Deflection of tandem archwire in a specific self-ligating metal bracket system: an in vitro study.

The aim of this study was to quantify the force exerted by tandem archwires in a specific system of passive self-ligating bracket. Forty-eight thermo-activated nickel-titanium orthodontic archwires were separated into four groups (n = 12): G1 - two .014" + .014" round archwires; G2 - two .014" + .016" round archwires; G3 - .014" x .025" rectangular archwire; and. G4 - .016" x .022" rectangular archwire. Brackets were fixed onto teeth 1.5 to 2.5 using a device that represented the upper teeth, maintaining an interbracket distance of 6.0 mm. The deflection tests were performed using the structure representative of tooth 1.1 as support on the Instron testing machine at a speed of 2.0 mm/min. The archwires were evaluated at deflections of 0.5 mm, 1.0 mm, and 1.5 mm. The data were analyzed by a generalized linear model, considering values at different deflections as repeated measurements in the same experimental unit (α = 0.5%). At 0.5 mm, higher forces were observed in G2 and G3, which did not differ significantly (p > 0.05). The lowest force was observed in G4 (p < 0.05). At 1.0 mm and 1.5 mm, the highest force was observed in G3, followed by G4 and G2 (p < 0.05). The lowest force was observed in G1 (p < 0.05). In general, tandem archwires (same or different calibers) in a specific passive self-ligating bracket exerted lower force when compared with rectangular archwires.

Relationship between aesthetic concern and self-esteem in adolescents with severe malocclusion.

OBJECTIVE: This study aimed to evaluate the relationship between aesthetic concern and self-esteem in adolescents with severe malocclusion. METHODS: A cross-sectional study developed with 543 adolescents from 11 to 13 years of age and severe malocclusion was selected. Dental aesthetic index (DAI) diagnosed the malocclusion and selected the groups with greater severity (DAI 3 and 4). Aesthetic concern was assessed using the oral aesthetic subjective impact scale (OASIS) and considered an outcome variable. The global negative self-evaluation (GSE) evaluated self-esteem. The variables were analysed using Poisson multiple regression and the model adjustment determined by the Akaike information criterion (AICC). The effect of each variable on OASIS was expressed as a prevalence ratio (PR) with 95% confidence intervals. The analyses were performed using the R program with a significance level of 5%. RESULTS: A significant association was observed between aesthetic concern scores and self-esteem (p<.05). Individuals with low self-esteem had OASIS scores 14% higher (PR: 1.14; 95% CI: 1.08-1.21). There was no significant association between OASIS and gender and age (p>.05). CONCLUSIONS: Self-esteem modulates how the individual perceives malocclusion. Adolescents with severe and very malocclusion and low self-esteem have greater aesthetic concerns.

Deflection of tandem archwire in a specific self-ligating metal bracket system: an in vitro study

Abstract The aim of this study was to quantify the force exerted by tandem archwires in a specific system of passive self-ligating bracket. Forty-eight thermo-activated nickel-titanium orthodontic archwires were separated into four groups (n = 12): G1 - two .014" + .014" round archwires; G2 - two .014" + .016" round archwires; G3 - .014" x .025" rectangular archwire; and. G4 - .016" x .022" rectangular archwire. Brackets were fixed onto teeth 1.5 to 2.5 using a device that represented the upper teeth, maintaining an interbracket distance of 6.0 mm. The deflection tests were performed using the structure representative of tooth 1.1 as support on the Instron testing machine at a speed of 2.0 mm/min. The archwires were evaluated at deflections of 0.5 mm, 1.0 mm, and 1.5 mm. The data were analyzed by a generalized linear model, considering values at different deflections as repeated measurements in the same experimental unit (α = 0.5%). At 0.5 mm, higher forces were observed in G2 and G3, which did not differ significantly (p > 0.05). The lowest force was observed in G4 (p < 0.05). At 1.0 mm and 1.5 mm, the highest force was observed in G3, followed by G4 and G2 (p < 0.05). The lowest force was observed in G1 (p < 0.05). In general, tandem archwires (same or different calibers) in a specific passive self-ligating bracket exerted lower force when compared with rectangular archwires.

Esthetic impact of maxillary midline diastema and mandibular crowding in children in the mixed dentition.

INTRODUCTION: This study aimed to investigate the esthetic impact of mandibular crowding and maxillary midline diastema in children in the mixed dentition. METHODS: The sample for this cross-sectional study comprised 785 children, aged 8-10 years, in the late mixed dentition. Mandibular crowding and maxillary midline diastema were evaluated clinically with the Dental Aesthetic Index. Mandibular crowding and maxillary midline diastema were evaluated to determine tooth size-arch length discrepancies. The sample was stratified as group 1, children without maxillary midline diastema or mandibular crowding (n = 177); group 2, children with maxillary midline diastema (n = 256); group 3, children with mandibular crowding (n = 208); and group 4, children with maxillary midline diastema and mandibular crowding (n = 144). The subjective esthetic impact was evaluated using the Orthodontic Aesthetic Subjective Impact Score. Descriptive and exploratory analyses of the data were performed. A generalized linear model was applied, adjusted for the possible confounding variables (age, gender, and race) with a significance level of 5% because the Orthodontic Aesthetic Subjective Impact Score did not meet the assumptions of analysis of variance. RESULTS: Children in groups 2 and 3 showed greater esthetic concern than group 1 (P <0.05). Children in groups 2 and 3 did not show a significant difference with children in group 4 (P >0.05). CONCLUSIONS: Children with mixed dentition with mandibular crowding or maxillary median diastema reported significantly more esthetic concern than children without these conditions.

