Molar Attrition Research Articles

Age Estimation through Molar Attrition in Korean Population

Methods available for estimating the age of a living body are somewhat limited when there is shortage of teeth. This study aimed to determine whether the average stage of attrition (ASA) method published in 1995 by Li and Ji is practical among Koreans in their 50s and 60s. A total of 173 cases using 265 molars from 92 patients in their 50s and 60s who underwent age assessment at the Department of Oral Medicine at Pusan National University Dental Hospital from 2012 to 2022 were analyzed through clinical photographs and diagnostic casts. ASA method was used to determine the average attrition of cusps and calculate the estimated age. There was a moderate correlation between the average attrition of molars and the patients’ actual age. In patients in their 50s and 60s, the error range between the estimated age and the actual age was less than 10 years in 139 of 173 cases (74.56%), and age was underestimated in 147 cases (84.98%). The tendency for age to be underestimated was higher in women than in men. Regression analysis using both the first and second molars showed that the influence of the first molar was greater than that of the second molar. Although the correlation is not very high, considering the limitations of age estimation in the living body, this method may be useful if coupled with another method such as dental radiograph analysis when there is an absolute shortage of available teeth.

Age Estimation from Attrition of Permanent Molars.

The average stage of attrition in permanent first and second molars is an established method of age estimation in the adult population. The study was conducted with an objective of age estimation from the average stage of attrition of permanent molars. A total of 451 individuals of age more than 20 years were examined. Nepalese individuals with intact first and second permanent molars in the maxillary and mandibular arch on either side were included. The average stage of attrition of the maxillary first and second permanent molars on either side was calculated and subjected to regression analysis to derive equations. Among a total of 451 participants, 231 (51.22%) were females and 220 (48.78%) males, with a mean age of 44.3 ± 13.9 years. There was a strong correlation between age and average stage of attrition of molars. The correlation was stronger for upper molars compared to the lowers. Additionally, the mean of the difference between real age and estimated age was lower for maxillary compared to mandibular molars. Compared to age estimation by univariable regression, multivariable regression had greater accuracy. Similarly, estimation of age from maxillary molars was more accurate as compared to mandibular (difference in years: 3.82 ± 3.03 for maxillary molars and 5.17 ± 4.2 for mandibular molars). Maxillary teeth are better for age estimation and using both maxillary first and second permanent molars gives better accuracy.

Sex diff erences in Late Iron Age Northeast Estonia as indicated in dental pathologies and enamel hypoplasia

Study of dental pathologies is important in investigating the health and diets of past populations. Dental pathologies of adult peoples show nutritional and hygienic habits in adulthood, but childhood metabolic stresses can be observed in the occurrence of linear enamel hypoplasia (LEH). Dental hard tissue pathologies (caries, pre mortem tooth loss, abscesses, calculus, reduction of alveolar bone, molar attrition) and LEH were observed over 15 years in individuals from Jõuga cemetery (11th–16th cc. Northeast Estonia). The aim of the study was to trace sexual differences in diet and subsistence patterns through an analysis of dental pathology.

Deletion of epithelial cell-specific Cdc42 leads to enamel hypermaturation in a conditional knockout mouse model

Recent evidence suggests that GTPases Rho family plays an important role in tooth development; however, the role of Cdc42 in tooth development remains unclear. We aimed to investigate the function of Cdc42 in tooth development and amelogenesis. We generated an epithelial cell-specific K5-Cdc42 knockout (KO) mouse to evaluate post-eruption dental phenotypes using a K5-Cre driver line. This model overcomes the previously reported perinatal lethality. Tooth phenotypes were analyzed by micro X-ray, micro-computed tomography (CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), wear rate, shear strength, and a microhardness test. Enamel matrix protein expression was determined by immunohistochemistry.KO mice displayed a hypomaturation phenotype, including incisors that lacked yellow pigmentation and were abnormally white, rapid attrition of molars following eruption, and decreased micro-hardness and shearing strength. Micro-CT data revealed that of incisor and molar enamel volumes were smaller in the KO than in wild-type (WT) mice. SEM analysis showed that the enamel prism structure was disordered. In addition, HE staining indicated a remarkable difference in the ameloblast morphology and function between KO and WT mice, and immunohistochemistry showed increased expression of amelogenin, ameloblastin, matrix metallopeptidase 20, kallikrein-related peptidase 4 and amelotin in the KO mice teeth.Our results suggest epithelium cell-specific Cdc42 deletion leads to tooth hypomaturation and transformation of the enamel prism structure that is likely due to altered ameloblast morphology and the secretion of enamel matrix proteins and proteases. This is the first in vivo evidence suggesting that Cdc42 is essential for proper tooth development and amelogenesis.

Abattoir survey of dental defects in cull cows

The teeth in the severed heads of 501 cull cows, all over 30 months of age, were examined at an abattoir in the north of England in 1997/98; 80 per...

