Phenotypic characteristics of molar-incisor mineralization-affected teeth. A light and scanning electron microscopy study

This study aimed to characterize the morphology of the first permanent molars affected by molar-incisor hypomineralization (MIH) using a light microscope (LM) and scanning electronic microscope (SEM). A total of 8 teeth were divided into two groups: experimental group − 4 first permanent molars being clinically diagnosed as MIH, and control group − 4 sound and healthy first permanent molars. The free surfaces of each tooth were split in half across in a buccolingual direction and then were examined using SEM and LM. Under LM observation the hypomineralized enamel appeared opaquer and demonstrated areas of porosity. The SEM observation of enamel with MIH revealed superficial defects which embedded numerous colonies of microorganisms as well as disorganized prisms and loosely packed crystallites. Our results support the idea that there is a significant distinction between the structure of MIH-affected and sound unaffected enamel. The clinical appearance of MIH-affected enamel correlated with the severity of enamel changes.