Influência da cor e dos ciclos de estiramento na degradação da força dos elásticos intermaxilares / Influence of the color and the stretching cycles in the force degradation of intermaxillary elastics

Resumo Este estudo in vitro teve como objetivo avaliar a força liberada por elásticos ortodônticos coloridos e naturais e a degradação da força ao longo de 24 horas. No total foram utilizados 40 elásticos com força leve, divididos em quatro Grupos (n = 10) de acordo com o diâmetro (1/4 pol. e 3/16 pol.) e cor (elásticos com borracha natural e elásticos coloridos). Para causar fadiga nos elásticos, foi utilizada uma máquina de ensaio simulando movimentos mandibulares. As leituras da força elástica foram feitas na máquina de Teste Universal Instron 4411 nos intervalos de tempo de 1, 4, 15 e 24 horas. Os dados de redução da força foram analisados pelo teste de Tukey (a= 5%). Os resultados demonstraram redução da força ao longo do tempo em todos os grupos, com o elástico colorido de 1/4 de polegada de diâmetro apresentando força significativamente maior do que o de borracha natural em todos os intervalos de tempo. Já os elásticos de 3/16 polegadas de diâmetro, apesar de apresentarem degradação de força, não apresentaram diferença significativa para os tipos de cor. Elásticos coloridos e de cor natural, de ambos os diâmetros, apresentaram degradação da força ao longo de 24 horas, porém os elásticos coloridos de 1/4 de polegada de diâmetro apresentaram valores de força superiores aos da cor natural (AU)

Abstract This in vitro study aimed to evaluate the force released by orthodontic colored and natural elastics and the degradation of force over the course of 24 hours. In total 40 elastics with light force were used, divided into four Groups (n=10) according to their diameter (1/4 inch and 3/16 inch) and color (elastics with natural rubber color and colored elastics). To cause fatigue on the elastics, a test machine simulating mandibular movements was used. The elastic force readouts were taken on the Instron 4411 Universal Test Machine in the intervals of 1, 4, 15 and 24 hours. The reduction in force data was analyzed by the Tukey test (a= 5%). The results demonstrated a reduction in force over the course of time in all the groups, with the colored elastic 1/4 inch in diameter showing significantly higher force than those of natural rubber color in all the time intervals. While the 3/16 inch diameter elastics, although showing degradation of force, did not show significant difference for types of color. Colored and natural elastics, of both diameters, showed degradation of force over 24 hours, however, the colored 1/4 inch diameter elastics showed higher force values than those of the natural color (AU)

Avaliação do tratamento de superfície de resina composta na resistência de união de bráquetes metálicos / Evaluation of composite resin surface treatment in the union resistance of metallic brackets

O objetivo deste estudo experimental in vitro foi avaliar a Resistência de União ao Cisalhamento (RUC) da colagem de bráquetes em diferentes tratamentos de superfície de resina composta, associados a dois agentes de união. Foram confeccionados 90 corpos de prova com resina composta Filtek Z350 (3M/ESPE). Os corpos de prova foram aleatoriamente divididos em nove grupos (n=10): (1) grupo controle; (2) silano e primer; (3) adesivo universal (5) ácido fosfórico, silano e primer (4) ácido fosfórico, adesivo universal; (6) ácido fluorídrico, silano e primer; (7) ácido fluorídrico e adesivo universal; (8) broca, silano e primer e (9) broca e adesivo universal. Em seguida, foi aplicado na superfície de colagem do bráquete metálico (Standart Edgewise para incisivo central superior ­ Morelli, Sorocaba/SP) a resina ortodôntica Transbond XT/3M. O bráquete foi colado na resina composta Filtek Z350 (3M/ESPE). Após 24 horas foram submetidos ao teste de cisalhamento na máquina Instron, com velocidade de 0,5mm/min. Os dados foram submetidos à ANOVA e teste de Tukey. Em seguida foi avaliado o Índice de Remanescente Adesivo (IRA). Não houve diferença significativa entre os agentes de união quanto à resistência de união (p>0,05). Os oito grupos que receberam agentes de união apresentaram resistência significativamente maior do que o grupo controle (p<0,05). O grupo preparado com ácido fluorídrico apresentou menor resistência que os preparados com ácido fosfórico (com silano + primer transbond) e broca diamantada (com silano + primer transbond e com adesivo universal), p<0,05. Concluiu-se que o tratamento de superfície influencia na resistência de união. (AU)

