Avaliação dos Efeitos da Remoção da Resina Residual e do Polimento na Superfície do Esmalte após Descolagem do Braquete / Evaluation of the Effects of Residual Resin Removal and Polishing on the Enamel Surface after Bracket Debonding

Considerando o uso de brocas para remoção da resina residual após descolagem do braquete e a possibilidade de injúrias à superfície do esmalte após o uso dessas brocas, este trabalho teve como objetivo realizar um estudo experimental, para avaliar a variação do aspecto superficial do esmalte de forma qualitativa, por meio da avaliação com imagens topográficas do esmalte dentário, utilizando-se a Microscopia Eletrônica de Varredura (MEV), a qual permitiu ilustrar e avaliar a superfície do esmalte após a fase de polimento final, realizada por dois métodos: taça de borracha ou escova Robinson. Foram utilizados 25 dentes pré-molares humanos, obtidos a partir de exodontias em pacientes que procuraram voluntariamente o curso de Residência em Cirurgia da Clínica Odontológica Universitária da Universidade Estadual de Londrina. Os dentes foram divididos em quatro grupos: A, B, C e D, contendo 6 dentes cada, de acordo com as brocas utilizadas para a remoção do remanescente adesivo e o polimento escolhido, além de um dente como "controle". Foi avaliada a rugosidade superficial do esmalte após a remoção da resina e a superfície do esmalte após o polimento com as duas opções apresentadas. Os resultados mostraram que, por observação e inspeção, as brocas removeram a resina residual de todos os dentes, porém, causaram riscos e ranhuras, como evidenciado nas imagens em MEV. Concluiu-se que não houve diferença estatística entre os métodos de polimento e que ambos foram importantes para a redução das marcas abrasivas, proporcionando uma superfície mais lisa do esmalte.

Considering the use of specific burs to remove residual resin after bracket debonding and the possibility of injuries to the dental enamel after using these burs, this study aimed to verify the variation in the enamel surface appearance in a qualitative way and evaluation with topographic images of the dental enamel. The use of Scanning Electron Microscopy (SEM) allowed to illustrate and evaluate the enamel surface after the final polishing phase using two methods: rubber cup or Robinson brush. Twenty-five human premolar teeth were obtained from extractions in patients who voluntarily sought the Oral Maxillofacial Surgery Residency at the Dental School from the State University of Londrina; the teeth were divided into four groups A, B, C and D containing 6 teeth each according to the burs used to remove the remaining adhesive and the chosen polishing, in addition to one tooth as a "control". Dental enamel surface roughness was evaluated after resin removal and enamel surface after polishing with the two methods presented. The results showed that by observation and inspection, the burs removed residual resin from all teeth, however, caused scratches and grooves as evidenced in the SEM images. Based on the results, there was no statistical difference between the polishing methods, and both were important for the reduction of abrasive marks and provided a smoother enamel surface.

Comparative evaluation of three methods of adhesive remnant removal after orthodontic bracket debonding

ABSTRACT Objective: This study aimed to assess the effects of three methods of adhesive remnant removal (carbide bur and low speed handpiece, carbide bur and high speed handpiece, and zircon-rich glass fiber reinforced composite bur), after orthodontic bracket debonding, on tooth color and enamel surface roughness. Methods: Ninety sound premolar teeth were selected. The baseline tooth color was assessed using Vita spectrophotometer. The teeth were subjected to bracket bonding processes and then randomly divided into three equal groups. In each group, composite remnant was removed by one of the three methods of adhesive removal, and the teeth were then subjected to color assessment again. To measure the surface roughness, a scanning electron microscope (SEM) with x400 magnification was used. Results: ANOVA showed that the effect of the three methods of adhesive remnant removal on ∆L, ∆b and ∆E was statistically significant (p=0.01), but without significant effect on ∆a. Comparison of the means showed that composite bur and high speed carbide bur yielded the highest ∆E (p=0.05), and had a significant difference when compared to carbide bur and low speed handpiece. The highest ∆L and ∆b values belonged to samples approached with composite bur and carbide bur with high speed handpiece, respectively. SEM analysis showed that the composite bur created a very smooth surface, compared to the other two methods. Conclusion: Zircon-rich glass fiber reinforced composite created the smoothest enamel surface and highest color change, when compared to the other two methods.

RESUMO Objetivo: O presente estudo teve como objetivo avaliar os efeitos de três métodos de remoção de adesivo remanescente (broca carbide e peça de mão em baixa rotação, broca carbide e peça de mão em alta rotação, e broca de compósito reforçado com fibra de vidro rica em zircônia), após a descolagem de braquetes ortodônticos, sobre a cor dos dentes e rugosidade superficial do esmalte. Métodos: Noventa pré-molares hígidos foram selecionados. A cor inicial dos dentes foi avaliada usando um espectrofotômetro Vita. Os dentes foram submetidos à etapa de colagem dos braquetes e, então, divididos aleatoriamente em três grupos. Em cada grupo, o adesivo remanescente foi removido usando um dos três métodos de remoção, e os dentes foram novamente submetidos à avaliação de cor. Para medir a rugosidade superficial dos dentes, foi usado um microscópio eletrônico de varredura (MEV) com aumento de 400x. Resultados: A ANOVA mostrou que os três métodos de remoção do adesivo remanescente tiveram efeito estatisticamente significativo (p=0,01) em ∆L, ∆b e ∆E, mas sem efeito significativo em ∆a. A comparação das médias mostrou que a broca de compósito e a broca carbide em alta rotação produziram o maior ∆E (p=0,05) e tiveram uma diferença significativa quando comparadas com a broca carbide e a peça de mão em baixa rotação. Os maiores valores de ∆L e ∆b foram encontrados, respectivamente, nos grupos com broca de compósito e broca carbide usando peça de mão em alta rotação. A análise MEV mostrou que o uso da broca de compósito resultou em uma superfície muito lisa, em comparação com os outros dois métodos. Conclusão: Em comparação aos outros métodos, a broca de compósito reforçado com fibra de vidro rica em zircônia criou a superfície de esmalte mais lisa e resultou em uma maior mudança de cor.

