Temporomandibular joint osteoarthritis in a British skeletal population

The potential role of dental function in TMJ osteoarthritis is examined in an ancient British population. Human skeletal remains from five archaeological sites in England (n = 369) were studied to assess the associations between the presence of osteoarthritis and dental function variables, in particular antemortem tooth loss and dental attrition. Individuals aged over 17 years with at least a portion of either the left or right TMJ were included in the study. Each individual was scored for the occurrence of arthritic lesions on the mandibular condyle and glenoid fossa, the level of dental attrition, and antemortem tooth loss. A loglinear analysis was performed with osteoarthritis as the dependent variable and tooth loss, attrition, sex, and age as the independent variables. Tooth loss and sex are not significantly associated with TMJ osteoarthritis when attrition and age are included in the analysis. Attrition is significantly associated with osteoarthritis even when the analysis corrects for age. The significant association of attrition with osteoarthritis suggests that dental functions may have an influence, separate from ageing, on the development of TMJ osteoarthritis.     

Dental paleopathology in a Serbian Medieval population.

Analysis of the pattern of dental disease in two Late Medieval populations from cemeteries excavated at archaeological sites in western Serbia was based on the study of tooth wear, ante-mortem tooth loss, caries, dental enamel hypoplasia, alveolar resorption, abscesses and calculus. The findings reported here show a high prevalence of attrition, alveolar resorption and caries, which suggest an abrasive diet and poor oral hygiene.     

The role of occlusal stress and gingival infection in the formation of exostoses on mandible and maxilla from Neolithic China

Exostoses on the mandible and maxilla is a frequently observed bone growth of controversial aetiology. The aim of this study is to analyse environmental factors that may stimulate the formation of exostoses on different regions of the maxilla and mandible. Sixty-six well-preserved crania from Neolithic China were studied for the presence of buccal exostoses on the maxilla (BE) and lingual exostoses on the mandible (LME). Other oral health indicators, such as occlusal wear on molars, pathology of temporomandibular joint (TMJ), carious lesions, calculus accretion, periodontal disease, and antemortem tooth loss were recorded. Buccal maxillary exostosis was unusually common on the Neolithic skulls from China, which thus resemble the Sinantropus crania described by Weidenreich (1943). We report a significant Spearman correlation between BE and LME (rho = 0.54, P < 0.00001), suggesting a partially shared aetiology of these two types of exostoses. The highest correlations between either form of exostoses and any oral indicator of stress were found for pathology at TMJ (rho = 0.46, P < 0.0001 for both types of exostoses). Smaller but significant correlations were observed between LME and the age adjusted wear rate on lower molars, as well as between BE and indicators of oral/dental pathology, e.g. caries, calculus, periodontoses, and antemortem tooth loss. Both types of exostoses tended to increase in frequency with age, although a significant trend was observed only for BE. We conclude that formation of exostoses is a complex process that can be invoked by any agent causing damage and inflammation of gingival tissue. However, severe occlusal stress, which is often manifested in TMJ disorder, is the main environmental factor leading to exostosis development in genetically pre-disposed individuals.     

Paleoepidemiology of a central California prehistoric population from CA-Ala-329: dental disease

Ala-329 is a prehistoric central California site located on the southeastern margin of San Francisco Bay, dating from approximately 500 AD up to pre-European contact. A large earth mound, Ala-329, has yielded many well preserved burials, approximately 300 of which are included in this study. The most common pathological lesions seen in this population are in the dentition. Advanced attrition is pervasive, affecting all individuals with teeth in occlusion for 2 years or more. Deciduous teeth are involved even in very young children and often show severe wear before replacement. In the permanent dentition, all elements are involved by the second decade; in the oldest age category (41+ years), all individuals show severe wear throughout their dentitions. In fact, by the end of the third decade, the majority of individuals have no enamel remaining. Mild periodontal involvement is found in 74% of adults, socket resorption in 53%, and abscesses in 31% of the relevant sample. Interestingly, although dental abscesses are found more than twice as often among males, socket resorption is seen more often among females. Dental caries are seen in only 10 individuals. The high incidence of periodontal remodeling, socket resorption, and dental abscesses is probably a secondary result of severe dental attrition. It is hypothesized that a large quantity of abrasives in the diet is responsible for the extreme degree of attrition, in fact, among the most severe for any population yet described.     

