Comparative evaluation of the dentoalveolar effects of three Class II correctors: A finite element analysis study.

OBJECTIVE: To compare the stress distribution and total strain applied to the dentition, periodontal ligament (PDL) and cortical and trabecular bones by three Class II correctors using finite element analysis. DESIGN: Three-dimensional analysis of stresses and total strain of the dentition with three Class II correctors. SETTING: Computational study. METHODS: Three-dimensional finite element models of Class II elastics, the Forsus Fatigue Resistant Device (FRD) and the Carriere Motion Appliance (CMA) were constructed from a cone-beam computed tomography (CBTC) image of an orthodontic Class II patient. The distribution of stress (von Mises and principal stress) and the total strain (mm) in maxillo-mandibular dentition, PDL, cortical and trabecular bone were analysed. RESULTS: The highest von Mises yield and the maximum principal stress in the three models were found at the teeth, followed by the cortical bone, trabecular bone and PDL. The maximum stress and total deformation were located at the upper canines and lower molars in the Class II elastics and CMA models, in the upper first molars in the Forsus FRD and CMA, and in the lower first premolars in the Forsus FRD. In addition, stress was distributed in the anterior and posterior regions of the teeth, and the total deformation was found in the distal direction in the upper arch and in the mesial direction in the lower arch. CONCLUSION: The stress concentrations in the three models were located close to the active components of each appliance, producing specific patterns of stress distribution and displacement that should be taken into account when planning the type of appliance to be used for the correction of the Class II malocclusion.

Validation of the Italian, European, North German, Malaysian, and South African black formulas on Cameriere method using panoramic radiographs in Kenyan children.

This study aimed to validate the accuracy of five different formulas based on the Cameriere method for age estimation in Kenyan children. We analyzed panoramic radiographs of 350 Kenyan children (184 males and 166 females) aged between 6 and 13 years. The dental development of each child was estimated by the analysis of the first seven left permanent teeth in the left mandible. Dental age was calculated by the Italian, European, North German, Malaysian, and South African black formulas previously published in peer-review journals. The children's mean chronological age (CA) was 9.34 ± 2.02 years and 9.26 ± 2.01 years for males and females. In males, the South-African formula overestimated CA least, by 0.12 years, followed by the Italian formula by 0.22 years, the European formula by 0.37 years, the Malaysian formula by 0.48 years, and the North-German formula overestimated the most, by 0.57 years. In females, the South-African formula underestimated CA by - 0.12 years. The Italian overestimated by 0.12 years, followed by the North-German formula by 0.29 years, the European formula by 0.31 years, and the Malaysian formula by 0.40 years. The Italian formula provided the best accuracy in the absolute difference within ± 1 year, by 75.72% and 75%, following the North-German formula by 66.47% and 70.27% for males and females, respectively. Therefore, the findings suggest that the Italian formula best estimates dental age in Kenyan children.

Third molar maturity index and legal age in different ethnic populations: Accuracy of Cameriere's method.

Molar development is widely accepted as a reliable indicator of chronological age in a forensic context. A quantitative method for age estimation has been proposed by Cameriere et al. based on the relationship between chronological age and the third molar maturity index (I3M), which is the ratio between the two apical pulp widths and the total tooth length. Cameriere's cut off value of 0.08 was found to be a reliable tool in assessing the threshold of 18 years of age. The aim of this study was to evaluate the accuracy of the I3M in different ethnic populations focusing on its specificity (subjects correctly classified as <18 years based on I3M >0.08) and sensitivity (subjects correctly classified as ≥18 years based on I3M <0.08). A review of 22 scientific articles was performed, representing data from panoramic radiographs of 12,286 individuals (5723 males and 6563 females) from all over the world, including some ethnical subgroups. The I3M showed an overall sensitivity for both sexes ranging from 51.8% to 93.4% and a specificity ranging from 86.2% to 100%. The proportion of correctly classified individuals ranged from 74% to 95%. These results can be useful to refer the age estimation with the margin of error of subjects correctly classified as minors (specificity) or adults (sensitivity), according to sex, ethnicity and geographical distribution. The I3M can be considered a suitable method for estimating adulthood in forensic settings, regardless of sex. However, ethnic group can affect the accuracy.

