Linear enamel hypoplasias as indicators of systemic physiological stress: evidence from two known age-at-death and sex populations from postmedieval London

Enamel hypoplasias are useful indicators of systemic growth disturbances during childhood, and are routinely used to investigate patterns of morbidity and mortality in past populations. This study examined the pattern of linear enamel hypoplasias in two different burial populations from 18th and 19th Century church crypts in London. Linear enamel hypoplasias on the permanent dentitions of individuals from the crypt of Christ Church, Spitalfields, were compared to enamel defects on the teeth of individuals from St. Bride's. The method used involves the identification of enamel defects at a microscopic level, and systemic perturbations are detected by matching hypoplasias among different tooth classes within each individual. The pattern of linear enamel hypoplasias was contrasted between individuals from the burial sites of Spitalfields and St. Bride's, between males and females, and between those aged less than 20 years of age and those aged over 20 years at death. Six different parameters were examined: frequency of linear enamel hypoplasias, interval between defects, duration of hypoplasias, age at first occurrence of hypoplasia, age at last occurrence of hypoplasia, and the percentage of enamel formation time taken up by growth disturbances. All individuals in the study displayed linear enamel hypoplasias, with up to 33% of total visible enamel formation time affected by growth disruptions. Multiple regression analysis indicated a number of significant differences in the pattern of enamel hypoplasias. Individuals from Spitalfields had shorter intervals between defects and greater percentages of enamel formation time affected by growth disturbances than did individuals from St. Bride's. Females had greater numbers of linear enamel hypoplasias, shorter intervals between defects, and greater percentages of enamel formation time affected by growth disturbances than males. There were also differences in the pattern of enamel hypoplasias and age at death in this study. Individuals who died younger in life had an earlier age at first occurrence of enamel hypoplasia than those who survived to an older age. The pattern of enamel hypoplasias detected in this study was influenced by tooth crown geometry and tooth wear such that most defects were found in the midcrown and cervical regions of the teeth, and greater numbers of defects were identified on the anterior teeth. Differences in sensitivity of the parameters used for the detection of enamel hypoplasias were found in this study. The percentage of visible enamel formation time affected by growth disturbances was the parameter that identified the greatest number of significant differences among the subgroups examined.     

Patterns of dental enamel defects at ancient Mendes, Egypt.

The dental remains of 88 individuals from Old Kingdom, First Intermediate, and Greco-Roman periods at the ancient Egyptian site of Mendes (Tell er-Rub(c)a) were examined for dental enamel hypoplasia, and the results reported here provide some of the first comparative data on enamel defects in ancient Egypt. Overall, 48% of the individuals in the sample have one or more teeth with hypoplasia, with 17% of permanent teeth and 8% of deciduous teeth affected. The permanent teeth account for 87% of the total number of affected teeth, a prevalence over deciduous teeth that is significant at alpha = 0.05. Permanent and deciduous teeth display different patterns of hypoplasia, with the former exhibiting both discrete pitting and linear furrowing, and the latter exhibiting only pits. Teeth with linear defects significantly outnumber those with pits by a factor of more than three to one. Only permanent canines display more than one lesion on a tooth, with a mean of 1.4 defects per affected tooth. Although calculation of the age of insult from lesion position is imprecise, it appears that stress episodes occurred most commonly between approximately 3-5 years of age. The presence of pits in the deciduous dentition, however, suggests that physiological stresses began in utero. There is no statistically significant difference in the frequency of enamel defects between males and females. An observed decrease in the frequency of defects from the Old Kingdom period to the subsequent First Intermediate and Greco-Roman periods is not significant at alpha = 0.05, although such a decrease is expected given epigraphic and other data that refer to prolonged drought and malnutrition in the late Old Kingdom. The calculated chi(2) value of 3.83 is significant at the 0.10 level, however, and since our sample is rather small and the magnitude of the chi-square statistic is a function of sample size, we recommend that future research investigate further the relationship between the frequency of enamel defects and the time period in which they occur.     

