Tooth Eruption Patterns Research Articles

A Comparison of Three Ageing Techniques for Feral Pigs From Subalpine and Semi-Arid Habitats.

Three ageing techniques were tested on samples of wild-caught feral pigs from subalpine (n =35) and semi-arid (n =64) areas in eastern Australia, and on a sample of known-age captive feral pigs reared from stock from semi-arid areas (n =15). Techniques employed were based on morphometric relationships, patterns of tooth eruption and wear, and counts of cementum lines in permanent incisors. Cyclic seasonal conditions led to apparently annular cementum line deposition for pigs from the subalpine area. In contrast, stochastic variation in seasonal conditions led to irregular cementum line deposition in pigs from the semi-arid area and captive-reared pigs of semi-arid stock. On the assumption that cementum lines are annular in pigs from the subalpine site, patterns of tooth eruption and wear and morphometrics returned reasonably accurate age estimates, the former being more precise. Patterns of tooth eruption and wear returned reasonably accurate age estimates for known-age captivereared pigs, whereas morphometrics gave increasing underestimates of age for progressively older pigs. On the assumption that patterns of tooth eruption and wear return similarly accurate age estimates for wild pigs from the semi-arid area, morphometrics again underestimated true age. A correction to the morphometric technique to improve its accuracy for semi-arid areas is given.

Eruption pattern of permanent teeth in a rural community in northeastern Finland

Cross-sectional data on permanent tooth eruption were collected by examining the children and adolescents 5-15 years old in a northeastern municipality of Finland. There were 1008 subjects in the whole sample, 483 girls and 525 boys. The results showed statistically significant differences between the girls and boys in timing of eruption of some permanent teeth, indicating earlier eruption in girls than in boys. This difference was most clearly seen in the second phase of the mixed dentition. Interindividual variation in the emergence age was also wider in the second phase of the mixed dentition. The present results seem to indicate earlier eruption of the permanent teeth in rural children in northeastern Finland than in other parts of the country.

The relative age structure and body masses of complete wild‐captured colonies of two social mole‐rats, the common mole‐rat, Cryptomys hottentotus hottentotus and the Damaraland mole‐rat, Cryptomys damarensis

The relative ages of individuals in a complete wild‐captured colony of 13 Cryptomys hottentotus hottentotus and a complete wild‐captured colony of 25 Cryptomys damarensis were determined by means of tooth wear and eruption patterns and through the degree of ossification of their skeletons.From sequential tooth wear and eruption patterns four relative age classes were discerned in C. h. hottentotus and five in C. damarensis. These relative age class allocations were supported by the studies on the ossification of the skeletons.In C. damarensis, older animals are not necessarily the larger‐sized individuals. In C. h. hottentotus, however, older animals are usually the larger‐sized individuals. The reproductive pair in each of the Cryptomys species are the oldest or amongst the oldest individuals in the colony.Individuals in a second colony of C. damarensis kept under laboratory conditions for three years maintained greatly disparate body masses which were correlated with the role of the individual within the colony and not, where it was known, with the age of the animal.An analysis of 13 body and skull measurements performed on a complete colony of 13 C. h. hottentotus and a complete colony of 25 C damarensis revealed that only C. damarensis showed sexual dimorphism. This dimorphism was apparent from an early age but became more pronounced in older animals.

Patterns of tooth eruption and replacement in multituberculate mammals

Dentitions of juvenile multituberculate mammals are rarely preserved in the fossil record. A previously undescribed skull and jaws of a juvenile individual of Taeniolabis taoensis contains in situ ...

Dental ontogeny of harp seals, Phoca groenlandica

Harp seal fetuses and neonates were examined to determine the development, resorption, and eruption characteristics of deciduous and permanent dentition. Early September fetuses had recently formed, deciduous teeth only. By early December the deciduous dentition was robust and enameled. Permanent teeth were also present. In late December the roots of the deciduous teeth were being resorbed and the permanent dentition was larger and better developed. About 80% of the deciduous teeth were resorbed by birth in March. The rest were resorbed or shed after birth. The pattern of permanent tooth eruption was not correlated with pup age but the total number of teeth erupted increased significantly with increasing pup age, from 38% in newborns to 100% in weaned pups about 3 weeks old. The neonatal line formed at birth rather than at weaning or the onset of moult.