Abstract The aim of this in vitro experimental study was to evaluate the shear bond strength of bracket bonding in different composite resin surface treatments associated with two bonding agents. Ninety specimens were made with Filtek Z350 composite resin (3M/ESPE). The specimens were randomly divided into nine groups (n=10): (1) control group; (2) silane and primer; (3) universal adhesive (5) phosphoric acid, silane and primer (4) phosphoric acid, universal adhesive; (6) hydrofluoric acid, silane and primer; (7) hydrofluoric acid and universal adhesive; (8) drill, silane and primer and (9) universal drill and adhesive. Transbond XT/3M orthodontic resin was then applied to the bonding surface of the metal bracket (Standart Edgewise for upper central incisor ­ Morelli, Sorocaba/SP). The bracket was bonded to the Filtek Z350 composite resin (3M/ ESPE). After 24 hours they were submitted to the shear bond test on the Instron machine at a speed of 0.5mm/min. Data were submitted to ANOVA and Tukey test. Then the Adhesive Remnant Index (ARI) was evaluated. There was no significant difference between bonding agents regarding bond strength (p> 0.05). The eight groups that received bonding agents showed significantly higher resistance than the control group (p <0.05). The group prepared with hydrofluoric acid presented lower resistance than those prepared with phosphoric acid (with silane + transbond primer) and diamond drill (with silane + transbond primer and universal adhesive), p <0.05. It was concluded that the surface treatment influences the bond strength.(AU)

Do dental bleaching sessions prior to orthodontic treatment change the bond strength of esthetic brackets?

OBJECTIVE: The aim of this experimental in vitro study was to evaluate whether dental bleaching performed before orthodontic treatment change the shear bond strength (SBS) of monocrystalline and polycrystalline esthetic brackets. METHODS: Sixty (60) bovine incisors teeth were used and randomly divided into the following six groups (n=10): SCP (without bleaching/polycrystalline brackets); SCM (without bleaching/monocrystalline brackets); 1CP (one bleaching session/polycrystalline brackets); 1CM (one bleaching session/monocrystalline brackets); 3CP (three bleaching sessions/polycrystalline brackets); and 3CM (three bleaching sessions/monocrystalline brackets). The brackets were bonded seven days after the bleaching sessions. The samples were submitted to the SBS test in a universal testing machine (Instron model 4411) at 1 mm/min crosshead speed. The two-way analysis of variance (ANOVA) and the Tukey tests were performed at a 5% level of significance. After the mechanical test, samples were evaluated to determine the adhesive remnant index (ARI). RESULTS: The SBS values were significantly higher for the monocrystalline brackets, when compared with the polycrystalline type (p< 0.0001), and significantly higher with three bleaching sessions than without bleaching (p< 0.0436). The ARI showed predominance of failures between the bracket and resin for all the groups (score 3). CONCLUSION: Three dental bleaching sessions increased the SBS values. Monocrystalline brackets showed higher SBS values than the polycrystalline type.

Comparison of friction of metallic and ceramic brackets during sliding mechanics after prophylaxis with sodium bicarbonate jet: An in vitro study.

OBJECTIVE: An in vitro experimental study was carried out with the objective to compare the friction in aesthetic and metallic brackets after prophylaxis with sodium bicarbonate jet during sliding mechanics. MATERIAL AND METHODS: Aesthetic monocrystalline (n=24) and polycrystalline (n=24) and metallic brackets (n=24) were used. Each group of brackets was divided into two groups, as follows: the first group received prophylaxis with a bicarbonate jet, while the second group did not. An acrylic plate was attached to the base fixature of the Instron 4411 universal testing machine, simulating the retraction movement of the canine during sliding mechanics. The bracket was pulled at a speed of 0.5mm/minute over a distance of 0.5mm. The data were analysed by analysis of variance (ANOVA) and Tukey test. RESULTS: After the sodium bicarbonate jet, conventional metal brackets showed less friction (P<0.05). While the aesthetic brackets did not show significant difference in friction between the exposed and non-exposed groups with the sodium bicarbonate jet (P>0.05), the polycrystalline brackets showed greater friction when compared to the other groups of brackets. CONCLUSIONS: It was concluded that prophylaxis with sodium bicarbonate jet did not influence the resistance to friction in aesthetic brackets; however, metal brackets showed a significant decrease in friction after prophylaxis with sodium bicarbonate jet. Our results suggest that the abrasion of the sodium bicarbonate particles can cause micromorphological changes, which may influence the friction; however, studies with scanning electron microscopy are necessary.

Can orthodontic need cause bullying? / A necessidade de ortodontia pode causar bullying?

ABSTRACT Objective: To determine the association between orthodontic treatment need and the self-reported bullying, and its impact on adolescents' self-esteem. Methods: The sample consisted of 160 schoolchildren from 11 to 14 years of age, enrolled in public schools. The history of bullying was evaluated by means of the Crozier; Dimmock adapted Questionnaire (1999). Self-esteem was determined by means of the Global Negative Self-Evaluation Scale (GSE). The normative orthodontic treatment need was determined by the Dental Health Component (DHC) and perceived need, by Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN). Individual analyses were made of the associations with the history of bullying (outcome). Results: The variables that presented P ? 0.20 in the individual analyses were tested in a multiple logistic regression model, and variables with P ? 0.05 remained in the model. The odds ratios with the intervals of confidence were estimated. According to the results 72.5% of the schoolchildren reported a history of bullying. The schoolchildren who presented negative impact on the quality of life related to oral symptoms and negative self-esteem were observed to have 4.59 and 5.44 times more chance, respectively to report a history of bullying (P < 0.05), which did not suffer the influence of normative and perceived orthodontic treatment need. Conclusion: The history of bullying was not influenced by orthodontic treatment need, but by the low self-esteem of adolescents.

