Two methods of treatment for skeletal Class Ⅲ malocclusion on airway changes before and after clinical research / 口腔疾病防治

Objective @# To investigate the changes in the sagittal diameter of the upper airway before and after the treatment of skeletal Class Ⅲ malocclusion in adults with microimplant anchorage and class Ⅲ intermaxillary elastics and to provide a reference for clinical treatment. @*Methods @#A total of 35 adult patients with skeletal Class Ⅲ malocclusion were selected to be treated with the straight-wire technique. Microimplant group, 15 cases (group A): patients with severe skeletal Class Ⅲ malocclusion (vertical high angle) were treated with the straight-wire technique combined with microimplant anchorage; class Ⅲ intermaxillary elastics group, 20 cases (group B): Patients with mild or moderate skeletal Class Ⅲ malocclusion (vertical low angle and average angle) were treated with the straight-wire technique combined with class Ⅲ intermaxillary elastics, and cephalometric radiographs obtained before and after treatment in the upper airway in the two groups were measured and analyzed.@*Results @#Changes in cranial and maxillofacial measurements after correction: in group A, (sella-nasion-supramental angle) the SNB angle decreased significantly (P < 0.05), and (subspinale-nasion-supramental angle) the ANB angle increased significantly (P < 0.05). In group B, the SNB angle decreased significantly (P < 0.05), while (subspinale-nasion-subspinale angle) the SNA angle、ANB angle and anterior skull base plane-mandibular plane angle (Sn-MP) angle increased significantly (P < 0.05). Changes in sagittal diameter of the upper airway measurements after corrections: In group A, the width of the glossopharyngeal segment of the upper airway (TB-TPPW) decreased significantly (P < 0.05). In group B, first segment width of the upper airway behind the hard palate (PNS-R) increased significantly (P < 0.05). After correction, the decreased SNB and increased ANB in group A was higher than that in group B, and the difference was statistically significant （P < 0.05）. The decreased of TB-TPPW in upper airway of group A was greater than that of group B, and the difference was statistically significant （P < 0.05）.@* Conclusions @#In the treatment of skeletal class Ⅲ malocclusion with microimplant anchorage, the sagittal diameter of the glossopharyngeal segment of the upper airway has a negative impact.

Without mini-plates, mini-implants and surgery: treatment of severe anterior open bite in an adult patient: a case report

Currently, there is a tendency to treat open bite with mini-implants, miniplates, and orthognathic surgeries and build ups when these protocols are not always indicated and to be apply them unnecessarily and excessively. Objectives: This case report describes treatment of a severe anterior open bite in an adult patient with step bends and vertical elastics. Case report: The female patient was 29 years and 8 months old and reported that she had low self-esteem; therefore, she wanted to have her untreated open bite closed. By examination, a convex profile, vertical growth pattern, dental midline deviation, and tongue exposure could be seen upon smiling. The dental and skeletal sagittal relationship was Class II. The overjet was +5 mm and the anterior overbite was -5.5 mm. The severe skeletal open bite involved the first molars to the anterior teeth, and it was treated only with step bends and vertical elastics over 2 years. Results: Significant facial improvement, maxillary incisor exposure upon aesthetic smiling, and adequate overbite and overjet were observed. The upper and lower dental midlines fit to the sagittal line. A counterclockwise rotation of the mandible was observed. The severe skeletal open bite was treated. Conclusions: Severe skeletal open bite malocclusion treated with step bends and vertical elastics in adult patient demonstrated efficient, predictable and stable open bite correction.