An osteometrical study of the cranium and mandible of the lesser mouse deer (Chevrotain), Tragulus javanicus.

The lesser mouse deer (Tragulus javanicus) is one of the most primitive ruminants. Skulls of lesser mouse deer were measured to evaluate their growth. The age was estimated from the eruption and attrition of molars on the mandible. A total of 95 specimens was divided into five age groups, and the growth pattern in each sex was established for some measurements. The relative growth coefficients were calculated for the head and body length and several parts of the cranium and mandible against the profile length. Sexual dimorphism could not be found on the skull in any age group except for measurements related to the upper canine. However, females showed a higher value in head and body length in the oldest group. This feature was consistent with an interpretation of mouse deer society as monogamous. Growth was more rapid in length than in width. Various statistical analyses showed that the visceral cranium related to masticatory facility was much better developed than the neurocranium. However, observations on the shape of the mandible ramus and of the premolars implied that the masticatory function was not suitable for taking roughage. This speculation agreed with previous reports on the feeding habits and digestive organs of the mouse deer.

The relation between tooth eruption and alveolar crest height in a human skeletal sample

It is commonly assumed that alveolar crest height increases with continuing tooth eruption unless affected by marginal inflammation. To test this hypothesis, the relation between eruption and alveolar crest height was examined in skulls from a sample consisting of the remains of 244 individuals from the late medieval period. The mandibular first and second molars and second premolars were analysed. The age of the skulls was determined on the basis of dental development and molar attrition. Radiographs were taken and points representing the levels of the inferior dental canal (IDC), root apices (AP), alveolar crest (AC), cementum-enamel junction (CEJ) and occlusal surface were determined on the radiographs. The level of the IDC was used as a reference not changing with age. The distances between the points were measured with a help of a computer-digitizer system. Variable IDC-AP increased with age, indicating continuous eruption of the teeth. The distance between AC and CEJ also increased while the distance between IDC and AC remained constant, showing that the alveolar crest height did not increase accordingly. The lack of inflammatory changes on the alveolar bone surface suggests that occlusal attrition may be compensated for by continuous eruption without bone growth in the alveolar margin.

Age at death estimates for the protohistoric Arikara using molar attrition rates: A new quantification method

AbstractDental attrition is positively related to ageing and has often been used to determine age at death of animals and prehistoric/historic humans. A newly designed molar‐attrition‐scoring standard was applied to a protohistoric skeletal sample, the Arikara (N = 143) from the North American Plains. Several criteria are used in producing a molar tooth crown wear (MTCW) score. These include: (i) the size of enamel wear facets, (ii) the amount of dentine and secondary dentine exposure, (iii) the height of the tooth, (iv) the enamel rim thickness, and (v) the amount of pulp‐cavity exposure in the advanced stages. Age‐at‐death estimates were generated from ordinary least‐squares (OLS) analysis, with estimated age regressed independently on the total molar attrition score (TMAS), mean molar‐1 tooth crown wear (ȲM1TCW), mean molar‐2 tooth crown wear (ȲM2TCW), and mean molar‐3 tooth crown wear (ȲM3TCW). In all analyses (with the exception of the third molar), the coefficient of determination (r2) revealed a strong relationship between molar attrition and age. Multiple‐regression analysis revealed a significant sex difference in molar‐attrition rates. Besides intercept and slope differences, the female scatter showed greater molar attrition variation than the male scatter. There was no statistical difference between mean upper molar attrition score (UMAS) and lower molar attrition score (LMAS). There was no significant difference in molar attrition rates by side, and side by molar tooth.

Using Molar Attrition to Age Live Prairie Dogs

Molar attrition was examined in 153 live black-tailed prairie dogs (Cynomys ludovicianus) of known ages determined from a history of permanently marked juveniles. Based on tooth wear, molars were assigned to 3 age classes: 0.5, 1.5, and -2.5 years. Molar attrition predicted the correct age class for 86% (131 + 153) of individuals. J. WILDL. MANAGE. 51(2):393-394 Several mammalian aging techniques are available, but most of these require maiming or killing of individuals (reviewed by Sherman et al. [1985]). One nondestructive method of aging wild mammals involves examining patterns of wear on molar teeth, which in most species are permanent and do not continue to grow after physical maturity (Vaughan 1978). Molars with little attrition (i.e., high cusps) indicate young animals and molars with extensive attrition (i.e., low cusps) indicate older animals. A major advantage of this method is speed, requiring only seconds to score each restrained individual. Aging by molar attrition compares favorably with estimates of age based on counts of cementum layers in teeth of several species; e.g., see Lockard (1972). However, rarely has aging by molar attrition been rigorously compared with known ages determined from tracking of marked juveniles over time, and all these comparisons have involved cervids; e.g., see Quimby and Gaab (1957). We evaluated molar attrition of black-tailed prairie dogs of known ages as a means to accurately and quickly age live individuals in the field. We thank the 105 field assistants who have helped over the years, especially J. G. Hoogland, M. V. Hoogland, S. T. Hoogland, J. Herron, G. Koscielny, and K. Roam. M. G. Garrett helped us to devise the method for categorizing molar attrition. For financial assistance, we thank The Natl. Sci. Found., The Natl. Geogr. Soc., The Am. Philos. Soc., The Cent. Field Res., The Eppley Found. for Res., The Harry Frank Guggenheim Found., The Max McGraw Wildl. Found., The Am. Soc. Mammal., The Univ. Maryland, Michigan, and Minnesota, and Princeton Univ. We also thank the staff at Wind Cave Natl. Park, especially L. F. McClanahan, J. Randall, E. Ortega, and R. Klukas. For help with the manuscript, we thank J. Barlow, H. Broadbrooks, S. Fancy, J. E. Gates, K. R. McKaye, C. Phillips, and D. I. Rubenstein. This paper is Sci. Ser. No. 1729-AEL from The Univ. Maryland's Cent. for Environ. and Estuarine Stud.