RESUMO Objetivos: Determinar a associação entre a necessidade de tratamento ortodôntico e o bullying autorrelatado e seu impacto na autoestima dos adolescentes. Métodos: A amostra foi composta por 160 escolares de 11 a 14 anos, matriculados em escolas públicas. A história de bullying foi avaliada por meio do Questionário Crozier; adaptado por Dimmock (1999). A autoestima foi determinada por meio do Global Negative Self-Evaluation Scale (GSE). A necessidade normativa de tratamento ortodôntico foi determinada pelo Componente de Saúde Bucal (DHC) e a necessidade percebida, pelo Componente Estético (AC) do Índice de Necessidade de Tratamento Ortodôntico (IOTN). Foram realizadas análises individuais das associações com a história de bullying (desfecho). Resultados: As variáveis que apresentaram P ? 0.20 nas análises individuais foram testadas em modelo de regressão logística múltipla, permanecendo no modelo as variáveis com P ? 0.05. Foram estimados os odds ratios com os intervalos de confiança. De acordo com os resultados, 72.5% dos escolares relataram história de bullying. Os escolares que apresentaram impacto negativo na qualidade de vida relacionado aos sintomas bucais e autoestima negativa tiveram 4.59 e 5.44 vezes mais chance, respectivamente, de relatarem história de bullying (P < 0.05), e não sofreram influência da necessidade de tratamento ortodôntico normativa e percebida. Conclusão: A história de bullying não foi influenciada pela necessidade de tratamento ortodôntico, mas pela baixa autoestima dos adolescentes.

Influence of topical fluoride on shear bond strength of orthodontic brackets and enamel white spot lesions formation / Influência do flúor tópico na resistência ao cisalhamento de braquetes ortodônticos e na formação de lesões de manchas brancas no esmalte

Introduction Fluoride is considered a key element in the remineralization process of tooth enamel. Objective To evaluate the influence of a topical solution of sodium fluoride (NaF) on the shear bond strength of orthodontic brackets and white spot lesions formation. Material and method Sixty bovine teeth were divided into three groups (n=20). Group 1 (Control): shear bond strength; Group 2: shear bond strength after pH cycling; Group 3: shear bond strength after pH cycling and treatment with 0.04% NaF solution. Groups 2 and 3 underwent pH cycling with demineralizing (6hs) and remineralizing (17hs) solutions at pH of 4.3 and 7.0 respectively for 15 days. The specimens were submitted to the shear bond strength and the Adhesive Remnant Index was verified (ARI). The specimens of each group (n=3) were qualitatively analyzed by means of Scanning Electron Microscopy (SEM). Kruskal-Wallis test assessed the shear bond strength and Fisher's exact test evaluated ARI, with significance level of 5%. Result There was no significant difference among the three groups in shear bond strength (p=0.2679). Significant difference was found in ARI (p=0.0199). The frequency of ARI 1 was 55% in group 1, 90% in group 2, and 80% in group 3. SEM showed difference between the enamel and bonding. Group 2 showed structural change of the enamel surface, adjacent to the bond area; and group 3 showed enamel with characteristics similar to those of group 1. Conclusion It was concluded that there was no NaF influence on the bracket shear bond strength and even in low concentrations it prevented the development of areas of demineralization of white spot lesions.

Introdução O flúor é considerado um elemento chave no processo de remineralização do esmalte dentário. Objetivo Este estudo teve como objetivo avaliar a influência da solução tópica de fluoreto de sódio (NaF) na resistência ao cisalhamento da colagem de barquetes ortodônticos durante a formação de lesões de manchas brancas. Material e método Sessenta dentes bovinos foram divididos em três grupos (n=20). Grupo 1 (Controle) - Cisalhamento imediato; Grupo 2 - Cisalhamento após ciclagem de pH; Grupo 3 - Cisalhamento após ciclagem de pH e tratamento com solução de 0,4% de NaF (Ortho Gard, Colgate-Palmolive®). Os Grupos 2 e 3 sofreram ciclagem de pH com soluções de desmineralização e remineralização em pH de 4,3 e 7,0 respectivamente, com ciclos de desmineralização (6 horas) e remineralização (17 horas), durante 15 dias. Os corpos de prova foram submetidos ao teste de resistência de união ao cisalhamento e remanescente adesivo (IRA). Espécimes de cada grupo (n=3) foram analisados qualitativamente por microscopia eletrônica de varredura (MEV). O teste de Kruskal-Wallis foi utilizado para avaliar a resistência ao cisalhamento e o teste exato de Fisher para avaliação do IRA, adotando nível de significância de 5%. Resultado Os resultados não encontraram diferença significativa entre os três grupos quanto à força de cisalhamento (p=0,2679). Diferença significativa foi encontrada no IRA (p = 0,0199). A frequência de IRA 1 foi de 55% no grupo 1, 90% no grupo 2 e 80% no grupo 3. A análise em MEV mostrou diferença entre o esmalte e a área de colagem submetida ao cisalhamento. Grupo 2 apresentou alteração estrutural na superfície do esmalte adjacente à área de colagem, e o Grupo 3 apresentou esmalte com característica semelhante ao do Grupo 1 na área que foi submetida à ciclagem de pH e NaF. Conclusão Concluiu-se que não houve influência do flúor na resistência ao cisalhamento de braquetes. O uso de soluções fluoretadas, ainda que em baixa concentração, preveniu o aparecimento de áreas desmineralizadas e lesões de manchas brancas.

