The Patterning Cascade Model and Carabelli's trait expression in metameres of the mixed human dentition: exploring a morphogenetic model

Since ancient times the Mediterranean island of Sardinia has been known for harboring a population with an average body height shorter than almost every other ethnic group in Europe. After over a century of investigations, the cause(s) at the origin of this uniqueness are not yet clear. The shorter stature of Sardinians appears to have been documented since prehistoric times, as revealed by the analysis of skeletal remains discovered in archaeological sites on the island. Recently, a number of genetic, hormonal, environmental, infective and nutritional factors have been put forward to explain this unique anthropometric feature, which persisted for a long time, even when environmental and living conditions improved around 1960. Although some of the putative factors are supported by sound empirical evidence, weaker support is available for others. The recent advent of whole genome analysis techniques shed new light on specific variants at the origin of this short stature. However, the marked geographical variability of stature across time and space within the island, and the well‐known presence of pockets of short height in the population of the southern districts, are still puzzling findings that have attracted the interest of anthropologists and geneticists. The purpose of this review is to focus on the state‐of‐the‐art research on stature, as well as the factors that made Sardinians the shortest among Europeans.     

Radiographic study of the Broadbeach Aboriginal dentition

This study forms part of a larger anthropological investigation of the Ngaraangbal Aboriginal Tribe's ancestral burial ground at Broadbeach, Australia. It examines the dentition, records the associated pathology in a noninvasive manner, and relates this to the likely subsistence diet of the tribe. The Broadbeach osteological collection was returned for reburial in 1985; however, radiographic and photographic records of 36 adult males were available. These form the basis of our study. The pathology noted in the study sample was compared with a representative sample (n = 38) of pre-European Aboriginal remains from throughout Queensland for verification purposes only. Rates of dental pathology and injury were calculated from the radiographic and photographic records. There was a significant rate of tooth-wear related intra-bony pathology (4.0%), moderate to severe alveolar bone loss, and heavy dental attrition, of which the mandibular posterior teeth were the most severely affected. Caries prevalence (0.8%) was low for hunter-gatherer populations. A large number of molar pulp chambers had a distinctive “cruciate” morphology resulting from the formation of secondary dentine and pulp stones. Injuries and abnormalities included upper central incisor avulsion (58.3%) and taurodontism. These results support the proposal that the Ngaraangbal tribe was a hunter-gatherer population subsisting on an abrasive diet that included marine foods. Am J Phys Anthropol 107:211–219, 1998. © 1998 Wiley-Liss, Inc.     

Brief communication: First evidence of LSAMAT in non-native Americans: Historic Senegalese from West Africa

To date, the distinctive dental wear pattern known as LSAMAT, or “lingual surface attrition of the maxillary anterior teeth,” has been documented in prehistoric samples from Brazil, Panama, and Puerto Rico only. However, new data from a historic Senegalese sample reveals the first example of this wear pattern outside the Americas. The Senegal LSAMAT is present in 45% of 22 adult crania, and is associated with a caries rate of 40% in 38 adults (6.7% of 534 permanent teeth). A correlation between LSAMAT and caries was also observed in the Latin American samples. In these cases, it was hypothesized that LSAMAT was caused by the specialized consumption of an abrasive, high carbohydrate food, such as manioc. Manioc is a common cultigen in Senegal; thus, it may have also caused the African LSAMAT. The chewing of sugar cane could have been an additional, contributing factor. Am J Phys Anthropol 102:141–146, 1997. © 1997 Wiley-Liss, Inc.     

The Vikings bare their filed teeth

Finds of deliberate dental modification have for the first time been found in archaeological human skeletal material from Europe. The type of modification is a horizontally filed furrow on the frontal upper part of the tooth crown. The furrows are single or, more usually, multiple, and are found on the front teeth in the maxilla. The affected individuals are 24 men from the Viking Age (ca. 800-1050 AD), found in present day Sweden and Denmark. The marks are so well-made that it is most likely they were filed by a person of great skill. The reason for, and importance of, the furrows are obscure. The affected individuals may have belonged to a certain occupational group (such as tradesmen), or the furrows could have been pure decoration.     

