Facial growth in relation to dental occlusion

Abstract

The problem was to investigate the relationship of growth in the face and head with the concomitant type of dental occlusion. Toward this end anthropometric measurements on face and head, and observations on dental occlusion, were made on groups of 50 native-born Jewish males at 2½ to 3½ years, and every other year thereafter until and including 20½ to 21½ years; a group of old men, averaging 74 years in age, was also examined for effects of senility. The data were organized according to stage of tooth eruption and with regard to type of dental occlusion. The results were as follows:

• 1.

  Completion of eruption of the deciduous dentition occurs somewhat earlier in abnormal than in normal occlusion; conversely, the permanent first molars seem to erupt earlier in normal than in abnormal occlusion. The permanent second molars, however, also appear earlier in abnormal occlusion. Practically no difference in time is evident in eruption of the third molars in either normal or abnormal occlusion.

• 2.

  Comparing the various dimensions of the head and face with respect to normal and abnormal occlusion, little or no difference was noted in the head except maximum width and width of the forehead (minimum frontal), each of which is appreciably narrower in abnormal occlusion cases in early childhood. In the face, the widths are also generally narrower in cases with abnormal occlusion, especially in early childhood (stage IIA); total length and upper length of face are longer in abnormal occlusion in the later dentition stages; lower face length, however, does not seem appreciably different in abnormal than in normal occlusion at any time. Depth of face at all levels is shorter, especially in the later stages, in abnormal occlusion.

• 3.

  A statistical test whether the differences between cases with normal and abnormal occlusion were significant or not revealed that the above noted tendencies were significant. In other words, during the process of growth differences in the head and widths of face, noted in early childhood between cases with normal and abnormal occlusion, became largely eliminated; whereas lengths of face and especially auricular depths to mouth became more differentiated, the face becoming significantly longer in height and shorter in depth in cases with malocclusion.

• 4.

  Profiles of the face were constructed according to the mean dimensions at the various dentition stages. These demonstrated graphically the above mentioned tendencies in the face, as well as greater growth in the mandibular than maxillary region in length and depth, in both normal and abnormal occlusion; greater facial prognathism in the adult is indicated thereby. The relative position of gonion point to the ear hole is remarkably stable in the course of growth, regardless of type of occlusion.

• 5.

  The consequence of old age in the face is a shortening in length and depth, primarily due to loss of teeth and alveolar absorption. But most striking is a considerable shift forward of the whole mandible with jutting out of chin.

• 6.

  Total increment between stages IIA and VA is on the whole not much different in normal than abnormal occlusion. There is, however, much difference with respect to character considered: total relative growth is least in the head, more in width of face, and most in length and depth of face.

• 7.

  Relative variability is greater in normal than in abnormal occlusion in early childhood, except depth of face in which the converse is true; with increasing age, however, there is a definite trend toward greater variability in abnormal than in normal occlusion. In both normal and abnormal occlusion, variability absolutely tends to increase with age whereas relatively it decreases. Relative variability is generally least in the head, more in depths of face, and most in widths and lengths of face in this order.

• 8.

  To combine all forms of malocclusion into one abnormal occlusion class, it was maintained, tends to obscure important differences; hence the material was reorganized according to various types of malocclusion.

• 9.

  Dimensions of the head now indicate: (a) marked divergences in length, width, and height, in groups with various types of malocclusion; (b) a tendency for the differences among each of the various occlusion types to diminish in the later dentition stages; (c) divergence from normal tends to be in one direction, plus or minus, especially in some forms of malocclusion.

• 10.

  Face widths in the various forms of malocclusion likewise manifest substantial deviation from conditions in normal occlusion, as well as each compared with the other. Direction of divergence from normal differs in the widths taken at the various levels of the face, albeit in the same type of occlusion and at the same dentition stage.

• 11.

  The divergence in length and depth of the face in the several types of malocclusion from conditions in individuals with normal occlusion is: (a) upper face length is generally longer in all forms of malocclusion except perhaps the open-bite in which the tendency is shorter length; (b) lower face length tends to be either alike or somewhat shorter except in the late dentition stages of retrusive bite and in Angle's Class III form of malocclusion, in which it is longer than in normal occlusion; (c) auricular depth to nasion is generally the same or somewhat greater in all but the retrusive bite form of malocclusion in which this depth is definitely less; (d) auricular depth to prosthion tends to be less except in Angle's Class II type of malocclusion which manifests generally greater depth; (e) auricular depth to infradentalc definitely tends to be less except in Angle's Class III form of malocclusion in the adult stage, in which this depth is much greater; (f) auricular depth to chin or menton is likewise definitely less except in Angle's Class III in the adult, in which it is also markedly greater; (g) depth of mandible and position of gonion differ with dentition stage and type of occlusion. All these differences, even when in the same direction, vary more or less in extent, evidently as a result of differences in rates of growth.

• 12.

  Chronologic age, when available and its use is practicable, is deemed a better criterion than dentition stage in studies of growth of the face in general.