Global variations in eruption chronology of primary teeth: A systematic review and meta-analysis

Objectives: This systematic review aimed to assess global variations in the eruption chronology of primary teeth in children and the role of sexes, jaws, and socio-economic status on eruption timing. Design: An extensive search of electronic databases, grey literature, and hand-searching was carried out until April 2023 Results: A total of 42,109 children, with an age range of 0-83 months were included from 42 studies (22 in Asia, 7 in Europe, 5 in Africa, 4 in North America, 3 in Oceania and 1 in South America). The mandibular central incisor was the first tooth to erupt at 6 months in North America and 13.5 months in Asia while the mandibular second molar erupted at 20.1 months in Europe and 29 months in South America. Conclusions: The age of primary teeth eruption was advanced in the European population followed by North America, Africa, Oceania, and Asia while it was delayed in the South American population. Meta-analysis showed that tooth eruption was earlier in the left quadrant than the right but the role of other factors (sexes, jaws, and socio-economic status) was insignificant. Population-specific data on primary teeth emergence may serve as a baseline for future research. In clinical practice, these population-based eruption charts can serve as a valuable asset for diagnosis and treatment planning in children.