BACKGROUND: Infraocclusion of deciduous teeth is a frequent dental anomaly caused by ankylosis accompanied by local growth disturbance. During puberal growth spurt an increasing progression of infraocclusion is detected. The clinical classification of ankylosed deciduous teeth varies considerably among scientific studies. The aim of this paper is to present an up-to-date overview of the variety of methods. METHODS: The systematic literature search followed the PRISMA guidelines and included the analysis of the following databases and study registries: PubMed (MEDLINE), the Cochrane Library, Web of Science, Embase.com and ClinicalTrials.gov from database inception until September 23, 2024. Studies that investigated at least one ankylosed deciduous tooth per participant in a quantitative or qualitative manner were included. Studies that evaluated only histological data were excluded. Controlled and uncontrolled clinical studies, retrospective studies, observational studies and cross-sectional studies were included. The studies were restricted to English and German languages. Case reports, case series, comments, expert opinions, letters to the editor, literature reviews and studies enrolling less than 10 patients or 10 infraoccluded teeth in total were excluded. RESULTS: Of 5645 records, 42 papers qualified for the final analysis. The evaluation of infraoccluded deciduous teeth was mainly (n = 37) performed by quantitative and semiquantitative assessment of the extent of infraposition at the occlusal level. The measurement reference differed considerably. Fewer studies have analyzed ankylosed deciduous teeth at the alveolar level by examining the contour of the alveolar ridge (n = 7) or the height of the alveolar process (n = 5). Even fewer studies (n = 4) have performed qualitative analysis at the skeletal level by evaluating the influence of the vertical skeletal growth pattern on the incidence of ankylosed deciduous teeth. CONCLUSIONS: To carry out a comprehensive evaluation of infraoccluded deciduous teeth, an assessment of the occlusal, alveolar and potentially skeletal levels is advisable. Radiographic investigations i.e. panoramic radiographs are therefore essential as a supplement to clinical examination. There is a need for standardization and objectification of the methods for the classification of infraoccluded deciduous teeth to give a general recommendation of clinical performance. REGISTRATION: This systematic review has been registered in the international prospective register of systematic reviews (PROSPERO) under the registration number: CRD42024555842.