Does dental trauma in early childhood have the potential to affect the quality of life of children and families? / Os traumatismos dentários na primeira infância têm potencial para afetar a qualidade de vida das crianças e das famílias?

ABSTRACT Objective: To evaluate the influence of dental trauma on oral health-related quality of life (OHRQoL) of children and their families. Methods: A total of 571 children aged five years were randomly selected at public schools. Trauma was clinically evaluated in accordance with the Andreasen classification. Caries experience in the anterior region and increased overjet were determined according to the World Health Organization criteria. The Early Childhood Oral Health Impact Scale (ECOHIS) was answered by the parents and used to evaluate OHRQoL. In addition, this questionnaire has aspects related to socioeconomic status. Simple logistic regression was performed, and the raw Odds Ratios with the respective 95% confidence intervals (95%CI) were estimated. The variables with p<0.20 were tested in multiple logistic regression models, and those with p≤0.05 remained in the model and the adjusted odds ratio with respective 95%CI was estimated. Results: Income showed a magnitude of association of 1.56 and 2.70 with the OHRQoL of children and families, respectively. The avulsion variable showed 9.65- and 8.25-times greater chance of influencing the OHRQoL of children and families, respectively. The experience of caries showed 3.80- and 2.42-times greater chance of influencing the OHRQoL of children and families, respectively. Conclusions: Dental trauma did not influence OHRQoL of children and their families negatively. However, avulsion and caries experience in low-income families was associated with a negative perception of OHRQoL.

RESUMO Objetivo: Avaliar a influência do traumatismo dentário na qualidade de vida relacionada à saúde bucal (QVRSB) de crianças e suas famílias. Métodos: 571 crianças de 5 anos de idade foram aleatoriamente selecionadas de escolas públicas. O trauma foi avaliado clinicamente de acordo com a classificação de Andreasen. A experiência de cárie na região anterior e a presença de overjet foram determinadas com base nos critérios da Organização Mundial da Saúde. A versão brasileira do questionário ECOHIS (Escala de Impacto na Saúde Oral na Primeira Infância) avaliou a QVRSB e foi respondida pelos pais; além disso, foram avaliados aspectos socioeconômicos. Realizou-se uma regressão logística simples, bem como as razões de chances brutas com os respectivos intervalos de confiança de 95%. As variáveis ​​com p <0,20 foram testadas nos modelos de regressão logística múltipla, e aquelas com p≤0,05 permaneceram no modelo. Resultados: A renda mostrou uma magnitude de associação de 1,56 e 2,70 com a QVRSB das crianças e famílias, respectivamente. A variável avulsão apresentou chance 9,65 e 8,25 vezes maior de influenciar a QVRSB de crianças e famílias, respectivamente. A experiência de cárie mostrou chance 3,80 e 2,42 vezes maior de influenciar a QVRSB de crianças e famílias, respectivamente. Conclusões: O trauma dental não influenciou negativamente a QVRSB das crianças e suas famílias. Entretanto, especificamente a avulsão, e a experiência de cárie nos dentes anteriores em famílias de baixa renda estiveram associadas a uma percepção negativa da QVRSB.

DOES DENTAL TRAUMA IN EARLY CHILDHOOD HAVE THE POTENTIAL TO AFFECT THE QUALITY OF LIFE OF CHILDREN AND FAMILIES?

OBJECTIVE: To evaluate the influence of dental trauma on oral health-related quality of life (OHRQoL) of children and their families. METHODS: A total of 571 children aged five years were randomly selected at public schools. Trauma was clinically evaluated in accordance with the Andreasen classification. Caries experience in the anterior region and increased overjet were determined according to the World Health Organization criteria. The Early Childhood Oral Health Impact Scale (ECOHIS) was answered by the parents and used to evaluate OHRQoL. In addition, this questionnaire has aspects related to socioeconomic status. Simple logistic regression was performed, and the raw Odds Ratios with the respective 95% confidence intervals (95%CI) were estimated. The variables with p<0.20 were tested in multiple logistic regression models, and those with p≤0.05 remained in the model and the adjusted odds ratio with respective 95%CI was estimated. RESULTS: Income showed a magnitude of association of 1.56 and 2.70 with the OHRQoL of children and families, respectively. The avulsion variable showed 9.65- and 8.25-times greater chance of influencing the OHRQoL of children and families, respectively. The experience of caries showed 3.80- and 2.42-times greater chance of influencing the OHRQoL of children and families, respectively. CONCLUSIONS: Dental trauma did not influence OHRQoL of children and their families negatively. However, avulsion and caries experience in low-income families was associated with a negative perception of OHRQoL.

Flexural strength and surface microhardness of materials used for temporary dental disocclusion submitted to thermal cycling: An in vitro study.

