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.     

Patterns of dental wear in the Lengua Indians of Paraguay

Wear patterns were examined on dental casts of 202 living Lengua Indians from the Chaco area of Paraguay. Consideration was given to the development of the molar helicoidal plane, age-related changes in occlusal attrition, coalescence of dentine exposures, interproximal attrition, and erupted crown height. This study lends support to Osborn's theory of the helicoidal plane development by showing that attrition enhances rather than modifies posteruption molar occlusal planes. The rate of interproximal attrition was found to slow down with the eruption and functional initiation of the third molars. Sinuous and cavo-convex interproximal contact areas that are generated with age, however, appeared to be less abrasion resistant than straight surfaces, hence leading to an increase in interproximal attrition rates with advanced age. Maximum crown height reduction occurred between the ages of 20 and 40 years in central incisors, canines, and first molars. Kruskal-Wallis tests and log linera models failed to demonstrate significant sexually dimorphic or antimeric differences in wear patterns of Lengua teeth.     

明万历帝及其两后的口腔情况

本文对明神宗万历帝及其两后的口腔情况进行了观察,尤其对龋齿、牙周病、氟牙症及磨耗等方面,作了分析和讨论。     

同口牙齿的磨耗级比较

本文比较和分析了同口同侧牙齿的相应的磨耗级,提供了除臼齿以外的牙齿磨耗年龄变化依据。同时还对上下对应牙、两侧对称牙的磨耗级作了比较和分析。     

Relationships between attrition and lingual tilting in human teeth

Associations between occlusal dental attrition and the lingual tilting of human teeth were investigated in two aboriginal California populations. A literature survey suggests lingual tilting is related geographically and temporally to the helicoidal occlusal plane in humans; if true, lingual tilting should be expected throughout the Homo osteological record. Buccal alveolar abscesses, exposed pulp chambers, extent of tooth attrition, angle of lingual tilt, and amount of overjet were observed for lingually tilted teeth. These attributes were analyzed statistically, leading to a conclusion that lingual tilting is slight and infrequent unless tooth attrition is pronounced. It is suggested that lingual tilting is due in part to masticatory stress. A feedback model considers lingual tilting as one conspicuous manifestation of a more complex “severe attrition syndrome,” the initial stimulus for which may derive from heavy occlusal tooth wear. Untested possibilities should be examined–e.g., age-related changes, the impact of the helicoidal occlusal plane, and the role of masticatory forces.     

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.     

Specialized wear facets and late ontogeny in mammalian dentitions

Abstract

Many types of wear facets can be found in mammalian teeth. Some are related to the initial surface, others use the cross-section of the enamel as the main tool. In primary occlusal surfaces facets mark the gradual wear, that are related to a relatively late ontogeny. Facets in teeth with secondary occlusal surfaces, however, represent specific arrangements of crests of enamel and dentine. Such facets require some initial wear to become fully functional. The tooth morphology guarantees such facets to be effective for a long period of time. Therefore they can be discriminated as specialized facets. From the different types of facets three specialized ones were selected, blade facets, rasp-facets, and nipper-facets, because they ate widely distributed, function differently, and are comparable with mechanical tools. They are long lasting and differ in the amount of exposed dentine. The amount of dentine is used to differentiate phases during late ontogeny, the part of the life history, when teeth are exposed to wear. Consequently the various types of facets can be related to different ontogenetic phases. The relevant phases are prolonged at the cost of other ontogenetic phases. Therefore, the various specialized wear facets represent heterochronies within the ontogeny of teeth.     

Mineralization and wear of mandibular first molars in red deer (Cervus elaphus) of known age

The degree of dental wear was measured in 41 mandibular first molars from red deer of known age (range 2–18 years). The calculated wear indices were positively correlated with age ( r = 0.780, P < 0.001). In the same sample, significant ( P < 0.001) differences in hardness (determined by microhardness testing) were observed between enamel and coronal dentine as well as between outer and inner enamel and dentine, respectively. In animals belonging to the same age group (three-year-olds, n = 11), a negative correlation ( r = -0.830, P = 0.0016) was found between wear index and maximum mean enamel hardness. In a sample of five specimens from this age group, a negative correlation ( r = -0.918, P = 0.028) between maximum calcium concentration of enamel (measured by electron microprobing) and wear index was also recorded. We concluded that the intensity of enamel mineralization had a decisive effect on the degree of dental wear. Measuring of enamel hardness and subsequent modification of wear scores or indices is therefore recommended for future studies on the relationship between age and the degree of dental attrition in deer.     