Pain and removal force associated with bracket debonding: a clinical study

Abstract Objective: Pain is a problem during bracket removal, and more comfortable treatment is needed. This study examined the association of pain with the removal force required for ceramic brackets, compared with metal and plastic brackets, to determine which removal method resulted in less pain and discomfort. Methodology: 81 subjects (mean age, 25.1 years; 25 males and 56 females) were enrolled, from whom 1,235 brackets (407 ceramic, 432 plastic, and 396 metal) were removed. Measured teeth were distinguished at six segments. Pain was measured with a visual analogue scale (VAS) during the removal of each bracket. An additional grip was placed on the grips of debonding pliers with right-angled beaks; a mini loading cell sensor pinched by the grips was used to measure removal force during debonding. VAS and force values were statistically analyzed. The Kruskal-Wallis test followed by the Mann-Whitney U test with Bonferroni correction were performed for multiple comparisons; multiple regression analysis was also performed. Results: Forces in the upper and lower anterior segments were significantly smaller (p<0.05) than those in the other segments. Pain tended to be greater in the upper and lower anterior segments than in the posterior segments. In all segments, the removal force was greater for metal brackets than for plastic or ceramic brackets. Ceramic brackets caused significantly greater pain than plastic brackets for the upper and lower anterior segments. Debonding force was involved in the brackets, following adjustments for pain, upper left segment, age, and sex. Conclusions Pain and discomfort are likely to occur during bracket debonding.

Tooth color alteration after debonding in orthodontic patients with adhesive removal using composite bur or tungsten carbide bur: a single center, randomized controlled clinical trial / Alteração da cor do dente após descolagem de braquetes em pacientes ortodônticos pela remoção de adesivo usando broca de compósito ou broca carbide de tungstênio: ensaio clínico unicêntrico randomizado e controlado

Objective: The objective of this study was to determine whether recently developed fiber reinforced composite burs provided better results by comparing tooth discoloration after debonding of orthodontic brackets. Material and Methods: A split-mouth, randomized controlled trial was carried out in one orthodontic office; including 23 patients with intact, vital and caries-free four upper incisors aged 12 to 30 years who completed their fixed orthodontic treatment. For each patient, upper central and lateral incisors on each side of the mouth were randomly selected to remove the adhesive with either a tungsten carbide bur (TC) (n = 46) or a fiber-reinforced composite bur (FC) (n=46). Color evaluation of each tooth was conducted at two time points: immediately after finishing and polishing procedure and two months afterwards. The primary outcome would be the amount of color change in each group during the post treatment phase. The participants, the person assessing the color change and the statistician were blinded to TC group assignment. Color changes in each group were analyzed with the Paired T-test. The color change corresponding to the resin removal method was also statistically analyzed with the Independent T-test at α=0.05 as the level of significance. Results: 86 teeth, 43 in each group, were analyzed. The ΔE value was 3.713±1.161, for teeth finished TC and 2.114±0.514 for teeth finished with FC (p<0.01). Conclusion: Adhesive removal with FC bur results in a more color-resistant tooth surface in comparison with tungsten carbide bur. (AU)

Objetivo: O objetivo deste estudo foi determinar se as brocas de material compósito reforçadas com fibras, recentemente desenvolvidas, proporcionam melhores resultados, pela comparação da descoloração dentária após a remoção de braquetes ortodônticos. Material e Métodos: Um ensaio clínico controlado randomizado com boca dividida foi realizado em um consultório ortodôntico, incluindo 23 pacientes, com idade entre 12 e 30 anos, com incisivos superiores intactos, vitais e livres de cárie, que completaram o tratamento ortodôntico com aparelho fixo. Para cada paciente, incisivos centrais e laterais superiores de cada lado da boca foram selecionados aleatoriamente para remover o adesivo ortodôntico com uma broca carbide de tungstênio (TC) (n = 46) ou uma broca de compósito reforçada com fibra (FC) (n = 46). A avaliação da cor de cada dente foi realizada em dois momentos: imediatamente após o acabamento e polimento e dois meses após. O resultado primário foi a quantidade de mudança de cor em cada grupo durante a fase pós-tratamento. Os participantes, a pessoa que avaliou a mudança de cor e o estatístico não tinham conhecimento da atribuição ao grupo TC. As mudanças de cor em cada grupo foram analisadas com o teste-t pareado. A mudança de cor correspondente ao método de remoção da resina também foi analisada estatisticamente com o teste-t independente considerando um nível de significância α = 0,05. Resultados: foram analisados 86 dentes, 43 em cada grupo. O valor de ΔE foi 3,713 ± 1,161, para dentes finalizados com broca TC e 2,114 ± 0,514 para dentes finalizados com broca FC (p <0,01). Conclusão: A remoção do adesivo com broca FC resulta em uma superfície de dente mais resistente à cor em comparação com a broca carbide de tungstênio (AU)

The contribution of ceramic thickness and adhesive type on the de-bonding strength of dental ceramic veneers using Er, Cr: YSGG laser / La contribución del espesor de la cerámica y el tipo de adhesivo a la resistencia de desunión de las carillas dentales de cerámica con láser Er, Cr: YSGG

