Forensic odontology
An alternative method of identification or a myth?
The ‘oral fingerprint’
W
ithin forensic odon- tology, the use of the dental restorations, teeth and supporting bone to compare
post-mortem findings with an ante- mortem record are the most commonly used and widely accepted methods of establishing identity. The reasons for this have been described:
“Under most conditions occurring in nature, the teeth are the least destructible part of the body and they may readily survive all of these changes... fire, putrefac- tion or prolonged immersion in water.”ı However, there may be circumstances where these tissues cannot be used – perhaps due to trauma, disease, absence of teeth, or significant change which has occurred within a dentition since the last record was made. The term palatoscopy or palatal rugos-
copy is the name given to the study of the palatal rugae in order to establish the iden- tity of an individual. It was first proposed as an alternative method of human identification in ı889 by Dr Harrison Allen2. Since then, many have attempted to classify the palatal rugae with a view to employing rugoscopy techniques in those instances where primary, standalone methods of identification, such as DNA analysis, finger print analysis and conven- tional dental identification have failed or cannot be used.
46 Scottish Dental magazine
“Are the palatal rugae of any relevance in the field of forensic odontology?”
The palatal rugae are irregular, asym-
metrical ridges of mucous membrane found in the roof of the human mouth extending laterally from behind the inci- sive papilla and across the anterior part of the median palatal raphe3. The rugae form in the ı2th to ı4th week of intra-uterine life from the hard connective tissue covering the palatal bone and their formation is under genetic control 3-4. Many researchers hypothesise that once
formed, the palatal rugae pattern is distinct to an individual, and does not change throughout life, except for an increase in size due to normal growth. It follows that the palatal rugae, as a characteristic feature, could potentially be considered as a type of ‘oral fingerprint’ and used as a tool in forensic human identification. However, very few studies using the
palatal rugae as a means of forensic identification have been published and the perceived usefulness of the palatal rugae as an individualising marker within
forensic odontology is controversial, throwing up numerous questions. Are the palatal rugae unique to the individual? Is the number of rugae stable throughout life? Does the palatal pattern change, other than due to normal growth? Can the palatal rugae pattern be classified and analysed? Is the interpretation of the analysis useful to an individual investigator, or on a universal basis? Are the palatal rugae of any relevance in human identification or in the field of forensic odontology? To answer these questions fully would
be beyond the scope of this article. In summary, published studies 5,8 concur that palatal rugae patterns are distinct to the individual. The sample sizes studied are generally small, but within each sample, distinctiveness to the individual is demon- strated. This concurs with the author’s own experimental research. The effect of age on the mean number
of palatal rugae does not appear to have, as yet, been fully addressed by the litera- ture, there being a number of apparent contradictions. Various studies have reported rugae numbers increasing with age, decreasing with age, being stable from age ı0 years until after death and rugae numbers increasing markedly from middle-age onwards9, ı3. The palatal pattern has been shown to
change in length, shape and orientation with growth and with orthodontic treat- ment. One study demonstrated that 32
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