We used sample size of 30 permanent teeth (premolar) and 30 primary teeth which selected based on previous study[15 (link)] that were extracted due to orthodontics. The teeth were examined by a stereomicroscope, and the nonhypoplastic, Nonhypocalcification and nonfractioned teeth were selected. The teeth were washed to remove the blood, saliva, and other debris, and they were then cleaned with slurry of pumice and placed in the physiologic serum until the start of the experiment. Subsequently, the samples were fixed to the acrylic resin so that enamel appears. Then, to create a smooth surface, the outer enamel surface of specimens was ground with sandpaper (600 grit and then 1200 grit). Then, the microhardness of the enamel in all specimens was measured with Vickers hardness tester (MHZ, Koopa Company, Mashhad, Iran) using Vickers diamond indenter with 50 g load for 10 s. For each specimen, three different hardness tests were performed and the mean degree was reported. Subsequently, the groups were divided as follows:
All specimens were exposed to a solution containing 5 g of popping chocolate/candy dissolved in 2 mL of saliva twice a day for 5 min in 5 days. After each exposure, specimens were washed into distilled water for 20 s and then immersed in the artificial saliva until the next stage of the test. Artificial saliva was changed daily.[15 (link)] Subsequently, retests were carried out with the Vickers hardness test. For each specimen, hardness was measured in triplicate and the average was reported. Before the start of the experiment, one sample of each group was sent to atomic force microscopy (AFM) (Easyscan2 Flex) to evaluate surface roughness, and topography was prepared. After the experiment, topography was made from the same sample [Figures2 and 3 ].
Primary tooth (D)–permanent teeth (P)
Popping chocolate (A)–strawberry popping candy (B)–orange popping candy (C).
All specimens were exposed to a solution containing 5 g of popping chocolate/candy dissolved in 2 mL of saliva twice a day for 5 min in 5 days. After each exposure, specimens were washed into distilled water for 20 s and then immersed in the artificial saliva until the next stage of the test. Artificial saliva was changed daily.[15 (link)] Subsequently, retests were carried out with the Vickers hardness test. For each specimen, hardness was measured in triplicate and the average was reported. Before the start of the experiment, one sample of each group was sent to atomic force microscopy (AFM) (Easyscan2 Flex) to evaluate surface roughness, and topography was prepared. After the experiment, topography was made from the same sample [Figures