Relationship of enamel hypoplasia to the pattern of tooth crown growth: A discussion

The defects of enamel hypoplasia can be related to the layered structure of enamel which represents the sequence of development in tooth crowns. From such studies, it is possible to see that furrow-type enamel defects (the most common form of hypoplasia seen with the naked eye) are just the most prominent expression of a continuum which extends ever smaller, down to a microscopic disturbance to a single layer in the crown formation sequence. Furthermore, the progressive decrease in spacing between development layers which occurs down the crown sides, from occlusal to cervical, affects both the prominence and apparent width of the defects. This makes it difficult to use measurements as a means of estimating the duration of the disturbance causing a particular defect. The difficulty is even greater for the less common pitted or exposed-plane-type defects, for which the apparent width bears very little relationship with the duration of the growth disturbance. The defects of enamel hypoplasia can therefore be understood clearly only when examined under the microscope in relation to the structures which mark the development sequence of the tooth crown. Am J Phys Anthropol 104:89–103, 1997. © 1997 Wiley-Liss, Inc.     

Influence of transmucosal height in abutments of single and multiple implant-supported prostheses: a non-linear three-dimensional finite element analysis

The aim of this study was to analyze the influence of three different transmucosal heights of the abutments in single and multiple implant-supported prostheses through the finite element method. External hexagon implants, MicroUnit, and EsthetiCone abutments were scanned and placed in an edentulous maxillary model obtained from a tomography database. The simulations were divided into two groups: (1) one implant with 3.75 × 10 mm placed in the upper central incisor, simulating a single implant-supported fixed prosthesis with an EsthetiCone abutment; and (2) two implants with 3.75 × 10 mm placed in the upper lateral incisors with MicroUnit abutments, simulating a multiple implant-supported prosthesis. Subsequently, each group was subdivided into three models according to the transmucosal height (1, 2, and 3 mm). A static oblique load at an angle of 45 degrees to the long axis of the implant in palatal-buccal direction of 150 and 75 N was applied for multiple and single implant-supported prosthesis, respectively. The implants and abutments were assessed according to the equivalent Von Mises stress analyses while the bone and ceramics were analyzed through maximum and minimum principal stresses. The total deformation values increased in all models, while the transmucosal height was augmented. The transmucosal height of the abutments influences the stress values at the bone, ceramics, implants, and abutments of both the single and multiple implant-supported prostheses, with the transmucosal height of 1 mm showing the lowest stress values.     

Biocultural implications of oral pathology in an ancient Central California population

Bioarchaeologists have long noted two unusual trends in the dentitions of prehistoric Native Californian populations: high rates of wear and low prevalence of caries. The Central California site of CA‐CCO‐548 offers a unique opportunity to examine the relationship between oral pathology and extreme dental wear in a large (n = 480), ancient (4,300–3,100 BP), and temporally well‐defined population sample. This study specifically examines three interrelated processes of the oral cavity in this population: dental wear, dental caries, and periodontal disease. The results show high levels of dental wear (average of 6.1, Smith system), low frequencies of carious lesions (2.5%), low frequencies of periodontal disease (17.8%), and high frequencies of periapical abscesses (10.7%). The pathological processes examined here have complicated multifactorial etiologies. However, they all share the common primary etiological agents of facultative pathogenic bacteria proliferation in the oral biofilm. Integration of the current etiological explanations for infections of the oral cavity, information from the ethnographic record pertaining to subsistence and activity patterns in Native Californian populations, and statistical analysis of specific disease and wear patterns leads to a novel explanation for the observed pattern of oral pathology in this population sample. Specifically, the introduction of antibacterial compounds through dietary items and non‐alimentary tooth use is suggested as the most likely explanation for the unusually low prevalence of dental caries and periodontal disease. Am J Phys Anthropol 154:171–188, 2014. © 2014 Wiley Periodicals, Inc.     