Introdução: Atualmente, existe uma tendência de tratar a mordida aberta com mini-implantes, miniplacas, cirurgias ortognáticas e levantes de mordida, quando estes protocolos nem sempre são indicados e a sua aplicação pode ser desnecessária e excessiva. Objetivo: Este relato de caso descreve o tratamento de uma mordida aberta anterior grave em paciente adulto com "step bends" e elásticos verticais. Relato do caso: A paciente tinha 29 anos e 8 meses de idade e relatou ter baixa autoestima; portanto ela queria fechar sua mordida aberta não tratada. Ao exame, um perfil convexo, padrão de crescimento vertical, desvio da linha média dental e exposição da língua podiam ser vistos ao sorrir. A relação sagital dental e esquelética era de Classe II. O overjet de +5 mm e o overbite anterior de -5,5 mm. A mordida aberta esquelética grave envolveu os primeiros molares até os dentes anteriores e foi tratada apenas com "step bends" e elásticos verticais por pouco mais de 2 anos. Resultados: Melhoria facial significativa, exposição dos incisivos superiores ao sorriso estético, sobremordida e overjet adequados foram observadas. As linhas médias dentárias superior e inferior adequadas à linha sagital. Foi observada rotação da mandíbula no sentido antihorário. A mordida aberta esquelética grave foi tratada. Conclusão: A má oclusão grave da mordida aberta esquelética tratada com "step bends" e elásticos verticais em pacientes adultos demonstrou correção eficiente, previsível e estável da mordida aberta.

Begg's mechanotherapy: Revisited!!!!!!!!!!

The Begg's light wire technique is a simple technique that is capable of producing good results with minimum efforts. It is an easy technique requiring a simplistic diagnosis and stereotype treatment. However, it lost popularity due to its projection as a “cook book” treatment and an overemphasis on extractions, based on theory of attritional occlusion. Here, a review is presented on various cases treated with Begg's mechanotherapy encompassing its advantages and disadvantages.

Comparação da degradação da força de elásticos ortodônticos intermaxilares de látex e sintéticos quando submetidos à distensão em saliva artificial / Comparison of force degradation intermaxilary latex and synthetic orthodontic elastics distended in artificial saliva

Introdução: os elásticos intermaxilares sintéticos surgiram como uma alternativa para uso ortodôntico em pacientes com sensibilidade ao látex, porém, diferenças podem ser observadas quando comparados aos elásticos naturais de látex. Objetivo: comparar a quantidade de degradação de força dos elásticos intermaxilares sintéticos e de látex quando distendidos em saliva artificial, a fim de buscar parâmetros clínicos para o uso de um protocolo sobre a frequência de troca desses elásticos nas terapias ortodônticas em pacientes com sensibilidade ao látex ou não. Metodologia: foram utilizados dois grupos contendo 30 elásticos cada. O grupo 1 com 30 elásticos de látex da marca Morelli de força média e diâmetro de 5/16" e o grupo 2, 30 elásticos sintéticos, sem látex, também da marca Morelli de força média e diâmetro de 5/16". Eles foram distendidos 4cm e submersos em saliva artificial a 37 graus Celsius e tiveram força mensurada com dinamômetro ortodôntico ao início e nos intervalos de 24, 48, 72 e 120 horas após a imersão. A avaliação da degradação da força foi realizada calculando o percentual de força perdida em relação à força inicial em cada intervalo de tempo, para cada grupo testado separadamente e também entre eles. Resultados e Discussão: a média de valores dos elásticos tanto de silicone quanto de látex teve um percentual parecido quanto à degradação de forças, visto que após as primeiras 24 horas ocorreu o maior declínio de força, de aproximadamente 11% ambos os elásticos. Após 48 horas esse percentual não se alterou significativamente. Conclusão: elásticos devem ser trocados em até 48 horas para que a força aplicada se mantenha em índices aceitáveis.

Introduction: synthetic intermaxillary elastics have emerged as an alternative for orthodontic use in patients with latex sensitivity, but differences can be observed when compared to natural latex elastics. Objective: compare the amount of force degradation of synthetic intermaxillary elastics and latex when distended in artificial saliva in order to find clinical parameters for the use of a protocol on the frequency of exchange of these elastics in orthodontic therapies in patients with latex sensitivity or not. Method: for this, two groups containing 30 elastics were used. Group 1 with 30 medium strength and diameter 5/16 "Morelli latex elastics and group 2, 30 synthetic latex-free elastics, also of the medium strength and 5/16" diameter Morelli brand. They were stretched 4cm and submerged in artificial saliva at 37 degrees Celsius and had strength measured with orthodontic dynamometer at the beginning and at the intervals of 24, 48, 72 and 120 hours after immersion. The force degradation assessment was performed by calculating the percentage of force lost in relation to the initial force at each time interval, for each group tested separately and also between them. Results and discussion: the mean elastic values of both silicone and latex had a similar percentage for the degradation of forces, since after the first 24 hours the greatest force decline occurred, of approximately 11% both elastics. After 48 hours this percentage did not change significantly. Conclusion: elastics should be changed within 48 hours so that the force applied remains at acceptable rates.

