Résumé
Self-ligating brackets encompass fast popularity over the past several decades and had various advantages with regard to the efficiency, effectiveness, and stability of treatment when compare with conventional brackets. Self ligating brackets are basically two main types, according to the design of the locking mechanism, the dimensions of the slot, and the dimensions of the arch wires; they are passive and active. Active self-ligating brackets have a spring clip that stores energy to press against the archwire for rotation and torque control. Self-ligating brackets appear to be the beneficiary of the most recent studies as their design and engineering can offer the clinician the ability to take advantage of our better understanding of arch wire/bracket interactions. Since we know the impact of different bracket –arch wire combinations on the resistance to sliding, it is now possible for us to select the best combination depending upon the case.
Résumé
9 adults aged 23 to 43 years old were treated with bidimensional self-ligating lingual bracket technique for upper teeth and labial ceramic or aesthetic bracket for lower teeth.After treatment the labioclination of anterior teeth in Angle's II patients decreased from 28.12°± 10.05°to 19.25°±3.12°(P <0.05),in Angle's III patients from 32.14°±4.71°to 28.15°±3.26(P <0.05).
Résumé
OBJETIVO: avaliar a resistência ao cisalhamento de braquetes metálicos (American Orthodontics) utilizados na técnica lingual, colados em facetas de cerâmica. MÉTODOS: foram utilizados 40 corpos de prova divididos em quatro grupos de 10, de acordo com o material de colagem e do preparo da porcelana: Grupo I -resina Sondhi Rapid-Set e ácido fluorídrico; Grupo II -resina Sondhi Rapid-Set e óxido de alumínio; Grupo III -resina Transbond XT e ácido fluorídrico; e Grupo IV -resina Transbond XT e óxido de alumínio. Previamente à colagem, os braquetes foram preparados com base de resina de carga pesada (Z-250) e as facetas de cerâmica receberam aplicação de silano. O teste de cisalhamento foi realizado por uma máquina de ensaios Kratos à uma velocidade de 0,5mm/min. RESULTADOS: os resultados obtidos foram analisados estatisticamente através do teste de Tukey (p<0,05) e demonstraram diferença significativa entre os grupos I (2,77MPa) e IV (6,00MPa), e entre os grupos III (3,33MPa) e IV. CONCLUSÕES: concluiu-se que a colagem de braquetes da técnica lingual em superfície de cerâmica foi mais resistente ao cisalhamento com o uso de óxido de alumínio associado às duas resinas utilizadas neste estudo, porém a resina Transbond XT apresentou maior resistência que a Sondhi Rapid-Set.
OBJECTIVE: The aim of this study was to evaluate the shear strength of lingual metal brackets (American Orthodontics) bonded to ceramic veneers. METHODS: A total of 40 specimens were divided into four groups of 10, according to bonding material and ceramics preparation: Group I -Sondhi Rapid-Set resin and Hydrofluoric acid, Group II -Sondhi Rapid-Set resin and aluminum oxide, Group III -Transbond XT resin and Hydrofluoric acid, and Group IV -Transbond XT resin and aluminum oxide. Prior to bonding, the brackets were prepared with heavy-duty resin base (Z-250) and the ceramic veneers were treated with silane. The shear test was conducted with a Kratos testing machine at a speed of 0.5 mm/min. RESULTS: The results were statistically analyzed by the Tukey test (p<0.05) and showed a statistically significant difference between groups I (2.77 MPa) and IV (6.00 MPa), and between groups III (3.33 MPa) and IV. CONCLUSION: In conclusion, the bonding of lingual brackets to ceramic surfaces exhibited greater shear strength when aluminum oxide was used in association with the two resins utilized in this study, although Transbond XT showed greater shear strength than Sondhi Rapid-Set.