Timing Of Tooth Emergence Research Articles

The relationship of obesity to the timing of permanent tooth emergence in Czech children

Background: The aim of this study was to investigate the influence of BMI on the timing of permanent tooth emergence in Czech children.Objectives: In this cross-sectional study, 1370 Czech children were examined. The age, gender, weight, height, all emerged permanent teeth (except third molars) of each child were all recorded. A tooth is defined as having emerged when at least any part of it has penetrated the gingiva.Methods: A logistic regression model was used to calculate the median emergence age per tooth for both genders separately and BMI was used as a factor variable to detect statistically significant differences in the times of tooth emergence within pairs of BMI groups. The data were statistically processed using IBM SPSS Statistics 23 (SPSS Inc., Chicago, IL).Results: Statistically significant differences were found for the following permanent teeth (using the FDI two-digit system): 13, 14, 15, 16, 17, 41, 44, 45, 46, 47, 33, 35, 37, 21, 24, 25, 26, 27 for girls and 12, 13, 14, 15, 16, 41, 43, 44, 45, 22, 25, 32, 34, 35, 36 for boys. These teeth were observed to emerge earlier in obese children. A similar correlation (although not statistically significant) was observed between the time of emergence of the remaining teeth and the BMI of the child.Conclusion: The data in this research highlight significant differences in emergence times of permanent teeth due to the influence of BMI in Czech children. These findings are important for dental treatment planning.

Delayed tooth emergence in children infected with human immunodeficiency virus

There is limited evidence that early deficits in growth might be reflected in tooth emergence in children infected with human immunodeficiency virus (HIV). The purpose of this study was to prospectively evaluate tooth emergence timing between children positive and negative for HIV in the exposed and unexposed groups, respectively. A longitudinal study of children positive for HIV and HIV-negative household peers, aged 2 to 15years was conducted between 1993 and 1996. Emergence status was determined for the maxillary and the mandibular permanent first molars and the central and lateral incisors. A multivariable, discrete time, proportional hazards model was fitted to the data. Median age of emergence for each of the six pairs of teeth was calculated using the parameter estimates from the regression model. A total of 116 participants (62 HIV positive, 54 HIV negative) completed six examinations over the 36-month study period. Statistical differences in tooth emergence timing were observed for five of the six tooth pairs, with children positive for HIV being less likely to have emergence of the corresponding tooth compared with the children negative for HIV. Age differences for each tooth pair ranged from 0.7 to 1.5years, with a median emergence age difference of 1.03years. Delayed tooth emergence of the permanent dentition was observed in children with HIV.

Association between body mass index and timing of permanent tooth emergence in Jordanian children and adolescents

This study aimed at investigating the association between body mass index (BMI) and the timing of permanent tooth emergence in Jordanian children and adolescents. A total of 2,498 Jordanian schoolchildren and adolescents aged 4–16 years were examined for permanent tooth emergence. The BMI was used to classify the subjects into 4 groups: underweight, normal weight, overweight and obese. Probit analysis was used to determine the median age at emergence of each tooth and BMI was used as a factor variable to detect statistically significant differences in the times of tooth emergence within pairs of BMI groups. In addition, binary logistic regression was used to assess the contribution of BMI grouping to the prediction of early emergence for each tooth. It was found that permanent teeth especially canines, premolars and second molars tended to emerge earlier in children with higher BMIs and later in children with lower BMIs. This study showed a significant and positive relationship between BMI and earlier emergence of permanent teeth, especially phase II mixed dentition permanent teeth. These findings could be relevant in managing children with varying BMIs in the fields of orthodontics, pediatric and forensic dentistry.

Irrompimento do primeiro molar permanente em crianças de 5 e 6 anos de idade: implicações da análise longitudinal para prevenção da cárie oclusal

The timing of tooth emergence is of considerable importance in the planning of prevention of occlusal caries. The aim was to estimate the trends of emergence of the first permanent molars in girls and boys between 5-6 years of age, since more children are included in the first grade after Brazilian elementary education has been extended from eight to nine years of duration. Dental spaces of 497 children aged 60 months or older were examined four times by a calibrated dentist (kappa > 0.97) during 18 months in a longitudinal study. The first permanent molar was considered emerged when any tooth surface could be reached by a ball point probe. Participants' age was measured in months; 95% confidence intervals were obtained for prevalence and incidence values for each sex in three age groups--60.0 to 65.9; 66.0 to 71.9; 72.0 to 77.9 months. Incidence rate ratios were estimated by Poisson regression analysis. The majority of children from 66.0 to 71.9 months and 72.0 to 77.9 months presented at least one emerged permanent molar. For each three children in the 66.0-71.9-month group, at least one had all four permanent molars emerged. The emergence trends observed justify the need for specific protection and surveillance measures for occlusal caries prevention.