Utilização dos elásticos intermaxilares nos estágios iniciais do tratamento ortodôntico / Use of intermaxillary elastics in early treatment stages

A Ortodontia contemporânea tem aumentado, substancialmente, a utilização de fios superelásticos durante o alinhamento e nivelamento dentário e a sua permanência tem alcançado estágios avançados do tratamento, com a premissa de trabalhar, o máximo possível, com forças de baixa intensidade. Essa mudança de protocolo tem desafiado os ortodontistas a criar mecanismos de controle de movimentação dentária e de efeitos colaterais indesejados, que comumente são atribuídos a esses fios, em razão da sua alta flexibilidade e baixa resistência à expressão dos momentos da força, gerados, por exemplo, por acessórios como os elásticos intermaxilares. O objetivo desse trabalho é descrever, ilustrando com casos clínicos, a viabilidade e aplicabilidade desses acessórios na correção das relações anteroposteriores ainda em estágios iniciais do tratamento, com fios superelásticos, com ou sem propriedade de transformação térmica (AU)

Contemporary orthodontics has considerably increased the use of superelastic wires during teeth alignment and leveling and their permanence has reached advanced stages of treatment with the premise of working as much as possible with low levels of force. This protocol change has been challenging orthodontists to create mechanisms to control tooth movement and unwanted side effects that are commonly attributed to these wires, due to their great flexibility and their low resistance to the expression of moments of force generated, for example, by accessories like intermaxillary elastics. The objective of this article is to describe, using clinical cases to illustrate, the viability and applicability of intermaxillary elastics in anteroposterior relationships correction during early stages of treatment with superelastic wires with or without heat activating properties.(AU)

Maxillary protraction using skeletal anchorage and intermaxillary elastics in Skeletal Class III patients / 대한치과교정학회지

The aim of this case report is to describe the treatment of a patient with skeletal Class III malocclusion with maxillary retrognathia using skeletal anchorage devices and intermaxillary elastics. Miniplates were inserted between the mandibular lateral incisor and canine teeth on both sides in a male patient aged 14 years 5 months. Self-drilling mini-implants (1.6 mm diameter, 10 mm length) were installed between the maxillary second premolar and molar teeth, and Class III elastics were used between the miniplates and miniscrews. On treatment completion, an increase in the projection of the maxilla relative to the cranial base (2.7 mm) and significant improvement of the facial profile were observed. Slight maxillary counterclockwise (1degrees) and mandibular clockwise (3.3degrees) rotations were also observed. Maxillary protraction with skeletal anchorage and intermaxillary elastics was effective in correcting a case of Skeletal Class III malocclusion without dentoalveolar side effects.

Tratamento das más oclusões sagitais com a utilização de elásticos intermaxilares / Treatment of sagittal malocclusions using intermaxillary elastics

Independentemente do tipo da má oclusão sagital, ou seja, de Classe ll ou de Classe lll, os planos de tratamento ortodôntico são elaborados objetivando-se a Classe l. Utilizando-se conceitos modernos de se promover movimentação ortodôntica em ambientes com baixa resistência ao deslizamento e, tomando alguns cuidados com relação ao seu uso, os elásticos intermaxilares são apontados, atualmente, como dispositivos principais para se obter os resultados propostos. O seu baixo custo e sua versatilidade fazem deste dispositivo uma importante ferramenta nos tratamentos ortodônticos.

Regardless the type of sagittal malocclusion (Class ll or Class lll), orthodontic treatment plans are established in order to achieve the Class I occlusion. Applying modern concepts to create orthodontic movement in settings with low sliding resistance and taking some precautions during their use, intermaxillary elastics are currently indicated as main devices to achieve the expected results. The low cost and versatility of this material make this device an important tool for orthodontic treatments.