Purpose: De-bonding strength of ceramic veneers by laser use needs to be evaluated in detail. The aim of this study, is to determine the contribution of ceramic thickness and cementing agents to the de-bonding strength of ceramic veneers using Er,Cr:YSGG laser. Methods: A total of 120 maxillary central incisors specimens were randomly divided into twelve groups on the basis of disc thickness, cementing agent, and Er,Cr:YSGG laser use. Under laboratory conditions, 120 IPS Empress II system discs 0.5mm, 1mm, and 2mm in thickness were applied to the tooth surfaces, for laser use. An Er,Cr:YSGG laser system was applied to the central surface of the IPS Empress II discs on specimens in all laser groups (Groups 1,3,5,7,9,11). Then the shear bond strength (SBS) for all specimens were tested with a testing machine at a speed of 0.5mm/min. The SBS values were considered as the de-bonding strength. Results: The mean de-bonding strength values for Groups 9 and 11 (0,5 mm disc thickness + laser application) have the lowest median load (0.000 N), while Group 4 (2mm disc thickness + no laser) has the highest median load (573.885 N). The de-bonding strengths of all the groups without laser application were higher than those of all groups with laser use. When laser is applied, the mean de-bonding strength decreases with decreasing disc thickness, and it reaches zero at 0.5mm thickness of discs cemented by self- or total-etch adhesives. Conclusions: The de-bonding strength decreases with laser use, and decreasing disc thickness. In the absence of laser, the mean de-bonding values of discs cemented by a total etch adhesive system are always higher than those of discs cemented with a self-etch adhesive system. Without any extra load, all 0.5mm thick discs were dislodged from teeth while applying or testing the laser.

Propósito: La resistencia de desunión de las carillas de cerámica mediante el uso del láser debe evaluarse en detalle. El objetivo de este estudio es determinar la contribución del espesor de la cerámica y los agentes de cementación a la resistencia de desunión de las carillas de cerámica utilizando el láser Er, Cr: YSGG. Métodos: Un total de 120 incisivos centrales maxilares se dividieron al azar en doce grupos según el grosor del disco, el agente de cementación y el uso del láser Er, Cr: YSGG. En condiciones de laboratorio, se aplicaron en las superficies de los dientes 120 discos del sistema IPS Empress II de 0,5mm, 1mm y 2mm de grosor, para uso con láser. Se aplicó un sistema láser Er, Cr: YSGG a la superficie central de los discos IPS Empress II en muestras de todos los grupos de láser (Grupos 1,3,5,7,9,11). Luego, la resistencia de la unión al cizallamiento (SBS) para todas las muestras se probó con una máquina de prueba a una velocidad de 0.5mm/min. Los valores de SBS se consideraron como la fuerza de desunión. Resultados: Los valores medios de resistencia de desunión para los Grupos 9 y 11 (espesor de disco de 0,5mm + aplicación de láser) demostró la carga media más baja (0,000 N), mientras que el Grupo 4 (espesor de disco de 2 mm + sin láser) tuvo la carga media más alta (573.885 N). Las fuerzas de desunión de todos los grupos sin aplicación de láser fueron superiores a las de todos los grupos con uso de láser. Cuando se aplica el láser, la fuerza media de desunión disminuye al disminuir el grosor del disco, y llega a cero con el grosor de 0,5mm de los discos cementados, para ambos adhesivos de grabado. Conclusiones: la fuerza de desunión disminuye con el uso del láser y disminuye con el grosor del disco. En ausencia de láser, los valores medios de desunión de los discos cementados con un sistema de adhesivo de grabado total son siempre más altos que los de los discos cementados con un sistema de adhesivo de autograbado. Sin ninguna carga adicional, todos los discos de 0,5mm de grosor se desprendieron de los dientes al aplicar el láser.

Comparison of Shear Bond Strength of Occlusal Pad Debonding Pliers Before and After Er-YAG Laser Application: An In vitro Study

Background: Er-YAG laser showed to be effective in debonding ceramic bracket from the enamel surface. Until lately, no previous study was conducted to assess the outcome of the laser in debonding ceramic brackets from tooth surface comparing it with conventional occlusal pad debonding pliers. Materials and methods: Total 60 ceramic brackets were bonded on the tooth surface which was divided randomly into 2 groups. One was assigned as a control non-lased group and the other was experimental lased groups. Er-YAG laser irradiated the experimental groups at the power of 5 W for 10 seconds with swiping motion and 50% air-water cooling. In the lased experimental group, the laser was applied at energy of 250 mJ, 20 Hz frequency, and pulse duration of 100 μs. Results: Shear bond strengths and adhesive remnant index scores were statistically calculated. A highly significant difference of SBS between the non-lased control group and the lased experimental group was observed (p<0.000). A non-significant difference in ARI scores was observed when the non-lased control group was compared with the lased experimental group. Conclusion: It could be concluded that Er-YAG laser is effective in ceramic bracket debonding. This protocol promotes debonding without bracket fracture or enamel surface cracks or damage.

Evaluation of pain perception during orthodontic debonding of metallic brackets with four different techniques

Abstract Objective The aim of this study was to evaluate patients' pain levels during four different debonding procedures. The null hypothesis was that the pain perception of the patients undergoing four different debonding applications was not statistically significant different. Material and Methods One hundred and twenty orthodontic patients who underwent orthodontic debonding were included in this study. The patients were randomly divided into 4 groups according to technique used in the patients. Debonding groups were as follows: Group 1) Conventional debonding group, Group 2) Medication group (acetaminophen was given 1 hour before debonding), Group 3) Soft bite wax group, and Group 4) Soft acrylic bite wafer group. The patients' levels of anxiety and fear of pain were evaluated before debonding, and Numerical Rating Scale (NRS) was applied to evaluate their pain perception during debonding. Mann-Whitney U and Kruskal-Wallis tests were used to evaluate non-normally distributed data. Categorical data analysis were carried by chi-square and McNemar tests. The significance level was set at p<0.05. Results Anxiety scores of the patients were not statistically significant between both genders and debonding groups. In the quadrants in which the patients were perceived, the highest pain level was in the left side of the mandible. The teeth in which the highest pain level was perceived were the lower left and upper right lateral incisors. Although there was no statistically significant difference among the pain scores of the patients in each group, quadrant scores of female patients showed significant differences, being the lowest scores in the soft bite wax group. Conclusions Majority of the patients had no fear of pain before debonding. Pain levels of the patients in the conventional debonding group were not significantly different from those of the other groups, except quadrant scores of females in the soft bite wax group. The null hypothesis was accepted.

