The effects of infraocclusion: Part 1. Tilting of the adjacent teeth and local space loss.

The normal arrangement of the transseptal fibers in the dentition is one of a completely horizontal system that links the mesial and the distal aspects of each tooth within the dental arch, from the most distal tooth of one side to the most distal tooth of the other, across the midline. This continuous fiber band is parallel to the occlusal plane, being attached to each tooth coronal to the level of the interradicular alveolar bone crest and apical to the cementoenamel junction. Alteration of the occlusal plane will be mirrored by a similar change in the plane of the transseptal fiber system. From the clinical observation of young people with infraoccluded deciduous teeth, over many years, the regular and concomittant occurrence of certain other, well-defined phenomena appears to be the rule. It was thought that these phenomena could be explained in terms of the inclusion of a vertical component (infraocclusion) into this horizontal system. Two of these phenomena are discussed here. The first and most obvious of these relates to the exaggerated tipping that affects the adjacent tooth mesially and distally. The second parameter measures the amount of actual horizontal (mesiodistal) space change that occurs locally, within the dental arch, between the two teeth adjacent to the infraoccluded tooth, measured at both the occlusal level and at the level of their root apices. With a high degree of statistical validity, it was found that infraocclusion is related to severe tilting of the two adjacent teeth toward the affected tooth, with minimal space loss in the dental arch at the occlusal level, but a wide separation of root apices.