Cytotoxicity of separation orthodontic elastics / Citotoxicidade de elásticos ortodônticos de separação

OBJECTIVE: To test the hypothesis that there is no difference in cytotoxicity between separating elastics of different manufacturers. METHODS: The present article compared latex elastics (4.0 mm, 4.4 mm and 4.8 mm) of four different manufacturers. The sample was allocated to seven groups of 9 elastics: Group A (American Orthodontics, green color, modules), Groups M1 and M2 (Morelli, blue color, modules and free in pack respectively), Groups M3 and M4 (Morelli, green color, modules and free in pack respectively), Group U (Uniden, blue color, free in pack) and Group T (Tecnident, blue color, free in pack) regarding their possible cytotoxic effects on oral tissues. Cytotoxicity assays were performed using cell culture medium containing epithelioid-type cells (Hep-2 line) derived from human laryngeal carcinoma and submitted to the methods for evaluating the cytotoxicity by the "dye-uptake" test, at time intervals 24, 48, 72 and 168 h. Data were compared by analysis of variance (ANOVA) and Tukey's test (p < 0.05). RESULTS: Results showed statistically significant difference (p < 0.05) between group U and all the other Groups (A, M1, M2, M3, M 4 and T) at 24 and 48 hours. CONCLUSIONS: Uniden elastics evoked more cell lysis at 24 and 48 h, although, all brands showed biocompatibility from 72 h onwards.

OBJETIVO: o propósito do presente estudo foi testar a hipótese que não existe diferença de citotoxicidade entre elásticos de diferentes marcas. MÉTODOS: foram comparadas entre si 4 marcas de elásticos de separação (4,0mm, 4,4mm e 4,8mm) intrabucais de látex quanto ao possível efeito citotóxico nos tecidos bucais, divididos em 7 grupos de 9 elásticos cada: grupo A (cor verde - modular, American Orthodontics), grupos M1 e M2, (cor azul - modular e a granel, respectivamente, Morelli), grupos M3 e M4 (cor verde - modular e a granel, respectivamente, Morelli), grupo U (cor azul - a granel, Uniden) e grupo T (cor azul - a granel, Tecnident). O ensaio de citotoxicidade foi realizado utilizando-se cultura de células da linhagem HEp-2 (do tipo epitelióide, que tem origem em carcinoma de laringe humana), sendo submetido o material ao teste para células viáveis em vermelho neutro ("dye-uptake"), no tempo de 24, 48, 72 e 168 horas. A análise de variância e comparação múltipla (ANOVA) e o teste de Tukey foram utilizados (p<0,05). RESULTADOS: os resultados evidenciaram diferença estatisticamente significativa dos grupos A, M1, M2, M3, M4 e T com o grupo U nos tempos de 24 e 48h (p<0,05). CONCLUSÃO: pôde-se evidenciar que os elásticos da marca Uniden causaram alta quantidade de lise celular em 24 e 48h, porém, todas as marcas mostraram-se biocompatíveis a partir de 72h.

Avaliação das tensões liberadas por elásticos ortodônticos em cadeia: estudo in vitro / Assessment of force decay in orthodontic elastomeric chains: an in vitro study

INTRODUÇÃO: os materiais elastoméricos são considerados importantes fontes de força para a movimentação ortodôntica. OBJETIVO: avaliar a liberação de tensões de quatro marcas comerciais de elásticos ortodônticos em cadeia (Morelli, Ormco, TP e Unitek), em função do tempo, quando mantidas tensionadas por uma força inicial de 150g e imersas em saliva artificial a 37ºC. MÉTODOS: os elásticos em cadeia foram tensionados entre pinos de aço, fixados em uma placa de resina acrílica à distância de 15mm (Morelli e TP) e de 16mm (Unitek e Ormco), ambas medidas correspondendo a uma força de 150g. A leitura da quantidade de tensão liberada pelos elásticos foi realizada com um dinamômetro nos intervalos 30 minutos, 7, 14 e 21 dias. Os dados obtidos foram submetidos à análise de variância (ANOVA) (p<0,05) e ao teste de Comparações Múltiplas de Tukey. RESULTADOS: após 30 minutos de teste, verificou-se redução entre 19 por cento e 26,67 por cento na quantidade de tensão liberada pelos elásticos; e entre 36,67 por cento e 57 por cento após 21 dias de estiramento constante. CONCLUSÕES: os elásticos em cadeia que apresentaram comportamento mais estável foram os da marca TP, pois relataram menor perda de potencial elástico nos intervalos de tempo testados. Os da marca Unitek demonstraram maior redução de tensão liberada. As marcas Ormco e Morelli obtiveram resultados semelhantes entre si.