Biocultural analysis of sex differences in mortality profiles and stress levels in the late medieval population from Nova Raca, Croatia

Human skeletal remains of 104 individuals from the late medieval (14th-18th century) Nova Raca cemetery, in continental Croatia, are described. Historic data from the parish Book of the Dead, relevant to a period in the early 19th century, suggest that females may have been under greater stress than males. To test this hypothesis, the skeletal material is analyzed for the presence and distribution of enamel hypoplasias and cribra orbitalia. Observations are also made on the presence and pattern of dental disease, skeletal infection, trauma, osteoarthritis, vertebral degenerative changes, and Schmorl's depression frequencies. The mortuary sample, consisting of 36 subadults and 68 adults, exhibits underrepresentation of subadults, and differential adult male/female mortality profiles. Peak female mortality is between 21-25 years, compared to peak male mortality between 31-35 years. Average adult female age at death is 29.9 years, compared to 34.1 years in adult males. Significant sex differences are present in the frequencies of enamel hypoplasia. Adult females have higher frequencies of hypoplastic teeth, and a larger number of defects in the teeth affected than in males. Subadults in the series also exhibit higher frequencies of hypoplastic teeth, and a larger number of defects in the teeth affected than in adults, documenting a relationship between enamel hypoplasia-causing stress events and reduced life expectancy. Significant sex differences are also present in dental pathology frequencies, possibly reflecting differences in resource access. Sex differences in vertebral osteoarthritis and Schmorl's depression frequencies may reflect differential activity patterns.     

Analysis of human skeletal remains from Nadin iron age burial mound

This analysis attempts to reconstruct health, disease and life conditions of the population buried in Nadin, a burial mound, situated in central Dalmatia, Croatia. The analyzed skeletal material belongs to Liburnian culture and could be dated to early Iron Age, from 9th to 6th century B.C. The sample consists of a minimum number of 37 individuals, 7 children and 30 adults. The frequency of all the observed conditions is relatively low. Cribra orbitalia was observed only in females, the frequency of periosteal reaction on the tibiae is 26.1%. Two cases of cranial trauma were observed. Analyzed teeth exhibit low prevalence of carious lesions, ante mortem tooth loss and linear enamel hypoplasia. The case of hyperostosis frontalis interna on the endocranial surface of the frontal bone was observed. The affected skull belongs to the older adult female.     

禄丰古猿牙齿釉质发育不全的观察研究

对出自禄丰石灰坝的26个禄丰古猿下颌齿列的246枚恒齿进行了观察研究,发现禄丰古猿具有普遍的带状釉质发育不全（LEH）现象,个体LEH比例为100%,恒齿LEH比例为85%。乳齿几乎没有LEH现象,第一恒臼齿的LEH比例也很低仅57%。根据牙齿萌出顺序及现代大猿的牙齿发育年龄特征,作者推断2—3岁之前的幼儿古猿很少出现釉质发育不全现象,这可能与母体的营养关照有关。禄丰古猿的LEH的发生频率具有明显的季节性,结合中新世晚期气候变化特征、古猿的生态环境、生活习性及食性特征分析,作者推测：季节性营养不良可能是造成禄丰古猿釉质发育不全的主要原因。     

Demographic, temporal and environmental effects on the frequency of cribra orbitalia in three Early Medieval populations from western Slovakia

The frequency of cribra orbitalia was examined in Early Medieval skeletal samples from Devín and Borovce (Slovakia). The effects of environmental and socio-economic factors on the distribution of orbital lesions are explored and discussed. The frequency of cribra orbitalia was lowest in Devín-Hrad (11th-12th c. A.D.), followed by Devín-Za kostolom (9th c. A.D.) and Borovce (8th-beginning of 12th c. A.D.). The increased frequency of cribra orbitalia at Borovce can be attributed to inadequate sanitation and increased pathogen load at this rural site compared to urban Devín. Borovce (BO) sub-adults displayed orbital lesions significantly more frequently than BO adults and sub-adults in the Devín-Za kostolom (FR) and Devín-Hrad (DH) samples. Although the total mortality of sub-adults did not differ between the sites, BO sub-adults with cribra orbitalia showed a considerably higher mortality. Their counterparts from FR and DH showed similar mortality patterns irrespective of the presence of orbital lesions. As in most reference samples, no significant sex differences in the frequency of cribra orbitalia were observed in BO, DH and FR. However, a considerably increased mortality was observed in young males from Devín-Hrad irrespective of the presence of orbital lesions. This finding can be attributed to their involvement in violent conflicts. Reference data from Medieval Central European skeletal samples suggest that an increased occurrence of cribra orbitalia was associated with crop failures, migration and interpersonal conflicts. These factors favour the spread of and vulnerability to infectious diseases, which are considered to be the major cause of iron deficiency anaemia.     

