Resistência ao cisalhamento entre tipos de bases de bráquetes cerâmicos / Shear strength between types of ceramic brackets bases

O objetivo neste estudo foi avaliar a influência da base de bráquetes cerâmicos na resistência de união ao esmalte bovino. Oitenta incisivos bovinos foram distribuídos em quatro grupos (n=20), de acordo com o tipo de base de retenção dos bráquetes ortodônticos: 1) Ceramic (Morelli): retenção por microcavidades; 2) Iceram (Orthometric): retenção por microcavidades; 3) Transcend Series 6000 (3M/ESPE): retenção por jateamento e 4) bráquetes 20/40 (American Orthododontics): retenção por canaletas. Os dentes foram condicionados com ácido fosfórico a 37% e os bráquetes colados com a resina composta Orthocem. Após 24 horas foi avaliada a resistência ao cisalhamento em máquina de ensaio Instron a uma velocidade de 0,5 mm/minuto. Após os testes, o índice de remanescente adesivo (IRA) foi analisado em lupa estereoscópica. Os dados foram analisados pelo teste de Kruskal-Wallis e Tukey com nível de significância de 5%. Os resultados mostraram que houve diferença significativa entre os bráquetes (p=0,003). Os bráquetes 20/40 (6,81 MPa) e Transcend 6000 (6,26 MPa) apresentaram resistência ao cisalhamento significativamente maior em relação aos Ceramic (4,00 MPa). Os bráquetes Iceram (5,83 MPa) não diferiram significativamente dos demais bráquetes. A avaliação do IRA mostrou que nos bráquetes com microcavidades houve predomínio de falhas entre a resina e o dente, diferentemente dos demais bráquetes. Pode-se concluir que os bráquetes com retenção de canaleta e jateados obtiveram melhores resultados comparados àqueles com retenção por microcavidades.(AU)

The aim of this study was to evaluate the influence of ceramic bracket bases on the bond strength to bovine enamel. Eighty bovine incisors were divided into four groups (n=20), according to the type of orthodontic bracket retention base: 1) Ceramic (Morelli): retention by means of microcavities; 2) Iceram (Orthometric): retention by means of microcavities; 3) Transcend Series 6000 (3M/ESPE): retention by sandblasting and 4) 20/40 brackets (American Orthododontics): retention by dovetail grooves. The teeth were etched with 37% phosphoric acid, and brackets were bonded with Orthocem composite resin. After 24 hours the shear bond strength was evaluated in an Instron test machine at speed of 0.5 mm/minute. After the tests, the adhesive remnant index (ARI) was analyzed under a stereoscopic magnifying glass. The data were analyzed by Kruskal-Wallis and Tukey test, significance level of 5%. The results showed statistically significant differences between the brackets (p=0.003). The 20/40 (6.81 MPa) and Transcend 6000 (6.26 MPa) brackets presented significantly higher shear bond strength than the Ceramic brackets (4.00 MPa). The Iceram brackets (5.83 MPa) did not differ significantly from other brackets. ARI evaluation showed that in brackets with microcavities there was a predominance of flawns between resin and the tooth, different from other brackets. It was concluded that brackets with dovetail grooves retention and sandblasted obtained better results than the brackets with microcavities. retention.(AU)

Dentoskeletal and aesthetic effects of mandibular protraction appliance (MPA) using Ricketts analysis / Efeitos dentoesqueléticos e tegumentares do aparelho de protração mandibular (APM) usando a análise cefalométrica de Ricketts

Objective: This study was designed to evaluate the skeletal, dental and soft tissue effects of mandibular deficiency treatment with the mandibular protraction appliance (MPA) using 12 factors of the Ricketts analysis. Material and method: This cross-sectional retrospective study sample consisted of a group (n = 27), with Class II malocclusion, convex facial profile, increased horizontal trespass and mandibular deficiency, with initial mean age of 12.27 and final of 15.18 years, treated with fixed appliance combined with the MPA, in an average time of 2.9 years. Initial and final radiographs were investigated using Ricketts analysis. The dependent t-test was used to compare the initial and final phases of the MPA group, with a significance level of 5%. Result: Statistically significant differences were observed for dental changes such as retrusion (p=0.000) and palatal inclination of the maxillary incisors (p=0.000); protrusion (p=0.000) and buccal inclination of the mandibular incisors (p=0.000); increased interincisal angle (p=0.002) and improved molar ratio (p=0.003). There was also a restriction of the anterior displacement of the maxilla (p=0.000) and a decrease in the mandibular plane angle (p=0.024). The variable inferior labial protrusion with significance (p=0.000), reiterated the improvement in the profile. Conclusion: The effects of MPA on correction of malocclusion Class II, verified by Ricketts analysis occurred predominantly by dentoalveolar changes, decrease in the Mandibular Plane Angle, and restriction of anterior displacement of the maxilla, which contributed to the improvement in the patient's profile.

Objetivo: Este estudo analisou as alterações dentárias, esqueléticas e tegumentares promovidas pelo Aparelho de Protração Mandibular (APM) por meio da análise de Ricketts. Material e método: A amostra contou com 27 pacientes (14 meninas e 13 meninos) com má oclusão de Classe II, perfil facial convexo, trespasse horizontal aumentado e deficiência mandibular, com idade média inicial de 12,27 e final de 15,18 anos, tratados com aparelho fixo combinado com o APM. A comparação das telerradiografias iniciais (T1) e finais (T2) foi realizada pelo teste t dependente, com nível de significância de 5%. Resultado: Observou-se diferença estatisticamente significante para a retrusão (p=0.000) e lingualização dos incisivos superiores (p=0.000), protrusão (p=0.000) e vestibularização dos incisivos inferiores (p=0.000), aumento do ângulo interincisivos (p=0.002), melhora da relação molar (p=0.003), restrição do deslocamento anterior da maxila (p=0.000), diminuição do ângulo do plano mandibular (p=0.024) e melhora do perfil facial (p=0.000). Conclusão: O APM promoveu alterações dentoalveolares, observadas principalmente pela diminuição do ângulo do plano mandibular e restrição do deslocamento para anterior da maxila que contribuíram para a melhora do perfil do paciente.