Brief communication: correcting overestimation when determining two-dimensional occlusal area in human molars

The robustness index (RI) is determined by multiplying dental mesiodistal and buccolingual diameters, and is used to estimate occlusal area. However, because teeth are not rectangular its calculation consistently causes overestimations. Moreover, teeth, in particular molars, are not identically shaped so overestimations vary. The current study seeks to determine the extent to which overestimations are affected by tooth shape and to improve RI's efficacy. Initially, 120 molars were sorted into six shape groups, which were determined by hypocone/hypoconulid expression. Three maxillary and three mandibular shape groups were set using the Arizona State University Dental Anthropology System. ANOVA results determined that RI overestimations, which averaged around 20%, were not the same for each shape category. Maxillary molars with large hypocones and mandibular molars with no hypoconulids were overestimated significantly less than the other molar groups. Regression-based correction formulae were generated and applied to the original sample. These formulae far more precisely estimated tooth area than RI and there were no differences in estimation based upon tooth shape. A subsequent validation study of 24 additional molars was undertaken to test the formulae on teeth not from the original sample. Overestimation/underestimation averaged 0.5% and was about the same for each of the tooth shape groups. Finally, six new correction formulae were generated using all 144 molars. The correction formulae provide, what is termed here, an adjusted robustness index (ARI), and it is recommended that ARI is used in future studies of molar occlusal area.     

Iatrogenic molar borings in 18th and early 19th century Native American dentitions

Six iatrogenic dental borings were identified in four individuals of a Native American skeletal collection from an 18th and early 19th century Middle Columbia River burial site. The borings, all in maxillary first molars with severe dental attrition and secondary dentin, demonstrate striated walls and associated periapical alveolar lesions. An ethnographic review of the subsistence pattern during the burial period indicates a diet that is consistent in dental attrition with other riverine fisher-hunter-gathers. Histological changes of dental pulp tissue during the process of attrition may result in dental necrosis. Access into the pulp chamber is a technique used to drain necrotic fluid. A common Euro-American therapeutic dental practice of the 18th and 19th centuries for diseases of the pulp was dental extraction. Multiple dental borings indicate that the practice of molar drilling into the pulp chamber was an effective and independent technique used by the Wishram and Wasco people.     

Brief communication: Population variation in human maxillary premolar accessory ridges (MxPAR)

The purpose of this brief communication is to report the results of an analysis of maxillary premolar accessory ridges (MxPAR), a common but understudied accessory ridge that may occur both mesial and distal to the central ridge of the buccal cusp of upper premolars. We developed a new five‐grade scoring plaque to better categorize MxPAR variation. Subsequently, we conducted a population analysis of MxPAR frequency in 749 dental casts of South African Indian, American Chinese, Alaskan Eskimo, Tohono O'odham (Papago), Akimel O'odham (Pima), Solomon Islander, South African Bantu, and both American and South African Whites. Northeast Asian and Asian‐derived populations exhibited the highest MxPAR frequencies while Indo‐European samples (South African Indians, American and South African Whites) exhibited relatively low frequencies. The Solomon Islanders and South African Bantu samples exhibited intermediate frequencies. Our analysis indicates that statistically significant differences in MxPAR frequency exist between major geographic populations. As a result, the MxPAR plaque has now been added to the Arizona State University Dental Anthropology System, an important contribution as maxillary premolar traits are underrepresented in analyses of dental morphology. Am J Phys Anthropol 2010. © 2009 Wiley‐Liss, Inc.     