Enamel hypoplasia in ancestral Puebloan populations from southwestern Colorado: I. Permanent dentition

Dental enamel hypoplasias are used to examine metabolic disruption experienced during early childhood by ancestral Puebloan (Anasazi) inhabitants of southwestern Colorado. The hypoplasia sample consists of the permanent anterior dentition from 147 individuals from Montezuma County and Mesa Verde National Park. Using the individual as the basis of analysis, the study compares different time periods of occupation of the region with respect to prevalence and timing of hypoplasia occurrence. The frequency of enamel hypoplasia in the combined regional sample is high, affecting 90% of the individuals and 66% of the anterior teeth. The earliest onset of hypoplasia in individuals occurs most commonly at 2.5–3.0 years, and the peak age for enamel disruption is 3.0–3.5 years. There are no significant differences in hypoplasia frequency or timing between males and females or between adults and subadults. The level of childhood stress appears to have increased significantly with time from the Basketmaker III to the Pueblo I and Pueblo II periods, then decreased slightly during the Pueblo III. The differences between the Pueblo I, II, and III periods are not significant. The Pueblo II sample from Yellow Jacket Canyon sites 5MT1 and 5MT3 and the Dolores Pueblo I sample show the highest levels of childhood stress in comparison to other Puebloan populations inhabiting this region prior to A.D. 1300. Am. J. Phy. Anthropol. 102:351–367, 1997. © 1997 Wiley-Liss, Inc.     

Health and differential survival in prehistoric populations: prenatal dental defects.

Linear hypoplasia of the deciduous teeth is rare in most human populations, but common where nutritional status is poor. Deciduous enamel hypoplasia, hypocalcification, and hypoplasia-related caries are described in Middle and Late Woodland skeletal series from the Lower Illinois Valley. Gross enamel defects that can be referred to pre-natal development are found in 83 of 170 children under six years of age at death. Circular caries secondary to hypoplasia is significantly more common in the Late Woodland series, reflecting the apparent higher cariogenicity of Late Woodland diets. There is a significant association between prenatal dental defects and bony evidence for anemia and infectious disease. Children with enamel defects show relatively higher weaning age mortality than those without. These relationships suggest that at least moderate levels of malnutrition existed in Illinois Woodland populations.     

Hardships of contact: Enamel hypoplasias in Tupí-Mondé Amerindians from the Brazilian Amazonia

This paper presents an assessment of enamel defects (hypoplasias) in the permanent anterior teeth of three Tupí-Mondé-speaking groups from the Brazilian Amazonia: the Gavião, Suruí, and Zoró. These are native societies that experienced the onset of permanent contact with Brazilian national society in different periods of the 20th century. Tupí-Mondé dentition is highly hypoplastic, which is possibly related to exposure to adverse health and nutritional conditions. Data for the Gavião, Suruí, and Zoró are in agreement with results from other populations that show that certain teeth, the maxillary central incisors and the mandibular canines in particular, tend to be more hypoplastic. Although all types of teeth show hypoplasia concentrations at some enamel zones, there is substantial intertooth variation in the age at which peaks occur. It is argued that hypoplasia concentrations at certain ages are unlikely to be related to postweaning stresses for the Tupí-Mondé. Statistically significant associations between presence of enamel defects and deficits in physical growth (height-for-age) were detected in children 7–11 years of age. Diachronic assessment of enamel defects, which rested upon the potential of enamel as “memory” of past periods of systemic physiological perturbation, allowed us to unravel aspects related to the dynamics of Tupí-Mondé life during the 20th century. Frequencies of enamel zones with defects peaked during the contact years of each of the Tupí-Mondé groups, attesting to the extreme social and biological hardships that characterized the contact experiences of these native societies with Brazilian national society. Am J Phys Anthropol 109:111–127, 1999. © 1999 Wiley-Liss, Inc.     

