Timing of Demirjian tooth formation stages

University of Adelaide, Tarndarnya, South Australia, Australia
Annals of Human Biology (Impact Factor: 1.27). 07/2006; 33(4):454-70. DOI: 10.1080/03014460600802387
Source: PubMed


Global differences in Demirjian et al.'s method of assessing dental maturity are thought to be due to population differences.
The aim of this study was to investigate the timing of individual tooth formation stages in children from eight countries.
This was a meta-analysis of previously published data from retrospective cross-sectional studies of dental maturity.
Data of mandibular permanent developing teeth from panoramic radiographs (Demirjian's stages) were combined from Australia, Belgium, Canada, England, Finland, France, South Korea and Sweden (n = 9002, ages 2-16.99 years). Age-of-attainment was calculated using logistic regression for each group by sex and meta-analysis of the total. Overlapping 95% confidence intervals of the means was interpreted as no significant difference.
Mean ages for each group and total were significantly different in 65 out of 509 comparisons (p < 0.05). Some of these were of small sample size but there was no consistent pattern. Apex closure of the first molar was significantly later in children from Quebec and this might explain differences found in the dental maturity score.
These results suggest no major differences in the timing of tooth formation stages between these children. This fails to explain previous findings of differences using Demirjian's dental maturity method.

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Available from: Helen M Liversidge, Oct 05, 2015
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    • "These groups are similar in their dental maturity and only small differences in mean age entering permanent tooth stages have been shown (Liversidge , 2011). Another comparative study of mostly White children in various world regions failed to show any meaningful difference or consistent pattern in the timing of tooth formation (Liversidge et al., 2006). This does not hold true for all teeth and there is some evidence of group difference in the timing of the third molars (Liversidge, 2008; Thevissen et al., 2010). "
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    ABSTRACT: Dental age estimation charts are frequently used to assess maturity and estimate age. The aim of this study was to assess the accuracy of estimating age of three dental development charts (Schour and Massler, Ubelaker, and the London Atlas). The test sample was skeletal remains and dental radiographs of known-age individuals (N = 1,506, prenatal to 23.94 years). Dental age was estimated using charts of Schour and Massler, Ubelaker, and The London Atlas. Dental and chronological ages were compared using a paired t-test for the three methods. The absolute mean difference between dental and chronological age was calculated. Results show that all three methods under-estimated age but the London Atlas performed better than Schour and Massler and Ubelaker in all measures. The mean difference for Schour and Massler and Ubelaker was -0.76 and -0.80 years (SD 1.27 year, N = 1,227) respectively and for the London Atlas was -0.10 year (SD 0.97 year, N = 1,429). Further analysis by age category showed similar accuracy for all three methods for individuals younger than 1 year. For ages 1-18, the mean difference between dental and chronological ages was significant (P < 0.05) for Schour and Massler and Ubelaker and not significant (P > 0.05) for the London Atlas for most age categories. These findings show that the London Atlas performs better than Schour and Massler and Ubelaker and represents a substantial improvement in accuracy of dental age estimation from developing teeth. Am J Phys Anthropol, 2014. © 2014 Wiley Periodicals, Inc.
    American Journal of Physical Anthropology 04/2014; 154(1). DOI:10.1002/ajpa.22473 · 2.38 Impact Factor
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    • "However, compared with the dental maturation in French-Canadian children, dental maturation of children in Kuwait was found to be delayed by approximately 0.7 years.[19] In addition, dental age in the Demirjian method is exactly as predicted in certain populations.[20] The age of the sample group, the statistical method, method reliability and each child's individual genetic and geographic variation can influence the differences reported in the results.[1521] "
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    ABSTRACT: Objective: The aims of this retrospective study were to determine compliance with dental and chronological ages and to analyze the relationships between dental age and orthodontic sagittal anomalies. Materials and Methods: A total of 221 subjects between the ages of 7 and 15.9 years (165 girls and 156 boys) were included in the study. The dental age of seven left mandibular teeth was assessed according to the Demirjian method. The maxillary protrusion, mandibular protrusion, maxillo-mandibular and vertical plane angles were measured from cephalometric films. Results: The mean difference between the chronological age and dental age in female patients was 0.94 years and 0.33 years in male patients (P < 0.01). No differences between the sagittal classification groups were found. There was no relationship between dental age and the SNA° or the GoGn-SN°. A statistically significant negative relationship was found between dental age and the SNB° and there was a significant linear relationship between dental age and the ANB°. Conclusion: Dental age in girls and boys has been estimated to be more advanced than chronological age in all classes and dental maturation advanced in cases with a tendency to develop Class II malocclusions.
    European journal of dentistry 03/2014; 8(1):38-43. DOI:10.4103/1305-7456.126238
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    • "Not all stages of ages of attainment for tooth formation in Pan and modern humans are easily compared in longitudinal radiographic and histological studies of dental development but some are more easily definable than others. Total tooth formation times, that include both enamel crown and root dentine formation times, are surprisingly similar for anterior teeth and overlap in their ranges for molars [6], [73], [79]. By way of example, equivalent ages of attainment of root formation stages in permanent incisors in Pan (‘Stage 7’) [73] and modern humans (‘Stage G’) [79] respectively, occur at 7.93 years (S.D., 0.68) and 7.85 years (S.D., 1.0). "
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    ABSTRACT: We explored the relationship between growth in tooth root length and the modern human extended period of childhood. Tooth roots provide support to counter chewing forces and so it is advantageous to grow roots quickly to allow teeth to erupt into function as early as possible. Growth in tooth root length occurs with a characteristic spurt or peak in rate sometime between tooth crown completion and root apex closure. Here we show that in Pan troglodytes the peak in root growth rate coincides with the period of time teeth are erupting into function. However, the timing of peak root velocity in modern humans occurs earlier than expected and coincides better with estimates for tooth eruption times in Homo erectus. With more time to grow longer roots prior to eruption and smaller teeth that now require less support at the time they come into function, the root growth spurt no longer confers any advantage in modern humans. We suggest that a prolonged life history schedule eventually neutralised this adaptation some time after the appearance of Homo erectus. The root spurt persists in modern humans as an intrinsic marker event that shows selection operated, not primarily on tooth tissue growth, but on the process of tooth eruption. This demonstrates the overarching influence of life history evolution on several aspects of dental development. These new insights into tooth root growth now provide an additional line of enquiry that may contribute to future studies of more recent life history and dietary adaptations within the genus Homo.
    PLoS ONE 01/2013; 8(1):e54534. DOI:10.1371/journal.pone.0054534 · 3.23 Impact Factor
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