Quantifying calculus: a suggested new approach for recording an important indicator of diet and dental health.

This paper describes a quantitative approach to the assessment of dental calculus in human archaeological skeletal samples. The approach combines the ranked calculus scoring method described by Buikstra and Ubelaker [1994. Arkansas Archeological Survey Research Series, Arkansas Archeological Survey, Fayetteville, Arkansas] and a modified Simplified Calculus Index, utilized by dental clinicians. We recorded amounts of calculus on the buccal, lingual, and interproximal surface of all extant teeth, and generated an index for the maxillary posterior dentition, maxillary anterior dentition, mandibular posterior dentition, and mandibular anterior dentition for three skeletal samples. They include 145 Egyptian Predynastic individuals from the site of Hierakonpolis, 104 Predynastic individuals from Naqada, Egypt, and 101 Meroitic Nubians from Semna South, present-day Sudan. Mann-Whitney U tests were used to analyze differences between the sexes and among age groups at each site. The results demonstrate that the calculus indices more effectively reveal trends and differences in calculus severity than frequency data can alone. For example, at Hierakonpolis, males (18-35 years) had significantly more calculus in the maxillary posterior dentition than females, while females (50+ years) had significantly more calculus in the maxillary posterior teeth. Frequency data merely showed that 94% of both males and females had calculus. The use of calculus indices can reveal how quickly calculus accumulates with age within the dental arcade and within a sample. Moreover, better understanding of the severity and location of calculus can improve a researcher's knowledge regarding the effect of calculus on dental pathologies, such as carious lesions and periodontal disease.     

Prevalence and patterning of maxillary premolar accessory ridges (MxPARs) in several human populations

We present new data on the prevalence and patterning of the maxillary premolar accessory ridge (MxPAR), a common but understudied morphological dental trait that is expressed as a linear elevation extending from the buccal cusp ridge to the medial sulcus of maxillary premolar teeth. A total of 579 sets of dental casts, representing six ethnic groups, were scored using the five‐grade system proposed by Burnett et al. (2010). The frequency and distribution of the MxPAR were determined by tooth type, sex, side, locus and ethnicity, and the applicability of the scoring system was assessed. The MxPAR was found in approximately two‐thirds of premolar teeth, more often on second than first premolars, and more often on the distal aspect of the occlusal surface than the mesial. There was some evidence that more pronounced forms of the feature occurred more often in males than females, and that there may be some directionality in its expression between sides. Variation was also noted in the frequency of occurrence and degree of expression of the MxPAR between ethnic groups. Intra‐ and inter‐observer concordance rates for scoring the MxPAR were low, confirming that it was difficult to score the trait identically on two different occasions. Our findings have clarified the distribution of the MxPAR within the dentition and between ethnic groups, and highlighted the need for researchers to carry out thorough replicability studies and to decide on an appropriate breakpoint for determining presence or absence of this feature before embarking on genetic studies or bio‐distance analyses. Am J Phys Anthropol 152:19–30, 2013. © 2013 Wiley Periodicals, Inc.     

Comparative microcomputed tomography and histological study of maxillary pneumatization in four species of new world monkeys: the perinatal period

In anthropoid primates, it has been hypothesized that the magnitude of maxillary sinus growth is influenced by adjacent dental and soft tissue matrices. Relatively, little comparative evidence exists for the perinatal period when secondary pneumatization is at its earliest stages in some primates. Here, dental and midfacial variables were studied in a perinatal sample of four anthropoid primates, including three callitrichines (Leontopithecus, Saguinus, and Callithrix) and Saimiri boliviensis. In the latter species, the maxillary recess (the ontogenetic precursor to a "true" maxillary sinus) does not undergo secondary pneumatization. Using histological methods and micro-computed tomography, midfacial and dental dimensions and radiographic hydroxyapatite density of tooth cusps were measured. The distribution of osteoclasts and osteoblasts was also documented. Kruskal-Wallis's one-way analysis of variance tests indicates significant (P < 0.05) differences among groups for dental and midfacial measurements. In particular, the posterior maxillary dentition is relatively larger and more mineralized in Saimiri compared to the callitrichines. At posterior dental levels, Saimiri has the lowest palatonasal index [interdental (palatal) width/width of the nasal cavity] and highest bizygomatic-interorbital index. Distribution of osteoclasts indicates that the inferomedial surfaces of the orbits are resorptive in perinatal Saimiri, whereas, in all callitrichines, these surfaces are depository. Taken together, these findings suggest that pneumatization in Saimiri is suppressed by an inward growth trajectory of the orbits, relatively large posterior dentition, and a correspondingly compressed nasal region.     