On the eruption pattern of the permanent incisors and first permanent molars in Paranthropus.

It has been claimed recently that Australopithecus exhibited a pattern of permanent tooth eruption like that of extant great apes, whereas a significantly different pattern was shared by Paranthropus and Homo (Dean, 1985). More particularly, each of the four Paranthropus specimens examined in that study was held to show advanced development and eruption of the permanent incisors relative to the first molar. It is demonstrated here that the eruption sequence that was posited for at least one of these four Paranthropus specimens (SK 61) is clearly erroneous, while the developmental/eruption sequences manifested by the other three specimens would appear to be more ambiguous than was claimed. Another juvenile specimen of Paranthropus (KNM-ER 1820) that was not included in Dean's study also does not necessarily support the eruption pattern that was said to characterize that taxon.

Age determination of Cape porcupines,Hystrix africaeaustralis

Attempts to determine the absolute age of free-ranging porcupines based on counts of cementum and periosteal lines, age-related changes In eye lens weight, sequential pattern of tooth eruption and replacement, and tooth attrition are described. Variation due to ramification and absorption of cementum and periosteal lines resulted in counts of these lines being unreliable indicators of age. Variation in counts of cementum lines apparently results from continual growth of the hypsodontic open-rooted premolars and molars. Heteroscadasticity resulted in the relationship between age and lens weight being unreliable for predicting age. Consistency In the age at which maxillary molars erupt and premolars are replaced, as well as the wear pattern of the occlusal surfaces, provide a method for distinguishing nine dental age classes. Chronological age, based on observations on captive porcupines could be accurately assigned to six of these.

Dentition and age determination of the Warthog <i>Phacochoerus aethiopicus</i> in Zululand, South Africa

Age-specific stages of tooth replacement, eruption and attrition are described for warthogs shot during population control in Zululand. Patterns of tooth replacement and eruption allowed reasonably accurate age determination up to 24 months, whereafter 2-3 year old warthogs could generally be distinguished from older individuals by the relative growth of their third molars. Although stages of wear and loss of the teeth, especially the three molars, were associated with broad age classes, age of adult warthogs may be determined more precisely by counting cementum annuli in sectioned incisor teeth. However, cementum annuli were insufficiently distinctive to permit age estimation in approximately 33 of sections, reflecting particularly variation in intensity and clarity of staining and splitting and merging of rest lines. The use of eye lens dry mass and tusk length: snout width ratios as indices of age was also evaluated. Eye lens dry mass became increasingly unreliable for predicting age beyond 24 months. Considering males and females separately, tusk length: snout width ratios for yearling, 2-3 year old and 3-4 year old warthogs were reasonably distinctive, but subsequent overlap was apparently unfavourable for reliable differentiation of year classes among older warthogs. Body size and tusk * development criteria for distinguishing between three age classes ofwarthogs in the field are presented.

Tooth replacement and skull growth inSmilodonfrom Rancho La Brea

ABSTRACT An extensive growth series of Smilodon skulls and mandibles from Rancho La Brea is divided into ontogenetic stages based on tooth-eruption pattern and occlusal wear. Eruption sequence is compared between Smilodon and Felis leo and an attempt is made to assess behavioral implications. A full description of all deciduous upper incisors and the DI3 is given. Skull growth and suture fusion are influenced by the formation and eruption of the dentition, and perhaps by the developing masticatory and neck musculature. Compared with Felis leo, the distinctive tooth-eruption sequence of Smilodon reflects differences in function. The lack of specimens with erupting deciduous dentitions indicates that Rancho La Brea was not preferred for denning by Smilodon.