INTRODUCTION: Elastomeric materials are considered important sources of orthodontic forces. OBJECTIVE: To assess force degradation over time of four commercially available orthodontic elastomeric chains (Morelli, Ormco, TP and Unitek). METHODS: The synthetic elastics were submerged in 37 ºC synthetic saliva and stretched by a force of 150 g (15 mm - Morelli and TP; 16mm - Unitek and Ormco). With a dynamometer, the delivered force was evaluated at different intervals: 30 minutes, 7 days, 14 days and 21 days. The results were subjected to ANOVA and Tukey's test. RESULTS: There was a force decay between 19 percent to 26.67 percent after 30 minutes, and 36.67 percent to 57 percent after 21 days of activation. CONCLUSIONS: TP elastomeric chains exhibited the smallest percentage of force decay, with greater stability at all time intervals tested. Meanwhile, the Unitek chains displayed the highest percentage of force degradation, and no statically significant difference was found in force decay between Ormco and Morelli elastomeric chains during the study period.

Evaluation of Change - In - Schedule of Intra Oral Orthodontic Elastic In A Simulated Oral Environment - An In - Vitro Study.

This project evaluated the change- in -schedule of intra oral orthodontic elastics in a simulated oral environment. The bands of two manufacturers’ American orthodontics and Dentarum were examined with three bands in each subgroup of two groups (I and II). The initial force delivered by randomly selected intra oral elastics was recorded for extensions of 225%, 300% and 450%. Then the elastics were engaged on to a special jig having posts at a distance of 14.8mm, 19mm and 28.4mm in order to extend the diameter of elastics by 225%, 300% and 450% respectively and incubated at 37˚C in artificial saliva for 24 and 48 hours of time. Force degradation of intra oral elastics was calculated in grams. Data was analyzed using ANOVA. The force degradation was high during first 24 hours and the elastics should be changed on a daily basis.

Cytotoxicity of orthodontic elastics: in vitro investigation with on L929 mouse fibroblasts

Aim: To test the hypothesis that there is no difference in the cytotoxicity among natural latex elastics of different manufacturers using a L929 cell line culture. Methods: Different latex intra oral elastics (I.D. = 5/16", 4.5 oz.) were tested. The sample was divided into 7 groups of 15 elastic seach: Group AO (American Orthodontics), Group GAC (GAC International), Group TP (TP Orthodontics), Group AD (Aditek), Group AB (Abzil), Group MO (Morelli) and Group UN (Uniden).Cytotoxicity assays were performed by using cell culture medium containing L-929 line cells(mouse fibroblast). The cytotoxicity was evaluated by using the “dye-uptake” test, which wasemployed at two different moments (1 and 24 h). Data were compared by ANOVA and Tukey’s test(P < 0.05). Results: The results showed a significant difference (P < 0.05) between all groups and the group CC (cell control) at 1 and 24 h. Groups AD, AB, MO and UN were noticeably more cytotoxic than the groups AO, GAC and TP at 1 h. After 24 h, a significant decrease in cell viability was observed in all groups. Conclusions: Intraoral elastics from American Orthodontics, GACand TP Orthodontics trademarks induced less cell lysis than Aditek, Abzil, Morelli and Uniden trademarks.

