关键词: 发育异常, 第一恒磨牙, 恒中切牙, 磨牙牙根-切牙发育畸形

Abstract: Molar-root incisor malformation（MRIM）is a dental development anomaly，primarily characterized by developmental defects in the roots of affected molars and the cervical region of anterior tooth crowns，which not only compromise anterior esthetics but also lead to clinical complications，such as pulp and periapical diseases. Currently，the etiology of MRIM remains undetermined. In clinical practice，personalized treatment plans should be developed for each case，involving sequential treatment through multidisciplinary collaboration. This article provides a comprehensive overview of the etiology，clinical and radiographic characteristics，histological features，diagnostic criteria，and management strategies for MRIM，aiming to offer evidence-based recommendations for clinical diagnosis and treatment.

Key words: development anomaly, first permanent molar, permanent central incisor, molar-root incisor malformation