Debonding forces of different pads in a lingual bracket system.

OBJECTIVE:: To evaluate the shear bond strength of lingual orthodontic brackets with resin or metal pads, the location of bond failure and the adhesive remnant index (ARI). METHODS:: A total of 40 extracted upper premolars were randomly divided into two groups of 20 each: bonding with brackets having (1) pads with extended resin directly on the lingual surface of teeth, and (2) pads with metal custom base on the lingual surface of teeth. The debonding force was measured with an Instron universal testing machine. A Student's t-test was used to assess the difference between groups (α = 0.05). RESULTS:: The results showed a significant difference between the groups (p < 0.001). The shear bond strength of metal pads was significantly higher than resin pads. CONCLUSIONS:: Within the limitations of this in vitro study, it was concluded that the bond strength of lingual brackets with metal pads was higher than that of brackets with composite resin pads, due to the metal part being a single unit and welded. The failure location in the region between the bracket and the resin pad affected a higher percentage of the resin pads than the metal pads.

Debonding forces of different pads in a lingual bracket system

ABSTRACT Objective: To evaluate the shear bond strength of lingual orthodontic brackets with resin or metal pads, the location of bond failure and the adhesive remnant index (ARI). Methods: A total of 40 extracted upper premolars were randomly divided into two groups of 20 each: bonding with brackets having (1) pads with extended resin directly on the lingual surface of teeth, and (2) pads with metal custom base on the lingual surface of teeth. The debonding force was measured with an Instron universal testing machine. A Student's t-test was used to assess the difference between groups (α = 0.05). Results: The results showed a significant difference between the groups (p < 0.001). The shear bond strength of metal pads was significantly higher than resin pads. Conclusions: Within the limitations of this in vitro study, it was concluded that the bond strength of lingual brackets with metal pads was higher than that of brackets with composite resin pads, due to the metal part being a single unit and welded. The failure location in the region between the bracket and the resin pad affected a higher percentage of the resin pads than the metal pads.

RESUMO Objetivo: avaliar a resistência de união ao cisalhamento de braquetes ortodônticos linguais com pads em resina e metálicos, assim como os locais de ocorrência das falhas, além do Índice de Adesivo Remanescente (ARI). Métodos: 40 pré-molares superiores extraídos foram aleatoriamente divididos em dois grupos de 20 espécimes cada, para a colagem de braquetes com: 1) pads em resina, estendida diretamente na face lingual dos dentes; e 2) pads com base metálica customizada, na face lingual dos dentes. A força de descolagem dos braquetes foi mensurada por meio de uma máquina de ensaio universal (Instron). O teste t de Student foi utilizado para avaliar diferenças intergrupos (α = 0,05). Resultados: os resultados demonstram haver diferença significativa intergrupos (p < 0,001). A resistência de união ao cisalhamento dos pads metálicos foi significativamente maior em comparação aos pads em resina. Conclusões: dentro das limitações desse estudo in vitro, foi possível concluir que a resistência de união de braquetes linguais com pads metálicos foi superior à resistência de braquetes com pads em resina composta, uma vez que os pads metálicos customizados e os braquetes são fundidos, formando uma única unidade. A porcentagem de falhas de colagem na região entre o braquete e o pad foi maior para os pads em resina, em comparação aos pads metálicos.

Influence of different treatments of the ceramic surface and thermal cycling on the bond strength of brackets to ceramic / Influência de diferentes tratamentos de superfície da cerâmica e ciclagem térmica na resistência de união de bráquetes à cerâmica

Objective: To evaluate in vitro the effect of different treatments of the ceramic surface and thermal cycling on the shear bond strength (SBS) of metallic brackets bonded to feldspathic ceramic. Material and method: Ceramic cylinders were divided into four groups (n=4) according to the treatment of ceramic surface: G1-Clearfil Ceramic Primer silane and Transbond XT (CCPT); G2-etched with 10% hydrofluoric acid (HFA) for 60 s, CCP and Transbond XT (ACCPT); G3-etched with 10% HFA for 60 s, Ambar Adhesive and Transbond XT (AAAT); and, G4 - etched with 10% HFA for 60 s, RelyX Ceramic Primer silane -RCP, adhesive primer Transbond and Transbond XT (ACPPT). Brackets were bonded to the cylinders with Transbond XT and light-activated for 40 s with LED Radii Plus. All specimens were stored in deionized water at 37 °C for 24 h, and two cylinders from each group were subject to 7,000 thermal cycles in a thermal cycler (5 °C/55 °C). After storage and thermal cycling, the SBS test was performed at a crosshead speed of 1 mm/min. Data were subjected to two-way ANOVA and Tukey's post hoc test (α=0.05). Result: The SBS of ACCPT was significantly higher than the other groups (p<0.05). The specimens submitted to thermal cycling showed significantly lower SBS than those without thermal cycling (p<0.05), regardless the ceramic surface treatment. The ARI showed predominance of score 0 for all groups. Conclusion: Acid etching, CCP silane and Transbond XT method obtained the best results for bracket bonding. Thermal cycling reduced SBS for all groups. Score 0 was predominant for ARI in all groups.

