Avaliação in vitro de bactérias e fungos na superfície de aparelhos ortodônticos removíveis / Evaluation in vitro of bacteria and fungi in surface removable orthodontic appliances

O acometimento do indivíduo por patologias, como a cárie e doenças periodontais, pode ser traumático e extremamente devastador, podendo levá-lo a situações de grande comprometimento da saúde bucal e sistêmica. A introdução dos aparelhos removíveis pode predispor o desenvolvimento destas de modo que, além de aumentar o número populacional destes microrganismos, induz uma grande queda do pH intrabucal, favorecendo o processo de desmineralização dos tecidos duros e agredindo concomitantemente os tecidos moles. Logo, é necessário pesquisar e entender a fixação destes na superfície de aparelhos ortodônticos. A coleta foi realizada antes e 15 dias após a instalação dos aparelhos ortodônticos removíveis na cavidade bucal, mediante um esfregaço com swab estéril, aplicando movimentos anteroposteriores sob pressão manual na região do acrílico e na região dos parafusos expansores, quando houvesse. Na coleta inicial, houve crescimento de microrganismos em 15% dos casos para o Agar Mitis Salivarius, e 5% para o Ágar Sabouraud. Já na coleta após os 15 dias de instalação, verificou-se aumento para 100% de contaminação nas placas de Agar Mitis Salivarius, e as placas de Ágar Sabouraud permaneceram com os 5% de contaminação. Um padrão de limpeza mais bem elaborado desses aparelhos deve ser praticado pelos que o utilizam, além de estar indicada a substituição do aparato após algum tempo de uso, pois a inserção do aparelho modifica o ambiente da cavidade bucal.

The involvement of the individual by diseases such as caries and periodontal disease can be traumatic and extremely devastating and can lead one to situations of great commitment of oral and systemic health. Also, the introduction of removable appliances may predispose the development of these so that in addition to increasing the population of these microorganisms, it induces a large drop in the intraoral pH value, favoring the process of demineralization of hard tissues and simultaneously attacking the soft tissue, thus it is important to research and understand the fixation of these on the surface of orthodontic appliances. Data collection was conducted prior to installation of removable orthodontic appliances and 15 days after by a swipe with a sterile swab, applying movements from front to back under manual pressure in acrylic region and the region of expander bolts. At the first exam, 15% of cases had Agar Mitis Salivarius and 5% Agar Sabouraud. Fifteen days later, all appliances were contaminated with Agar Mitis Salivarius, while only 5% of devices were contaminated with Agar Sabouraud. A detailed cleaning must be exercised over these devices, along with replacement of the orthodontic device after some period because it can change the oral environment.

Shear bond strength of metallic brackets: an in vitro study

To evaluate in vitro the shear bond strength of metallic brackets.Material and Methods:Forty premolars were divided into four groups (n = 10) according to the type of brackets used (G1: Morelli® Light; G2: Morelli® Standard; G3: Morelli® Max; G4: Abzil® Agile). For bonding, Transbond XT® (3M Unitek) resin was used in all groups. Teeth were embedded in ¾ inch PVC tubes with special plaster stone, perpendicular to the ground. Brackets were fixed on the geometric centers of the exposed crowns. After bonding, teeth were stored in distilled water, incubated at 37ºC for 24 hours and submitted to 500 thermal cycles for 30 seconds in each bath (5°C and 55°C), respectively. The bond strength test was performed on the Instron® mechanical testing machine with 3kg load cell at speed of 0.5mm/min. Data were submitted to statistical analysis through the Statistica® software, version 5.0, by Kruscal Wallis test, ANOVA and Tukey (p< 0.05).Results:There was no statistically significant difference in the ARI scores; whereas for shear resistance, this difference was significant (Averages: G1 -Light: 17.53MPa; G2 -Standard: 18.11MPa; G3 -Max: 29.33MPa; G4 -Agile: 11.37MPa) and G3 showed better performance, compared to the others. All other groups showed similar behavior among themselves. Conclusion:Max bracket had the highest shear strength. Further studies should be conducted to investigate the meshes of brackets tested in this study...