Abstract
The object of this study was to know what changes take place on the dental arch during the changing dentition. For this purpose, two excellent cases were observed from six to twelve years of age, and the following results were obtained from its observation. Enlargement of dental arch was observed till the shedding of the deciduous second molar. In the anterior segment, not only the increment of the arch width but also the labial inclination and/or movement of the permanent incisors was noted in conjunction with the eruption of these teeth. These tendencies were slightly observed during the eruption of the permanent canine. In the buccal segment, the space for the permanent buccal teeth increased during the time of eruption of the permanent canine and first premolar, and this increase made it possible for these teeth to align normally.
