In vitro studies of the penetration of adhesive resins into artificial caries-like lesions

Instead of removing the porous carious tissue at a relatively late stage in the disease process, attempts have been made to 'fill' the microporosities of lesions at a much earlier stage of lesion development. This would not only reduce the porosity and therefore access of acid and egress of dissolved material, but also afford some mechanical support to the tissue and perhaps inhibit further attack. Successful infiltration of materials into lesions has been demonstrated previously using resorcinol-formaldehyde which, however, was clinically unacceptable. The advent of dental adhesives with potentially suitable properties has prompted a re-examination of this concept. Artificial lesions of enamel were generated in extracted human teeth using acidified gels. A range of currently available adhesive materials was then used to infiltrate the porosities. The extent of occlusion of the lesion porosities was determined both qualitatively using light microscopy and quantitatively using a chloronaphthalene imbibition technique. The effect of such treatment upon subsequent exposure to acid gels was also investigated. Results showed that up to 60% of the lesion pore volume had been occluded following infiltration with some of the materials and that this treatment was capable of reducing further acid demineralization. The development of such treatment strategies could offer potential noninvasive means of treating early enamel lesions.