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 Primekote® polymer in orthodontic bonding / Influência do polímero Primekote® na colagem ortodôntica

Objective: The Primekote® (TP) polymer was incorporated to the of Orthodontic Bracket mesh base to improve bond strength and make it more efficient. The purpose of this study was to assess the shear bond strength and adhesive remnant index (ARI) of these brackets. Material and method: The test sample consisted of thirty bovine incisors divided into 2 groups: with a group with TP® brackets (n=15), and a control group with Morelli® brackets (n=15) without Primekote® technology. The TransbondTM XT was used as adhesive system in both groups, following the same protocol and manufacturer’s instructions. Specimens were stored in distilled water for 24 hours and then submitted to shear bond strength test in a universal testing machine (EMIC DL2000). The assessment of ARI was performed under stereomicroscope by two calibrated examiners. Result: No significant differences (p>0.05) in shear bond strength were found between the two groups according to the independent t-test. The Wilcoxon test was used to assess ARI data and statistical difference was found between Morelli® and TP® Nu-Edge brackets; the last one left less remaining adhesive on tooth surface. Conclusion: TP® brackets had higher adherence to the adhesive system as shown by lower ARI scores, but this does not improve its clinical performance.

Objetivo: Avaliar a resistência ao cisalhamento e o índice de remanescente adesivo (IRA) dos bráquetes que tiveram o polímero Primekote® incorporado a suas bases. Material e método: Foram confeccionados trinta corpos de prova com incisivos bovinos, divididos em dois grupos: o colado com bráquete TP® Nu-Edge(n=15) e grupo controle com bráquetes Morelli® (n=15) sem tratamento na base. O sistema adesivo TransbondTM XT foi utilizado nos dois grupos seguindo o mesmo protocolo de colagem e respeitando as instruções do fabricante. Os corpos de prova foram armazenados em água destilada por 24 horas, e posteriormente submetidos ao teste de cisalhamento na máquina de ensaios universais (EMIC-DL2000). O IRA foi avaliado por dois examinadores calibrados utilizando lupa estereoscópica com aumento de 20 vezes. Resultado: Na resistência ao cisalhamento o teste T-independente mostrou não haver diferença estatisticamente significante entre os grupos (p>0,05), ambos tiveram desempenho semelhante. O teste Wilcoxon foi utilizado nos valores obtidos no IRA revelando diferença estatística, sendo que os bráquetes TP® deixaram menos remanescente adesivo na superfície dental que os bráquetes Morelli®. Conclusão: Bráquetes TP® apresentaram maior adesão ao sistema adesivo pois foi encontrado menor IRA nos mesmos, porém esta característica não reflete em melhora no desempenho clínico.

Does the CO2 laser reduce bond strength in different types of ceramic brackets?

ABSTRACT OBJECTIVE: The aim of this study was to assess in vitro the influence of the CO2 laser and of the type of ceramic bracket on the shear bond strength (SBS) to enamel. METHODS: A total of 60 enamel test surfaces were obtained from bovine incisors and randomly assigned to two groups, according to the ceramic bracket used: Allure (A); Transcend (T). Each group was divided into 2 subgroups (n = 15): L, laser (10W, 3s); C, no laser, or control. Twenty-four hours after the bonding protocol using Transbond XT, SBS was tested at a crosshead speed of 0.5 mm/min in a universal testing machine. After debonding, the Adhesive Remnant Index (ARI) was evaluated at 10 x magnification and compared among the groups. Data were analyzed by one-way ANOVA, Tukey’s, Mann-Whitney’s and Kruskal-Wallis tests (α = 0.05). RESULTS: Mean SBS in MPa were: AL = 0.88 ± 0.84; AC = 12.22 ± 3.45; TL = 12.10 ± 5.11; TC = 17.71 ± 6.16. ARI analysis showed that 73% of the specimens presented the entire adhesive remaining on the tooth surfaces (score 3). TC group presented significantly higher SBS than the other groups. The lased specimens showed significantly lower bond strength than the non-lased groups for both tested brackets. CONCLUSION: CO2 laser irradiation decreased SBS values of the polycrystalline ceramic brackets, mainly Allure.

RESUMO OBJETIVO: o objetivo deste estudo foi avaliar in vitro a influência do laser de CO2 sobre a resistência ao cisalhamento da colagem (RCC) no esmalte dentário, usando diferentes tipos de braquetes cerâmicos. MÉTODOS: no total, 60 superfícies de esmalte de incisivos bovinos foram obtidas e aleatoriamente divididas em dois grupos, de acordo com o braquete cerâmico utilizado: Allure (A) e Transcend (T). Cada grupo foi dividido em dois subgrupos (n = 15): L, laser (10W, 3s); C, sem laser, ou controle. Vinte e quatro horas após a colagem dos braquetes com o sistema Transbond XT, foi realizado o teste de resistência ao cisalhamento, com velocidade de 0,5 mm/min, em máquina universal de ensaios mecânicos. Após a descolagem, o Índice de Remanescente de Adesivo (IRA) foi avaliado com aumento de 10X e comparado entre os grupos. Os dados foram analisados pelo ANOVA one-way, testes de Tukey’s, Mann-Whitney’s e Kruskal-Wallis (α = 0,05). RESULTADOS: as médias da RCC em MPa foram: AL = 0,88 ± 0,84; AC = 12,22 ± 3,45; TL = 12,10 ± 5,11; TC = 17,71 ± 6,16. A análise do IRA mostrou que 73% dos corpos de prova apresentaram todo o compósito remanescente aderido à superfície do esmalte (escore 3). O grupo TC apresentou valor significativamente maior de RCC do que os outros grupos. Os corpos de prova dos grupos com laser obtiveram valores adesivos significativamente menores do que os corpos de prova dos grupos sem laser, com ambos os tipos de braquetes. CONCLUSÃO: a irradiação com laser de CO2 diminuiu os valores de RCC dos braquetes policristalinos testados, principalmente do Allure.

