The abrasion of acrylic resin by cleaning pastes

The physical removal of plaque from dentures by brushing is important in the maintenance of oral health. However, there is a danger that brushing will abrade acrylic resin. A machine using a rotary brushing action was therefore utilized for laboratory tests of possible cleaning pastes, employing a toothbrush with good access and adaptability to denture surfaces. Crest toothpaste produced the most abrasion on acrylic resin, Dentu-Creme the least. An experimental paste produced an appreciably lower abrasion rate. Self-cured specimens wore more than heat-cured ones. The rate of abrasion decreased as the temperature was raised. Brushing with water alone, or with a 10% solution of soap, did not produce detectable wear. The wear produced by proprietary cleaners when hand brushing the lingual flanges of dentures and flat blanks of heat-cured acrylic was also measured. Boots denture cleaning paste produced the greatest abrasion, Dentu-Creme the least. The wear measured by reference to a glass plane was at least twice that recorded by the decrease in depth of a groove. The machine did not quantitatively produce the same abrasion as hand brushing, nor did it qualitatively rank the pastes in the same order of abrasiveness. The clinical relevance of these results is discussed.