The Pathology of the First Permanent Molar during the Mixed Dentition Stage—Review

Background: The eruption of the first permanent molar (FPM) marks the beginning of the mixed dentition, which is one of the most dynamic periods in the development and growth of the stomatognathic system. Aim: The purpose of the study was to investigate the pathology of the first permanent molar (FPM) during the transition stage between the primary and permanent dentition. Materials and Methods: A literature search was performed in Clarivate Web of Science, Google Scholar, and PubMed databases. Cohort and cross-sectional studies, reviews, case reports, background information, and expert opinion were included. Results: Ectopic eruption is one of the most frequent pathologies during the mixed dentition period, and ectopic eruption of the maxillary FPM is the most encountered. Hypomineralization is currently the most prevalent pathology of the hard dental tissue in FPM, often in association with the same type of damage on the incisors in the context of the so-called molar incisor hypomineralization (MIH). FPM particular vulnerability to caries is due to its posteruptive enamel maturation, which is accomplished during the mixed dentition stage. Conclusions: Proper clinical management of FPM pathology is a demanding task for the pediatric dentist and is of great importance for the development of a healthy permanent dentition and stable occlusion.