Individual tooth macrowear pattern guides the reconstruction of Sts 52 (Australopithecus africanus) dental arches

The functional restoration of the occlusal relationship between maxillary and mandibular tooth rows is a major challenge in modern dentistry and maxillofacial surgery. Similar technical challenges are present in paleoanthropology when considering fragmented and deformed mandibular and maxillary fossils. Sts 52, an Australopithecus africanus specimen from Sterkfontein Member 4, represents a typical case where the original shape of the dental arches is no longer preserved. It includes a partial lower face (Sts 52a) and a fragmented mandible (Sts 52b), both incomplete and damaged to such an extent to thwart attempts at matching upper and lower dentitions. We show how the preserved macrowear pattern of the tooth crowns can be used to functionally reconstruct Sts 52's dental arches. High‐resolutiondental stone casts of Sts 52 maxillary and mandibular dentition were mounted and repositioned in a dental articulator. The occlusal relationship between antagonists was restored based on the analysis of the occlusal wear pattern of each preserved tooth, considering all dental contact movements represented in the occlusal compass. The reconstructed dental arches were three‐dimensional surface scanned and their occlusal kinematics tested in a simulation. The outcome of this contribution is the first functional restoration of A. africanus dental arches providing new morphometric data for specimen Sts 52. It is noteworthy that the method described in this case study might be applied to several other fossilspecimens. Am J Phys Anthropol, 2013. © 2013 Wiley Periodicals, Inc.     

Genetic structure of a tribal population, the Yanomama Indians. XIII. Dental microdifferentiation.

Data are presented on the frequency of the following eight dental traits in 635 Yanomama and 65 Makiritare Indians: upper central incisor rotation or winging, shoveling of maxillary incisors, maxillary molar hypocone reduction, Carabelli's trait, mandibular molar cusp number, mandibular molar cusp pattern rotation of second lower premolar, and pattern of second lower premolar cusps. Yanomama dentition is unusual in the high frequency of six cusps on the mandibular molars. There is marked dental microdifferentiation between villages; significant agreement was observed between a matrix of pairwise "dental distances" based on six morphological traits and corresponding matrices based on 11 genetic systems and on geographic location.     

Cultural alteration of human teeth in the Mariana Islands

Evidence of cultural dental modification in a precontact (pre-1521) skeletal sample from the Academy of Our Lady of Guam gymnasium site in Agana, Guam, is documented. Two of the four individuals recovered at the Academy Gym site exhibit modification of the maxillary teeth. One individual displays vertical incising of a single tooth, and the other exhibits horizontal abrading of the anterior teeth which may be a purposeful or an incidental alteration. Although deliberate alteration of the dentition, including tooth extraction, notching, filing, and drilling, has been documented in human groups worldwide, little has been written about these cultural practices in the Mariana Islands. Examination of the available literature on precontact human remains from the region reveals at least three patterns of dental incising and similar cases of dental abrasion. While the origins of these practices are not known, the presence and style of these cultural alterations may be sex-specific, cosmetic in nature, or an indication of status in a ranked society. Alternatively, they may signify membership in a particular group or lineage, or mark a rite of passage. Because the comparative samples are limited in number and small, and the provenience of many of the skeletons is obscure, temporal variation cannot be ruled out. Am J Phys Anthropol 104:381–391, 1997. © 1997 Wiley-Liss, Inc.     