Avaliação do esmalte dental na remoção de resíduos resinoso fluorescente com diferentes fontes luminosas / EvaluaLon of dental enamel in the removal of fluorescent resin residues with different light sources

Objetivo: Avaliar através de simulação clínica a efetividade da remoção de resíduos fluorescentes do esmalte dental bovino, após remoção de bráquetes ortodônticos, utilizando dispositivos emissores de luz branca e fluorescente. Materiais e Métodos: 180 dentes bovinos anteriores hígidos foram seccionados em discos de esmalte/dentina. A remoção do material resinoso cimentante foi realizada por três operadores. Os dentes foram divididos em quatro grupos de estudo. Os fatores em estudo foram: a fonte de iluminação empregada durante a remoção dos materiais resinosos cimentantes de bráquetes ortodônticos em 4 níveis (n = 45): Convencional (C), LED branco (W), LED fluorescente (F) e fotopolimerizador com filtro fluorescente (FL). Foram consideradas como variáveis de resposta: o tempo para remoção dos resíduos das amostras; a área de remanescente resinoso fluorescente superficial e a mensuração da altura de material adesivo fluorescente remanescente (PICO) e a profundada de esmalte desgastado (VALE). Na comparação entre as técnicas empregou-se o teste Kruskal-Wallis seguido do pós-teste Mann-Whitney U (P≤0,05). Resultados: As Técnicas F e FL apresentaram-se, estatisticamente, semelhantes e as menores medianas de tempo consumido para a remoção do resíduo resinoso. As técnicas C e W apresentaram estatisticamente, a presença de maiores e semelhantes medianas de áreas fluorescentes remanescentes e de PICO (altura do remanescente), com relação as técnicas F e FL; enquanto que as técnicas FL e F postaram, estatisticamente, uma maior mediana de VALE que a técnica C. Conclusões: A associação de emissor de luz fluorescente com um material resinoso fluorescente, colaborou significativamente e de forma eficaz, na redução do tempo consumido para remoção e evidenciação dos resíduos resinosos cimentantes fluorescentes, possibilitando uma remoção efetiva, após a remoção dos bráquetes ortodônticos(AU)

Objective: Evaluate, through clinical simulation, the effectiveness on the removal of fluorescent resin residues from bovine dental enamel after brackets debonding using white and fluorescent light emitting devices. Materials and Methods: 180 healthy anterior bovine teeth were sectioned on enamel / dentin disks. The removal of the resinous material was performed by three operators. The teeth were divided into four groups. The factors studied were: the light source used to remove orthodontic resin residue in 4 levels (n = 45): Conventional (C), white LED (W), fluorescent LED (F) and photocuring unit with Fluorescent filter (FL). Response variables were: the time spent to remove the sample residues; The surface area of the fluorescent remaining resin and the depth measurement of the remaining fluorescent adhesive thickness (PEAK) and the enamel thickness removed (VALLEY). In the comparison between the techniques, the Kruskal-Wallis test was used, followed by the Mann-Whitney U post-test (P≤0.05). Results: In terms of time, the groups F and FL were similar to each other and statistically different for groups C and W. The techniques C and W presented statistically, the presence of larger and similar medians of remaining fluorescent areas, in relation to the F and FL techniques. The techniques C and W presented, statistically, a larger and similar median of peaks than the F and FL techniques. The FL technique statistically demonstrated a higher median of valleys than the C technique. The W, F and FL techniques were statistically similar to each other, as were C and W techniques. Conclusions: Fluorescent light with a fluorescent resinous material, significantly and effectively collaborated in the reduction of the time consumed for evidencing and removal of fluorescent resin residues, allowing an efficient removal after removal of orthodontic brackets(AU)

Efficiency of different protocols for enamel clean-up after bracket debonding: an in vitro study

Objective: This study aimed to assess the efficiency of six protocols for cleaning-up tooth enamel after bracket debonding.Methods:A total of 60 premolars were divided into six groups, according to the tools used for clean-up: 12-blade bur at low speed (G12L), 12-blade bur at high speed (G12H), 30-blade bur at low speed (G30L), DU10CO ORTHO polisher (GDU), Renew System (GR) and Diagloss polisher (GD). Mean roughness (Ra) and mean roughness depth (Rz) of enamel surface were analyzed with a profilometer. Paired t-test was used to assess Ra and Rz before and after enamel clean-up. ANOVA/Tukey tests were used for intergroup comparison. The duration of removal procedures was recorded. The association between time and variation in enamel roughness (∆Ra, ∆Rz) were evaluated by Pearson's correlation test. Enamel topography was assessed by scanning electron microscopy (SEM).Results:In Groups G12L and G12H, original enamel roughness did not change significantly. In Groups G30L, GDU, GR and GD, a smoother surface (p < 0.05) was found after clean-up. In Groups G30L and GD, the protocols used were more time-consuming than those used in the other groups. Negative and moderate correlation was observed between time and (∆Ra, ∆Rz); Ra and (∆Ra, ∆Rz); Rz (r = - 0.445, r = - 0.475, p < 0.01).Conclusion:All enamel clean-up protocols were efficient because they did not result in increased surface roughness. The longer the time spent performing the protocol, the lower the surface roughness.

