Secular trend in the maturation of permanent teeth in a sample of Turkish children over the past 30 years

Study of secondary dentine deposition in central incisors as an age estimation method for adults

This work aimed to assess the pulp/tooth area ratio's utility in the upper central incisors using orthopantomograms. A convenience sample of 801 adult patient orthopantomograms was studied. Image J® software was used to measure the pulp/tooth area ratio, and a regression model was developed. Our results conclude that the methodology assessing upper incisors' pulp/tooth area ratio using orthopantomograms can lead to age overestimation and statistically significant differences between chronological and estimated age. For those over 50, no correlation between pulp/tooth area ratio and chronological age was found, suggesting that this may be the upper limit of this technique in this population. This methodology may not be suitable for age estimation, particularly in older adults.

Dental Maturation in Two Groups of Children Born in 1969-1973 and 2005-2010

This study compared differences in dental maturation and dental age in Scandinavian children born in 1969-1973 and 2005-2010. The study was based on 130 ethnic Scandinavian children, who were divided in two groups corresponding to the time periods and matched on age and sex. Each group consisted of 65 children (30 girls, 35 boys, mean age 9.29 years and 9.30 years, respectively). Dental maturation was analysed by orthopantomographs, in accordance with Demirjian and Haavikko. Dental age was analysed by orthopantomographs in accordance with Demirjian. Boys and girls were analysed separately by linear regression analysis adjusted for age. For the children born in 2005-2010, teeth matured significantly earlier (Demirjian: 0.21 maturities, CI 95% 0.11-0.31, p < 0.000. Haavikko: maxilla: 0.39 maturities, CI 95% 0.21-0.56, p < 0.000. Mandible: 0.42 maturities, CI 95% 0.17-0.67, p = 0.001) and the dental age was significantly higher (Demirjian: 6.04 months, CI 95% 0.23-0.77, p < 0.000) in comparison with the children born in 1969-1973. In conclusion, the teeth of Scandinavian children born 2005-2010 matured significantly earlier than those of children born in 1969-1973. The results may prove valuable in forensic dentistry, pedodontics, and for the timing of pedodontic and orthodontic treatment.

Dental maturation in a Chinese sample using Demirjian method

BACKGROUND

Dental calcification information is relevant for clinical, archaeological, and forensic applications. However, dental maturity measurements in current cohorts of Chinese children are insufficient.

AIM

This study aimed to establish the mandibular dental maturity table and determine the accuracy of dental age estimation using the Demirjian method in a Chinese sample.

SUBJECTS AND METHODS

Permanent mandibular teeth, excluding the third molar, in 2091 panoramic radiographs of 1008 males and 1083 females aged 3-15 were graded, and dental age was estimated according to Demirjian's criteria. Age-of-attainment was calculated with probit regression for each stage by sex, and sex differences were analysed using the Mann-Whitney U test. Dental age was compared with chronological age using paired t-tests.

RESULTS

Although females showed earlier age-of-attainment than males, significant sex differences were only found in stages D-G (p < 0.05). The Demirjian method overestimated the dental age in both males (0.68 ± 1.05 years) and females (0.59 ± 0.97 years).

CONCLUSIONS

The relationship between mineralisation stage and chronological age in this study can be applied as a reference for mandibular dental maturity of Chinese children and adolescents. The Demirjian method overestimated the chronological ages of this sample.

Presence and Maturation Dynamics of Mandibular Third Molars and Their Influence on Late Mandibular Incisor Crowding: A Longitudinal Study

The objective of this study was to investigate the relationship between the absence, presence and dynamics of mandibular third molar development and the occurrence and amount of late mandibular incisor crowding. Dental plaster casts and panoramic radiographs of 72 orthodontically untreated subjects from the Nittedal growth study, Norway were analyzed. The subjects were recalled for a checkup at 12, 15, 18 and 21 years of age. Mandibular incisor crowding was assessed using Little's irregularity index and dental maturation of the third molars by the Cameriere's index. The majority of the subjects (64%) had ≥1 mm increase in irregularity; 22% experienced an increase of 0.1-0.9 mm and 14% had unchanged or decreased irregularity. Incisor irregularity increased with age, regardless of absence or presence of third molars. The amount of change in incisor irregularity from 12 to 21 years did not differ significantly between subjects with hypodontia of third molars, extraction and those with third molars present. No differences were observed between erupted, unerupted or impacted third molars. No correlation was found between the amount of change in irregularity and maturation of the third molars. In conclusion, occurrence and amount of mandibular late incisor crowding is not significantly influenced by the presence of mandibular third molars or their development dynamics.

