Dental misidentification on the basis of presumed unique features

Positive identification of skeletal remains by dental comparison depends on the demonstrable concordance between postmortem and antemortem records. However, there is no accepted norm for the number of points of concordance and there are circumstances when a single (or a few) unique features may allow positive identification. We present a recent case in which superficial similarity may have led to misidentification. We argue that misidentification is particularly likely with over-reliance on apparently unique features. The fact that a single inexplicable inconsistency will rule out a positive dental identification is highlighted.

Bite injuries: pathophysiology, forensic analysis, and management

Bites are serious injuries that constitute 1 percent of all emergency-department visits in the United States of America. Human bite injuries may lead to loss of function, infection, and gross disfigurement, and often are associated with interpersonal and sexual violence, and child abuse. Issues with infection from oral contaminants, tissue damage, and difficult surgical reconstruction make the management of human bite injuries a challenge. The unique nature of teeth and the bite marks they produce are invaluable in forensic pathology. A systematic and detailed evaluation of bite injuries should be performed by a forensic odontologist in order to provide the necessary information for forensic purposes. Management of human bite injuries includes wound debridement, surgery to repair or replace damaged tissue, and long-term antibiotic therapy.

Anatomical knowledge and clinical evaluation of the muscles of mastication

In this survey, we identify the positive role that an instructional anatomy course has prior to a workshop on temporomandibular dysfunction. Not only did it result in enhanced clinical evaluation of the muscles of mastication acquired by the participants, but it also approximated the skills of dental and medical practitioners.

Odontological identification in two high-impact, high-temperature accidents

Here we report on two high-impact accidents both of which were complicated by fire. The first accident involved a light aircraft which crashed in a gorge while performing a low, slow flight. Both victims were found to have experienced extensive dental fracturing. The second accident was a high speed motor vehicle crash followed by incineration which left the two victims without dental fracturing. In the absence of comparative data on the effect of burning on teeth the cause of the foregoing remains unanswered.

Root canal anatomy of anterior and premolar teeth in Down's syndrome

AIM

The aim of this study was to examine tooth length and root canal anatomy of 281 anterior and premolar teeth from 66 DS individuals using a standard protocol.

RESULTS

The results indicated that root canals in DS are relatively simple and that there is a significant reduction in root and crown length.

CONCLUSIONS

We propose that these observations are commensurate with the suggestion that trisomy 21 exerts its effect by slowing the mitotic cycle and rate of cell proliferation, resulting in generalized retardation of growth.

Relationship between juvenile bruxing and craniomandibular dysfunction

A longitudinal study was conducted over 5 years to investigate the relationship between juvenile bruxing and craniomandibular disorders. A total of 150 bruxers between the ages of 6 and 9 years were examined for oral parafunctions and TMJ symptoms. Of these, 126 were re-examined for the same signs and symptoms after 5 years. The results showed that only 17 individuals had retained their bruxing habit. In common with other studies, we found that symptoms reduced with age. It was concluded that juvenile bruxing was a self-limiting condition which does not progress to adult bruxism and which appeared to be unrelated to TMJ symptoms.

Basicranial flexion, facial reduction and temporomandibular joint dysfunction

Although dysfunction is the major condition affecting the bilateral temporomandibular joint (TMJ), it has defied previous attempts to explain, predict, or prevent its clinical manifestations. A hypothesis is developed that there is an anatomical predisposition to TMJ dysfunction which should be sought in the phylogenetic flexing of the hominid basicranium. It is argued that the glenoid fossa, caught between an ever-increasing brain size and more ventrally oriented facial apparatus, has become deepened and hence labile to dysfunction.

Dental asymmetry, maternal obesity, and smoking

This study examines the levels of fluctuating dental asymmetry in four samples of school children: those whose mothers were obese and had smoked during the pregnancy concerned (n = 111); those whose mothers were obese non-smokers (n = 114); those whose mothers were non-obese smokers (n = 104); and those whose mothers were lean non-smokers (n = 111). The degree of fluctuating asymmetry was assessed by means of a rescaled asymmetry measure. Obesity was defined as Quetelet's index in excess of 30, and smoking status as at least 20 cigarettes per day during the pregnancy concerned. When the magnitudes of fluctuating asymmetry in children of lean smokers were compared to the control group of lean non-smokers, no significant univariate differences were found. Children of obese mothers, whether these smoked or not, were found to have significantly raised levels of asymmetry. An analysis of variance confirmed that the combination of obesity and maternal smoking was a significant predictor of fluctuating dental asymmetry. The teeth involved tended to be the maxillary first incisor and molars. It is concluded that maternal obesity has a destabilizing effect on the developing fetus and that this effect appears to be enhanced in obese mothers who smoked. This effect was absent in lean mothers, irrespective of their smoking status.

