Avaliação in vitro de resinas ortodônticas autoadesivas experimentais associadas a bráquetes cerâmicos

• Autor(a) principal: Costa, Ana Carolina de Figueiredo
• Data de Publicação: 2017
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Ceará (UFC)
• Texto Completo: http://www.repositorio.ufc.br/handle/riufc/28726
• topic: Odontologia; Materiais Dentários; Ortodontia

Objectives: To evaluate the degree of conversion, flexural strength, shear bond strength before and after the thermal cycling of experimental autoadhesive orthodontic resins with ceramic brackets and the fracture pattern after simulation of clinical removal. Materials and Methods: The functional monomers MDP (10-methacryloyloxy-decyl-dihydrogen phosphate) and GDMA-P (glycerol-dimethacrylate-phosphate) acids were used in experimental autoadhesive orthodontic resins. These were compared to the same experimental resin (without acid monomer) in the Positive Control group (with acid and adhesive conditioning) and in the Negative Control group (without acid or adhesive conditioning). The degree of conversion was evaluated by Raman micro-spectroscopy. Ceramic brackets were glued to bovine teeth and the shear strength was evaluated before and after 2000 thermal cycles. For evaluation of the clinical fracture pattern, representative specimens of each group were removed manually with a specific pliers and analyzed by scanning electron microscopy. The results were analyzed by ANOVA and Tukey post-hoc test (p <0.05). Results: The degree of conversion of the control resin (84.5 ± 4.3%) was significantly higher (p <0.05) to GDMA-P and MDP (58.8 ± 4.0% and 23.0 ± 5 , 2%, respectively). The three-point flexural test showed no significant difference between the resins (p = 0.451). At adhesion, Positive Control (8.47 ± 0.88 MPa) and MDP (7.07 ± 2.69 MPa) obtained higher results before thermocycling, with no statistical difference between them. The shear strength was statistically reduced for all groups after thermocycling (p <0.05). The predominant fracture pattern of the Positive Control and MDP was mixed fracture and the other groups were adhesive. Conclusion: MDP orthodontic resin obtains similar adhesion to conventional three-step resin with similar mechanical properties and fracture pattern. However, the presence of functional acid monomer reduces the degree of conversion.