Dental health and lifestyle in four early mediaeval juvenile populations: Comparisons between urban and rural individuals, and between coastal and inland settlements

Dental stress markers such as enamel hypoplasia and caries are suitable indicators of population health and lifestyle, although they must be recorded and interpreted carefully. To date, they have been predominantly studied in adult samples, whereas juvenile remains are also affected by these lesions. In this study, dental enamel hypoplasia and caries were both evaluated on 613 non-adult individuals from four early mediaeval Moravian and Frankish skeletal series, who had experienced contrasting environments and lifestyles. The aim of this study is to assess the relationship between these biological traits and living conditions, and how this is manifested in the juvenile dental remains.Significant differences between populations were found in stress markers, dental lesions and the way these were manifested. Exposure to stressful conditions varies between urban and rural populations and is related to age groups. Although the children under investigation seem to have had different diets, it is difficult to distinguish the biological contribution (different enamel susceptibility) from the lifestyle contribution (different food, environment) in the formation of caries. Moreover, such studies must be interpreted carefully due to the possibility of intra- and inter-observer errors and the subjectivity of the scoring techniques.Nevertheless, this study also demonstrates that results of an investigation of juvenile skeletal remains can be as informative as a study of adults and that juvenile skeletons can be included in large bioarchaeological population studies.     

Dento-alveolar lesions and nutritional habits of a Roman Imperial age population (1st–4th c. AD): Quadrella (Molise, Italy)

The study of teeth is very important in archaeoanthropology for reconstruction of the nutritional habits and living conditions of past populations. We have analysed dental lesions of pathological (caries, abscesses and ante mortem tooth loss) and non-pathological origin (calculus), linear enamel hypoplasia and tooth wear in 67 adults from the Roman Imperial age necropolis (1st-4th c. AD) of Quadrella (Molise, Italy). The high frequency of caries (likely giving rise to the abscesses and ante mortem tooth loss), the abundant calculus and the low frequency of heavy wear are probably due to a limited use of hard fibrous foods and a high consumption of carbohydrates. The high frequency of linear enamel hypoplasia suggests metabolic problems during growth. Comparison of these data with those for two coeval Italian necropoleis near Rome (Latium), Isola Sacra and Lucus Feroniae, indicates poorer living conditions in the Quadrella population.     

Gross enamel hypoplasia in molars from subadults in a 16th-18th century London graveyard

Dental Enamel Hypoplasia has long been used as a common nonspecific stress indicator in teeth from archaeological samples. Most researchers report relatively minor linear and pitted hypoplastic defects on tooth crown surfaces. In this work we report a high prevalence and early age of onset of extensive enamel defects in deciduous and permanent molars in the subadults from the post-medieval cemetery of Broadgate, east central London. Analysis of the dentition of all 45 subadults from the cemetery, using both macroscopic and microscopic methods, reveals disturbed cusp patterns and pitted, abnormal and arrested enamel formation. Forty-one individuals from this group (93.2%) showed some evidence of enamel hypoplasia, 28 of them showing moderate or extensive lesions of molars, deciduous or permanent (63.6% of the sample). Scanning Electron Microscope images reveal many molars with grossly deformed cuspal architecture, multiple extra cusps and large areas of exposed Tomes' process pits, where the ameloblasts have abruptly ceased matrix production, well before normal completion. This indented, rough and poorly mineralized surface facilitates both bacterial adhesion and tooth wear, and when such teeth erupt fully into the mouth they are likely to wear and decay rapidly. We suggest that this complex combination of pitted and plane-form lesions, combined with disruption of cusp pattern and the formation of multiple small cusps, should henceforth be identified as "Cuspal Enamel Hypoplasia."     

Reconstructing infant weaning histories at Roman period Kellis, Egypt using stable isotope analysis of dentition

Studies of infant feeding and weaning patterns in past populations that rely on a cross-sectional approach must make the assumption that no infant mortality bias exists. Previous investigations of infant weaning patterns at the Dakhleh Oasis, Egypt, relied on cross-sectional isotope data. In this study, we re-examine this weaning pattern, using a simulated longitudinal approach, which does not require any assumptions regarding potential infant mortality biases. This involves examining the dental isotopic signatures of individuals who survived the weaning process. Stable isotope signatures from juveniles and adults (102 individuals, 297 teeth) were examined to reconstruct the weaning history of those that survived the weaning process. Both deciduous and permanent teeth were sampled. Homogenized enamel and dentin samples were isolated from each tooth and analyzed for delta(13)C(ap) and delta(18)O(ap) from the enamel and delta(15)N(coll) and delta(13)C(coll) from dentin collagen. We investigate differences between in utero versus postbirth, preweaning versus postweaning, and juvenile versus adult stable isotope values as reflected in the dentition. A random permutation procedure was used to test for statistically significant differences in stable isotope values between tooth types. Statistically significant differences were observed in all stable isotopes between permanent and deciduous teeth, and between early and later forming permanent teeth in delta(13)C(ap) and delta(15)N(coll) isotopes. These results indicate dietary change between in utero and postbirth, and changes occurring during the weaning period. These results provide a more comprehensive picture of infant weaning practices at Kellis and provide further support that complete weaning occurred by 3 years of age.     