In vitro cytotoxicity of latex orthodonticelastics / Citotoxicidad de los elásticos ortodònticos de látex

Natural latex does not fall into the category of materials known to be entirely inoffensive. The objective of the present in vitro study is to test the hypothesis that there is no difference in the cytotoxicity between natural latex elastics of different colours. The present article compared different latex intra-oral elastics (5/16 = 7.9 mm). The sample was divided into four groups according to their manufacturer: Group N (Natural latex elastic, Morelli), Group R (Red colour elastic, Morelli) Group Y (Yellow colour elastic, Morelli) and Group G (Green colour elastic, Morelli). Cytotoxicity assays were performed by using cell culture medium containing L-929 line cells (mouse fibroblast). The cytotoxicity was evaluated by using the “dyeuptake” test, which was employed at two different moments (1 and 24 h). Data were compared by analysis of variance (ANOVA) and Tukey’s test (p<0.05). The results showed a significant difference (p<0.05) between the groups N, R, Y, G and the negative cytotoxicity control at 1 and 24 h (p<0.05), it did not have presented significant difference between the groups N, R, Y, G tested (p>0.05) at 1 and 24 h. Morelli intra-oral elastics were found to be highly cytotoxic, regardless of their colour and immersion time.

El látex natural no entra en la categoría de materiales que se sabe del todo inofensivo. El objetivo del presente estudio in vitro es poner a prueba la hipótesis de que no hay diferencia en la citotoxicidad entre elásticos de látex natural de diferentes colores. El presente artículo compara diferentes elásticos intraorales de látex (5/16 =7,9 mm). La muestra se dividió en cuatro grupos según su fabricante: Grupo N (elástico látex, Morelli), Grupo I (elástico de color rojo, Morelli) Grupo Y (elástico de color amarillo, Morelli) y el Grupo G (elástico color verde, Morelli). Pruebas de citotoxicidad se realizaron mediante el uso de medio de cultivo celular que contiene líneas celulares L-929 (fibroblastos de ratón). La citotoxicidad se evaluó mediante el test “dye-uptake”, que se empleó en dos momentos diferentes (1 y 24 h). Los datos se compararon mediante análisis de varianza (ANOVA) y test de Tukey (p<0,05). Los resultados mostraron una diferencia significativa (p<0,05) entre los grupos N, R, Y, G y la negativa citotoxicidad del control en 1 y 24 h (p<0,05), no han presentado diferencias significativas entre los grupos N, R , Y, G probado (p>0,05) en 1 y 24 h. Elásticos intraorales Morelli resultaron ser altamente citotóxicos, independientemente de su color y tiempo de inmersión.

Orthodontic treatment for the second molar crossbite / 实用口腔医学杂志

Crossbite of upper and lower second molars is a common malocclusion. It is difficult to treat such cases. 4 kinds of treatments according to different situations are recommended. One is a mutual elastics on the upper and lower teeth. The second method is to move upper and lower teeth by archwire lingually and bucally. The third is to extract the second molars, while the third molars drift automatically. The fourth is using mini-implant as an anchorage to move the teeth to correct position. This article evaluated the advantages and disadvantages of the 4 kinds of methods. We also discussed how to choose the appliances as well as what we should pay attention to treat this malocclusion.

Cytotoxicity of latex and non-latex orthodontic elastomeric ligatures on L929 mouse fibroblasts

This study investigated the cytotoxicity exists between latex and non-latex Orthodontic elastomeric ligatures. Six elastomeric ligatures (1 latex, 2 latex-free and 3 polyurethane) from different manufacturers were divided into 6 groups of 15 elastics each: A (Latex-free, American Orthodontics), M (Polyurethane, Morelli), G (Polyurethane,GAC International), Te (Polyurethane, Tecnident), TP (Natural latex,TP Orthodontics) and U (Latex-free,3M Unitek). The cytotoxicity assay was performed using cell cultures (L929 mouse fibroblast cell line), which were subjected to the cell viability test with neutral red ("dye-uptake") at 1, 2, 3, 7 and 28 days. Data were analyzed statistically by ANOVA and Tukey's test (α=0.05). No statistically significant differences (p>0.05) were observed between Groups M and Te in all experimental periods, except at 2 days. No significant differences (p>0.05) in cell viability were found either among Groups A, G, TP and U or between Groups M and Te at 24 h or among Groups CC, A, G, TP and U at 2 and 28 days. It may be concluded that latex-free elastomeric ligatures from American Orthodontics and Unitek trademarks induced less cell lysis compared to latex and polyurethane ligatures.