牙缺损伴牙颌畸形的正畸与修复联合治疗效果分析

目的探讨牙缺损伴牙颌畸形的正畸与修复联合治疗效果。方法对牙缺损伴牙颌畸形患者采用正畸与修复联合治疗。结果 38例牙缺损伴牙颌畸形患者经过正畸与修复联合治疗,其中36例成功,成功率达94.74%。修复后牙排列整齐,咬合关系良好,基牙无松动、移位,患者对疗效满意。2例失败,占5.26%,表现为固定义齿有移位现象,出现不同程度的牙列间隙。结论正畸与修复联合治疗牙缺损伴牙颌畸形患者,克服了单一治疗方法的局限性,从根本上改变患者的面形和咬合关系,修复治疗效果良好。     

Experiences and perceptions of oral health and oral health care among a sample of older New Zealanders

doi: 10.1111/j.1741‐2358.2010.00402.x Experiences and perceptions of oral health and oral health care among a sample of older New Zealanders Background: Most research on older people’s oral health has been quantitative. A need for more in‐depth understanding of the oral health of that age group has pointed to a need for more qualitative investigations. Objective: To explore experiences and perceptions of oral health and oral health care among an ethnically‐mixed sample of older New Zealanders. Methods: In‐depth interviews were conducted with 24 older people in two communities in New Zealand’s South Island. Thematic analysis of transcribed data was undertaken. Results: Three main themes that emerged were: (1) the processes of negotiating a tension between cost and convenience of access; (2) the experiential constraining of oral health maintenance; and (3) trusting in dental professionals. These serve to organise processes such as normalising, justifying and social comparisons that create an equilibrium or tolerance and acceptance of what might otherwise be considered to be relatively poor oral health. Conclusions: We identified a number of shared experiences which affect older people’s ability to maintain their oral health in the face of material and social barriers to oral health care. Because expectations were generally lower, there was greater concordance between experience and expectation, and people tended to be fairly satisfied with their oral health and the care they had received.     

Radiographic inspection of porosity in pure titanium dumbbell castings

Radiographic inspection of porosity in pure titanium dumbbell castings Background: Titanium frameworks are frequently indicated for implant supported prostheses; however, voids are usually encountered inside cast titanium. Objective: This study aimed to confirm the efficacy of a radiographic technique for inspection of porosity in commercially pure titanium castings with different diameter. Materials and methods: Sixty dumbbell rods (n = 20) with a central 1.5, 2.0 and 3.5 mm diameter were prepared by lost‐wax casting. Cast specimens were finished and polished and submitted to radiographic examination (90 kV, 15 mA, 0.6 s and 10–13 mm of distance) using periapical film. The radiographs were visually analysed for the presence of porosity in the extension of the dumbbell or in the central portion of the rods. Data were submitted to Pearson Chi‐square test (5%). Results: The tested radiographic method proved to be suitable for the evaluation of cast frameworks. Internal porosities were observed in most of the specimens (91.7%) (p = 0.0005); however, only 20% occurred on the central portion of the rods (p = 0.612). Conclusion: Internal porosities can be visualised through radiographs and occur mostly in small diameter structures. The radiographic evaluation of metal structures can improve the quality of frameworks and thereby potentially increase the longevity of the rehabilitation.     

Edentulous patients' knowledge of dental hygiene and care of prostheses

Objective: The aim of this study was to analyse denture users’ oral care habits with regard to the use of their prostheses. Background: Rehabilitative treatment is only successful when patients are motivated and aware of correct prosthesis use and hygiene. Materials and methods: Questionnaires were distributed to 150 complete denture users at the Federal University of Bahia School of Dentistry, the Esmeralda Natividade Health Center, the Bahian Science Development Foundation and a Salvador nursing home. The questionnaire included information on gender, age, length of prosthesis use, cleaning methods and materials, etc. The data were analysed using EpiInfo version 6 software. The chi‐squared test was used for statistical analysis, with a significance level of 5%. Results: Questionnaire results showed that 78% of the subjects, with an average age of 67.3 years, had used the same complete denture for over 5 years. 64% slept with their prostheses and 44% removed them from the mouth only for cleaning. None of the patients interviewed knew anything about brushes designed specifically for complete dentures. 37.3% had a restricted diet and 44% believed that a complete denture would last for more than 10 years. Conclusion: Within the limitations of this study, it was concluded that the edentulous patients surveyed had limited awareness of prosthetic hygiene and long‐term oral care despite extended periods of denture use.