DENTITION IN THE LOW BIRTHWEIGHT INFANT

Two hundred twenty seven infants with birthweights <1501g showed a similar timing and pattern of primary tooth eruption as reported for normal full term infants. The average number of erupted teeth at the post-term age of 6,9,12, and 18 months were 0.5±1.0, 2.9±2.2, 5.8±2.3, and 11.6±3.6 respectively. There was no sex difference. The 40 IUGR infants had significantly fewer teeth at 9 and 18 months post-term than the rest of the sample (p <0.05). The results suggest that the timing of tooth eruption is determined by post-conceptional age but may be delayed by prolonged malnutrition. Enamel development in primary teeth was studied in another sample of 106 children <1501g birthweight at ages 2 to 8 years. 37% showed hypoplasia in the maxillary anterior teeth located predominantly in the incisal half. Less than 10% of the other teeth were affected. Similar lesions have been reported in 1-9% of full term children. Permanent incisors were present in 37 children: 21 (58%) showed areas of enamel hypocalcification compared with 3 of 40 full term controls. The location of both the hypoplasia in primary tooth enamel and the hypocalcification in the permanent enamel suggest a neonatal origin specific to prematurity, but no statistical relationship could be shown with the degree of prematurity, IUGR or neonatal calcium levels.

A longitudinal study on the transverse palatine folds and the eruption pattern of teeth in miniature Swines.

A longitudinal study on the transverse palatine folds and the eruption pattern of teeth in miniature Swines.

Development of deciduous and permanent dentition in Tarsius and its phylogenetic significance.

The earliest stages of development and differentiation of deciduous and permanent teeth were studied in prenatal and perinatal tarsiers. Both deciduous and successional teeth develop at loci for I1, I2, C, P2-4. Relationships among the dental lamina, enamel organs, and successional lamina were used to determine tooth homologies. During the second half of prenatal life, dP2 and dI2 undergo abnormal development. Their dentin becomes fragmented, and these teeth are shed or resorbed without eruption during the perinatal period. Our study provides evidence of an intermediate phase in evolutionary tooth loss. These findings do not corroborate recent hypotheses of primate phylogeny based mainly on tooth eruption patterns.

Oral conditions in Australian children of Aboriginal and Caucasian descent.

Oral health parameters were examined for 211 schoolchildren (128 Aborigines and 83 Caucasians) representative of the 6--8 and 10--11 year age groups in the Brewarrina and Walgett areas of western New South Wales (fluoride in water less than or equal to 0.02-0.26 parts/10(6)). Despite similar dietary carbohydrate challenge and tooth eruption patterns, Aboriginal children, most of whom were members of a transitional community within a low socioeconomic stratum, had higher prevalence of caries (DIMFT) and severity rating of carious lesions (SR), poorer oral hygiene (OHI) and more gingivitis (PI) than Caucasian children, in both age groups. Tooth defects were more frequent (2.5 times) and severe in Aborigines than in Caucasians. Outstanding treatment needs were very high in both ethnic groups, but more so in Aborigines.

Age determination of Reindeer introduced into South Georgia

The ages of South Georgia Reindeer collected from the introduced herds, and of carcasses from natural deaths were determined using patterns of tooth replacement and eruption, and annulations in the cementum of incisor teeth. Replacement and eruption patterns are typical of the species. The difficulties encountered with the patterns of cementum deposition on the incisors, and consequently with the assignment of age to animals with established permanent dentition, are described in detail. The overall result is the underageing of a proportion of the specimens, and the problems demonstrated are ascribed to the influence of the alien environment and oceanic climate in which the animals live.

Serial extraction

The purpose of this study was to document craniofacial growth and the pattern of tooth eruption for patients undergoing a planned program of serial extraction, with emphasis on those procedures that enhance the results of treatment. Serial extraction, while beneficial in selected cases, is not, in itself, an acceptable treatment procedure, but requires supplemental appliance therapy to correct axial inclinations, rotations, close extraction spaces, and level the plane of occlusion. The purpose of this study was to document craniofacial growth and the pattern of tooth eruption for patients undergoing a planned program of serial extraction, with emphasis on those procedures that enhance the results of treatment. Serial extraction, while beneficial in selected cases, is not, in itself, an acceptable treatment procedure, but requires supplemental appliance therapy to correct axial inclinations, rotations, close extraction spaces, and level the plane of occlusion.

Effect of undernutrition during the perinatal period on caries development in the rat. IV. Effects of differential tooth eruption and exposure to a cariogenic diet on subsequent dental caries incidence.