Este estudo investigou a citotoxicidade entre ligaduras elásticas ortodônticas de látex e não-látex. Seis ligaduras elásticas de diferentes fabricantes (1 látex, 2 não-látex e 3 poliuretano) foram divididos em 6 grupos de 15 elásticos cada: Grupo A (látex-free, American Orthodontics), M (Poliuretano, Morelli), G (Poliuretano, GAC International), Te (Poliuretano, Tecnident), TP (látex natural, TP Orthodontics) e U (Látex-free, 3M Unitek). O ensaio de citotoxicidade foi realizado utilizando culturas de células (células da linhagem L929, fibroblastos de camundongo) que foram submetidos ao teste de viabilidade celular com vermelho neutro ("dye-uptake") em 1, 2, 3, 7 e 28 dias. A análise de variância (ANOVA), com comparações múltiplas e teste de Tukey foram empregados (α=0,05). Os resultados mostraram que não houve diferença estatisticamente significante entre os Grupos M e Te em todos os tempos experimentais (p>0,05), exceto em 2 dias. Não houve diferença estatisticamente (p>0,05) entre a viabilidade das células nos grupos A, G, TP e U ou entre os grupos M e Te em 24 h, ou entre os grupos CC, A, G, TP e U em 2 e 28 dias. Concluiu-se que as ligaduras elásticas látex-free das marcas American Orthodontics e Unitek induziram menor quantidade de lise celular comparado às ligaduras de látex ou poliuretano.

Evaluation of the in vitro biocompatibility of orthodontic elastics

Aim: Latex has been extensively used in orthodontics since the advent of the specialty. Natural latex does not fall into the category of materials known to be entirely inoffensive. The objective of the present in vitro study is to test the hypothesis that there is no difference in the cytotoxicity between natural latex elastics of different colors. Methods: The present article compared different latex intra-oral elastics (5/16 = 7.9 mm, mean load). The samples were divided into six groups of 15 elastics according to their manufacturer: Groups N, Y, V, R, G and P (Uniden, natural latex elastics and colored elastics, namely, yellow, violet, red, green and pink, respectively).Cytotoxicity assays were performed by using cell culture medium containing cells from mouse fibroblast cell line L929. The cytotoxicity was evaluated by using the “dye-uptake” test, which was employed at two different moments (1 and 24 h). Data were compared by ANOVA and Tukey’s test (P < 0.05). Results: There was statisticallysignificant difference (P < 0.05) between the groups N, Y, V, R, G, P and the cell control at 1 h. After 24 h, a decrease in cell viability was observed in all groups. There was statistically significant difference (P < 0.05) between all test elastics groups and the cell control at 24 h. No statistically significant difference (P >0.05) was found among the test elastics groups at 24 h. Conclusion: Latex elastics from natural, yellow, violet and red colors induced a lowest amount of cell lysis compared to the elastics green and pink colors at 1 h, all latex elastics were found to be highly cytotoxic, regardless of their color at 24 h.

Cytotoxicity of intermaxillary orthodontic elastics of different colors: an in vitro study

OBJECTIVES: Natural latex does not fall into the category of materials known to be entirely inoffensive. The purpose of this in vitro study was to test the hypothesis that there is no difference in the cytotoxicity between elastics of different colors and those from different manufacturers. MATERIAL AND METHODS: Different latex intraoral elastics of different colors (5/16 = 7.9 mm, mean load) were compared. The sample was divided into 7 groups of 24 elastics each: Group T (TP Orthodontics, natural latex elastics, control); Groups U1, U2, U3, U4, U5 and U6 (Uniden, natural latex elastics and colored elastics, namely, green, pink, yellow, red and purple, respectively). Cytotoxicity assays were performed by using cell culture medium containing epithelioid-type cells (Hep-2 line) derived from human laryngeal carcinoma. The cytotoxicity was evaluated by using the "dye-uptake" test, which was employed at two different moments (0 and 24 h). Data were compared by analysis of variance (ANOVA) and Tukey's test (p<0.05). RESULTS: There was statistically significant difference (p<0.05) between Group T and all other groups (U1, U2, U3, U4, U5 and U6) at 0 and 24 h. No statistically significant difference (p<0.05) was found between Groups U1 and U5, U1 and U6, U2 and U3, U2 and U4, U2 and U5, U2 and U6, U3 and U4, U3 and U5, U3 and U6, U4 and U5, U4 and U6, and U5 and U6 at 0 and 24 h. CONCLUSIONS: The TP Orthodontics elastics promoted less cell lysis compared to the Uniden elastics regardless of their color.