OBJECTIVE: The objective of this study was to evaluate the effect of temperature variation on surface microhardness and resistance to flexion of different materials used for making a temporary dental disocclusion. METHODS: One hundred specimens were made of the following materials (n=20): glass ionomer cement (GIC); compomer (CP); composite resin (CR); Blue colour resin composite for temporary dental disocclusion (BTDD); ultraviolet colour resin composite for temporary dental disocclusion (UVTDD). They were stored in distilled water for 24hours and, subsequently, half of the specimens in each group were subjected to thermal cycling (n=10). All samples were subjected to the microhardness test (HMV-2000) and the flexural strength analysis (INSTRON). The data were submitted to parametric statistical analysis (ANOVA) and Tukey's complementary test with a significance level of 5%. In the mechanical tests, all materials except the GIC showed a statistically significant difference between the groups subjected to thermal cycling and not submitted, and thermal cycling (P<0.05) was responsible for the reduction of the values found, except for GIC. RESULTS: In the mechanical tests, all materials except the GIC showed a statistically significant difference between the groups subjected to thermal cycling and not submitted, and thermal cycling (P<0.05) was responsible for the reduction of the values found, except for GIC. For microhardness, the highest average was found for BTDD and UVTDD (P≤0.05). As for the resistance, the flexion was found that in the groups not submitted to thermal cycling there was no statistically significant difference for all materials, except for GIC, for the groups with thermal cycling the materials BTDD and UVTDD showed a statistically significant difference from GIC, however, they did not differ statistically from the CP and CR groups. CONCLUSION: BTDD and UVTDD presented higher average results of surface microhardness and, in the resistance test, the flexion of these materials behaved similarly to the CP and the CR studied. The temperature variation has an effect on the properties of these materials.

Whitening Dentifrices Effect on Enamel with Orthodontic Braces after Simulated Brushing.

OBJECTIVE: This study aimed to evaluate in vitro the effects of whitening dentifrices on enamel color, the shear bond strength of orthodontic brackets and adhesive remnant index (ARI). MATERIALS AND METHODS: Eighty bovine teeth with brackets were randomly divided into four groups (n = 20): control group (GC)-water, test group 1 (GT1)-Colgate Total 12, test group 2 (GT2)-Curaprox Black Is White, and group test 3 (GT3)-Luminous White. All groups were submitted to brushing, simulating 12 months. The specimens were exposed to spectrophotometer color evaluation and to a shear strength test in a universal test machine using a 300 kN load with a crosshead speed of 0.5 mm/min. The ARI was evaluated with a stereoscopic magnifying glass. STATISTICAL ANALYSIS: Nonparametric Kruskal-Wallis and Dunn's tests were used for the color analysis, and Friedman and Nemenyi tests were used to compare the times in the variable. To compare the shear force between the groups, the data were evaluated by one-way analysis of variance and Tukey's test, and ARI was analyzed using Fisher's exact test, always with a significance level of 5%. RESULTS: In the color analysis, GT3 presented the greatest progression in whitening effect. GT1 had greater shear strength than GT3 did (p ≤ 0.05). For ARI, the score 1 was predominant in the GC and GT1. The GT2 and GT3 groups had scores of 3. CONCLUSION: The whitening dentifrices promoted significant color change over the 12-month brushing time and may have interfered in the resistance to shear bond strength and ARI.

Influence of photobiomodulation on pain perception during initial orthodontic tooth movement / Influência do fotobiomodulação na percepção da dor durante o movimento ortodôntico inicial

Introduction: Laser in low intensity (LLI) has been used to reduce the discomfort and pain that is triggered by the forces applied during orthodontic treatment. Objective: To evaluate the effect of LLI application in the pain perception of periodontal ligament initial compression, during orthodontic tooth movement; and to compare the effect of this therapy between men and women. Material and method: The sample consisted of 30 volunteers, who needed orthodontic band placement on mandibular first molars. After insertion of the elastic separators, LLI was applied to the mesial and distal apical region (wavelength 808nm, energy 2J, time 20s and fluency of 8.32J/cm2) and at three points on the root region (wavelength 808nm, energy 1J, time 10s and fluency of 4.16J/cm2) of the first molar (irradiated side) and compared to the contralateral first molar (non-irradiated side), in three time intervals: 0hs, 24hs and 48hs. Pain perception was evaluated by the Visual Analog Scale (VAS), at 0hs, 24hs and 48hs after insertion, with significance of 5%. Result: The pain level was observed to be significantly lower (p<0.05) on the irradiated side, irrespective of gender and time. Women presented a significantly higher pain level (p<0.05) than men, irrespective of time and side. There were no significant differences between the time intervals (p>0.05). Conclusion: It was concluded that LLI reduced the perception of initial pain in patients in whom compression of the periodontal ligament was promoted by elastic separation, and that women had a greater perception of pain sensitivity in the time intervals studied.