Objetivo: Avaliar in vitro o efeito de diferentes tratamentos de superfície da cerâmica e ciclagem térmica na resistência da união ao cisalhamento (RUC) de bráquetes metálicos colados na cerâmica felspática. Material e método: Cilindros cerâmicos foram separados em 4 grupos (n=4) de acordo com os tratamentos da superfície da cerâmica: G1-Clearfil Ceramic Primer silano e Transbond XT (CCPT); G-condicionamento com ácido hidrofluorídrico a 10% (AHF) por 60s, CCP e Transbond XT (ACCPT); G3-condicionamento com AHF a 10% por 60s, Adesivo Ambar e Transbond XT (AAAT); e, G4 condicionamento com AHF a 10% por 60s, RelyX Ceramic Primer silano, primer adesivo Transbond e Transbond XT (ACPAT). Os bráquetes foram fixados nos cilindros com Transbond XT e fotoativado por 40s com LED Radii Plus. Todas as amostras foram armazenadas em água deionizada a 37 °C por 24 h e dois cilindros de cada grupo foram submetidos a 7.000 ciclos térmicos na máquina para ciclagem térmica (5 °C/55 °C). Após armazenagem e ciclagem térmica, a RUC foi realizada à velocidade de 1 mm/min. Na Análise de Variância de 2 fatores e ao teste de Tukey's post hoc test (α=0,05) a RUC do G2 foi significante maior do que dos demais grupos (p<0,05). Resultado: As amostras submetidas à ciclagem térmica apresentaram valores de RUC significantemente menores do que as amostras sem ciclagem térmica (p<0,05), independente do tratamento de superfície da cerâmica. Conclusão: Nas condições desse estudo o melhor resultado para colagem foi obtido com o condicionamento, silano CCP e Transbond XT. A ciclagem térmica reduziu a RUC em todos os grupos.

Avaliação da resistência da união de braquetes metálicos fixados utilizando diferentes fontes de luz e técnicas de fotoativação / Metal bracket bond strength of the evaluation set using different light sources and curing techniques

O objetivo foi avaliar a resistência de união de braquetes fixados com diferentes fontes de luz (halógena e LED) e técnicas de fotoativação (contínua e soft-start). Oitenta incisivos bovinos foram separados em quatro grupos (n=20): HC – fotoativação com lâmpada halógena e técnica contínua (40 s com 600 mW/cm2); HS – fotoativação com lâmpada halógena e técnica soft-start (8 s/150 mW/cm2 + 36 s/600 mW/cm2); LC – fotoativação com LED e técnica contínua (40 s/1.000 mW/cm2); LS – fotoativação com LED e técnica soft-start (8 s/250 mW/cm2 + 36 s/1.000 mW/cm2). Para colagem, foi utilizada resina Transbond XT e braquete metálico para incisivo central superior, prescrição Edgewise (Morelli). A resistência ao cisalhamento foi avaliada em máquina de ensaio (Instron 4411) com velocidade de 1 mm/min. Após a fratura, foi determinado o índice de remanescente adesivo (IRA) em lupa estereoscópica com magnificação de 40 vezes. Os dados de resistência de união (MPa) foram submetidos à análise de variância dois fatores eteste de Tukey com nível de significância de 5%. Os resultados mostraram que a fonte de luz não influenciou significativamente na resistência de união dos braquetes (p < 0,05). Entretanto, as amostras fotoativadas pela técnica soft-start apresentaram resistência de união ao cisalhamento significativamente menor, quando comparada à técnica contínua. A análise do índice de remanescente adesivo (IRA) mostrou que para todos os grupos não houve predominância de nenhum material aderido ao dente (escore 0). A menor frequência foi encontrada para o escore 3, onde todo o material fica aderido ao dente. Concluiu-se que para colagem de braquetes deve ser utilizada a técnica contínua, independente da fonte de luz, halógena ou LED...

The aim of this study was to evaluate the shear bond strength (SBS) of brackets fixed with different light sources (halogen lamp and LED) and photoactivation techniques (continuous and soft-start). Eighty bovine incisors were divided into four groups (n=20): G1 – photoactivation with halogen lamp (QTH) and continuous technique (40 s/600 mW/cm2); G2 – photoactivation with QTH and soft-start technique (8 s/150 mW/cm2 + 36 s/600 mW/cm2); G3 – photoactivation with LED and continuous technique (40 s/1.000 mW/cm2); G4 – photoactivation with QTH and soft-start technique (8 s/250 mW/cm2 + 36 s/1.000 mW/cm2). The bonding material was Transbond XT (3M) and metallic bracket for upper central incisor, Edgewise prescription (Morelli). After 24 h, the SBS was evaluated in a universal testing machine (Instron 4411) with 1 mm/min at crosshead speed. The adhesive remnant index (ARI) was verified after SBS test with stereoscopic microscope at 40X magnification. SBS data (MPa) were submitted to two-way Anova and Tukey’s test with 5% significance level. The results showed that light source had no influence on SBS (p < 0.05). However, the samples photoactivated with soft-start showed SBS significantly lower than continuous technique. The ARI evaluation showed that for all groups there was no predominance of material attached to the tooth (score 0) and the lowest frequency was found for the score 3, where all the material adheres to the tooth. It can be concluded that continuous light must be used to bonding brackets, independent of light source (halogen or LED)...