Objetivo: esse estudo objetivou avaliar a eficiência de seis protocolos de remoção de resina do esmalte após a descolagem de braquetes.Métodos:sessenta (60) pré-molares foram divididos em seis grupos conforme as ferramentas utilizadas: broca de 12 lâminas em baixa rotação (G12L), broca de 12 lâminas em alta rotação (G12H), broca de 30 lâminas em baixa rotação (G30L), polidor DU10CO-ORTHO (GDU), Renew System (GR) e polidor Diagloss (GD). As médias de rugosidade (Ra) e profundidade média de rugosidade (Rz) da superfície do esmalte foram analisadas com perfilômetro. Teste t pareado foi utilizado para avaliar Ra e Rz antes e depois da limpeza do esmalte; testes de ANOVA/Tukey foram utilizados para avaliar a diferença intergrupos. A duração dos procedimentos de remoção da resina foi registrada. Ainda, a associação entre o tempo e a variação da rugosidade do esmalte (ΔRa, ΔRz) foi avaliada pelo teste de correlação de Pearson. A topografia do esmalte também foi avaliada, por microscopia eletrônica de varredura (MEV).Resultados:nos grupos G12L e G12H, a rugosidade do esmalte original não se alterou significativamente. Nos Grupos G30L, GDU, GR e GD, foi verificada superfície mais lisa após a limpeza (p< 0,05). Nos Grupos G30L e GD, os protocolos utilizados foram mais demorados que nos demais grupos. Foi observada correlação negativa e moderada entre tempo, ΔRa e ΔRz (r = -0.445, r = -0.475, p< 0,01).Conclusão:todos os protocolos de limpeza do esmalte foram eficientes, pois não resultaram no aumento da rugosidade superficial. Quanto maior o tempo gasto, menor a rugosidade da superfície.

Enamel Quality after Debonding: Evaluation by Optical Coherence Tomography

The aims of this study were to evaluate quantitatively the enamel fractures, adhesive remnants and bracket fragments on enamel after debonding of metal and ceramic brackets, and to quantify the layer of adhesive remnants in depth after two different cleanup procedures. Metal and ceramic brackets were bonded on 120 human incisors and then debonded using two different techniques with Side Cutter (SC) and Anterior Bracket Removal plier (ABR). After this, a high-speed tungsten carbide finishing bur or a low-speed tungsten carbide finishing bur was used. The debonded samples were submitted to enamel assessment with optical coherence tomography (OCT). In sequence, two different methods of removing the remaining adhesive (tungsten carbide burs at high and low speed) were performed and at the end of these procedures, the remaining adhesive layer was measured with OCT. The results demonstrated that enamel fractures were observed only in the samples bonded with ceramic brackets, and the type of pliers did not influence the incidence and extent of enamel damage. Moreover, the type of debonding technique (with side-cutting pliers or anterior bracket removal pliers) and the type of bracket did not influence the amount of adhesive remaining after debonding. The burs at low speed removed the remaining adhesive more effectively during cleanup procedures.

Os objetivos deste artigo foram avaliar quantitativamente a presença de fraturas de esmalte, adesivo remanescente e fragmentos de bráquetes no esmalte após a descolagem de bráquetes metálicos e cerâmicos e quantificar a camada de adesivo remanescente após a realização de diferentes procedimentos de limpeza. Bráquetes metálicos e cerâmicos foram colados em 120 incisivos humanos e descolados usando duas técnicas diferentes: com alicate de corte (SC) e alicate removedor de bráquete (ABR). Após isso, brocas de carboneto de tungstênio em alta ou baixa velocidade foram utilizadas. As amostras de esmalte foram então submetidas à avaliação com tomografia de coerência óptica (OCT). Na sequência, foram realizados dois métodos diferentes de remoção do adesivo remanescente (brocas de carboneto de tungsténio em alta e baixa velocidade), e no final destes procedimentos, a camada de adesivo remanescente foi medida com OCT. Os resultados demonstraram que as fraturas de esmalte foram observadas apenas nas amostras coladas com bráquetes cerâmicos e o tipo de alicate não influenciou a incidência nem a extensão dos danos ao esmalte. Além disso, o tipo de técnica de descolamento com alicate de corte ou alicate de remoção de bráquetes e o tipo de bráquete não influenciaram a quantidade de adesivo remanescente após a descolagem. O uso de brocas em baixa velocidade mostrou-se mais efetivo na remoção do adesivo remanescente durante os procedimentos de limpeza.

Enamel surface evaluation after bracket debonding and different resin removal methods

OBJECTIVE: To assess enamel surface under scanning electron microscopy (SEM) after resin removal and enamel polishing procedures following brackets debonding, as well as compare the time required for these procedures. METHODS: A total of 180 deciduous bovine incisors were used. The enamel surface of each tooth was prepared and brackets were bonded with light cured Transbond XT composite resin. Brackets were removed in a testing machine. The samples were randomized and equally distributed into nine groups according to the resin removal and polishing technique: Group 1, 30-blade tungsten carbide bur in high speed; Group 2, 30-blade tungsten carbide bur in high speed followed by a sequence of 4 Sof-lex polishing discs (3M); Group 3, 30-blade tungsten carbide bur in high speed followed by Enhance tips (Dentsply). All groups were subdivided into (a) unpolished; (b) polished with aluminum oxide paste; and (c) polished with water slurry of fine pumice. Subsequently, the enamel surface was assessed and statistical analysis was carried out. RESULTS: There were statistically significant differences in enamel roughness and removal time among all groups. Groups 3a, 3b and 3c appeared to be the most efficient methods of removing resin with low damages to enamel. Groups 2a, 2b and 2c were the most time consuming procedures, and Group 2a caused more damages to enamel. CONCLUSION: The suggested protocol for resin removal is the 30-blade tungsten carbide bur in high speed followed by Enhance tips and polishing with aluminum oxide paste. This procedure seems to produce less damages and is less time consuming. .

