Forensic Aspects of the Teeth and Jaws

SEVERAL years ago, in conjunction with a colleague, I set a question in the dental surgery paper fQr a degree in dentistry which no candidate attempted to answer. I do not think it was a particularlv difficult question, but it was novel, and asked what might be learnt of the age, habits and life-history of the individual from the study of the teeth and jaws. Really it is a very interesting study, and as no one has, so far as I know, tabulated what may be learnt from such a studv, I am attempting here to answer the question, but on a wider aspect than that set in the examination paper. Some of the evidence which may be gathered in this manner is evidence of fact, some of probability and some perhaps of a rather hypothetical nature. The various points which may be thought 'worthy of consideration can be grouped under different headings:Age.-The age of the individual may be assessed with relative but not absolute accuracy, chiefly from the teeth and to a lesser extent from the jaws. From birth till the full eruption of the permanent dentition we have as guides the dates of the commencement of calcification, the eruption of the teeth, the absorption of the deciduous teeth and the amount of wear shown by functional teeth; but the exactness of all assessments of age based on these evidences mav at times be upset bv variation within the range of normal. Thus, though it is usually taken that calcification of the mandibular permanent first molar begins at birth, American evidence on this point published some vears ago showed that the calcification of this tooth, perhaps one of the most constant, had often not commenced at that time. Similarly I have seen this same tooth erupted at 4 years 10 months and unerupted at 7 years 6 months ; as in neither case was anything else abnormal found in these individuals one must allow for these variations as being within the range of normal. Similarly isolated deciduous teeth, especially molars, may not be reliable evidence with regard to absorption, occasionally there are no permanent successors to these teeth, and though even in these circumstances their roots usually become absorbed such absorption is generally later, and occasionally it does not take place at all. The rate of wear will also varv with the phvsical characters of the food and the functional activity of the teeth, and this latter will vary with the presence of dental caries, pain, the degree of occlusal perfection and the health and vigour of the individual. Deciduous teeth too show wear very much more readily than do permanent teeth. The presence of diseases which may accelerate or delay the eruption of teeth must also be taken into account, remembering too that very rarely one or more deciduous teeth may be erupted at birth. Concerning the jaws, the degree of growth, closing of sutures, measurement of the angle of the mandible, the condyle and the presence of sockets of teeth or their crypts are also evidence; but in the total absence of teeth accuracy can only be relative, as the ages at