Tissue response to air-abrasive powder, to pulverized enamel and dentin.

XYJHEN the airbrasive technic for cavity preparation is used, there is alW ways a hazard that some of the powder, tooth substance, and old filling material will be inhaled or introduced into the adjacent gingival tissues. It seemed desirable, therefore, to investigate tissue reactions to these substances. According to specifications from the manufacturer of the airbrasive powder,* it contains A1203-94.56 per cent, Si02-2.23 per cent, TiO2-2.75 per cent, FeO-0.41 per cent, CaO-trace. The particle size is specified by the company to be between 10 to 50 microns (average, 40 microns). A cursory study of the powder smeared on a glass slide and placed under a microscope revealed that there were numerous particles present with particle size less than 10 microns, but no conclusive study was undertaken on particle size. One component of the formula, silica, is known to produce definite toxic effects resulting in a granulomatous reaction. The effect of aluminum oxide is controversial. It is claimed to be inert' by some investigators and toxic by others.2-4 That implanted teeth are gradually resorbed is well established, but no report could be found on the fate of finely pulverized enamel and dentin implanted into living tissues. In reaction to dust, particle size is a very important factor with increasing tendency for granulomatous reaction with smaller particle size.'