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A roentgencephalometric study of the facial profile has been performed on 22 patients before and one year after surgical treatment or mandibular protrusion by transverse osteotomy bilaterally in the ascending rami. In another 10 patients treated in the same way the facial profile has also been studied 11 years after treatment. A change in position of the lower lip and chin contour corresponding to the positional change of the underlying mandibular bone and mandibular incisors was recorded. The upper lip became elongated and also a slight retroposition was recorded after treatment. During the 10 year period no considerable positional changes were observed. The result of the maxillo-facial treatment seems to be relatively permanent during the long observation period one to 11 years after treatment.
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Björk et al. (1971) studied this question.
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