The tooth eruption pattern in well- and under-nourished rat pups was investigated. A one-day lag was observed in those pups born to, and suckled on, dams that received a low protein diet when compared with control pups from mothers given a high protein diet. The difference in susceptibility to dental caries between these two groups could not be accounted for by this differential eruption and time of exposure to the cariogenic stress.

Studies on dog saliva. IV. The effect of carbohydrate diet on the activity of some hydrolytic enzymes.

Six mongrel dogs were reared after weaning on a daily diet composed of (1) raw bovine meat (35 %) containing sucrose (65 %), (2) bovine milk with 10 % sucrose, and (3) water. Five control dogs were kept on a similar diet without sucrose. the experiment was carried out for 260 days. No differences between the groups were observed when comparing the rate of growth, eruption pattern of deciduous and permanent teeth and blood sugar concentration. Hydrolases acting on ester and peptide bonds and glycosyl compounds were studied in the supernatant and sediment fraction of centrifuged dog saliva using altogether 41 different substrates. When comparing the values obtained to those of man the following deviations were observed: the sugar diet did not induce the appearance of salivary α-amylase (EC 3.2.1.1.), proline iminopeptidase (EC 3.4.1.4.) nor acid phosphatase (EC 3.1.3.2.) activity. With a few exceptions, the total hydrolytic enzyme activity in the oral cavity seemed to be constant. However, a fourfold increase was noticed in the hydrolysis of 6-hromo-2-naphthyl-α-D-glucoside, possibly representing a-glucosidase (EC 3.2.1.20) activity. the salivary protein concentration increased in the sugar group whereas it decreased in the meat group. No initiation of dental caries was obtained in any of the dogs. These observations were though to support the view that in the oral enzyme spectrum differences due to the diet and interspecies variations do occur.

The eruption pattern of permanent teeth in miniature swine

Since miniature swine are being used extensively as a research animal and since the literature concerning tooth eruption of domestic swine is not very precise, it seemed advisable to observe and record tooth eruption in the miniature swine being used and to make comparisons between this strain and domestic swine. A total of 33 animals from six litters of Pitman-Moore swine were observed weekly until eruption of their permanent teeth was complete, a period from 16 to 136 wk of age. In addition to noting the range of eruption time for each tooth, a median was given—the time when the tooth was present in half of the sample. Comparison of median eruption times indicated earlier eruption for some teeth in males. A mean sequence of eruption for each arch was established for the group based on rank correlations and coefficients of concordance for each arch. The sequence of eruption was different in the two arches, with less variation in the mandibular pattern of eruption, but there was no significant difference in sequence due to sex. The eruption time and sequence noted for Pitman-Moore swine differed somewhat from that reported for domestic swine. Eruption appeared to be later in miniature swine, with the greatest difference noted for the maxillary arch. This may be attributed to limited observations of maxillary teeth in domestic swine, and the assumption that the time and sequence of eruption was the same as in the mandibular arch. No precise sequence of eruption in domestic swine was available for comparison, but general comparisons were made with the pattern of deciduous eruption in swine, and with the eruption patterns of human teeth.

The eruption pattern of deciduous teeth in miniature swine.

AbstractSince “miniature swine” are being used extensively as a research animal and since the literature concerning tooth eruption is not very precise, it has seemed advisable to observe and record tooth eruption in the “miniature swine” being used and to make comparisons with existing literature of domestic swine.A total of 55 pigs of the Pitman‐Moore strain were observed weekly from birth until their dentition was complete at about 26 weeks. Lateral x‐ray head plates and study models of both arches were made weekly for two members of the group. The study models and x‐rays served for orientation and positive identification of teeth; and with the weekly observations constitute the data.Analysis of the data indicated there was no significant difference in the eruption time for any tooth due to the sex of the individual. A mean sequence of eruption for each arch was established for the group based on coefficients of concordance. There was no significant difference in sequence of eruption due to sex or litter.The eruption time and sequence noted for Pitman‐Moore swine differed slightly from that recorded for domestic swine. The differences observed were slight and could be explained by the probably infrequent observations of domestic swine or small sample size.