Validation of the third molar maturity index cut-off value of <0.08 for indicating legal age of 18 years in Eastern Chinese region.

Having a reliable, inexpensive and simple method to estimate 18 years of age would be of help in the forensic field. This study aimed to test the accuracy of the third molar maturity index (I3M) in indicating the legal adult age of 18 years. This retrospective cross-sectional study analysed 450 digital panoramic images of Eastern Chinese children and young adults (226 females and 224 males) aged between 14 and 22 years. A cut-off value of I3M < 0.08 was tested in discriminating adults from minors for both sex. For females, the sensitivity of the test (Se) was 75.0%, with a 95% confidence interval (95%CI) of 67.5% to 82.5%. The specificity of the test (Sp) was 100%. The proportion accurately classified (Ac) individuals was 85.8% (95%CI, 81.3% to 90.4%). The Bayes post-test probability was 100% (93.6% to 100%). For males, Se, Sp and Ac were 91.9% (95%CI, 87.1% to 96.7%), 92.0%(95%CI, 86.7% to 97.3%) and 92% (95%CI, 88.4% to 95.5%), respectively. The Bayes post-test probabilities was 92% (95%CI, 88.4% to 95.5%). Males were ahead in the development of third molars comparing to females according to I3M. A stepwise logistic regression analysis showed that both I3M and sex contribute to the regression model to discriminate adults (≥18 years) from minors (<18 years), while a receiver operating curve (ROC) analysis indicated some better accuracy of I3M < 0.12 in females, without statistically significant difference when compared to I3M < 0.08. The results of this study show that the cut-off value of I3M < 0.08 may help to discriminate Eastern Chinese adults from minors. However, further study should evaluate the usefulness and possible variability of I3M cut-off value in a specific population before used for legal and forensic procedures.

Carpals and epiphyses of radius and ulna as age indicators using longitudinal data: a Bayesian approach.

The aim of this study is to develop a new formula for age estimation in a longitudinal study of a sample from the radiological collection of wrist bones of growing infants, children, and adolescents recorded at the Burlington Growth Centre. A sample of 82 individuals (43 boys and 39 girls), aged between 3 and 16 years, were analyzed with a total of 623 X-rays of left hand-wrist bones by measuring the area of carpal bones and epiphyses of the ulna and radius (Bo) and carpal area (Ca). The intra-class correlation coefficient (ICC) and its 95% confidence interval were used to evaluate intra-observer agreement. Hierarchical Bayesian calibration has been adopted to exceed the bias deriving from the classical regression approach used for age estimation in forensic disciplines, since it tends to overestimate or underestimate the age of the individuals. Calibration distributions of the dataset obtained by the evaluation of BoCa (the ratio of Bo and Ca) suggested mean absolute errors (MAE) of 1.07 and 1.34 years in boys and girls, respectively. The mean interquartile range (MIQR) was 1.7 and 2.42 years in boys and girls, respectively. The respective bias of the estimates was ßERR = - 0.025 and - 0.074. Furthermore, a correspondence between different BoCa values and estimated age with its standard deviation (SD) was calculated for boys and girls, respectively. In conclusion, the Bayesian calibration method appears to be suitable for assessing both age and its distribution in subadults, according to hand-wrist maturity. Furthermore, it can easily incorporate other age predictors, obtaining a distribution of the subjects with multivariate predictors.

Assessment of second (I2M) and third (I3M) molar indices for establishing 14 and 16 legal ages and validation of the Cameriere's I3M cut-off for 18 years old in Chilean population.

