There are several causes of midline discrepancy: functional abnormalities, bone structure abnormalities and the displacement of teeth from their proper position in the jaw. In the case of some functional abnormality, early detection and treatment will prevent it from becoming a major bone structure abnormality. To treat bone structure abnormalities in the post adolescent growth period, surgery is an effective way of treating the root of the problem.
However, in actual cases, the cause of midline discrepancy is usually a combination of these, and there is no magic bullet that works for every situation. Here, I'd like to report on a case of an adult male with a combined midline discrepancy and deep overbite, who was treated with extraction of the first upper right premolar.

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The purpose of this study is to compare the treatment results obtained by two different methods; the first being to treat cases with use of bite plane effects in the anterior teeth and the second being to treat cases by building up resin on posterior teeth, thus preventing anterior interference.
From this study, it can be said that, though some substantial differences are seen in some of the measured items between the ‘Resin buil-up’ group and the ‘Bite-plane group’, they are not so meaningful clinically. We can achieve good treatment results either way. However in most high angle cases, early bracket interference often causes Various problems. We have to exercise caution, especially in treating Mongoloids including Japanese, who tend to be more dolichofacial than Caucasians. Therefore, it can be said that the ‘Resin build-up’ method is much better for treatment of high angle cases where we seek to prevent clockwise rotation of the mandible. Use of the ‘Resin build-up’ method is further recommended for treatments where anterior intrusion is desirable.

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