THE INFLUENCE OF AIR-DRYING ON HYPER-REMINERALIZATION OF DEMINERALIZED DENTIN - A STUDY ON BULK AS WELL AS ON THIN WET SECTION OF BOVINE DENTIN

The influence of air-drying on the remineralization of demineralized b ovine dentine was examined in wet bulk samples, in dried bulk samples as well as in wet thin sections. Bulk samples of bovine dentine were f irst demineralized in an acidic gel (pH = 5) at 37 degrees C for 3 wee ks. After 24-hour pre-treatment of either air-drying or immersion in w ater, the bulk samples were remineralized in a solution containing 1.5 mM Ca, 0.9 mM phosphate and 10 ppm F- (pH = 7) at 37 degrees C for 2, 4 or 8 days. Separately thin sections prepared from demineralized bul k dentine were immersed in water for 24 h and were also exposed to the remineralization solution for 2, 4 or 8 days. The results show that a ir-drying of the bulk samples increased remineralization of dentine co nsiderably; the microradiographic parameters (1(d), Delta Z and 1(a)) show that the degree of remineralization ranks: thin wet sections > bu lk dried > bulk wet. Especially, the remineralization inside lesions w as greatly enhanced in thin sections and dried samples. It is presumed that the increased remineralization in dried samples is caused by a ' sponge effect', in which the remineralization fluid is sucked up in a dried shrunken lesion, resulting in fast and deep penetration of remin eralization solution and/or presumably increased nucleation.