Observations of dental diseases among prehistoric populations of Hungary

The incidence of dental disease among people in developing countries today raises questions about the variation in the oral health of prehistoric populations. Considering these questions, we offer observations describing several types of dental disease which occurred among certain prehistoric populations of Hungary. The dental remains of 162 individuals recovered from seven sites of the Neolithic, Copper, and Bronze Age periods were examined for evidence of caries, hypoplasia, and periodontal disease. Appropriate methods were used to describe and record these dental lesions. The incidence of dental caries was low by comparison to other prehistoric agriculturists except for two forms of root caries: cervical and cemental. These types accounted for 68% of all the carious teeth recorded. Enamel hypoplasia was also lower than expected, occurring on only 4% of the total number of teeth. Periodontal abscesses were rare but other milder forms of periodontal lesions were frequent. Alveolar bone resorption occurred in varying degrees and followed the expected age distribution. The few exceptions were children or adolescents whose crania had other lesions suggesting a mineral metabolic disturbance. The lower incidence of enamel caries is likely due to high fluoride ingestion which also may have influenced the expression of enamel hypoplasia. No clear population trends were seen in dental disease incidence except for cemental caries which were found among Copper and Bronze Age remains.     

Factors affecting the distribution of enamel hypoplasias within the human permanent dentition

Frequencies and morphological and chronological distributions of enamel hypoplasias are presented by tooth type (permanent I1 to M2s), based on a sample of 30 prehistoric Amerindians with complete and unworn dentitions. There is nearly a tenfold variation in frequency of defects by tooth, ranging from 0.13 per mandibular second molar to 1.27 per maxillary central incisor. The six anterior teeth average between 0.70 and 1.27 defects/tooth, whereas the eight posterior teeth average between 0.43 and 0.13 defects/tooth. Earlier developing teeth, such as incisors, have earlier peak frequencies of defects (2.0-2.5 years), while later developing teeth, such as second molars, have subsequent peak frequencies (5.0-6.0 years). These variations are relevant when comparing hypoplasia data based on different teeth. Differences in hypoplasia frequencies among teeth are not solely due to variation in time of crown development, as is usually reported. Rather, there is evidence for biological gradients in susceptibility to ameloblastic disruption. Anterior teeth are more hypoplastic than posterior teeth. More developmentally stable "polar" teeth are more hypoplastic than surrounding teeth. Polar teeth may be more susceptible to hypoplasias because their developmental timing is less easily disrupted. In all teeth, hypoplasias are most common in the middle and cervical thirds. Crown development and morphological factors, such as enamel prism length and direction, may influence the development and expression of enamel surface defects.     

Simple recessive mutation in ENAM is associated with amelogenesis imperfecta in Italian Greyhounds

We report a familial enamel hypoplasia in Italian Greyhounds resembling non‐syndromic autosomal recessive amelogenesis imperfecta (AI) of humans. The condition uniformly affects deciduous and permanent teeth and is manifested by enamel roughening/thinning and brownish mottling. Affected teeth are often small and pointed with increased gaps. However, basic tooth structure is usually maintained throughout life, and fractures and dental cavities are not a serious problem as in humans. No tissues or organs other than teeth were affected by this mutation, and there was no relationship between enamel hypoplasia and either autoimmunity or periodontal disease, which also are prevalent in the breed. The enamel hypoplasia was associated with a 5‐bp deletion in exon 10 of the enamelin (ENAM) gene. The prevalence of the enamel defect in Italian Greyhounds was 14%, and 30% of dogs with normal teeth were carriers. Genome analyses suggest that the trait is under inadvertent positive selection. Based on the deletion detected in the ENAM gene, a genetic test was developed for identifying mutation carriers, which would enable breeders to manage the trait.     