北票喇嘛洞三燕文化墓地人骨的牙病

本文对辽宁北标喇嘛洞三燕文化墓地出土人骨的牙病作了详细的观察。初步探讨了龋病和牙周病的罹患率与性别和年龄的关系,结果显示：（1）龋病的罹患率男女间差异不显著,而牙周病的罹患率性别差异显著。（2）龋病的罹患率与年龄变化具有一定关系,而牙周病的罹患率则与年龄变化关系密切。此外,对多生牙、先天缺额牙、融合牙、错位牙、第三臼齿的阻生情况也分别作了记录与分析。     

Sex Differences in Hadza Dental Wear Patterns

Among hunter-gatherers, the sharing of male and female foods is often assumed to result in virtually the same diet for males and females. Although food sharing is widespread among the hunting and gathering Hadza of Tanzania, women were observed eating significantly more tubers than men. This study investigates the relationship between patterns of dental wear, diet, and extramasticatory use of teeth among the Hadza. Casts of the upper dentitions were made from molds taken from 126 adults and scored according to the Murphy dental attrition scoring system. Females had significantly greater anterior occlusal wear than males when we controlled for age. Males exhibited greater asymmetry in wear, with greater wear on the left side in canines, first premolars, and first molars. We suggest that these sex differences in wear patterns reflect the differences seen in the diet, as well as in the use of teeth as tools.     

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 wear study in a 14th century skull of the Sao tribe, Cameroon

The aim of this work was to study the wear affecting the almost complete dentition of a Sao individual fossil from Cameroon prehistory (XIVth century). Occlusal surfaces of the fossil fragile pieces were plaster replicated with an original technique adapted from usual dental impression methods (silicon elastomer polymerising by addition). Axial macro-photographs of both sectional dental casts and original pieces made it possible to produce drawings of the occlusal areas on transparencies in order to superimpose the lateral hemiarch counterparts in their optimal intercuspal position. The study of interarch contacts was completed by confronting and observing the occluding position of hemiarch replicas. The occlusal analysis revealed that the wear extent was equivalent on left and right molars. Hall's occlusal wear index and Van Reenen and Reinach's classification of proximal wear allow assessment of the degree of wear extent on premolar and molar sections in relation to the side or the arch observed. The even bilateral proximal and occlusal wears observed on the different kinds of homologous teeth appeared as the main contributor to this well-balanced interarch occlusion. The mandibular incisor losses and the particular type of wear affecting lower canines led to the conclusion of the presence of a labret, a great number of which was found in the area. According to Miles' method of age assessment based on tooth wear, the pieces studied belonged to an individual between 30 and 40 years old.     

广西敢造遗址史前居民口腔的健康状况

广西扶绥敢造遗址是华南新石器时代一处典型的河岸贝丘遗址,其人骨测年结果的上限为8488 BC,下限为6492 BC。本文对敢造遗址2014年出土的108例个体的999枚恒齿进行观察统计,结果显示居民的饮食结构应是以肉食为主并辅以富含淀粉的块茎类植物。该遗址居民的龋齿率高于部分农业人群,但远低于同为华南渔猎—采集经济的鲤鱼墩、甑皮岩和顶蛳山遗址,其原因应与食用块茎类植物的多寡有关。较高的牙结石罹患率(89.86%)可能与鱼类、贝类等高蛋白饮食有关。相比农业、游牧或狩猎人群,该遗址居民偏重的牙齿磨耗可能与食用含沙量较大的螺类、贝类等有关;肉类食物的食用导致该遗址居民上颌前部牙齿磨耗重于后部牙齿,而“上颌前部牙齿舌侧过度磨耗”现象的出现则与食用块茎类植物有关。     

Dental wear and oral pathology: possible evidence and consequences of habitual use of teeth in a Swedish Neolithic sample

Atypical wear and oral lesions were studied in the dental remains from the Middle Neolithic Pitted Ware Culture site Ajvide on the island of Gotland in the Baltic Sea. Teeth (n = 764) from 17 males and 11 females were examined microscopically to document unusual wear, assess wear patterns and oral lesions as evidence of habitual behavior, and determine their effect on the oral health of this population. Five atypical wear types were observed: occlusal facets, occlusal excessive load, labial vertical striae, labial horizontal striae, and interproximal striae. Three oral lesions were recorded: chipping, periapical lesions, and dental tilting. Results indicate that teeth were used in a habitual manner at Ajvide, based on the morphology and regularity of the patterns of atypical wear. Differences were observed between the sexes, indicating gender-related differences in the habitual use of teeth. Some wear categories showed a significant correlation with age, signifying increased or accumulated wear with age. Statistically significant positive correlations were found in the molars between occlusal excessive load wear and periapical lesions as well as tilting. Other apparent links were also observed between chipping and vertical striae as well as excessive load, although these were not significant. This suggests a relationship between dental wear and dental pathologies at this site, suggesting that habitual use of teeth indirectly affected the general oral health at the site. Wear patterns, furthermore, seem to mirror both frequent activities as well as single events.     

