چكيده لاتين :
Introduction: The low contents fluoride tooth pastes are effective and safe in pedodontics. The purpose of this in vitro experimental study was comparing microhardness changes following application of crest 1100 ppm, crest 500 ppm, pooneh 500 ppm and pooneh without fluoride.
Materials & Methods: In this experimental invitro study fifty-six primary incisors were mounted in cylindrical tubes by epoxy resin. The initial surface microhardness of exposed surface was measured based on Vickers unit in 1500, 1000 and 500 micrometer by Buhler instrument. Then dental blocks were randomly divided into four groups as, Crest 1100 ppm, Crest 500 ppm, Pooneh 500 ppm and Pooneh without fluoride. The four groups were immersed in demineralization solution and tooth pastes suspension in PH-cycling Process. Surface microhardness of the samples was again measured after demineralization and suspension. Paired ?-test, ANOVA and Tukey test were used for statistical analysis. Results: The mean and standard deviation of initial surface microhardness was 341+29, The mean and standard deviation of surface microhardness after exposed suspensions of crest 1100 ppn\ crest 500 ppm, pooneh 500 ppm and pooneh without fluoride were 258±5.6, 241+9.3, 248+7.6 and 238+7.9 respectively. The mean change in surface microhardness in crest 1100 ppm, crest 500 ppm, pooneh 500 ppm and pooneh without fluoride were 45.4, 28.6, 35.4 and 23.7 respectively. Conclusion: The mean change in surface microhardness between crest 500 ppm and Pooneh 500 ppm was not different. The difference in surface microhardness between crest 500 ppm, pooneh 500 ppm and pooneh without fluoride was insignificant.