Timing of colonization of caries-producing bacteria: an approach based on studying monozygotic twin pairs.

Findings are presented from a prospective cohort study of timing of primary tooth emergence and timing of oral colonization of Streptococcus mutans (S. mutans) in Australian twins. The paper focuses on differences in colonization timing in genetically identical monozygotic (MZ) twins. Timing of tooth emergence was based on parental report. Colonization timing of S. mutans were established by plating samples of plaque and saliva on selective media at 3 monthly intervals and assessing colony morphology. In 25% of individuals colonization occurred prior to emergence of the first tooth. A significant proportion of MZ pairs (21%) was discordant for colonization occurring before or after first tooth emergence, suggesting a role of environmental or epigenetic factors in timing of tooth emergence, colonization by S. mutans, or both. These findings and further application of the MZ co-twin model should assist in development of strategies to prevent or delay infection with S. mutans in children.

Delayed Tooth Emergence

1. Jeffrey M. Karp, DMD, MS* 1. *Assistant Professor, Division of Pediatric Dentistry, Departments of Dentistry and Pediatrics, University of Rochester Medical Center, Rochester, NY. After completing this article, readers should be able to: 1. Recognize abnormalities in tooth emergence timing and order based on oral inspection. 2. Discuss local and systemic causes of delayed tooth emergence. 3. List treatment modalities available for management of delayed tooth emergence. 4. Determine when timely referral to a dentist is necessary. Delayed tooth emergence (DTE) is a clinical term used when exposure of a tooth or multiple teeth through the oral mucosa is overdue, according to population norms based on chronologic age. DTE is common in childhood and adolescence, yet it is often overlooked or dismissed in pediatric primary care. Timely screening and recognition of DTE by clinicians can minimize medical, developmental, functional, and esthetic problems resulting from untreated underlying local and systemic causes. This article provides clinicians with an overview of conditions responsible for DTE in children. Multidisciplinary care for patients who experience DTE in medical, dental, and surgical settings also is discussed. Human teeth develop through a series of complex, reciprocal interactions between the oral epithelium and migrating cranial neural crest ectomesenchymal cells of the first branchial arch. This process is tightly regulated by more than 300 genes expressed temporospatially within the jaws. Dental patterning of the primary and permanent dentition is expressed in three dimensions, exerting morphogenetic controls over tooth number, position, size, and shape. In the end, the normal primary dentition consists of three tooth classes (four incisors, two canines, four molars) in each jaw, for a total of 20 teeth. Thirty-two teeth distributed among four tooth classes (8 incisors, 4 canines, 8 premolars, 12 molars) comprise the permanent dentition. Tooth emergence, the clinical exposure of any part of a …

Genetic Modeling of Primary Tooth Emergence: A Study of Australian Twins

The aim of this study was to quantify contributions of genetic and environmental factors to variation in timing of emergence of the primary teeth in a sample of monozygotic and dizygotic twins, using univariate model-fitting approaches. The sample comprised 94 pairs of monozygotic twins and 125 pairs of dizygous twins, all of European ancestry, aged from 2-6 years. Tooth emergence timing was based on parental report, with a subset of data validated by clinical assessment. Heritability estimates for tooth emergence timing were generally high, around 90%, however estimates for the lower right lateral incisor and the lower canines were around 50%. These findings confirm a strong genetic influence on observed variation in the timing of emergence of the human primary teeth.

Effect of Caries Experience in Primary Molars on Cavity Formation in the Adjacent Permanent First Molar

This study sought to address the influence of a sound versus affected first and/or second deciduous molar on the incidence of visible caries experience in the adjacent permanent first molar. Clinical and questionnaire data were obtained from a 6-year prospective oral health screening project in Flanders, Belgium (Signal-Tandmobiel^® project), where 4,468 children (born in 1989) were examined annually during their primary school time. A multiple survival model allowing for dependent data with possible censoring was applied. The impact of timing of tooth emergence (determining the period at risk), gender, presence of sealants and reported oral hygiene habits was also considered. Cavity formation in permanent first molars was clearly influenced by the status of the adjacent primary molars;the effect of the second deciduous molar was most pronounced. Moreover, if both deciduous molars experienced caries and the child presented with poor oral hygiene, a peak in cavity formation of the permanent first molar 1–2 years after emergence was noticed. On the other hand, if a child presented with good oral hygiene, no peak was observed;caries risk increased slightly over time. No significant benefit from restoring primary molars could be demonstrated, possibly because of methodological limitations.