Relative age determination of the skull of the chacma baboon (Papio ursinus)

Relative age determination was carried out on the skulls of 261 chacma baboons (Papio ursinus), 117 from the Loskopdam Nature Reserve and 144 from the Messina district in the Northern Transvaal. Seven age groups were distinguished, of which classes I-IV were based on the eruption and displacement of milk and permanent teeth. Adults with a complete set of permanent dentition were subdivided into three additional classes (V- VII), mainly on the basis of the degree of molar attrition. For comparative purposes the pattern of maturation of craniometric parameters which reflect the general size and shape of the skull, as well as the degree of closure of ectocranial sutures, were treated on the same basis. From this it is apparent that a most reliable estimate of relative age can be obtained by using all the above-mentioned criteria.

Assessment of age‐at‐death from mandibular molar attrition in medieval Danes

Stages of occlusal attrition of the permanent mandibular molars were recorded in 235 Danish medieval skulls, 52 of which were in various states of mixed dentition. For the first and second molar, ages at emergence and ages at occurrence of the earlier stages of attrition were estimated from the mixed dentitions, on the assumptions 1) that the age at eruption of a given number of permanent teeth was similar in medieval and contemporary Danish children, and 2) that the rate of attrition was similar for the first and second molars. Estimation of ages at occurrence of the later attrition stages and of the age at third molar emergence was based on percentage frequency distributions of the stages of attrition using reiterative calculating procedures. Third molar emergence was estimated at the early age of 14 years. It is argued that assessments of age-at death could be made fairly accurately for the age range 5-30 years, and with decreasing accuracy until about 40 years of age.

Oral and genetic study of Chileans, 1960—V: Factors that influence the severity of periodontal disease

An attempt was made to weigh the relative importance of several nutritional and physiological factors in the severity of periodontal index and gingival recession scores. The sample used in this study consisted of 549 Chilean persons on whom complete examinations were performed. The data were analysed by multiple correlation; the relative importance of each factor was assessed by calculating the separate determination coefficient, expressing it as per cent of the total variance ( R 2), and also by partial correlation, keeping constant the effects of age and oral hygiene. Blood levels of serum protein, haemoglobin, ascorbic acid and vitamin A, and urinary levels of thiamine and riboflavin showed essentially no effects in the variance of periodontal index and gingival recession scores. Age and oral hygiene were responsible for most of the variance ( R 2), age being responsible for a larger proportion of the variance in gingival recession scores. Oral hygiene accounted for 85 per cent of the variance in non-destructive periodontal disease, and for only 15 per cent in destructive disease. In the latter, age (46 per cent), molar attrition (20 per cent), and the number of DMF teeth (17 per cent) were the factors that explained most of the variance.

Dental Caries and Periodontal Diseases among Ethiopian Civilians

THE Interdepartmental Committee on Nutrition for National Defense (1) conducted a nutiition surv-ey in Ethiopia during the fall of 1958. A team of American and Ethiopianl nutritionists, food technologists, biochemists, plhysicians, and a dentist visited widely withiin the country. Inl each area visited an attempt was made to assess certain physical characteristics in a selected sample of men, womeni, and clhildren. Blood and urine samples were taken for biochemical analysis. Data concerning food productioni and availability and dietary patter ns were also obtained. I)ental examinations, included as a part of the physical appraisals, were completed on 1,085 civilian males and females aged from 5 tlhrough 84 years. This sample included residents of 8 of ii geographic regions visited by the team (fig. 1), and it had representation from the major ethnic groups. The survey presented an opportunity to study oral diseases in a population for which little information has been available. All dental observations were made by the one dentist, usin.g a portable chair and standard dental mirrors and explorers, under natural light. Findings for dental caries, fluorosis, molar attrition, periodontal diseases, dental calcu1lus, and debris are discussed below.