Modular Wear Facet Nomenclature for mammalian post-canine dentitions

Abstract

Dental wear facets on the occlusal surface of premolars and molars are traces of their main function, the mastication and therefore reflect masticatory movements and also paramasticatory (i.e. non-dietary use of teeth) behavior. Here we present the Modular Wear Facet Nomenclature applicable to most mammalian dentitions. Topographic positions of wear facets in relation to the major cusps and crests of the teeth are used to designate the areas of the occlusal surface the facets occupy (e.g. their mesial, distal, lingual, or buccal position). Previous published systems for labeling wear facets have been inconsistent with each other. Therefore, we provide a synoptic review of the most widely-used terminologies, and introduce the alternative Modular Wear Facet Nomenclature. This nomenclature aims to overcome the difficulties caused by the existing inconsistent wear facet terminologies. Our new approach is applicable to dentitions where the occlusal morphology does not change significantly for most of the lifetime of the animal. In those dentitions, the primary occlusal surfaces are not significantly modified as wear facets become more extensive with wearing. This appears to be a common pattern in pre-tribosphenic, tribosphenic molars, and the teeth derived from tribosphenic precursors (e.g. bunodont molar morphologies). In teeth where the secondary occlusal surface is functionally intensely modified (i.e. high-crowned and evergrowing teeth with large areas of dentine exposed) any facet labeling system appears to be challenging, since the identification of individual facets is blurred and their spatial position may be indeterminable.     

On dental wear, dental work, and oral health in the type specimen (LB1) of Homo floresiensis

The claim that the lower left first mandibular molar of LB1, the type specimen of Homo floresiensis, displays endodontic work, and a filling is assessed by digital radiography and micro-CT scanning. The M(1) tooth crown is heavily worn and exhibits extensive dentine exposure that is stained white, but there is no trace of endodontic treatment or a dental filling in this Indonesian fossil dated to 17.1-19.0 kya. Dental calculus (commonly observed in foragers) is present on the teeth of LB1, but there are no observable caries. The pattern of dental attrition in the mandibles of both LB1/2 and LB6/1 (moderate to extensive flat wear across the entire arch) is consistent with that seen in Plio-Pleistocene Homo fossils and in modern hunter-gatherers, and is not typical of most agriculturalists. We conclude that the dental-work and farming hypotheses are falsified and therefore irrelevant to the debate over the taxonomy and phylogeny of H. floresiensis.     

可摘局部义齿基牙易发龋坏部位致龋菌的检出比较

通过对戴入可摘局部义齿后基牙易发龋坏部位的早期细菌组成的测定,探讨可摘局部义齿与基牙龋坏之间的潜在关系。观察１２个６活动桥的２４颗基牙,其中５、７各１２颗。病人平均年龄２５５岁。采取基牙靠缺隙侧邻面１／３区域的菌斑。采用细菌培养技术,持续观察了３个月,测定了菌斑细菌的组成。结果发现,变形链球菌的检出率在实验中呈逐渐上升趋势,且在牙位７上的检出率比在牙位５上的检出率高。结论戴用可摘局部义齿造成了口腔微生态环境的改变,促进了某些致龋细菌的生长,成为基牙发生龋坏的潜在因素     

郑州汪沟遗址仰韶文化居民的牙齿磨耗及口腔健康状况

对汪沟遗址出土的174例仰韶文化居民的2816枚牙齿进行统计与分析,计算出牙齿的平均磨耗等级和前后部牙齿磨耗差别指数,统计特殊磨耗、龋齿、骨质隆起在样本中的出现率。结果显示,汪沟组牙齿平均磨耗等级为3.403262级,男性牙齿平均磨耗等级为3.63级,女性为3.61级;男女两性牙齿磨耗差异不显著(p>0.05);前后部牙齿磨耗差别指数比达到1:1;出现26例由于深覆■导致的特殊磨耗;臼齿咬合面凹坑式磨耗出现率为2.50%;龋齿患病率68.97%,龋齿率26.56%,龋均4.30;骨质隆起的出现率为5.20%,颌骨粗壮程度不显著。汪沟人群的牙齿磨耗程度总体偏轻,牙齿磨耗程度与河南下王岗组居民接近。基于以上特点,我们认为中原地区仰韶文化人群在饮食结构和用牙习惯上存在一定的共性。     

Hanuman Langur: Monkey of India

An apparently new type of dental wear pattern, lingual surface attrition of the maxillary anterior teeth (LSAMAT), has been found in 85% of 46 adult crania from a 3000–4200 BP Archaic site called Corondó near the Atlantic Ocean coast of Brazil. LSAMAT is associated with a high caries rate (60% of 77 adults; 11% of 1,219 permanent teeth) in what on archeologica grounds alone would be considered a mainly meat-eating population. It is suggested that both LSAMAT and caries resulted from eating some starchy plant like manioc.     

Form and patterning of anterior tooth wear among aboriginal human groups

Form and severity of dental attrition was assessed in aboriginal human groups including hunter-gatherers (Eskimos, Australians) and those with dependence to a varying degree on food production (Southwest U.S. and Ohio American Indians). Wear on anterior teeth was both relatively and absolutely greater in the hunter-gatherers, as indicated by comparisons of wear on anterior and posterior teeth which come into occlusion at roughly the same time. Distinct differences in form of anterior wear were also apparent: The hunter-gatherers exhibited steadily increasing incidences of labially rounded wear with greater functional age, while the food-producing groups showed little or no rounding but instead high frequencies of heavily cupped wear (especially in those with premature loss of posterior teeth). These differences were attributed to nonmasticatory utilization of the front teeth in hunter-gatherers and to employment of the anterior teeth in masticatory (grinding) activities necessitated by large-scale molar loss in food producers.