ANB, AF-BF, Wits, TPi e FABA) com seus respectivos padrão de normalidade; determinar o grau de correlação entre estas medidas; avaliar a presença de dimorfismo sexual.Método: Foram utilizadas 23 telerradiografias em norma lateral de brasileiros portadores de oclusão clinicamente normal com idade acima de 18 anos e o sexo escolhido ao acaso. Os valores foram avaliados entre si e comparados com o padrão para cada medida utilizando-se o teste t-student com nível de significância de 5%, bem como determinação do grau de correlação de Pearson entre as medidas para ambos os sexos e avaliação do dimorfismo sexual através do teste Kruskal-Wallis assumindo o nível de signifcância de 5%. Resultados: Para o sexo masculino, as medidas AF-BF e TPi apresentaram valor p<0,05, enquanto para o feminino, este valor foi encontrado apenas para a medida TPi. As medidas TPi, AO-BO e ANB para o sexo masculino apresentaram grau de correlação de Pearsonsuperior a 0,7, e para o sexo feminino, além destas, a medida FABA apresentou valor superior a 0,7. Para o dimorfismo sexual, todas as medidas apresentaram valor p>0,05.Conclusão: As medidas AO-BO, ANB e FABA dos indivíduos do sexo masculino da amostra estudada não apresentam diferença estatisticamente significativa em relação aos valores padrão. Já para os indivíduos do sexo feminino da amostra, não houve diferença estatisticamente significativa em relação aos valores padrão para as medidas AF-BF, AO-BO, ANB e FABA; existe um alto grau de correlação entre as medidas TPi, AO-BO e ANB para o sexo masculino e TPi, AOBO, ANB e FABA para o sexo feminino; não houve dimorfismo sexual para nenhuma das medidas estudadas

Objective: To copare the values of the measurements used in the analysus of the anteroposterior maxillomandibular relationship (ANB, AF-BF, Wits, TPi and FABA) with standard values of normality; to evaluate the degree of correlation between the measurements; to evaluate the presence of sexual dimorphism for each measurement in the sample under study.Method: Twenty three lateral cephalometric radiographs of Brazilian individuals with normal occlusion, over 18 years of age, with sex randomly selected, were taken. The values were evaluated between them and compared with the standard values for each measurement using t-Student test with significant at the 5% level of significance, as well as the determination of the degree of Pearson's correlation between the measurements for both sexes, and the evaluation of sexual dimorphism throught Kruskal-Wallis test at the 5% level of significance.Results: For the male sex, the measurements AF-BF and TPi showed value p<0,05, while for femile, this value was found just for TPi. The measurements TPi, AO-BO and ANB for male showed degree of Pearson's correlation upper than 0,7, and for femile, beyond these, FABA showed value upper than 0,7. For sexual dimorphom, all measurements was noticed value p>0,05.Conclusion: The measurements AO-BO, ANB and FABA of the male subjects did not show statistically significant difference when compared to standard values. As for the female individuals, there was no significant difference relative to standard values for the AF-BF, AOBO, ANB and FABA measurements. There is a high degree of correlation between the TPi, AO-BO and ANB measurements for males and TPi, AOBO, ANB and FABA for females. No sexual dimorphism was noticed in any of the studied measurements

Alterações esqueléticas craniofaciais em portadores de anemia falciforme na cidade de Juiz de Fora / Craniofacial skeletal alterations in sickle cell anemia patients of Juiz de Fora

Este trabalho avaliou as características esqueléticas craniofaciais de 30 indivíduos negros portadores de anemia falciforme, com idade variando entre 20 e 46 anos, cadastrados na Fundação Centro de Hematologia e Hemoterapia de Minas Gerais - Fundação Hemominas, na cidade de Juiz de Fora/MG. Após a obtenção das radiografias cefalométricas em norma lateral de perfil de todos os pacientes, foram realizados os traçados cefalométricos, utilizando alguns ângulos da análise cefalométrica de Steiner e Downs, os quais foram comparados com os valores encontrados por Fortes. As variáveis avaliadas neste trabalho foram os ângulos SNA, SNB, ANB, SND, GoGn.SN, ângulo facial, ângulo de convexidade e ângulo do eixo Y que, após aferidos, foram divididos em tabelas e comparados aos valores padrão preconizados por estes autores e submetidos ao tratamento estatístico, utilizando o teste t-student. O nível de significância adotado foi de 5%. Para avaliação da confiabilidade, foram utilizados os testes t-student para amostras pareadas e de correlação de Pearson. Neste estudo, as variáveis que apresentaram diferença estatisticamente significante entre a média dos valores medidos e o valor padrão de cada variável (p < 0,05) foram SNA, SNB, SND, GoGn.SN e o ângulo de convexidade. As alterações ósseas craniofaciais observadas nestes pacientes foram protrusão da maxila, retrusão da mandíbula, aumento do plano mandibular e perfil facial convexo, com características do padrão esquelético de classe II, sugerindo que a anemia falciforme tem participação nas alterações esqueléticas craniofaciais observadas.

The present study evaluated craniofacial skeletal characteristics of 30 black patients with sickle cell anemia. Their age ranged from 20 to 46 years-old and all of them were enrolled for treatment at Fundação Centro de Hematologia e Hemoterapia de Minas Gerais - Hemominas, in Juiz de Fora. After obtaining all the cephalometrics radiographs of the patients in lateral profile position, cephalometric tracings were done using specificangles of the analysis of Steiner and Downs, and comparing them with values founded by Fortes. Variables assessed in this study were SNA, SNB, ANB, SND, GoGn.SN angle, facial angle, convexity angle and Y axis angle. Angular measurements were them divided into tables and compared to standard values as described by these authors. Statistical analysis was performed using Student's t-test. Significance level was set at 5%. For reliability evaluation, Student's t-test with paired samples and Pearson correlation test were performed. In this study, variables that showed statistically significant difference between the mean of the values obtained and the standard value of each variable (p<0.05) were SNA, SNB, SND, GoGn.SN angle and convexity angle. Craniofacial skeletal alterations founded in these patients were: maxillary protrusion, mandibular retrusion, increase of mandibular plane and convex facial profile. These are characteristics of a Class II skeletal malocclusion, suggesting that sickle cell anemia is involved in the onset of these skeletal alterations.

O aparelho ortopédico funcional Twin Block estimula o crescimento mandibular? / Does the Twin Block functional appliance stimulate mandibular growth?

O conhecimento pelos ortodontistas do mecanismo de ação dos aparelhos ortopédicos-funcionais, prescritos para inteceptar as más oclusões esqueléticas de Classe II ocasionadas por retrognatismo mandibular, em pacientes em crescimento, é de suma importância. Estes aparelhos poderiam auxiliar no tratamento desta más oclusões através da formação óssea e, assim, interferir no desenvolvimento e crescimento facial. A existência de acréscimos nos incrementos do crescimento mandibular durante a fase ativa do tratamento com estes aparelhos e a estabilidade detas alterações são importantes questionamentos a serem respondidos. O aparelho funcional Twin Block se presta a proporcionar a correção funcional da oclusão de Classe II de Angle e atualmente diversos artigos discutem sua efetividade quanto à sua interferência no crescimento mandibular. Este trabalho realiza uma revisão de publicações e discute a possibilidade do aparelho funcional Twin Block atuar efetivamente no crescimento do corpo e côndilo mandibulares em favor da correção destas más oclusões