Multivariate survival analysis for the identification of factors associated with cavity formation in permanent first molars

This investigation used a multivariate survival model, which allowed for dependent caries data with possible censoring, to analyse the impact of timing of tooth emergence, gender and several reported oral hygiene and dietary habits on the incidence of cavity formation in permanent first molars (PFM) in young children. A 6-yr prospective oral health screening project in Flanders, Belgium, provided clinical and questionnaire data on 4,468 children. The results revealed that PFM in children who reported frequent brushing, who had no visible caries experience in the primary dentition, and who presented without occlusal plaque on the PFM had the best survival estimates. Girls had a higher incidence than boys of cavity formation in mandibular molars. The multiple survival analysis confirmed the major impact of the caries status of the deciduous dentition and self-reported oral hygiene habits on the incidence of cavities in permanent first molars.

The effect of fluorides and caries in primary teeth on permanent tooth emergence.

This study addressed two questions: (i) is there an effect of exposure to fluorides on the timing of emergence of permanent teeth? and (ii) can a difference in timing of tooth emergence be explained by the impact of fluorides on the caries experience of the predecessors? Data were obtained from a long-term follow-up study of the oral health condition in a sample of 4468 Flemish children. Survival analyses with log-logistic distribution were performed to calculate median emergence ages and 95% confidence intervals; four fluoride exposure parameters (fluorosis, use of systemic fluoride supplements, age at which tooth brushing started and frequency of tooth brushing) and caries experience were taken as covariates in the model. The present study indicates that the impact of any of the four fluoride exposure parameters on permanent tooth emergence was relatively minimal. Caries experience in the primary molars had a more pronounced impact on the timing of emergence of the successors than exposure to any of the four fluoride parameters.

Time and order of eruption of primary teeth for children in Mosul City, Iraq

The aims of the study were to determine the time and sequence of eruption of primary teeth. Also, to determine the differences in timing of tooth emergence according to side, jaw and gentler variation.Tinning and sequence of cruption were studied cross-sectionally in a group of (1843) children from Mosul City, Iraq:(940) were males and(903) were females aged between (2-37)months. The data were statistically analysed by using Karber's analysis in order to compute the mean and standard deviation of emergence.The results showed that there are no significant differences between the mean time of corresponding right and left teeth in both genders. The findings of the study indicated that the males have their primary teeth to emerge earlier than those of females. The differences between the two genders are clearly seen in the eruption of maxillary lateral incisor and maxillary first molar. The males acquired all their primary teeth to emerge in shorter time span than the females (difference 2.04 months).The results demonstrated that the maxillary teeth emerge before their mandibular opposing teeth in males with the exception of central incisor. However, in females, the mandibular teeth emerge before their maxillary opposing teeth with the exception of the canine and second molar.A specific sequence of primary teeth emergence was found in both arches and for both genders. In general, the emergence of primary teeth started with the emergence of mandibular central incisor and ended with mandibular second molar.

Primate molar crown formation times and life history evolution revisited.

Comparative studies have convincingly demonstrated that the pattern and timing of tooth emergence are highly correlated with life-history variables and brain size. Conversely, a firm relationship between molar formation time and life-history variables has not yet been established. It seems counterintuitive that one aspect of dental development should be correlated with life-history variables, whereas the other should not. In order to shed light on this apparent discrepancy this study analyzed all data on primate molar crown formations available in the published literature in relation to life-history variables, brain size, and female body mass. Crown formation times were found to be particularly highly correlated with both female body mass and brain size. Species that depart from the overall brain/body allometry by being relatively large-bodied, e.g., Gorilla gorilla and later Theropithecus oswaldi, also have shorter molar crown formation times than expected. The reverse is not found for species that depart from the overall brain/body allometry due to their larger brains, i.e., Homo sapiens. This finding is interpreted within an evolutionary and ecological framework. Specifically, by focusing on ecological commonalities, a scenario is proposed which may allow predictions to be made about the evolutionary history of other extinct primates also. If confirmed in future studies, crown formation time may again become a powerful tool in evolutionary enquiry.

A histological reconstruction of dental development in the common chimpanzee, Pan troglodytes.

