“…Asano (1965), one of our coworkers, revealed that the mesiodistal crown diameters of the deciduous teeth were consider- ably controlled by the genetic factors. The time of eruption of deciduous teeth (Hatton, 1955) and the salivary acidity-alkalinity (Turner et al, 1953) revealed also high similarity in monozygous twins. The average number of DEF experience of each child in both groups was shown in Table III and Fig.…”