Dental pathologies in ten free-ranging chimpanzees from Gombe National Park, Tanzania

The dental remains of ten adult chimpanzees from Gombe National Park, Tanzania, were examined for enamel attrition, caries, abscesses, periodontal disease, and tooth loss. Age was the underlying factor in the development of dental pathology, in that enamel wear was present to some extent in all ten but was uniformly severe only in the three for whom estimated age at death was 39-43 years. In turn, enamel wear appears to have been the direct cause of abscess development, periodontal disease, and tooth loss. Periodontal disease was commonly expressed as alveolar resorption, particularly around the premolars and molars. This involvement was variable in all except the two youngest. Some interesting wear patterns were evident in the form of deep grooves in the upper incisors and dramatic notching of the lower canines. These patterns, and enamel attrition in general, were attributed to normal mastication and to various stripping activities. Only one carious lesion was observed, in a male with an estimated age of 26 years. An accurate assessment of the actual prevalence of caries was obscured by enamel wear and tooth loss in the older individuals.     

Periodontal disease in the Mycenean (1450–1150 BC) population of Aghia Triada, W. Peloponnese, Greece

This study investigates the incidence of periodontitis in a Mycenaean population unearthed at the cemetery of Aghia Triada (West Peloponnese, Greece) during the 1989–1997 field season. The material consists of 172 dry skulls. Demographic parameters of sex and age were difficult to be assigned due to the bad state of preservation of the skeletal material. The ratio was 50 males, 48 females, 65 unidentified and 9 children, and we estimated an average age of 38 years. In this work we used traditional and modern methods to determine the incidence of periodontitis in the archeological human dental bone. We also recorded other dental diseases, such as ante mortem tooth loss, caries and attrition. The results showed that periodontitis has affected 35% of the jaws. A notable percentage of the individuals — 24% — lost three or more teeth during their lifetime and a total 53% of the population had extracted teeth before death. This paper points out that the ancient jaws present a high proportion of ante-mortem tooth loss, attrition and deep caries, whereas the frequency of periodontitis does not seem to differ from that of other prehistoric samples.     

Dental pathology of prehistoric residents of Oregon

Dentitions of 208 prehistoric skeletal specimens from five geographic regions of Oregon were studied to describe their dental status. Comparisons were made of the incidence of specific pathologies among regions and between jaws. Maxillary premortem tooth losses were significantly higher than mandibular tooth loss. A relatively high caries incidence occurs in samples from the Willamette Valley and Klamath Basin, where plant foods were used aboriginally to a significant extent. A high frequency of abscesses was recorded in the Klamath Basin and the Lower Columbia River sample, which also showed the highest levels of attrition. Each of the five subsamples shows patterns of dental pathology consistent with former use of natural resources.     

Tooth dislocation: the relationship with tooth wear and dental abscesses

Tooth dislocation (tilting) was recorded in 1,200 skulls from 34 museum collections. The findings of dislocation by tooth type, tooth wear, and abscess location are presented. A model for dislocation based upon the progressive loss of tooth support provides a rational explanation for the phenomenon. Physiological continuous tooth eruption was considered to account for a component of the progressive loss of tooth attachment. The process of attrition, pulp perforation, and dental abscess cavity formation resulted in further, more severe loss of tooth support. Heavy functional forces, in association with greatly reduced bone support, tilted the crown lingually and root buccally. When the tooth had tilted to such an extent that the root apices protruded from the bone and, presumably (in life) through the gingival/mucosal tissues, the infected root canals were effectively isolated from the internal environment. The tooth continued to function. The more typical consequence of severe attrition and dental abscess formation was tooth loss; it also isolated an infected tooth from living tissue, but without the benefit of retaining function.     