Morphological integration in the hominin dentition: evolutionary, developmental, and functional factors

As the most common and best preserved remains in the fossil record, teeth are central to our understanding of evolution. However, many evolutionary analyses based on dental traits overlook the constraints that limit dental evolution. These constraints are diverse, ranging from developmental interactions between the individual elements of a homologous series (the whole dentition) to functional constraints related to occlusion. This study evaluates morphological integration in the hominin dentition and its effect on dental evolution in an extensive sample of Plio- and Pleistocene hominin teeth using geometric morphometrics and phylogenetic comparative methods. Results reveal that premolars and molars display significant levels of covariation; that integration is stronger in the mandibular dentition than in the maxillary dentition; and that antagonist teeth, especially first molars, are strongly integrated. Results also show an association of morphological integration and evolution. Stasis is observed in elements with strong functional and/or developmental interactions, namely in first molars. Alternatively, directional evolution (and weaker integration) occurs in the elements with marginal roles in occlusion and mastication, probably in response to other direct or indirect selective pressures. This study points to the need to reevaluate hypotheses about hominin evolution based on dental characters, given the complex scenario in which teeth evolve.     

Brief communication: Identification reassessment of the isolated tooth Krapina D58 through occlusal fingerprint analysis

High variability in the dentition of Homo can create uncertainties in the correct identification of isolated teeth. For instance, standard tooth identification criteria cannot determine with absolute certainty if an isolated tooth is a second or third maxillary molar. In this contribution, using occlusal fingerprint analysis, we reassess the identification of Krapina D58 (Homo neanderthalensis), which is catalogued as a third maxillary molar. We have hypothesized that the presence/absence of the distal occlusal wear facets can be used to differentiate second from third maxillary molars. The results obtained confirm our hypothesis, showing a significant difference between second and third maxillary molars. In particular we note the complete absence of Facets 7 and 10 in all third molars included in this analysis. The presence of these facets in Krapina D58 eliminates the possibility that it is a third maxillary molar. Consequently it should be reclassified as a second molar. Although this method is limited by the degree of dental wear (i.e., unworn teeth cannot be analyzed) and to individual molars in full occlusion, it can be used for tooth identification when other common criteria are not sufficient to discriminate between second and third maxillary molars. Am J Phys Anthropol 143:306–312, 2010. © 2010 Wiley‐Liss, Inc.     

The Copenhagen Oral Health Senior Cohort: design, population and dental health

Gerodontology 2010; doi: 10.1111/j.1741‐2358.2010.00383.x The Copenhagen Oral Health Senior Cohort: design, population and dental health Background: In order to study the way old age influence oral health, the Copenhagen Oral Health Senior Cohort (COHS) has been established. Objectives: To describe the design, measurement procedures, and baseline values for COHS including spatial distribution of restorations and dental caries as well as reasons for non‐participation. Materials and methods: Seven hundred and eighty‐three individuals aged 65 years or older, from a total of 1918 invited elderly people, underwent an interview regarding oral health‐related behaviour and a clinical oral examination including measurement of unstimulated whole saliva flow rate. Results: Twelve percent of the COHS was edentulous. The number of dental restorations was higher for women compared to men; however, men had more caries than women. Coronal caries was most frequent on mesial and distal surfaces and on the maxillary incisors and canines; root caries was most frequent on labial surfaces and evenly distributed within the dentition. Only 41% of all invited elderly people accepted the invitation, with old age and poor health being the primary reasons for non‐participation. Conclusion: The baseline values for COHS show that a substantial proportion of the participants had retained a natural dentition and that dental caries was prevalent with the anterior maxillary teeth being most affected.     

Plate-like permanent dental laminae of upper jaw dentition in adult gobiid fish, Sicyopterus japonicus

Sicyopterus japonicus (Teleostei, Gobiidae) possesses a unique upper jaw dentition different from that known for any other teleosts. In the adults, many (up to 30) replacement teeth, from initiation to attachment, are arranged orderly in a semicircular-like strand within a capsule of connective tissue on the labial side of each premaxillary bone. We have applied histological, ultrastructural, and three-dimensional imaging from serial sections to obtain insights into the distribution and morphological features of the dental lamina in the upper jaw dentition of adult S. japonicus. The adult fish has numerous permanent dental laminae, each of which is an infolding of the oral epithelium at the labial side of the functional tooth and forms a thin plate-like structure with a wavy contour. All replacement teeth of a semicircular-like strand are connected to the plate-like dental lamina by the outer dental epithelium and form a tooth family; neighboring tooth families are completely separated from each other. The new tooth germ directly buds off from the ventro-labial margin of the dental lamina, whereas no distinct free end of the dental lamina is present, even adjacent to this region. Cell proliferation concentrated at the ventro-labial margin of the dental lamina suggests that this region is the site for repeated tooth initiation. During tooth development, the replacement tooth migrates along a semicircular-like strand and eventually erupts through the dental lamina into the oral epithelium at the labial side of the functional tooth. This unique thin plate-like permanent dental lamina and the semicircular-like strand of replacement teeth in the upper jaw dentition of adult S. japonicus probably evolved as a dental adaptation related to the rapid replacement of teeth dictated by the specialized feeding habit of this algae-scraping fish.     