Delayed tooth formation in children exposed to tobacco smoke

Panoramic radiographs of 203 Caucasoid children between the ages of seven and ten years were examined for an evaluation of dental development. Four groups were studied: a control group in which neither parent had smoked during the pregnancy concerned, a group exposed to tobacco smoke from the mother only, a group exposed to smoke from the father only, and finally a group exposed to tobacco smoke from both parents. In each case, the dental age (determined according to the method of Moorrees) was contrasted to the chronological age of the subject. Overall results showed that there were no differences in dental ages related to gender. Maximum differences between chronological and dental ages were found in children subjected to cigarette smoke from both parents. Here, a 35% reduction in dental maturation was noted. Most affected teeth were the maxillary second premolars, while the central incisors were the least affected.

Inequalities in the pattern of dental delivery in South Africa

The pattern of dental delivery of three groups of private general practitioners were evaluated. The first group consisted of dentists who charged fees based on the National Schedule of the Dental Association of South Africa, the second charged fees at the recommended Scale of Benefit and served an urban population, while the last group served township dwellers at the Scale of Benefits. In each case, sequential claims of 500 medical scheme members were evaluated for ten randomly selected dentists within each group. Uni- and multivariate analyses revealed significant differences between these groups which centred on the use of cast restorations, bleaching of vital teeth and treatment of diseases of the oral mucosa. Because these differences do not conform to documented differences in dental needs between the two groups, it is concluded that other non-clinical factors influence the delivery of private dentistry.

Effects of prenatal exposure to tobacco smoke on developmental stability in children

The effects of maternal and paternal smoking on fetal and neonatal dental development were investigated in a sample of 199 school children. Fluctuating asymmetry was evaluated in the maxillary arcades of four groups of children: those whose mothers had smoked, those whose fathers had smoked, those whose parents both had smoked, and finally, those whose parents had not smoked. When the magnitudes of fluctuating asymmetry in children exposed to parental tobacco smoke from one parent only were compared with the control group, no general univariate differences were found. Children exposed to smoke from both parents, however, showed significantly elevated levels of asymmetry in four out of six comparisons. In contrast, an analysis of variance failed to find significant differences on the basis of sex, parity, smoking status, or their interactions. It is concluded that parental smoking does not result in developmental destabilization of the fetus and neonate.

Heterodonty and patterns of tooth replacement in Crocodylus niloticus

Patterns of tooth replacement in the Nile crocodile Crocodylus niloticus were evaluated in the lateral radiographs of six dried skulls of 1-year-old individuals. Additionally, the ontogeny of the succession of teeth in this species was investigated in four embryos and a hatchling, which were serially sectioned. Three-dimensional, computer-generated reconstructions of these individuals suggested that there was a regular pattern of odontogenic progression. Three morphogenetic zones could be identified in each of the age classes: an incisor, a canine, and a molar region. It was thus concluded that the Nile crocodile is hetero- rather than homodont. Zahnreihen, or tooth rows, with a periodicity of one were easily identified. © 1993 Wiley-Liss, Inc.

Sex allocation of skeletal material by analysis of the proximal tibia

In this study we contrasted the confidence with which individuals may be grouped and then reallocated on the basis of a set of measurements from the proximal tibia. The data were derived from 100 Caucasoid (50 male) and 102 Negro (50 male) tibia housed in the R.A. Dart Collection. Multivariate discrimination was effected by means of canonical and stepwise discriminant analyses, whilst probabalistic models were used to allocate individuals. High levels of correct classification (84.62-92%) were matched by high levels of reallocation, suggesting that, in contrast to dental or craniobasal measurements, those of the proximal tibia may be usefully employed to allocate an individual on the basis of sex.