Avaliação in vitro da citotoxicidade de elásticos ortodônticos intermaxilares / In vitro cytotoxicity evaluation of intermaxillary orthodontic elastics

Objetivo: Avaliar a citotoxicidade de quatro diferentes marcas comerciais de elásticos intermaxilares intra-orais utilizando ensaio de citotoxicidade em culturas de células. Metodologia: Quatro marcas comerciais de elásticos foram avaliadas: American Orthodontics (Grupo 1), TP Orthodontics (Grupo 2), Morelli (Grupo3) e Uniden (Grupo 4). Os elásticos foram previamente esterilizados em luz ultravioleta e colocados em placas de Petri, as quais continham cultura de células HEp-2 em concentração de 105. Foram utilizadas cinco placas para cada grupo, num total de 15 elásticos testados por grupo (n=15). Após 24h, as monocamadas de células foram coradas para avaliação dos halos de difusão e de lise celular de acordo com o Índice de Resposta de Stanford. Resultados: Houve ausência de citotoxicidade para os elásticos das marcas American Orthodontic e TP Orthodontic e alta citotoxicidade nos elásticos das marcas Morelli e Uniden. Conclusão: Com base na metodologia utilizada e nos resultados encontrados, conclui-se que os elásticos da marca Morelli e Uniden apresentaram alta citotoxicidade.

Purpose: To evaluate the cytotoxicity of four different commercially marketed intermaxillary orthodontic elastics using cell culture. Methods: Four brands of orthodontic elastics were evaluated: American Orthodontics (Group1), TP Orthodontics (Group 2), Morelli (Group 3) and Uniden (Group 4). The elastics were previously sterilized using ultraviolet light and then placed on Petri dishes containing tissue cultures of HEp-2 cells at concentration of 105 for 24h. Five Petri dishes were used for each group, and a total of 15 elastics were tested per group (n=15). The cell monolayers were stained for evaluation of the diffusion halo and cell lysis according to the Response Index by Stanford. Results: There was absence of cytotoxicity for American Orthodontic and TP Orthodontic elastics, but high cytotoxicity produced by Morelli and Uniden elastics. Conclusion: Based on the methods used, the results suggest that Morelli and Uniden orthodontic elastics have high cytotoxicity.

The effects of changes of mandibular position on temporomandibular joint in adult rabbits whose retrodiscal tissues were incised / 대한치과교정학회지

The purpose of this experiment was to study the effects of changes of mandibular position on temporomandibular joint in internal derangement patients. Twenty-four female New Zealand White Rabbits, weighing over 3.5kg, were utilized in this study. Bilateral temporomandibular joint surgery was performed in twenty one of the rabbits to displace disc anteriorly through incising the retrodiscal tissue 1-2mm posterior to the disc, thus inducing internal derangement. They were divided into three groups: nine were left untreated after surgery, six were fitted with functional protrusive appliances 4 weeks after surgery, and six wore collar appliances to apply 4 ounces of mandibular retractive force per side 4 weeks after surgery. The remaining three served as the control group. Histologic examinations were performed after sacrificing them by threes at 4-week intervals. The results were as follows: 1. Histologic findings similar to internal derangement were observed in the rabbits whose retrodiscal tissues had been incised. 2. In the rabbits untreated after surgery, articular surface on condylar process and articular eminence showed severe erosion and deformation, and displaced disc manifested changes in both shape and internal architecture. 3. Functional protrusion after surgery resulted in progressive remodeling on posterosuperior portion of condyle and glenoid fossa, while it also brought about erosion on articular eminence and anterior portion of condyle. 4. Mandibular retraction after surgery resulted in compression of retrodiscal tissue and regressive remodeling of posterior portion of condyle.