Maxillary sinusitis as an indicator of respiratory health in past populations

Chronic infectious respiratory disease in a past human population is investigated through the quantification of maxillary sinusitis among Iroquoian horticulturists. Three hundred forty-eight right and left maxillae of a Southern Ontario Iroquoian skeletal sample, Uxbridge Ossuary, ca. AD 1440, were examined for evidence of chronic infection (minimum number of individuals = 207: 114 adults, 22 adolescents, 38 juveniles and 33 infants). Modern clinical criteria were applied to differentiate lesions of respiratory and dental origin. Osseous lesions of the maxillary sinuses were observed in 50% of the individuals examined. These lesions are morphologically consistent with nonspecific lesions observed in other past populations that have been attributed to the presence of pathogens. The prevalence of maxillary sinusitis increases with age. Osseous changes suggestive of maxillary sinusitis of respiratory origin are at a maximum prevalence in juveniles and adolescents. In adults, infection of dental origin becomes a confounding factor in the identification of sinusitis of respiratory origin. Fifteenth century Iroquoians were experiencing high airborne pathogen levels and poor indoor air quality. The prevalence of maxillary sinusitis and the exploration of the origin of tissue injury may contribute to our reconstruction of the quality of life and the respiratory health status of past human populations.     

Deciduous dentition eruption sequence of the laboratory-reared chimpanzee (Pan troglodytes)

Eruption sequence and age ranges for the maxillary and mandibular deciduous dentition were generated from serial dental study models from 28 laboratory-reared chimpanzees (Pan troglodytes). These data can serve as additional normative, baseline information for the evaluation of fetal insults on neonatal growth and development in the laboratory-reared chimpanzee.     

Tooth morphology of Notosuchus terrestris (Notosuchia: Mesoeucrocodylia): New evidence and implications

Notosuchia is a large and diverse group of Crocodyliforms, characterized, among other features, by a heterodont dentition. New information on the tooth anatomy of Notosuchus terrestris is presented, based on well-preserved specimens from the Late Cretaceous of Patagonia (southern Argentina). This allows a complete characterization of its dental anatomy (composed by incisiviform, caniniform, and molariform teeth) that includes autapomorphic features and derived features shared with Sphagesaurus and Mariliasuchus. This includes the extensive wear facets in molariforms, indicative of tooth–tooth occlusion and a sharp keel that bears rounded denticles. Notosuchus also shares with Mariliasuchus the presence of a tooth with a transitional morphology located at the premaxilla–maxilla contact and the absence of interalveolar septa in the entire premaxillary and maxillary dentition.     

Talon cusp from two archaic period cemeteries in North America: implications for comparative evolutionary morphology

Talon cusps are rare morphological features of the anterior dentition that represent a spectrum of lingual cingulum diversity. In this paper, talon cusp prevalence is described in two Archaic period North American samples, Windover Pond (Florida) and Buckeye Knoll (Texas). Given the early date of these cemeteries (~7500 BP), these specimens represent the oldest reported cases of lingual talon cusp in the New World, and perhaps globally. Windover preserves three cases of talon cusp (representing three different individuals) affecting the permanent maxillary lateral incisors. The sample frequencies were 1.8% and 3.1% for the left and right maxillary lateral incisors, respectively. Buckeye Knoll preserves four cases of talon cusp representing three individuals. Talon cusps at this site were distributed throughout the maxillary anterior dentition, including a permanent maxillary central incisor, bilateral permanent maxillary lateral incisors, and a deciduous maxillary lateral incisor. The multicomponent nature of this site complicates sample frequency calculation with by-tooth estimates ranging from 3.6% to 25%. This paper discusses the difficulties with comparative frequency estimation, resulting from a proliferation of terminology that is discipline-specific. Understanding the evolutionary basis and significance of dental morphological variation requires an inclusive approach to the comparative literature that focuses on homology within the context of odontogenetic process.     