Fluctuating odontometric asymmetry and maternal alcohol consumption

Fluctuating asymmetry was evaluated in the dental arcades of 112 children (60 male, 52 female) of alcoholic mothers. Only individuals who showed no signs of the fetal alcohol syndrome were included. When these results were compared with those of a control group of 120 normal children, the former group was found to be significantly more asymmetric. The present study showed that canines were the least asymmetric whilst lateral incisors showed the greatest levels of asymmetry. It is suggested that the elevated levels of fluctuating odontometric asymmetry in children of alcoholic mothers may be ascribed to prenatal stress, especially during the soft tissue stage of odontogenesis.

High-dimensional plots in the evaluation of interpopulation differences in human tooth size

The use of high-dimensional plots is explored in the evaluation of interpopulation differences in tooth size. Buccolingual and mesiodistal diameters were determined on the teeth of 202 Paraguayan Lengua Indians, 100 skeletal Blacks, 206 living South African Blacks and 125 living South African caucasoids. Multivariate discrimination between the four populations was effected by means of canonical variate analyses and stepwise discriminant analyses. These results were then compared to Andrews plots generated for males and females in each of these populations. Our results show that Blacks and caucasoids have significantly differing curves and that Amerindians share characteristics of both these groups.

Mandibulodental allometry in the African wild dog, Lycaon pictus

Mandibulodental relations were evaluated in a sample of 34 adult Lycaon pictus crania (18 males, 16 females). Standard mesiodistal and buccolingual measurements, together with 8 mandibular measurements (intercondylar distance, intercarnassial breadth, mandibular length, arch length, condylar height, canine-condylar length, mandibular width, mandibular height) were allometrically scaled to total skull length. These results were then compared with those of domestic dogs and of 3 smaller southern African canids, Vulpes chama, Canis adustus and C. mesomelas. The results highlighted the differences in mandibulodental relations between males and females and provided support for the theory that females have relatively larger postcanine tooth sizes to match the higher masticatory demands of lactation and pregnancy. The African wild dog is shown to be more closely related dentally to the domestic dog than has previously been supposed.

Comparative morphology of the mandibulodental complex in wild and domestic canids

The relationships between mandibular and dental measurements were investigated in a sample of 60 adult domestic dogs, 17 black-backed jackals Canis mesomelas, 18 side-striped jackals C. adustus and 16 Cape foxes Vulpes chama. Standard mesiodistal and buccolingual tooth measurements, together with 8 mandibular measurements (intercondylar distance, intercarnassial breadth, mandibular length, arch length, condylar height, canine-condylar length, mandibular width, mandibular height) were scaled allometrically to total skull length. Despite wide differences in diet and sexual dimorphism between the 3 wild canid species, larger canids were found to be scaled up versions of smaller canids. While males showed a highly concordant patterning when compared with domestic dogs of equivalent size, females showed a remarkably mosaic pattern. Relative to skull size, the only teeth that appear to be larger than those of equivalently sized domestic dogs were the second molars. It is suggested that those theories of sexual dimorphism and functional integration which apply to skeletodental dimensions in primates may not be applicable to canids.

The reliability of human odontometric data

The present analysis addressed the reliability of human dental mensuration, with special reference to intra- and inter-observer error, the effect of time and of tooth type. Two observers were asked to measure the same 35 incisors, premolars and molars, using the same mensurational technique and the same instrumentation. Standard mesiodistal (MD) and buccolingual (BL) measurements were repeated on the next day and after six months. Measurement error was evaluated by means of Pearsonian correlation coefficients, mean absolute error, the Bland-Altman procedure, percentage error and an analysis of variance. It was concluded that human dental mensuration is subject to a large error component which is more marked in the MD than in the BL dimension, higher in the anterior than the postcanine teeth and greater between than within observers. These error components were shown to be random rather than systematic.

An allometric perspective on primate postcanine tooth size

The allometric relations of postcanine tooth size were evaluated in a sample of 66 adult Galago crassicaudatus (34 males, 32 females). Postcanine tooth area and length (estimated from mesiodistal and buccolingual measurements of upper and lower cheek teeth) were scaled to 4 cranial measures: bimaxillary width, maxillo-alveolar length, mandibular length and bigonial width. Postcanine tooth size was also scaled to body weight, body length and total skull length. It was found that postcanine surface and length were significantly correlated to the cranial measures employed in females, showing positive allometric scaling. These correlations were, however, lacking in males. In neither sex was postcanine size found to be significantly correlated to body length or weight.