Hypoplasia and health status: a comparison of two lifestyles

Enamel hypoplasia was recorded for the primary and permanent teeth of Natufians (terminal Pleistocene Hunter-Gatherers) and Early Arabs (Subsistence farmers). Minimal hypoplasia was found in the primary teeth of the Natufians, but in the Early Arab population, 31% of upper first primary molars showed enamel defects. In the permanent teeth, the Early Arab population again showed a significantly higher frequency of hypoplasia, with all teeth affected. In the Natufians, only later developing teeth showed enamel defects. These findings suggest that health status in the Early Arab population was poor throughout life, affecting pregnant mothers, their foetuses, young infants and children. These results confirm other studies that have shown deterioration in health status of early agriculturalists relative to hunter- gatherers. Comparisons of these findings with those of recent populations indicate that health status in the Natufians was comparable to that of modern populations with subsistence diets and mediocre health care. Health status in the Early Arab population was comparable to that of modern populations suffering from severe malnutrition and chronic disease.     

Prevalence and age at development of enamel hypoplasias in Mexican children

Enamel hypoplasias, deficiencies in enamel thickness resulting from disturbances during the secretory phase of enamel development, are generally believed to result from nonspecific metabolic and nutritional disruptions. However, data are scare on the prevalence and chronological distributions. of hypoplasias in populations experiencing mild to moderate malnutrition. The purpose of this article is to present baseline data on the prevalences and chronological distributions of enamel hypoplasias, by sex and for all deciduous and permanent anterior teeth, in 300 5 to 15-year-old rural Mexican children. Identification of hypoplasias was aided by comparison to a published standard (Federation Dentaire Internationale: Int. Dent. J. 32(2):159-167, 1982). The location of defects, by transverse sixths of tooth crowns, was used to construct distributions of defects by age at development. One or more hypoplasias were detected in 46.7% (95% CI = 40.9-52.5%) of children. Among the unworn and completely erupted teeth, the highest prevalence of defects was found on the permanent maxillary central incisors (44.4% with one or more hypoplasias), followed by the permanent maxillary canine (28.0%) and the remaining permanent teeth (26.2 to 22.2%) Only 6.1% of the completely erupted and unworn deciduous teeth were hypoplastic. The prevalence of enamel defects on the permanent teeth was up to tenfold greater than that found in studies of less marginal populations that used the FDI method. The prevalence of defects in transverse zones suggests a peak frequency of hypoplasias during the second and third years for the permanent teeth, corresponding to the age at weaning in this group. In the deciduous teeth, a smaller peak occurs between 30 and 40 weeks post gestation. The frequency of defects after three years of age is slightly higher in females than males, suggesting a sex difference in access to critical resources.     

Increasing human tooth length between birth and 5.4 years

Most previous studies of tooth development have used fractional stages of tooth formation to construct growth standards suitable for aging juvenile skeletal material. A simple alternative for determining dental age is to measure tooth length throughout development. In this study, data on tooth length development are presented from 63 individuals of known age at death, between birth and 5.4 years, from an archeological population recovered from the crypt of Christ Church, Spitalfields, London. Isolated developing teeth (304 deciduous, 269 permanent) were measured in millimeters and plotted against individual age. Regression equations to estimate age from a given tooth length, are presented for each deciduous maxillary and mandibular tooth type and for permanent maxillary and mandibular incisors, canines, and first permanent molars. Data on the earliest age of root completion of deciduous teeth and initial mineralization and crown completion of some permanent teeth in this sample are given, as well as the average crown height and total tooth length from a small number of unworn teeth. This method provides an easy, quantitative and objective measure of dental formation appropriate for use by archeologists and anthropologists. © 1993 Wiley-Liss, Inc.     

山东广饶县中南世纪城墓地出土明代人骨的初步研究

本文对广饶县中南世纪城墓地出土的明代人骨进行了多方面的生物考古学研究,包括性别、年龄的分布,身高的复原以及古病理的观察。牙病方面,对龋病、牙釉质发育不全和错牙合畸形进行了观察记录,从性别、年龄、龋患程度及好发牙位等方面对该人群的龋患情况进行统计分析。研究结果表明,该人群牙齿患龋率不具备明显的性别差异,与年龄变化也无显著相关性,好发牙位多为臼齿。此外,还观察到多孔性骨肥厚、骨关节疾病等病理现象以及一处愈合较好的骨折创伤。