AIR-ROTOR STRIPPING AND ENAMEL DEMINERALIZATION IN-VITRO

This investigation sought to evaluate the effects of air-rotor strippi ng on the susceptibility of human enamel to demineralization using an in vitro caries model. Crowns of extracted premolar teeth were abraded (0.5 mm) on one proximal surface by air rotor stripping. The teeth we re placed in a demineralizing gel and removed at various intervals up to 336 hours. Lesion depth and mineral content on the abraded and inta ct surfaces was measured with contact microradiography and computerize d image analysis (double window technique). For each time interval mea sured, lesion depth was greater (p < 0.05) on the abraded surfaces and mineral density was significantly less (p < 0.05). In a second experi ment, the effect of fluoride supplements (dentifrice or topical gel) w ere examined on abraded and intact enamel surfaces that were exposed t o the acid gel for 192 hours. The data showed that fluoride treatments significantly reduced lesion penetration on intact and abraded surfac es compared with a no fluoride group. Lesion depth on the abraded, flu oride treated surfaces was significantly greater (p < 0.05) than on th e intact untreated surfaces. No significant differences (p < 0. 05) we re apparent between the fluoride treatment groups with respect to lesi on depth and mineral density within the lesion. These results suggest that air-rotor stripping significantly increases the susceptibility of proximal enamel surfaces to demineralization. As a result, the clinic ian should use caution in the application of this technique until the long-term effects on caries susceptibility have been determined.