Altered dietary habits are becoming etiological factor in the development of dental erosion. Evaluation of changes in microhardness of enamel after exposure to acidic center-fi lled chewing gums. Exposure of enamel to center filling (concentrated acid) and outer coating along with center filling in artificial saliva (dilute acid) of two chewing gums (Center Fresh and Bubbaloo) to evaluate the difference in microhardness change between primary and permanent enamel, on exposure to concentrated and dilute acids and two chewing gums. A total of 120 primary and permanent molar extracted teeth were painted with acid resistant varnish except a small buccal window and divided into eight groups according to type of dentition, chewing gum and acid exposure. 5 min acid exposures were done twice a day for 5 days. Then, specimens were submitted for microhardness studies. Independent sample t -test and paired t-test were used in statistical analysis. Statistically significant difference in reduction of microhardness is seen between groups exposed to dilute and concentrated acid, reduction of microhardness is more with dilute acids than concentrated acids.; but the difference is seen neither on exposure to two chewing gums nor between primary and permanent enamel. (1) Dilute acid causes a defi nite reduction in microhardness than concentrated acid. (2) Two types of chewing gums are equally effective. (3) Permanent and primary teeth are equally affected. (4) Outer coating of center-filled chewing gum is not protective against reduction in microhardness of enamel. Therefore, acidic center-fi lled chewing gums cannot be suggested to children.