OBJETIVO: avaliar a superfície do esmalte, por meio de microscopia eletrônica de varredura, após descolagem de braquetes e o polimento do esmalte, com diferentes técnicas de remoção de resina, bem como comparar o tempo necessário para a realização do procedimento. MÉTODOS: foram utilizados 180 dentes bovinos decíduos. A superfície do esmalte dos dentes foi preparada e realizada a colagem dos braquetes com resina Transbond XT. Os braquetes foram removidos em máquina de ensaio mecânico. Foram formados, aleatoriamente, nove grupos, de acordo com o tipo de remoção da resina e de polimento, sendo: Grupo 1, broca de tungstênio de 30 lâminas em alta rotação; Grupo 2, broca de tungstênio de 30 lâminas em alta rotação e sequência de quatro discos Soflex (3M); Grupo 3, broca de tungstênio de 30 lâminas em alta rotação e pontas de acabamento Enhance (Dentsply). Todos os grupos foram subdividido em (a) sem polimento, (b) polimento com pasta de óxido de alumínio e (c) polimento com pedra-pomes. As superfícies foram avaliadas e foi realizada análise estatística. RESULTADOS: houve diferença estatística entre os grupos em relação à rugosidade de superfície e ao tempo de remoção. Os grupos 3a, 3b e 3c demonstraram ser os métodos mais eficientes de remoção da resina, promovendo pouco dano à superfície do esmalte. Os grupos 2a, 2b e 2c consumiram maior tempo de procedimento, e o grupo 2a causou maior dano ao esmalte. CONCLUSÃO: sugere-se como protocolo de remoção o uso de broca de tungstênio de 30 lâminas para remoção do maior volume da resina, pontas de acabamento Enhance e polimento com a pasta de óxido de alumínio, por produzirem menor dano. .

Effect of sodium ascorbate on the bond strength of silorane and methacrylate composites after vital bleaching

We investigated the effect of sodium ascorbate (SA) on the microtensile bond strengths (MTBSs) of different composites to bovine enamel after vital bleaching with hydrogen peroxide (HP) or carbamide peroxide (CP). Thirty bovine incisors were randomly divided into five groups and treated with no bleaching application (control), 35% HP alone, 35% HP + 10% SA for 10 minutes (HP + SA), 16% CP alone, or 16% CP + 10% SA for 10 minutes (CP + SA). Specimens were restored with Silorane adhesive and Filtek Silorane composite (designated as S / group) or with Clearfil SE bond and Filtek Supreme XT (designated as F / group). Composite build-up was created on the enamel. Sectioned specimens (n = 10 per group; 1 mm2; cross-sectional area) were created and stressed in a universal testing machine at 1 mm/min crosshead speed. The application of 10% SA immediately after bleaching with 16% CP or 35% HP increased the enamel MTBS, regardless of the adhesive / composite resin used. The resulting MTBS values were similar to those of the control groups. Use of 16% CP and 35% HP alone decreased the enamel MTBS, regardless of the adhesive / composite resin used, with F / CP + SA = F / HP + SA = F / CP = S / CP + SA = S / HP + SA = S / C > S / CP = S / HP = F / CP = F / HP (p < 0.05). We concluded that the application of SA for 10 minutes immediately after vital bleaching increases the enamel BS for dimethacrylate- and silorane-based composites.

Assessment of shear bond strength of brackets bonded by direct and indirect techniques: an in vitro study / Avaliação da resistência ao cisalhamento de braquetes colados pelas técnicas direta e indireta: estudo in vitro

OBJECTIVE: This in vitro study was designed to evaluate the shear bond strength (SBS) of orthodontic metal brackets bonded by direct and indirect techniques. METHODS: Thirty healthy human maxillary premolar teeth were used. The teeth were divided into three groups of 10 teeth each: Group I - indirect bonding with SondhiTM Rapid-Set system (3M/Unitek), Group II - indirect bonding with TransbondTM XT adhesive system (3M/Unitek) and Group III - direct bonding with TransbondTM XT adhesive system (3M/Unitek). After bonding and obtaining the specimens for the study, the specimens were subjected to SBS testing in a universal testing machine (Emic, model DL-500). The Kolmogorov-Smirnov test was applied to ascertain that the data had a normal distribution and the Bartlett test to check whether there was homogeneity of variance. One-factor analysis of variance was performed and, subsequently, Tukey's test for paired means. A 5% significance level was adopted. RESULTS: The results of Group I were 67.6 (N) and 5.9 (MPa); Group II, 68.9 (N) and 6.1 (MPa) and Group III (control), 92.5 (N) and 8.1 (MPa). CONCLUSION: It can therefore be concluded that the means for Group III were significantly higher compared with Groups I and II in both Newton (N) and Megapascal (MPa) values. The means attained by the indirect bonding technique used in Groups I and II, however, exhibited no statistically significant differences.

OBJETIVO: objetivou-se com esse trabalho avaliar, em um estudo realizado in vitro, a resistência ao cisalhamento de braquetes metálicos ortodônticos colados pelas técnicas direta e indireta. MÉTODOS: foram utilizados 30 dentes pré-molares superiores humanos hígidos. Os dentes foram divididos em três grupos de 10 dentes: Grupo I - colagem indireta com sistema Sondhi Rapid-Set (3M/Unitek); Grupo II - colagem indireta com sistema Transbond XT (3M/Unitek); e Grupo III - colagem direta com sistema Transbond XT (3M/Unitek). Após realização das colagens e confecção dos corpos de prova, esses foram submetidos ao teste de cisalhamento em uma máquina universal de ensaios da marca comercial EMIC, modelo DL-500. Foram aplicados os testes de Kolmogorov-Smirnov, para verificar se os dados tinham uma distribuição normal, e o teste de Bartlett, para verificar se existia igualdade entre as variâncias. Aplicou-se a análise de variância de um fator e, posteriormente, o teste de Tukey para o contraste pareado de médias. O nível de significância foi de 5%. RESULTADOS: os resultados do Grupo I foram 67,6N e 5,9MPa; do Grupo II foram 68,9N e 6,1MPa; e do Grupo III (controle), 92,5N e 8,1MPa. CONCLUSÃO: pode-se concluir que tanto para os valores em Newtons (N) como para os valores em Megapascal (MPa), a média do Grupo III foi significativamente maior em relação aos Grupos I e II. Já para as médias onde a técnica indireta foi usada (Grupos I e II), não houve diferenças estatisticamente significativas.