Introdução: O tratamento com Laser em Baixa Intensidade (LBI) tem sido utilizado para reduzir o desconforto e a dor desencadeados pelas forças aplicadas durante o tratamento ortodôntico. Objetivo: Avaliar o feito da aplicação de LBI na percepção da dor na compressão inicial do ligamento periodontal durante o movimento dentário ortodôntico; e comparar o efeito desta terapia entre os sexos. Material e método: A amostra foi composta por 30 voluntários, que necessitavam de bandagem dos primeiros molares inferiores. Após a instalação dos elásticos separadores, aplicou-se o LBI infravermelho na região apical mesial e distal (comprimento de onda 808nm, energia 2J, tempo 20s e fluência de 8,32J/cm2) e em três ponto na região radicular (comprimento de onda 808nm, energia 1J, tempo 10s e fluência de 4,16J/cm2) no lado irradiado e comparou-se com o primeiro molar contralateral não irradiado (lado controle), em três tempos: 0hs, 24hs e 48hs. A percepção de dor foi avaliada pela interpretação da Escala Visual Analógica (EVA) em 0hs, 24hs e 48hs após a instalação, com nílvel de significância de 5%. Resultado: Observou-se que o nível de dor foi significativamente menor (p<0,05) no lado irradiado, independentemente do sexo e do tempo. O sexo feminino apresentou nível de dor significativamente maior (p<0,05) que o sexo masculino, independentemente do tempo e do lado. Não houve diferença significativa entre os tempos (p>0,05). Conclusão: Concluiu-se que o LBI diminui a percepção de dor inicial em pacientes onde se promoveu a compressão do ligamento periodontal por meio de separação elástica, e que o sexo feminino apresentou maior percepção da sensibilidade dolorosa nos tempos observados.

Effect of Hydrofluoric Acid Concentration and Thermal Cycling on the Bond Strength of Brackets to Ceramic.

This study to evaluate the effects of different hydrofluoric acid (HF) concentrations and thermal cycling on the shear bond strength (SBS) of brackets to ceramic. Cylinders of ceramic were divided into 10 groups (n=15), according to HF concentrations: 1-1%;2-2.5%;3-5%;4-7.5%;5-10% (storage 24 h); 6-1%;7-2.5%;8-5%;9-7.5%; and, 10-10% (thermal cycling). All cylinders were etched for 60s and received one layer of silane. Metallic brackets were bonded to the cylinders using Transbond-XT, light activated for 40 s, using a LED (Radii Plus) and stored in deionized water at 37o C for 24h. The groups 6 to 10 were submitted to thermal cycling (7,000 cycles - 5o/55oC). SBS was performed in an Instron at crosshead speed of 1.0 mm/min. Data were submitted to two-way ANOVA and Tukey's post-hoc test (α=0.05). The Adhesive Remaining Index (ARI) was evaluated at 40x magnification. The different HF acid concentrations influenced on the SBS of the brackets to ceramic (p<0.05). The thermal cycling decreased the SBS of the brackets to ceramic for all acid concentrations (p<0.05). The ARI showed a predominance of scores 0 for all groups, with an increase in scores 1, 2 and 3 for the group storage for 24 h. In conclusion, the different HF acid concentrations 5.0%, 7.5% and 10% influenced on the SBS of brackets to ceramic. The thermal cycling decreased significantly the SBS of brackets to ceramic.

Effect of hydrofluoric acid concentration and thermal cycling on the bond strength of brackets to ceramic

Abstract This study to evaluate the effects of different hydrofluoric acid (HF) concentrations and thermal cycling on the shear bond strength (SBS) of brackets to ceramic. Cylinders of ceramic were divided into 10 groups (n=15), according to HF concentrations: 1-1%;2-2.5%;3-5%;4-7.5%;5-10% (storage 24 h); 6-1%;7-2.5%;8-5%;9-7.5%; and, 10-10% (thermal cycling). All cylinders were etched for 60s and received one layer of silane. Metallic brackets were bonded to the cylinders using Transbond-XT, light activated for 40 s, using a LED (Radii Plus) and stored in deionized water at 37o C for 24h. The groups 6 to 10 were submitted to thermal cycling (7,000 cycles - 5o/55oC). SBS was performed in an Instron at crosshead speed of 1.0 mm/min. Data were submitted to two-way ANOVA and Tukey's post-hoc test (α=0.05). The Adhesive Remaining Index (ARI) was evaluated at 40x magnification. The different HF acid concentrations influenced on the SBS of the brackets to ceramic (p<0.05). The thermal cycling decreased the SBS of the brackets to ceramic for all acid concentrations (p<0.05). The ARI showed a predominance of scores 0 for all groups, with an increase in scores 1, 2 and 3 for the group storage for 24 h. In conclusion, the different HF acid concentrations 5.0%, 7.5% and 10% influenced on the SBS of brackets to ceramic. The thermal cycling decreased significantly the SBS of brackets to ceramic.