Influence of elastic chain in the degradation of orthodontic forces - in vitro study / Influência de elásticos corrente na degradação de forças ortodônticas – estudo in vitro

Introduction: Elastic chains are indispensable accessories in orthodontic treatment. Changes in their properties are of great interest to professionals in order to gain greater control over tooth movements. Objective: Evaluate the influence of trademark and length of the spacer chain on force degradation of elastic. Material and method: We used the following elastic chain types: TP, Rocky Mountain (RMO) and GAC short, medium and long varieties. The elastics, which contained links corresponding to 12.5 mm, were tensioned between steel pins using Instron 4411 universal testing machine up to 25 mm. The value was recorded. After initial measurement of the force, the elastics were fixed on an acrylic resin plate and kept distended to 25 mm. They were inserted in a container with deionized water and kept in an incubator at 37º. The elastic force data was collected at time intervals of 24 hours, 48 hours, 7 days, 14 days, 21 days and 28 days. These records were subjected to an appropriate statistical test, with significance level of 5%. Result: TP elastics showed significantly higher force in all periods. RMO and GAC elastics showed similar elastic forces. Short and long TP elastics exhibited significantly higher strength than the average elastic chain. As regards GAC and RMO, short elastics showed higher than average force values, and higher values than the long type. Conclusion: The spacer chain and the brand influenced the results, reinforcing the importance of knowledge of different types of elastic.

Introdução: Os elásticos corrente são acessórios indispensáveis no tratamento ortodôntico, e suas propriedades de grande interesse para o profissional, a fim de obter maior controle sobre os movimentos dos dentes. Objetivo: Avaliar a influência da marca comercial e comprimento da cadeia espaçadora de elásticos corrente na degradação de força. Material e método: Foram utilizadas ligaduras elásticas ortodônticas em cadeia, tipo curto, médio e longo das marcas: Rocky Mountain (RMO), TP e GAC. Os elásticos, contendo elos correspondentes a 12,5 mm, foram tensionados entre pinos de aço na máquina de ensaio universal Instron 4411 até 25 mm. O valor foi anotado. Após a aferição inicial da força, os elásticos foram fixados em placa de resina acrílica e mantidos distendidos a 25 mm. Foram inseridas em recipiente contendo água deionizada e mantidas em estufa a 37 °C. A leitura da força dos elásticos foi feita nos tempos de 24 horas, 48 horas, 7 dias, 14 dias, 21 dias e 28 dias. Os dados foram submetidos ao teste estatístico apropriado, com nível de significância de 5%. Resultado: Os elásticos TP apresentaram força significativamente maior em todos os períodos. Os elásticos GAC e RMO apresentaram forças estatisticamente semelhantes. Os elásticos TP cadeia curta e longa apresentaram força significativamente maior que os elásticos cadeia média. Para GAC e RMO os elásticos curto apresentaram força maior que os médios e este maior que os longos. Conclusão: A cadeia espaçadora e a marca comercial influenciaram nos resultados obtidos, reforçando a importância do conhecimento dos tipos de elástico.

Resistência de união ao esmalte com aplicação do adesivo na base do braquete / Shear bond strength to enamel after application of adhesive on the mesh of brackets

O objetivo deste estudo foi verificar o efeito da aplicação do adesivo na base do braquete, na resistência de união ao cisalhamento ao esmalte bovino. Um total de 160 incisivos bovinos foi condicionado com ácido fosfórico a 37% durante 30 segundos, e o adesivo Transbond XT Primer foi aplicado na base de retenção de 80 braquetes Edgewise para incisivo central superior, enquanto que nos demais braquetes as resinas compostas Transbond XT, Natural Ortho, Tetric Ceram e Z100 foram aplicadas diretamente na base de retenção. As amostras foram armazenadas em água a 37°C durante 24 horas e submetidas ao ensaio de resistência de união ao cisalhamento (RUC) em uma máquina de ensaio universal Instron 4411, com velocidade de 1,0 mm/min. Em seguida, foi avaliado o índice de remanescente adesivo (IRA). Os dados de RUC foram submetidos à Anova 2 fatores e teste de Tukey (α=0,05). A aplicação do Transbond XT Primer na base dos braquetes aumentou significativamente a RUC das resinas Transbond XT, Natural Ortho e Z100, mas diminuiu significativamente a RUC da Tetric Ceram. A maior RUC foi apresentada pela resina Transbond XT. Sem adesivo, a Tetric Ceram demonstrou RUC significativamente maior do que a Z100 e a Natural Ortho. Com adesivo na base do braquete, ocorreu o inverso. A adição do adesivo nos braquetes aumentou as falhas adesivas. Concluiu-se que a aplicação do adesivo na base dos braquetes é indicada para melhorar a união entre a resina e os braquetes...

The aim of this study was to investigate the effect of application of adhesive in the mesh of brackets on bond strength to enamel. One hundred and sixty bovine incisors were acid etched with 37% phosphoric acid for 30s. The adhesive system Transbond XT Primer was applied to the etched enamel and photo activated by LED Ultralume 5 for 10s. Resin composites Transbond XT, Natural Ortho, Tetric Ceram and Z100 were used to bond brackets to enamel. In the half of the sample adhesive Transbond XT Primer was applied to the mesh of brackets before bonding. Shear bond strength was evaluated after 24 h in a universal testing machine Instron 4411 at 1.0 mm/min crosshead speed. The adhesive remnant index (ARI) was evaluated after shear bond strength test. Data were submitted to two-way Anova and Tukey’s test (α=0.05). The use of adhesive in the mesh of brackets significantly increased the bond strength of Transbond XT, Natural Ortho and Z100; however, Transbond XT Primer applied in the mesh of bracket significantly decreased the bond strength of Tetric Ceram. Transbond XT showed significantly the highest shear bond strength. Transbond XT Primer increased the adhesive failures. It can be concluded that the use of adhesive in the mesh of brackets is a good alternative to improve the bond strength of resin to bracket...