[Epidemiological rationale for community-based programs of caries prevention of permanent teeth for children of Samara city]

INTRODUCTION

The global objectives of WHO in the field of oral health by 2020 include the average intensity of caries among 12-year-old children no more than 1.5 by the DMFT index. In Samara the value of the DMFT among the adolescents at age 12 is 3.5.

AIM

To identify the appropriate timing for a launching of community-based schemes of dental caries prevention of permanent teeth for children of Samara.

MATERIAL AND METHODS

In a cross-sectoral multisample research from March to May 2017, the time of eruption and intensity of caries of the first permanent molars among children in Samara were studied. A total of 405 children aged 5 to 8, attending preschool and school educational institutions were examined. The quantity and the stage of eruption of the first permanent molars were assessed; the initial and manifest forms of caries were considered during the calculation of indexes of caries intensity of teeth and surfaces.

RESULTS

One to four first permanent molars were erupted among 26.3% of children aged 5, at an average 0.6±0.14 per one surveyed, the prevalence of caries of the first permanent molars was equal to 1.3%, including 1.3% of the initial carious defeats. In 6-year-old children - 65% had the first permanent molars, at an average of 2.38±0.199, and the prevalence of caries in these teeth was 29.63%, including initial forms of caries 27.16%. The results among 7-year-old children - 87.18% and 3.12±0.156, 60.3% and 51.28%, respectively. In 8-year-old children these figures were equal: 97.26%, 3.79±0.091, 68.49% and 60.27%, respectively. The rate of eruption of the first permanent molars and the prevalence of their carious lesions among girls was significantly higher than among boys.

CONCLUSION

The optimal age of children of Samara for inclusion in the regional programs of dental caries prevention is the age of 4 years - the age of the beginning of the first permanent molar eruption.

Study on Traffic Multi-Source Data Fusion

In order to alleviate urban traffic congestion, it is necessary to obtain roadway network traffic flow parameters to estimate the traffic conditions. Single-detector data may not be sufficient to obtain a comprehensive, effective, accurate and high-quality traffic flow data. Neural networks and regression analysis data fusion methods are employed to expand data sources as well as for improving data quality. The multi-source detector data can provide fundamental support for traffic management. An empirical analysis was conducted using acquisition technology employed by the Beijing urban expressway to estimate traffic flow parameters. The results show that the proposed data fusion method is feasible and provides reliable data sources.

Dental age assessment on panoramic radiographs: Comparison between two generations of young Finnish subjects

Objective

To analyse the accuracy of a meta-analysis-based dental age assessment (DAA) method in Finnish paediatric patients and to compare the dental development between two generations of Finnish children.

Methods

Panoramic radiographs of Finnish Caucasian healthy children from two generations (early: born 1981–1984; subsequent: born 1996–2008) were analysed. All developing teeth on the left maxilla and mandible as well as the third permanent molars were analysed following Demirjian’s classification. For each patient, dental age was calculated and compared with chronological age. Dental maturation patterns between the two groups were compared.

Results

The study included 200 Finnish Caucasian healthy children from two generations (early: aged 7–13 years; subsequent: aged 6–15 years). In the early generation, DAA underestimated the chronological age by a mean of 3.15 years. The underestimation was only 0.11 years in patients < 10 years, but 3.86 years in patients ≥ 10 years. In the subsequent generation, the dental age was overestimated by a mean of 0.34 years; by 0.40 years in patients < 10 years and by 0.08 years in patients ≥ 10 years.

Conclusions

The present DAA method is applicable to current Finnish children. Differences in dental development between two generations of Finnish children were detected.