关键词: 乳牙下沉, 牙根固连, 乳牙萌出异常, 咬合诱导, 早期矫治

Abstract: Ankylosis of primary teeth（also known as ankylosed primary teeth or submerged primary tooth）is a common abnormal clinical condition during the primary and mixed dentition periods，characterized by the occlusal plane of primary teeth being lower than adjacent teeth. Its etiology is complex，involving systemic factors（such as genetics and hormonal imbalances）and local factors（such as trauma and periodontal infections）. Ankylosis of primary teeth can lead to a series of complications，such as abnormal development of permanent teeth，occlusion disorder，and malocclusion. This article reviews the etiology，clinical manifestations，diagnosis，and treatment strategies of primary tooth ankylosis，emphasizing the importance of early diagnosis and multidisciplinary combined treatment，and providing references for clinicians.

Key words: primary tooth ankylosis, tooth roots are firmly attached, abnormal eruption of deciduous teeth, occlusal guidance, early orthodontic treatment