Influence of bleaching and desensitizing gel on bond strength of orthodontic brackets.

OBJECTIVE: The objective of this study was to assess, in vitro, the influence of bleaching gel and the use of desensitizing agent over bond strength of ceramic brackets bonded to bovine enamel. METHODS: One hundred bovine incisors were selected and randomly divided into five groups (n = 20): Group 1, control group (without bleaching); Group 2, bleached with 35% hydrogen peroxide; Group 3, bleached with 35% hydrogen peroxide (three applications, 15 minutes each) and desensitizing agent applied for 10 minutes; Group 4, bleached with 35% hydrogen peroxide for 40 minutes; Group 5, bleached with 35% hydrogen peroxide for 40 minutes with desensitizing agent applied for 10 minutes. Brackets were bonded 7 days after bleaching and submitted to shear bond strength test after 24 hours at a compression rate of 1 mm/minute. After fracture, the adhesive remnant index (ARI) was assessed under stereoscopic at 40 x magnification. Shear strength data (MPa) were submitted to one-way ANOVA and Tukey's test with significance level set at 5%. RESULTS: Group 5 (29.33 MPa) showed significantly higher bond strength than Group 1 (19.19 MPa), Group 2 (20.59 MPa) and Group 4 (23.25 MPa), but with no difference in comparison to Group 3. There was no significant difference among the other groups. The adhesive remnant index showed predominance of score 3, that is, all resin remained adhered to enamel for all groups. CONCLUSION: Bleaching with 35% hydrogen peroxide with calcium associated with desensitizing agent application produced higher bond strength values of brackets bonded to bovine enamel.

Influence of bleaching and desensitizing gel on bond strength of orthodontic brackets

OBJECTIVE: The objective of this study was to assess, in vitro, the influence of bleaching gel and the use of desensitizing agent over bond strength of ceramic brackets bonded to bovine enamel. METHODS: One hundred bovine incisors were selected and randomly divided into five groups (n = 20): Group 1, control group (without bleaching); Group 2, bleached with 35% hydrogen peroxide; Group 3, bleached with 35% hydrogen peroxide (three applications, 15 minutes each) and desensitizing agent applied for 10 minutes; Group 4, bleached with 35% hydrogen peroxide for 40 minutes; Group 5, bleached with 35% hydrogen peroxide for 40 minutes with desensitizing agent applied for 10 minutes. Brackets were bonded 7 days after bleaching and submitted to shear bond strength test after 24 hours at a compression rate of 1 mm/minute. After fracture, the adhesive remnant index (ARI) was assessed under stereoscopic at 40 x magnification. Shear strength data (MPa) were submitted to one-way ANOVA and Tukey's test with significance level set at 5%. RESULTS: Group 5 (29.33 MPa) showed significantly higher bond strength than Group 1 (19.19 MPa), Group 2 (20.59 MPa) and Group 4 (23.25 MPa), but with no difference in comparison to Group 3. There was no significant difference among the other groups. The adhesive remnant index showed predominance of score 3, that is, all resin remained adhered to enamel for all groups. CONCLUSION: Bleaching with 35% hydrogen peroxide with calcium associated with desensitizing agent application produced higher bond strength values of brackets bonded to bovine enamel. .

OBJETIVO: o objetivo do presente estudo foi avaliar, in vitro, a influência do gel clareador e da utilização de dessensibilizante na resistência adesiva de braquetes cerâmicos colados ao esmalte bovino. MÉTODOS: cem incisivos bovinos foram aleatoriamente divididos em cinco grupos (n = 20). Grupo 1, sem clareamento (controle); Grupo 2, clareamento com peróxido de hidrogênio a 35%; Grupo 3, clareamento com peróxido de hidrogênio a 35%, sendo três aplicações de 15 minutos cada, e aplicação do dessensibilizante por 10 minutos; Grupo 4, clareamento com peróxido de hidrogênio a 35% durante 40 minutos; Grupo 5, clareamento com peróxido de hidrogênio a 35% durante 40 minutos e aplicação do dessensibilizante durante 10 minutos. Os braquetes foram colados sete dias após o clareamento e submetidos ao teste de resistência ao cisalhamento após 24 horas, a uma velocidade de compressão de 1mm/minuto. Após a fratura, avaliava-se o braquete, com lupa estereoscópica, com magnificação de 40x, e o Índice de Remanescente Adesivo (IRA). Os dados de resistência ao cisalhamento (MPa) foram submetidos à análise de variância e ao teste de Tukey, com nível de significância de 5%. RESULTADOS: os resultados mostraram que as amostras do Grupo 5 apresentaram resistência de união significativamente superior à dos grupos 1, 2 e 4, mas sem diferença do Grupo 3. Não houve diferença significativa entre a resistência de união dos demais grupos. O Índice de Remanescente Adesivo mostrou predominância do escore 3, ou seja, toda resina permaneceu aderida ao esmalte, para todos os grupos. CONCLUSÃO: pôde-se concluir que o clareamento com peróxido de hidrogênio a 35%, com cálcio associado à aplicação do dessensibilizante, produziu maior resistência dos braquetes ao esmalte bovino. .

