Crown dimensions of primary teeth-A systematic review and meta-analysis

Odontometrics, also known as metric traits, includes mesiodistal, buccolingual dimensions, and crown height. The purpose of this study was to assess pancontinental odontometric variations in the crown dimensions of primary teeth. Ten electronic databases were searched to identify studies that measured crown dimensions of primary teeth, published in English language, without year restriction up to July 2020. Studies included cross-sectional research measuring on casts, subjects, and on radiographs of healthy children. Meta-analysis was performed, and risk of bias was assessed using modified Newcastle-Ottawa Scale. Eighty-seven observational studies were included, with 24,634 participants (9487 males, 11,083 females; 19 studies lacked gender information). Only one study showed a low bias risk, whereas 81 and 5 studies had moderate and high risk, respectively. Sixty-five studies included for meta-analysis revealed heterogeneity in mean mesiodistal dimensions of maxillary first molars from Asia (I² -99.7%), buccolingual measurements of mandibular first molars from Europe (I² -99.9%), crown height of mandibular second molars from Africa and Europe (I² -79.8%). Among mesiodistal and buccolingual dimensions, Australians have larger while Asians have smaller teeth. Pertaining to crown height, very few studies could be found in the literature. This review highlights the variations in crown dimensions of primary teeth among populations.