Mineralization in the midpalatal suture after orthodontic expansion.

A new method is described for an objective measurement of the mineralization in the anterior part of the midpalatal suture after its orthodontic expansion. The radioisotope 125I is used as radiation source and is placed intraorally in the same position on each measurement occasion. The extraoral part of the apparatus consisted of a scintillation crystal and a pulse-height analyzer to determine the number of roentgen quanta transmitted. The measurements showed that the mineral content within the suture rose rapidly during the first month after the completion of suture opening. In the bone beside the suture, the mineral content decreased sharply during the first month of measurement; later it returned to the initial level.