Resumo Este estudo avaliou os efeitos de diferentes concentrações de ácido hidrofluorídrico (HF) e ciclagem térmica na resistência de união ao cisalhamento (RUC) de bráquetes metálicos a cerâmica. Cilindros da cerâmica feldspática foram divididos em 10 grupos (n=15). De acordo com as concentrações do ácido HF: 1-1%;2-2,5%;3-5%;4-7,5%; e, 5-10% (armazenagem por 24 h); 6-1%;7-2,5%;8-5%;9-7,5%; e, 10-10% (ciclagem térmica). Todos os cilíndros foram condicionados por 60s e receberam uma camada de silano. Bráquetes metálicos foram colados aos cilíndros usando o transbond-XT, fotoativado por 40 s, usando o LED (Radii Plus; SDI) e armazenados em água deionizada a 37o C por 24 h. Os Grupos 6 a 10 foram submetidos à ciclagem térmica (7.000 ciclos - 5o/55oC). RUC foram realizadas na Instron a velocidade de 1.0 mm/min. Os dados foram submetidos à análise de variância dois-fatores e ao teste de Tukey's post-hoc (α=0,05). O Índice de Remanescente do Adesivo (IRA) foi avaliado com 40x de aumento. As diferente concentrações do ácido HF influenciou na RUC dos bráquetes na cerâmica (p<0,05). A ciclagem térmica diminuiu a RUC dos bráquetes na cerâmica para todas as concentrações do ácido (p<0,05). O IRA mostrou predominância de escores 0 para todos os grupos, com aumento de escores 1, 2 e 3 para os grupos armazenados por 24 h. Concluíndo, as concentrações do ácido HF 5,0%, 7,5% e 10% influenciaram na RUC de braquetes à cerâmica. A ciclagem térmica diminuiu significativamente a RUC do bráquetes à cerâmica.

Pharyngeal Airway Modifications in Skeletal Class III Patients Undergoing Bimaxillary Advancement Surgery.

PURPOSE: The purposes were to study the pharyngeal airway in patients with skeletal Class III malocclusion submitted to surgical orthodontic treatment and to correlate the alterations with bone movements. MATERIALS AND METHODS: The sample consisted of multislice computed tomography images from 13 patients obtained before and 6 months after maxillomandibular advancement surgery. The following measurements were obtained using Dolphin Imaging software (Dolphin Imaging, Chatsworth, CA): volume and area of the oropharynx, nasopharynx, and total airway, as well as the most constricted area, anteroposterior and lateral dimensions of the narrowest axial cross-sectional area, and airway length. The paired t test was applied at a significance level of 5%. RESULTS: Sagittal displacement of the maxilla and mandible was correlated with airway alterations using the Pearson correlation test. Alterations in airway measurements were observed in all patients after surgery. We noted a significant increase (P < .05) in total airway area, oropharyngeal area, and anteroposterior dimension of the most constricted area, as well as a significant reduction (P < .05) in airway length. A significant correlation (P < .05) was observed between nasopharyngeal area and maxillary movement and between airway length and mandibular movement (P < .05). CONCLUSIONS: The results of this study suggest significant alterations in pharyngeal airway measurements when preoperative and postoperative periods of bimaxillary advancement surgery were compared.

Evaluation of friction on self-ligating and conventional brackets associated with different types of archwires submitted to sliding mechanics

Aim: The aim of this study was to verify the frictional force during sliding mechanics in orthodontic tooth movement, using conventional metal brackets of the active and passive self-ligating types with stainless steel and copper nickel titanium archwires. Methods: This experimental in vitro study was conducted with conventional metal (Morelli, Sorocaba, SP, Brazil) brackets, active self-ligated (SLI Morelli, Sorocaba, SP, Brazil) and passive self-ligated (SLP Morelli, Sorocaba, SP, Brazil), with slot 0.022 x 0.028 inches and Roth prescription. The brackets were tested with rectangular section 0.019 x 0.025 inch copper nickel titanium and stainless steel archwires. For each type of bracket, 10 sets of plate/bracket/archwire segment (n=10) were fabricated. Non-parametric Kruskal Wallis and Dunn tests were used for comparison between types of brackets and Wilcoxon tests for comparison between types of archwires. Results: The results showed that the frictional force values were higher with copper nickel titanium than with stainless steel archwires (p<0.05). When copper nickel titanium archwires were used, the active self-ligating brackets showed higher frictional force values than the other types, followed by the conventional brackets. Lower frictional force values were observed with passive self-ligating brackets. For stainless steel archwires, no difference was observed between conventional and active self-ligating brackets, the passive self-ligating type presented lower frictional force values than the others. Conclusion: It was concluded that the higher frictional force was observed when active self-ligating brackets were associated with copper nickel titanium archwires. Lower frictional force was verified between passive self-ligating brackets combined with stainless steel archwires

Can the chlorhexidine gluconate solution potentiate the staining of polycrystalline ceramic brackets?

Aim: The present study aimed to assess, in vitro, the effect of chlorhexidine on the potentiation of polycrystalline ceramic bracket staining. Methods: Seventy-two polycrystalline ceramic brackets of upper right central incisors were divided into six groups (n=12) according to immersion solution. The groups were G1 - distilled water (control); G2 - chlorhexidine; G3 - coffee; G4 - red wine; G5 - chlorhexidine associated with coffee; and G6 - chlorhexidine associated with red wine. The samples were analyzed by means of a spectrophotometer according to the CIEL*a*b* system, and color change (ΔE*) was calculated. The readings were performed at the following times: T0 - After package removal and T1 - After staining. The data were analyzed by Kruskal Wallis and t tests (p<0.05) at 5% significance level. Results: The total color variation (ΔE*) was greater in the group that received chlorhexidine associated with red wine (p<0.05) and lower in the groups that received distilled water. All other groups showed greater value variations when compared to G1 and G2. Group G6 showed a greater color change due to the potentiation of chlorhexidine with the dye substance. Conclusion: It is concluded that chlorhexidine potentiates the staining caused by red wine in polycrystalline ceramic brackets