Avaliação dos efeitos de três métodos de remoção da resina remanescente do braquete na superfície do esmalte / Effects evaluation of remaining resin removal (three modes) on enamel surface after bracket debonding

INTRODUÇÃO: é fundamental, para alcançar a correta técnica de descolagem, a seleção adequada do instrumental para remover o braquete e a resina remanescente. OBJETIVO: avaliar a superfície do esmalte com Microscópio Eletrônico de Varredura (MEV) após a utilização de três métodos de remoção da resina remanescente da descolagem do braquete. MÉTODOS: foram selecionados 18 incisivos bovinos, divididos em três grupos (A, B e C), contendo 6 dentes cada. Previamente à colagem do braquete, os dentes foram moldados com silicone de adição e preenchidos com resina epóxi, para o registro das características do esmalte, assim formando o Grupo Controle. Os métodos de remoção da resina remanescente utilizados foram: Grupo A - Soflex granulações grossa e média; Grupo B - broca Carbide em baixa rotação; Grupo C - broca Carbide em alta rotação. Polimento com Soflex granulações fina e ultrafina no Grupo A, pontas de borracha nos grupos B e C, e pasta de polimento para esmalte nos três grupos. Após cada etapa de remoção da resina remanescente e polimento, os dentes foram novamente moldados, duplicados e as réplicas analisadas em MEV. Foram, então, comparadas as características do esmalte inicial (Grupo Controle) com o aspecto do esmalte após as etapas de remoção de resina, assim possibilitando avaliar o método que gerou menor abrasão ao esmalte. RESULTADOS E CONCLUSÃO: a remoção do remanescente adesivo com broca Carbide multilaminada em baixa rotação, polimento com pontas de borracha, e polimento final com pasta de polimento é o procedimento que ocasiona menor dano ao esmalte.

INTRODUCTION: An appropriate selection of instruments is essential to perform a correct debonding technique, by properly removing orthodontic brackets and the remaining resin.OBJECTIVE: The aim of this study was to evaluate three methods of remaining resin removal on enamel surface after bracket debonding, by means of Scanning Electron Microscopy (SEM).METHODS: Eighteen bovine incisors were selected and divided into three groups (A, B and C) of six teeth each. Before bracket bonding, epoxy resin casts were obtained by impression of the teeth with addition silicon, in order to register baseline enamel characteristics and representing the control group. The methods for remaining resin removal were: Group A - gross and medium granulation Soflex discs; Group B - carbide bur in low-speed; Group C - carbide bur in high-speed. Soflex polishing system fine and ultrafine granulation discs were used for Group A, rubber tips for Groups B and C, and polishing paste for all groups. After polishing, impression of teeth were taken and casts were analyzed by means of SEM. The baseline enamel characteristics (Control Group) were compared to the final aspect of enamel to determine the method that generated less enamel abrasion.RESULTS AND CONCLUSION: The remaining resin removal by carbide bur in low-rotation, and enamel polished with rubber tips followed by polishing paste produced the smaller damage to the enamel.

Evaluation of enamel roughness after ceramic bracket debonding and clean-up with different methods

Aim: This study evaluated the surface roughness (Ra) and the topography (scanning electron microscopy) of the dental enamel after use of different methods for removal of residual resin after debonding of orthodontic brackets. Methods: Nine roughness measurements in three directions were made on enamel surface of 60 human premolars before bracket bonding (Ra initial).Ceramic brackets were bonded with Transbond XT and stored for 24 h/37°C before debonding with pliers. The specimens were divided in five groups according to the method used for removal of residual resin: control (C); carbide bur at slow-speed (CL); carbide bur at high speed (CH); Shofu tip at low speed (SB); Shofu tip at high speed (HB); debonding pliers (ZP). Nine final surface roughness measurements (Ra final) were made and one specimen of each group was observed by SEM. The data were analyzed statistically by ANOVA, Tukey’s test and paired t test(p<.05). Results: Ra final of SB was significantly higher than C, CL, CH, and ZP groups. The test showed that the Ra final was significantly higher than Ra initial for SB and CL. Conclusions:The method used for removal of residual resin influenced the roughness of the enamel. Carbide bur at high speed presented the best results and Shofu at low speed presented the worst results.

Shear bond strength of orthodontic brackets bonded using halogen light and light-emitting diode at different debond times

The aim of this in vitro study was to compare the photoactivation effects of QTH (Quartz-Tungsten-Halogen) and LED (Light-Emitting Diode) on the SBS (Shear Bond Strength) of orthodontic brackets at different debond times. Seventy-two bovine lower incisors were randomly divided into two groups according to the photoactivation system used (QTH or LED). The enamel surfaces were conditioned with Transbond self-etching primer, and APC (Adhesive Pre-Coated) brackets were used in all specimens. Group I was cured with QTH for 20 s and Group II with LED for 10 s. Both groups were subdivided according to the different experimental times after bonding (immediately, 24 h and 7 days). The specimens were tested for SBS and the enamel surfaces were analyzed according to the Adhesive Remnant Index (ARI). The statistical analysis included the Tukey's test to evaluate the main effects of photoactivation and debond time on SBS. The Chi-square test was used to compare the ARI values found for each group, and no statistically significant difference was observed. The debond time of 7 days for QTH photoactivation showed statistically greater values of SBS when compared to the immediate and 24 h periods. There was no statistically significant difference between the QTH and LED groups immediately and after the 24 h period. In conclusion, bonding orthodontic brackets with LED photoactivation for 10 s is suggested because it requires a reduced clinical chair time.