Brief communication: Possible third molar impactions in the hominid fossil record

Impacted third molars affect 15%–20% of modern Americans and Western Europeans. In contrast, third molar impactions have not been reported in the early hominid fossil record. It is uncertain whether the lack of reports reflects an absence of impactions or a failure to recognize them. This communication is intended to raise awareness of the possibility of impactions by describing the appearance of impacted teeth and by noting two possible instances of impaction in early hominids. Specifically, the mandibular third molars of the Sterkfontein specimen, STS52b (Australopithecus africanus), and the left maxillary third molar of the Lake Turkana specimen, KNM-WT17400 (Australopithecus boisei), are positioned in a manner which suggests that they would not have erupted normally. Both specimens also exhibit strong crowding of the anterior dentition, providing further support for the view that these individuals lacked sufficient space for normal eruption of the third molars. Other published reports of dental crowding in the hominid fossil record are noted, and it is suggested that more attention be paid to dental impaction and dental crowding in hominid evolution. © 1993 Wiley-Liss, Inc.     

秦岭野生大熊猫牙齿的形态机能

大熊猫(Ailuropoda melanoleuca)是国家一级保护动物,被誉为国宝.牙齿作为大熊猫消化器官之一,相对于其他动物而言,大熊猫牙齿有其自身的构造特点.以往学者和专家对大熊猫牙齿形态的研究侧重于为大熊猫的种群分类寻找根据(Dvadi,1869; Milne-Edwards,1870;王将克,1974),更多关注牙齿在大熊猫进化、演变过程中的意义(王令红等,1982;黄万波,1993).研究的齿位大多局限于臼齿(张鹤宇和刘理,1959),所得结果或数据并不详细和全面.此外,还有一些学者对大熊猫牙齿釉质的超微组织结构进行研究(赵资奎等,1984 ).     

Palatal growth in baboons (Papio cynocephalus anubis)

In this study the structure and development of the palate as observed in a cross-sectional collection of olive baboons (Papio cynocephalus anubis) skulls are described and analyzed using craniometric techniques. Considered are structural functional relationships among different parts of the palate, and between the palate and other parts of the craniofacial skeleton. Several inferences are drawn and speculated upon. These inferences are as follows: odontogenesis affects premaxillary growth the most during late fetal and early postnatal development; maxillary length is significantly affected by development and eruption of the maxillary dentition, whereas maxillary breadth is less affected by dental development. Growth of the palatine bones and nasopharyngeal airway is correlated with dentomasticatory changes; the developmental and functional significance of these correlations is unclear. Further inferences are that growth rates for each palatal component differ for each sex even though lengths of the components relative to total palatal dimensions show no sexual dimorphism. Also, it is determined that maxillary length remains constant, premaxillary length reduces and palatine length increases relative to total palatal length with growth.     

Interproximal grooving in the Atapuerca-SH hominid dentitions

The dental sample recovered from the Sima de los Huesos (SH) Middle Pleistocene cave site of the Sierra de Atapuerca (Spain) includes 296 specimens. Interproximal wear grooves have been observed in 20 maxillary and mandibular posterior teeth belonging to at least five of the 32 individuals identified so far in the SH hypodigm. Interproximal grooving affected only the adults, and at an age between 25 and 40 years. The appearance, morphology, and location pattern of the SH wear grooves are similar to those reported in other fossil hominids and in more recent human populations. Two alternative proposals, the toothpicking and the fiber or sinew processing hypotheses, compete for explaining the formation of this anomalous wear. The characteristics observed in the wear grooves of the SH teeth are compatible only with the habitual probing of interdental spaces by means of hard and inflexible objects. Dietary grit may also have contributed to the abrasion of the root walls during the motion of the dental probes. Am. J. Phys. Anthropol. 102:369–376, 1997. © 1997 Wiley-Liss, Inc.     

Anterior tooth reductions inRamapithecus

A metric study comparing the maxillary dentition ofRamapithecus to modern hominoids is undertaken. From such a study, one can determine whether the criterion of relative anterior tooth reduction is significant enough to support the placement ofRamapithecus in the hominid line of evolution. As it turns out, the anterior dental reduction is not significant and thus this particular criterion cannot be used for this purpose.