Force decay in orthodontic elastomeric chains after immersion in disinfection solutions

Aim: To evaluate the force decay of orthodontic elastomeric chains after immersion in disinfecting solutions. Methods: One-hundred and fifty segments of elastomeric chains were divided in 3 groups: Control group - no disinfection; Chlorhexidine group - disinfection in 0.12% chlorhexidine digluconate solution; and Peracetic acid group - disinfection in 0.2% peracetic acid solution. Elastomeric chains of 14 mm were stretched up to 20 mm and the given force (kgf) was evaluated in an Instron universal testing machine at the following intervals: 1 h, 1 day, 7, 14, 21 and 28 days after the immersion in the disinfecting solutions. Data (kgf) were analyzed statistically by Analysis of Variance and Tukey's test at a 5% significance level. Results: Both groups presented similar force decay along 7 days and remained stable up to 28 days. Force degradation was observed in the first hours of activation (~50%). Conclusions: It may be concluded that there were no significant differences among the investigated groups, in most interval times, indicating that both chemical solutions can be used for previous disinfection of orthodontic elastomeric chains.

Correlação Entre o Ângulo Z e a Posição do Incisivo Inferior / Correlation between Angle Z and Lower Incisor Position

No presente trabalho o objetivo foi avaliar a correlação entre o ângulo Z de Merri e a posição do incisivo inferior (IMPA) nas maloclusões de Classe I, II, III esqueléticas, nos diferentes tipos faciais. A amostra consistiu de 135 telerradiografias de indivíduos do gênero feminino e masculino, com idades a partir de 18 anos, selecionados aleatoriamente nos arquivos de uma clínica privada na cidade de Canoinhas, Santa Catarina, Brasil. Os indivíduos foram classificados em três grupos: mesofacial, braquifacial e dolicofacial; cada um destes grupos foi subdividido em maloclusões de Classe I, II, III (n=15) esqueléticas. A partir das telerradiografias foram mensurados o Ângulo Z e o IMPA. Os dados foram submetidos à análise estatística utilizando-se o teste de correlação de Pearson (p<0,05). Os resultados mostraram que houve correlação negativa entre os ângulos Z e IMPA para os indivíduos Classe I e III mesofaciais e braquifaciais; para os indivíduos Classe II não houve correlação estatisticamente significante para nenhum dos três tipos faciais; para os indivíduos dolicofaciais também não houve correlação entre a linha do perfil e a posição do incisivo inferior.

The aim in this study was to evaluate the correlation between the Merri Z Angle and the position of the lower incisor (IMPA) in Class I, II, III malocclusion in different skeletal facial patterns. The sample consisted of 135 teleradiographs from males and females patients aged 18 years or older, randomly selected from a private orthodontic practice located in Canoinhas, Santa Catarina, Brazil. Subjects were classified into three groups (mesofacial, brachyfacial and dolichofacial) and subdivided into Class I, II, III skeletal malocclusion (n=15). The Angle Z and IMPA were measured in the teleradiographs. Data were statistically analyzed using the Pearson correlation test (p<0.05). The results showed a negative correlation between the Z Angle and IMPA for individuals Class I and III, mesofacial braquifacial; there was no statistically significant correlation for Class II individuals in any of the three facial types; there was also no correlation between the profile line and the lower incisor position for dolichofacial individuals.

Antimicrobial effect of Melaleuca alternifolia dental gel in orthodontic patients.

The aim of this study was to evaluate the antimicrobial effect and sensorial analysis of the gel developed with the essential oil of Melaleuca alternifolia. Thirty-four volunteers, divided into 2 groups, were monitored for 4 weeks. Initially, clinical biofilm (plaque index) and saliva samples (bacteria count) were collected, from which the standard values for each patient were obtained. For 7 days, group 1 used the melaleuca gel (Petite Marie/All Chemistry, São Paulo, Brazil), and group 2 used Colgate Total (S.B. Campo, São Paulo, Brazil). After 7 days, the plaque index was performed again, as well as the bacteria count and the sensorial analysis (appearance, color, odor, brightness, viscosity, and first taste sensation). The volunteers were instructed to return to their usual dental hygiene habits for 15 days. After this, group 1 started using Colgate Total, and group 2 started using the melaleuca gel, with the same evaluation procedures as the first week. The data were analyzed statistically with a significance level of 5%. In the bacteria count and clinical disclosure, the melaleuca gel was more effective in decreasing the dental biofilm and the numbers of bacteria colonies. According to the data from the sensory evaluation, Colgate Total (the control) showed better results regarding flavor and first sensation (P <0.05). We concluded that melaleuca gel is efficient in bacteria control but needs improvement in taste and first sensation.

Degradação e corrosão de bráquetes metálicos / Degradation and corrosion of metal brackets

Este estudo in vitro teve como objetivo analisar, por meio de microscopia ótica, as alterações superficiais de bráquetes metálicos submetidos ao processo de degradação química. Para este estudo foram utilizadas amostras de três diferentes bráquetes metálicos, separados de acordo com a marca (Morelli®, Aditek® e Abzil®) e soluções de imersão (solução salina 0,05%, saliva artificial, Coca-Cola®, suco de tomate e vinho). A superfície dos bráquetes foi avaliada inicialmente através do microscópico ótico e fotografada para avaliação qualitativa. Em seguida, os bráquetes foram imersos nas soluções por 15, 30 e 60 dias e as alterações decorrentes da exposição das amostras às soluções foram analisadas por meio do microscópico ótico em cada período (15, 30 e 60 dias). Os resultados mostraram que o vinho, Coca-Cola, suco de tomate e saliva artificial não causaram alterações na superficial dos bráquetes. Entretanto, a imersão em solução salina causou corrosão na superfície de todas as marcas avaliadas. Concluiu-se que a solução salina foi a única solução capaz de causar danos à superfície dos bráquetes metálicos, não havendo distinção entre as marcas comerciais dos bráquetes.

