Abstract
The unbalance of the reciprocal relation of the upper and lower alveolar ridges were found from the observation and measurement including its cross sections of the dental casts of the patient. It is reasonable to assume that the unbalance is caused by the underdevelopment of maxillary bone.
The length and width of the upper edentulous arch of the patient were 55-65% compared with normal. The length of the lower edentulous arch was 77.6% and the width was 88-95% compared with normal.
The interalveolar crest line angles were only 60-67.5 degrees in several regions.On the contrary, the interalveolar crest distance showed twice as large as normal distance.
The upper edentulous arch form was V shaped and the lower edentulous arch form wasoval.
The palate was deeply grooved with the upper alveolar ridge severely resorbed.
