A micro-structural study of caries arrested with silver diamine fluoride

Method:  Eight carious primary upper-central incisors were collected from 6-year-old children. Four teeth had arrested caries after 24-month biannual SDF applications and 4 had active caries when there was no topical fluoride treatment. The elemental contents and surface morphology of cavitated dentinal lesion were assessed by energy-dispersive X-ray spectrometry (EDX) and scanning electrode microscopy (SEM).

Result: EDX examination detected a higher intensity of calcium and phosphate within approximately 150 µm from the surface (surface zone) than in the inner zone, but this zone was absent in the active cavitated dentinal lesion. The surface morphology of the arrested dentinal lesion under SEM showed a relatively smooth surface with few dentin collagen fibres exposed. Dense granular structures of spherical grains were found in the inter-tubular area at high magnification. The surface morphology of the active dentinal lesion was porous and rough. Collagens were found to be exposed, disorganized, and sparsely distributed at high magnification.

Conclusion: A remineralised zone rich in calcium and phosphate was found on the arrested cavitated dentinal lesion of primary teeth which were treated with SDF applications. The collagens were protected from being exposed in the arrested cavitated dentinal lesion.