This in vitro study aimed to analyze, by means of optical microscopy, surface changes on metallic brackets subjected to chemical degradation process. For this study we have used samples from three different metallic brackets separated according to their brand (Morelli, Aditek e Abzil), and dip solutions (saline solution 0.05%, artificial saliva, Coca-Cola, tomato juice and wine). The surface of the brackets was initially evaluated by optical microscope and photographed for qualitative evaluation. Then, the brackets were immersed in the solutions for 15, 30 and 60 days. The changes resulting from exposure to the solutions were analyzed by optical microscope in each period (15, 30 and 60 days). The results showed that wine, Coca-Cola, tomato juice and artificial saliva did not cause changes in the surface of the brackets. However, immersion in saline solution caused corrosion on the surface of all brands studied. It was concluded that the saline solution was the only solution capable of damaging the surface of metal brackets, with no distinction among the tested brands.

Influência do clareamento dental na resistência da união de braquetes cerâmicos / Influence of dental bleaching on the bond strength of ceramic brackets

O objetivo neste estudo foi avaliar a influência do clareamentodentário sobre a resistência da união de braquetes ortodônticos decerâmica ao esmalte. Os dentes foram aleatoriamente separados emtrês grupos (n=20), sendo: Grupo 1(controle): os dentes não receberamnenhum tipo de agente clareador; Grupo 2: os dentes foram clareados ea colagem realizada 24 horas após o término do clareamento; Grupo 3:os dentes foram clareados e a colagem foi realizada sete dias apóso término do clareamento. Para o clareamento dentário dos Grupos 2e 3, foi utilizado o gel clareador Whitness HP Blue com cálcio a 35%- peróxido de hidrogênio 35%. Utilizou-se o agente clareador após aaplicação do dessensibilizante Dessensibilize a 2% KF,que foi mantidopor dez minutos. Para a colagem, os dentes foram condicionados porácido fosfórico 37% e fixados com o sistema adesivo Transbond XT.Foram utilizados braquetes de cerâmica fotoativados por 40 segundos.Após 24 horas, os corpos-de-prova foram submetidos ao teste decisalhamento com velocidade de compressão de 1 mmjminuto. Osdados foram submetidos à análise de Kruskal-Wallis e ao teste de Tukey(p < 0,05). Houve diferença significativa entre o grupo controle e ogrupo clareado e colado após 24 horas (p < 0,05), entretanto, o grupocolado após sete dias não diferiu significativamente dos demais grupos(p > 0,05). O índice de remanescente adesivo mostrou predominânciade escore 3, em que toda resina permaneceu aderida ao dente. Portanto,concluiu-se que após o clareamento dentário é indicado esperar,no mínimo, sete dias para a colagem dos braquetes ortodônticos.

The aim in this study as to evaluate the influence of dentalbleaching on the bond strength of ceramic brackets to enamel. The teethwere separated in three groups (n=20). Group 1 (control group): theteeth did not receive any bleaching agent; Group 2: the brackets werebonded 24 hours after dental bleaching; Group 3: the brackets werebonded seven days after dental bleaching. For the dental bleaching ofgroups 2 and 3 it was used Whitness HP Blue 35% with calcium (35%hydrogen peroxide). The bleaching agent was used after the applicationof the Desensitizer 2% KF, which was kept for ten minutes. For thebracket bonding, the teeth were conditioned by 37% phosphoric acidand fixed with the adhesive system Transbond XT. Ceramic bracketswere light activated for 40 seconds. After 24 hours the specimens weresubmitted to the shear bond strength test with a compression speedof 1 mmjminute. The data was submitted to the Kruskal-Wallis analysisand the Tukey test (p < 0.05). There was significant difference betweenthe control group and the group bleached and bonded after 24 hours(p < 0.05). However, the group bonded after seven days did not differsignificantly from the other groups (p > 0.05). The adhesive remnantindex showed a predominance of score 3, in which ali resin remainedattached to the tooth. Therefore, it is recommended to wait at leastseven days before bonding orthodontic brackets.

Effect of Activation Mode on Shear Bond Strength of Metallic Brackets

The aim of this study was to evaluate the shear bond strength (SBS) of metallic orthodontic brackets bonded to bovine teeth using light-activated or chemically activated composite resins. One hundred and twenty bovine mandibular incisors were divided into 6 groups (n=20), according to the bonding materials: Transbond XT (T); Enforce Dual (ED); Enforce chemical (EC); Enforce Light-activated (EL); Concise Orthodontic (C); and RelyX Unicem Capsule (UN). Metallic brackets were positioned and firmly bonded to the teeth. Light-activation for T, ED, EL and UN was carried out with four exposures on each side of the bracket with 20 s total exposure times using XL2500 (3M ESPE). EC and C were chemically cured. Next, all specimens were stored in deionized water at 37 °C for 24 h. The shear bond strength was carried out at a crosshead speed of 1.0 mm/min. Data were subjected to one-way ANOVA and Tukey's test (α=0.05). The adhesive remnant index (ARI) was evaluated at 8× magnification. C (17.72±4.45) presented significantly higher SBS means (in MPa) than the other groups (p<0.05), followed by EC (11.97±5.77) and ED (10.57±1.32). EL (5.39±1.06) and UN (4.32±1.98) showed the lowest SBS means, while T (9.09±2.56) showed intermediate values. For ARI, there was a predominance of score 0 for EC, C and UN, and score 3 for T, ED and EL. In conclusion, the activation mode influenced the SBS.

