Análise morfológica da superfície dentinária hígida e afetada por cárie e da camada híbrida após aplicação de emulsão à base de óleo de copaíba (Copaifera multijuga Hayne)

Abstract

The copaiba oleoresin, extracted from Copaifera multijuga Hayne is used popularly for various purposes. Because of biological properties, a copaiba oil emulsion was formulated to be used before applying the adhesive in order to improve the quality of dentin bonding. The aim of this study was to evaluate the morphological characteristics of the dentin surface and the hybrid layer formed with etch-and-rinse and self-etching adhesive systems in sound and caries-affected dentin after using copaiba oil emulsion. 96 third molars from Biobank of the School of Dentistry, University Federal of Amazonas, were used. Half of the teeth underwent artificial induction of dental caries and the other half was formed by sound teeth. All teeth had their roots removed; yielding dentine disks were divided into groups according to test substances (2% chlorhexidine, copaiba oil emulsion, calcium hydroxide solution and distilled water), the dentin (sound or caries-affected) and the adhesive system (Adper Single Bond 2® or Clearfil SE Bond®). The dentin surface and the hybrid layer of the obtained specimens were analyzed by SEM according to the experimental groups. The treatment of dentin surface with copaiba oil emulsion showed no physical barrier to the adhesive penetration. The dentin surface treated with 2% chlorhexidine showed phosphate salts in two types of dentin. The treatment of the dentin surface with calcium hydroxide solution resulted in the deposition of mineral precipitate obstructing the lumen of the tubules in sound dentin. The calcium hydroxide solution applied on the conditioned sound dentin was different from the other substances (p<0.05). In smeared surface, distilled water in sound dentin showed a significant difference from all experimental groups (p <0.05). There was no statistical difference between the hybrid layer formed with the Adper Single Bond 2® adhesive in sound and caries-affected dentin treated with the test substances. The hybrid layer with Clearfil SE Bond® in caries-affected dentin treated with copaiba oil emulsion showed no statistical difference in relation to the tested substances, shown statistical difference only with calcium hydroxide solution in caries-affected dentin (p <0.05). In sound dentin, there was no statistical difference in the hybrid layer with Clearfil SE Bond® irrespective of the tested substances. The application of copaiba oil emulsion showed no morphological change in sound and caries-affected dentin, regardless of phosphoric acid etching; and presented a uniform hybrid layer, regular and large monomer infiltration in sound and caries-affected dentin, regardless of the adhesive system.