Measurements of tooth wear among Australian Aborigines: I. Serial loss of the enamel crown

The dental casts made from Aboriginal children during the course of a longitudinal growth study in Central Australia provided material for analyzing tooth wear under known environmental conditions. The wear facets produced on the occlusal surfaces were clearly preserved on the dental stone casts and recorded the progress of enamel attrition from ages 6 to 18. These casts were photographed and traced by electronic planimetric methods that automatically recorded the location and size of wear facets on the first and second permanent molars. These areas of worn tooth surface were compared to the total tooth surface. The worn surface was regressed on age to calculate wear rates of each tooth. Discriminant analyses were also performed to determine the significance of dental attrition differences between the sexes at each age group. The total wear on each tooth was highly correlated with age as expected but females wore their teeth at a significantly higher rate than males. The mandibular molars wore more rapidly than maxillary teeth in both sexes. The discriminant analysis successfully grouped 91% of the cases according to age and sex. Pattern of wear, the location, and size of wear facets also differed between age groups and sex. The questions of why there is a difference between male and female wear or why there is greater wear on one arch or arch region have no ready answers. The differing rates and pattern of dental wear do suggest that arch shape and growth rates may be the answer though it has yet to be tested. However, the occlusal surface wear is useful for age estimation in a population and provides a record of shifting masticatory forces during growth.     

Enhancement of chondrocyte autophagy is an early response in the degenerative cartilage of the temporomandibular joint to biomechanical dental stimulation

Autophagy is a cell protective mechanism for maintaining cellular homeostasis. The present study aimed to investigate whether autophagy is enhanced in the biomechanically induced degenerative cartilage of the temporomandibular joint (TMJ) and the potential role of mitogen-activated protein kinase kinase kinase kinase 3 (MAP4K3) and mammalian Target of rapamycin (mTOR) in this observation. To induce degenerative changes in the TMJs, rats were subjected to biomechanical dental stimulation by moving 4 molars away from their original position as we previously reported. The ultrastructure of autophagosome was observed by transmission electron microscopy. The number of lysosomes was analyzed by flow cytometry. The expression levels of Beclin1 and LC3 and the involvement of MAP4K3 activity were detected by immunohistochemistry, real-time PCR and western blot. The activity of the mTOR pathway indicated by p-mTOR and p-p70S6 K was assayed by western blot. TMJ degeneration, characterized by irregular cell arrangement and cell-free area, was induced in the experimental groups. Under transmission electron microscopy, we observed the presence of autophagosomes, small patches of condensed chromatin, abundant rough endoplasmic reticulum and Golgi apparatus. The number of lysosomes and the expression levels of Beclin1 and LC3 increased, while the activity of mTOR and the expression level of MAP4K3 decreased in the experimental groups. Cartilage in TMJ which was induced to be degenerative biomechanically exhibited autophagy accompanied by reduced mTOR and MAP4K3 activity.     

Analysis of dental attrition and mortality in the Medieval village of Tirup, Denmark

New directions and new questions raised in the study of health in the past justify this reanalysis of the pattern of dental attrition in the Medieval Danish population of Tirup. Dental attrition was scored on all permanent molars from the Tirup skeletal sample. Scores were analyzed by means of logistic regression of the probability of having entered a given stage of wear for a given tooth in a way that is very similar to transition analysis. The primary determinant of dental attrition was age at death. In addition to age, the effects of sex, side, and dating were analyzed. In order to assess the homogeneity of the process of wearing teeth down, a third-order polynomial in age-at-death was also fitted to the transition probabilities. It was found that age is the single most important determinant of dental attrition, and that sex or side did not differentiate the rate of attrition. In several transitions, there was evidence of heterogeneity, indicating both random and systematic interpersonal differences in the rate of attrition and an association between the rate of attrition and age-at-death. It was found that attrition proceeded more quickly after AD 1300 than prior to that date. It is suggested that this was due to a possible general deterioration of living conditions in Northern Europe and an increased reliance on grain for food during the first half of the 14th century. The temporal effect on attrition rate accounts for some but not all the observed heterogeneity wear.     