Much is known about the dental development of Pan compared with that for other extant great apes. The majority of information available has concentrated either on the emergence times of teeth or on the sequence of mineralization stages of the teeth as revealed from radiographs. However, the problems of defining stages of tooth formation sufficiently accurately on radiographs are only now becoming recognized. All of the data available to date suggest the presence of a more variable picture for the timing of mineralization stages in chimpanzees than for the timing of tooth emergence. In particular, arguments persist in the literature over the time of initial mineralization and the time it takes to form each anterior tooth crown in chimpanzees. Therefore we attempt to provide a more precise chronological time scale for dental development in our closest living relative. Furthermore, we examine the sequence of molar cusp formation relative to enamel formation times related specifically to those cusps and to try to tie these data in with information from functional studies of molar crowns. Histological sections of 14 maxillary and 28 mandibular teeth from four chimpanzee (Pan troglodytes) individuals and three molar teeth from three chimpanzees of unknown origin were prepared in accordance with a well-established protocol. By combining data on short-period and long-period incremental lines (including daily secretion rates, periodicity, prism lengths and enamel thickness) in both enamel and dentine, we reconstruct times for the onset and duration of crown formation as well as construct a schedule for the pattern and timing of dental development in this one hominoid species. Interestingly, our histologically-derived data confirms that the data from radiographic studies underestimate crown formation times by the following amounts for each tooth type: I1 2.5 years, I2 3.1 years, C 1.6 years, P3 1.9 years, P4 0.1 years, M1 0.8 years, M2 1.1 years and M3 0.3 years. When combined with data on gingival emergence, it seems that chimpanzee teeth have a greatly reduced time for root growth before emergence occurs and that the major differences between Homo sapiens and Pan lie in the first part of the root formation rather than in the total period of crown formation. Maxillary and mandibular molar functional cusps take longer to complete enamel formation to the cervix than any other cusp in that same tooth, which makes sense as these cusps are thick enamelled. These results suggest that new links can be made between developmental aspects, occlusal morphology and tooth function.

Patterned asymmetry in tooth emergence timing.

Patterned asymmetry in tooth emergence timing.

Eruption sequence similarities in the maxilla and mandible.

Maxillary and mandibular dentitions exhibit correspondences to a truly remarkable degree. Correlations of upper and lower opponents (isomeres) in both the deciduous and permanent dentitions are exceeded only slightly by right-left (antimere) correspondences, both in crown size (Garn and Burdi, J Dent Res 50:1407, 1971) and in tooth emergence timing (Garn and Smith, J Dent Res, in press, 1980). Under these circumstances one might also expect inter-jaw correspondences in the order of tooth emergence, such that an M2P2 or P2M2 emergence order in one jaw would be associated with the same sequence in the opposing dentition. To explore this possibility we have made use of two data sources, restricting data analysis to those boys and girls for whom sequences were completely clear for both upper and lower dentitions. The first data base, which we have extensively explored, is that of the Ten-State Nutritional Survey of 1968-1970 (Garn et al., J Dent Res 51:1506, 1972). The second data base includes the participants of the University of Michigan Longitudinal Study (Moyers et al., Standards ofHuman Occlusal Development, Ann Arbor, Center for Human Growth and Development, 1976). The first data base provides 220 black individuals and 284 white individuals, analyzed separately because of population differences in emergence sequence and timing. The second data base yields a total of 60 boys and

Developmental communalities in tooth emergence timing.

Intercorrelations and communalities are now well known for tooth formation (Garn et al., J Dent Res 39:1049, 1960), crown size of the permanent teeth (Moorees and Reed, Arch Oral Biol 9:685, 1964; Garn et al., J Dent Res 44:350, 1965), the deciduous teeth (Garn et al., JDentRes 56:1214, 1977), and crown size of deciduous teeth during odontogenesis (Garn et al., J Dent Res 58:554, 1979). However, comparable analytic information has not been presented for postnatal tooth emergence timing of 11 through M2. To explore these emergence relationships and their relative magnitudes, tooth emergence (timing) correlations were calculated using coded emergence data derived from serial casts of 204 participants in the Longitudinal Study of the University of Michigan (Moyers et aL, Standards of Human Occlusal Development, Ann Arbor: The Center for Human Growth and Development, 1976). Individual ages of tooth emergence were Z-scored for males and females separately for each of 28 permanent teeth, and the entire matrix of 121 pooled-sex tooth-pair intercorrelations was then computer correlated. Correlation coefficients for intra-quadrant pairs, antimeres, isomeres, and teeth separated by numbers of intervening teeth were separately averaged using the z transform of r As snown in the Table, where correlations are

Canadian Eskimo permanent tooth emergence timing.

To identify the times of emergence of the permanent teeth of Canadian Eskimos (Inuit), 368 children and adolescents were examined. The presence or absence of all permanent teeth except the third molars was recorded and these data subjected to probit analysis. Female emergence times were advanced over males. Generally, the Inuit of both sexes showed statistically significant earlier emergence times than Montreal children, except for the incisors. The present results do not support hypotheses indicating that premature extraction of the deciduous teeth advances the emergence of their succedaneous counterparts. There is some indication the controls of deciduous tooth emergence continue to play some part in emergence of the permanent dentition, especially the first permanent teeth that emerge.

The timing of tooth emergence in four population samples

From examination of 4000 Caucasian children aged 5–14 years, variation was apparent between samples derived from four regions in England. The data suggested that even within a population there is such variation in both the order and timing of tooth emergence into the oral cavity that caution must be applied in the interpretation of such information.