O objetivo deste estudo foi avaliar a resistência de união ao cisalhamento (RUC) de braquetes ortodônticos metálicos colados ao dente bovino utilizando resinas compostas ativadas por luz ou quimicamente ativadas. Cento e vinte incisivos mandibulares bovinos foram divididos em 6 grupos (n=20), de acordo com o material de colagem: Transbond XT (T); Enforce Dual (ED); Enforce químico (EC); Enforce ativado por luz (EL); Concise Ortodontico (C); e RelyX Unicem Capsula (UN). Braquetes metálicos foram posicionados e firmemente colados aos dentes. A ativação por luz para os grupos T, ED, EL e UN foi realizada em quatro exposições, sendo uma em cada lado do braquete, para um tempo total de exposição de 20 s usando o aparelho XL2500 (3M ESPE). Os grupos EC e C foram ativados quimicamente. Após, todas as amostras foram armazenadas em água deionizada a 37 °C por 24 h. O teste de resistência de união ao cisalhamento foi realizado após o período de armazenagem, à velocidade de 1 mm/minuto. Os dados foram submetidos à Análise de Variância e ao teste de Tukey (α=0,05). O índice de remanescente adesivo (IRA) foi avaliado em aumento de 8x. O valor de RUC (MPa) do grupo C (17,72±4,45) foi significantemente maior do que o de outros grupos (p<0,05), seguido pelo grupo EC (11,97±5,77) e ED (10,57±1,32). Os menores valores de RUC foram obtidos pelos grupos EL (5,39±1,06) e UN (4,32±1,98). O grupo T (9,09±2,56) apresentou valor intermediário. O IRA mostrou predominância de escore 0 para os grupos EC, C e UN e escore 3 para os grupos T, ED e EL. Em conclusão, o modo de ativação influenciou nos valores da RUC.

Effect of elastomeric ligatures on frictional forces between the archwire and orthodontic bracket

Aim: To evaluate the frictional force between the archwire and orthodontic bracket generated by elastomeric ligatures with polymer coating (Super slick, TP Orthodontics) and conventional ligatures (Morelli) using two types of insertion techniques. Methods: Forty elastomeric ligatures, 20 with polymer coating and 20 conventional, were evaluated. Each type of ligature was separated into two groups (n=10), according to the insertion mode: conventional or crossed (from mesial to distal region crossed in front). To analyze friction, 40 5-cm-long segments of stainless steel orthodontic archwire 0.019" x 0.025" (Morelli) and Edgewise brackets (slot 0.022" x 0.028"; Morelli) were used. Each set (bracket, wire and elastic) was submitted to frictional testing in a universal test machine (Instron 4411) at a crosshead speed of 5 mm/min. Each bracket was moved 5 mm on the wire, with maximum friction and mean friction being recorded by software. Three readouts were taken for each bracket. Data were submitted to two-way ANOVA and Tukey’s test (p<0.05). Results: It was shown that for maximum and mean friction, the polymer-coated ligature did not differ statistically from the conventional type in a dry environment condition. Ligatures placed incrossed mode promoted significantly greater friction than those placed in conventional mode, irrespective of the type of elastomeric ligature. Conclusions: Friction depended on the insertion mode, but not on the type of elastomeric ligature.

Preparo ortodôntico em cirurgia ortognática / Orthodontic preparation in orthognathic surgery: clinical case report

A deformidade dentofacial é um problema severo de má-oclusão, que pode provocar alterações na estética facial, problemas mastigatórios, desordens temporomandibulares, alterações na respiração e na fala. O tratamento desta má-oclusão, na idade adulta, envolve a correção ortodôntica combinada com a cirurgia ortognática. O preparo ortodôntico-cirúrgico merece considerável atenção em relação às descompensações dentárias, com a finalidade de permitir correto posicionamento das bases ósseas durante a cirurgia ortognática. O objetivo deste trabalho foi discorrer sobre os pontos importantes do preparo ortodôntico-cirúrgico, a fim de permitir uma adequada correção estética e funcional da oclusão.

Dentofacial deformity is a severe problem of malocclusion that may cause alterations in facial esthetics, masticatory problems, temporomandibular disorders, alteration in respiration and speech. Treatment of this malocclusion at an adult age involves orthodontic correction combined with orthognathic surgery. Orthodontic-surgery preparation deserves considerable attention as regards dental decompensations, with the purpose of allowing correct positioning of the bony bases during orthognathic surgery. The aim of this study is to discourse about important points of orthodontic-surgery preparation, in order to allow adequate static and functional correction of the malocclusion.

Effect of activation mode on shear bond strength of metallic brackets.

The aim of this study was to evaluate the shear bond strength (SBS) of metallic orthodontic brackets bonded to bovine teeth using light-activated or chemically activated composite resins. One hundred and twenty bovine mandibular incisors were divided into 6 groups (n=20), according to the bonding materials: Transbond XT (T); Enforce Dual (ED); Enforce chemical (EC); Enforce Light-activated (EL); Concise Orthodontic (C); and RelyX Unicem Capsule (UN). Metallic brackets were positioned and firmly bonded to the teeth. Light-activation for T, ED, EL and UN was carried out with four exposures on each side of the bracket with 20 s total exposure times using XL2500 (3M ESPE). EC and C were chemically cured. Next, all specimens were stored in deionized water at 37 °C for 24 h. The shear bond strength was carried out at a crosshead speed of 1.0 mm/min. Data were subjected to one-way ANOVA and Tukey's test (α=0.05). The adhesive remnant index (ARI) was evaluated at 8× magnification. C (17.72 ± 4.45) presented significantly higher SBS means (in MPa) than the other groups (p<0.05), followed by EC (11.97 ± 5.77) and ED (10.57 ± 1.32). EL (5.39 ± 1.06) and UN (4.32 ± 1.98) showed the lowest SBS means, while T (9.09 ± 2.56) showed intermediate values. For ARI, there was a predominance of score 0 for EC, C and UN, and score 3 for T, ED and EL. In conclusion, the activation mode influenced the SBS.

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.