Tooth eruption and browridge formation

One of the most reasonable hypotheses regarding the functional significance of the browridge is that the supraorbital torus forms in response to masticatory stress during development. Oyen, Walker, and Rice (1979) have recently proposed a model that tests this hypothesis: if browridges are functionally related to masticatory stresses on the cranial vault, then changes in the biomechanics of the masticatory system ought to be reflected by changes in the browridge. To test their model they attempted to relate biomechanical discontinuities resulting from tooth eruption to episodes of bone deposition on the supraorbital tori of a developmental series of dry Papio crania. This paper reports on a parallel test of the model on a cross-sectional sample of Australian Aboriginal juvenile crania. This sample showed no relation between tooth eruption and the supraorbital surface morphology thought to be indicative of active bone deposition. It is also demonstrated that no significant relationship between tooth eruption and episodes of bone deposition is shown by the Papio sample. It is concluded that the use of small cross-sectional samples of dry crania does not provide a valid test of the model.     

Cranial growth in the squirrel monkey (Saimiri sciureus): a quantitative analysis using three dimensional coordinate data.

Improvements in data gathering technology have made it possible to quickly and accurately digitize large numbers of objects. The three dimensional coordinates of 44 homologous landmarks were obtained from a sample of 104 squirrel monkey (Saimiri sciureus) crania. After sorting by sex, the crania were assigned to one of four dental age groups. Two quantitative methods, Euclidean distance matrix analysis (EDMA) and finite element scaling analysis (FESA), were used to study craniofacial form change during growth within each sex. Form differences between the sexes at each developmental age were also examined. Both sexes show a small amount of cranial growth overall; however, there are areas of substantial local growth. These areas include the anterior neurocranium and basicranium, the basioccipital, and the anterior palate. Sexual dimorphism in the craniofacial complex is minimal. The most dimorphic regions are the orbitonasal portion of the lower face, the cranial base, and the palate.     

新石器时代人骨颞下颌关节的研究

对宝鸡、华县新石器时代人骨22个成年个体的颞下颌关节进行研究。发现该时期人类中23％者存在髁状突和关节结节骨质的严重磨损、不对称磨损和不规则增生,认为这是由于强大的咀嚼压力所造成的继发性关节退行性变。颞下颌关节的测量结果表明,与现生人类相比较,新石器时代人类的髁状突较大,关节结节较高,关节凹较深,关节结节后斜面斜度较小,反映了人类进化过程中由于生活方式和口腔功能的改变颞下颌关节的变小和关节承压结构的减弱。     

The mandible--an analysis.

In this study, an attempt has been made to examine and analyse the ancient mandibles of people who have died several hundreds of years ago during the second and first millenium B.C. These mandibles have been recovered from the burial mounds in Bahrain (Arabian Gulf) and preserved in the National Museum and the Department of Antiquities in Bahrain. The dental conditions recorded are e.g. attrition, caries, fluorosis, periodontitis or antemortem tooth loss. The results indicate the age, sex, diet, occupation and environmental conditions that existed and even the culture of the people. A comparative study of the ancient mandibles and those of the present generation has been carried out.     

Pathological traits observed in a historic Great Basin Native American Indian Skeleton

During the excavation of an irrigation ditch in Churchill County, Nevada, a burial was encountered, with associated artifacts indicative of historical provenience. The pattern of occlusal attrition, the lack of dental work, and the skeletal morphology indicate the individual was a Great Basin Native American Indian. Sex determination was female and age at death estimated as 40±. The skeleton is nearly complete and several of the long bones, as well as the vertebrae, scapulae, sternum and xiphoid process have minor pathologies, either osteophytic growths or areas of porosities and pitted appearances. The left sacroiliac joint is extensively affected by an unusual pathology, with the auricular surfaces of both the sacrum and ilium having a scooped out or hollowed appearance. Although the other pathologies are interpreted as being related to both age and possibly the lifestyle of a female Great Basin Indian during historic times, the sacroiliac pathological condition is construed as a manifestation of a more severe affliction.     

