The purpose of this study was to evaluate the surface micromorphology of resin modified glass-ionomer cements and flowable compomers. In the study two resin modified glass-ionomers and two flowable compomers were used to prepare standardized 20 cylinderic samples. Samples were divided into four groups. Surface treatments with APF gel for experimental groups (group B,C,D) or distilled water as a control (group A) were performed four times. In group B, only APF gel was applied. In group C, after the APF gel application, the samples were immersed into the demineralizing and remineralizing solutions. In group D, before the APF gel application, the buffer solution was applied. The examinations of the surface micromorphology of the materials were made by using scanning electron microscope (SEM). Results showed that in group B all of the materials except Compoglass Flow, and in group C all of the materials showed erratic behaviours. In group D, severe erratic effect (score 2) was obtained on the surfaces of Vivaglassliner and Dyract Flow, and for the others score 1 signals were found. The moderate degradation was obtained by applying of only APF gel on the surfaces of both material groups. The addition of pH circulation caused increasing of micromorphologic changes on the surfaces of all materials. The effect of application of buffer solution on the surfaces before APF gel changed according to the materials. If acidulated fluoride gel is preferred for prophylactic therapy in patients' mouth, for the success, either buffer or neutral fluoride have to be applied on the restored teeth by resin based materials before acidulated fluoride application.