Apoptosis of the reduced enamel epithelium and its implications for bone resorption during tooth eruption

Bone remodeling, the selective deposition and resorption of bone, is an important cause of tooth eruption. During tooth eruption, reduced enamel epithelia of the enamel organ interact with follicle cells to recruit osteoclasts for bone remodeling. However, little is known about the relationship between cellular activity of reduced enamel epithelium and bone resorption during tooth eruption. The purpose of this study was to investigate the effect of apoptosis in reduced enamel epithelium on osteoclastogenesis and its implications for bone resorption. We have analyzed erupting mandibular molars in mice by TdT-mediated dUTP-biotin nick end labeling assay, tartrate-resistant acid phosphatase (TRAP) staining, and immunohistochemistry. TRAP-positive cells were detected in the osteoclasts near both the buccal and lingual sides of tooth socket at postnatal day 0 (PN0). They significantly increased until PN3 and decreased thereafter as the tooth erupted. Interestingly, apoptosis was barely detected in the reduced enamel epithelium at PN3 but clearly at PN7. A few apoptotic cells were also investigated within the dental follicle surrounding developing tooth at PN7 and PN10. We observed apoptotic osteoblast-lineage cells along the inner margin of alveolar bone facing the buccal cusp and at the base of the bony crypt at PN3 decreasing until PN10. In contrast, expression levels of bone sialoprotein increased at PN10 compared to levels at PN3. These results suggest that apoptosis of reduced enamel epithelium resulted in a reduction of osteoclast activity and of bone resorption mediated by dental follicle during tooth eruption.     

Dental investigation of mummies from the Capuchin Catacombs of Palermo (circa 18th–19th century CE)

Within the framework of the Sicily Mummy Project, the orofacial complex of a significant sample of individuals (n = 111) from the Capuchin Catacombs of Palermo, Italy, was inspected. The heads and dentitions of the mummies were documented and the recorded findings described: the state of preservation of skeletal and soft tissues; dental pathologies such as carious lesions and alveolar bone loss; enamel hypoplasia; and ante- and post-mortem tooth loss. Despite limitations in data collection, the oral health of these mummies was assessed and the frequencies of pathologies were compared to those of similar populations. From their position within the corridors of the Catacombs, sex and social status of the mummies were also inferred, allowing the dental pathologies to be specified in the social and historical context. Most interestingly, the rate of oral health problems did not differ between the groups of the members of the Capuchin Order and the laymen of the city of Palermo, despite their different lifestyles.     

Dental effects of diet and coca-leaf chewing on two prehistoric cultures of northern Chile

Two ancient cultures of northern Chile, the Chinchorro (9000-3500 BP) and the Maitas Chiribaya (850-700 BP) were examined for dental pathology in search of possible correlations between dental health, diet, and the cultural practice of coca-leaf chewing. The Chinchorro occupied the river mouth of the Azapa valley, subsisting almost exclusively on a maritime economy. The Maitas Chiribaya, descendants of migrant highlanders, had a rather well-developed agricultural subsistence base. The Chinchorro demonstrated extreme attrition rates and a correspondingly high frequency of periapical abscesses. They were essentially caries-free and enjoyed a moderate antemortem tooth loss frequency. The Maitas Chiribaya suffered light attrition, a high caries frequency, especially at the cementoenamel junction of crown and root, and a remarkably high antemortem tooth loss frequency. The cultural practice of coca-leaf chewing is implicated in the excessive posterior edentulism of the Maitas Chiribaya. © 1996 Wiley-Liss, Inc.     

Relationships between age and dental attrition in Australian aboriginals

Tooth wear scores (ratios of exposed dentin to total crown area) were calculated from dental casts of Australian Aboriginal subjects of known age from three populations. Linear regression equations relating attrition scores to age were derived. The slope of the regression line reflects the rate of tooth wear, and the intercept is related to the timing of first exposure of dentin. Differences in morphology between anterior and posterior teeth are reflected in a linear relationship between attrition scores and age for anterior teeth but a logarithmic relationship for posterior teeth. Correlations between age and attrition range from less than 0.40 for third molars (where differences in the eruption and occlusion of the teeth resulted in different patterns of wear) to greater than 0.80 for the premolars and first molars. Because of the generally high correlations between age and attrition, it is possible to estimate age from the extent of tooth wear with confidence limits of the order of +/- 10 years.