This retrospective cross-sectional study has two-fold aims: the first is to assess new cut-offs at the legal age thresholds (LATs) of 14 and 16 years old and the second is to validate the cut-off of third molar index I3M=0.08 for 18 years of age in Chilean people. Orthopantomographs from 822 Chilean children aged from 11 to 22 (472 girls and 350 boys) were analysed. For LAT of 14 years, cut-offs were found using the ROC curves singly for boys and girls. The cut-offs for boys were I2M=0.16 and I3M=0.73 while for girls we obtained I2M=0.10 and I3M=0.77. For LAT of 16 years we obtained the same cut-offs regardless of gender, which were 0.06 and 0.36 for I2M and I3M respectively. Concerning the validity of I3M cut-off for 18 years old in Chilean population, the proportion of correctly classified individuals was 83% and estimated post-test probability, PPV, was 93.2%, with a 95% confidence interval equals to 91.3%, 94.6%. Hence, the probability that a subject positive on the test was 18 years of age or older was 93.2%, confirming the validation of the I3M cut-off for Chilean population.

Measurement of open apices in tooth roots in Colombian children as a tool for human identification in asylum and criminal proceedings.

Dental age estimation was recognized as an imperative issue in clinical and medico-legal practice. However, very few studies on dental age estimation in children have been published in Colombia. This study evaluated the accuracy of Cameriere's method of measurement of open apices on tooth roots in a sample of 526 digital panoramic radiographs (OPTs) of children (274 boys and 252 girls), aged between 6 and 14 years, from Bogotá, Valle del Cauca, Buga and Villavicencio, in Southwest Colombia. Only first seven permanent lower teeth, except third molar, from the left side of mandible were studied. Difference between dental age and chronological age was evaluated for boys and girls across nine age classes. Intra-class correlation coefficient and Kappa score was used to test intra- and inter-observer agreement error rate. Dental age was overestimated by 0.08 years and standard deviation (±SD) of 0.68 years in boys which was not statistically significant (p = 0.06), while in girls dental age underestimated by -0.25 ± 0.65 years which was statistically significant difference (p < 0.001). The absolute difference between DA and CA or mean prediction error (ME) was 0.57 ± 0.38 years in boys and 0.57 ± 0.41 in girls (p = 0.966) which implies that Cameriere's European formula is similarly accurate in both sexes in this sample of Colombian children.

A new formula for assessing skeletal age in growing infants and children by measuring carpals and epiphyses of radio and ulna.

The aim of this study is to develop a specific formula for the purpose of assessing skeletal age in a sample of Italian growing infants and children by measuring carpals and epiphyses of radio and ulna. A sample of 332 X-rays of left hand-wrist bones (130 boys and 202 girls), aged between 1 and 16 years, was analyzed retrospectively. Analysis of covariance (ANCOVA) was applied to study how sex affects the growth of the ratio Bo/Ca in the boys and girls groups. The regression model, describing age as a linear function of sex and the Bo/Ca ratio for the new Italian sample, yielded the following formula: Age = -1.7702 + 1.0088 g + 14.8166 (Bo/Ca). This model explained 83.5% of total variance (R(2) = 0.835). The median of the absolute values of residuals (observed age minus predicted age) was -0.38, with a quartile deviation of 2.01 and a standard error of estimate of 1.54. A second sample test of 204 Italian children (108 girls and 96 boys), aged between 1 and 16 years, was used to evaluate the accuracy of the specific regression model. A sample paired t-test was used to analyze the mean differences between the skeletal and chronological age. The mean error for girls is 0.00 and the estimated age is slightly underestimated in boys with a mean error of -0.30 years. The standard deviations are 0.70 years for girls and 0.78 years for boys. The obtained results indicate that there is a high relationship between estimated and chronological ages.

Third molar development by measurements of open apices in an Italian sample of living subjects.

The aim of this study is to analyse the age-predicting performance of third molar index (I3M) in dental age estimation. A multiple regression analysis was developed with chronological age as the independent variable. In order to investigate the relationship between the I3M and chronological age, the standard deviation and relative error were examined. Digitalized orthopantomographs (OPTs) of 975 Italian healthy subjects (531 female and 444 male), aged between 9 and 22 years, were studied. Third molar development was determined according to Cameriere et al. (2008). Analysis of covariance (ANCOVA) was applied to study the interaction between I3M and the gender. The difference between age and third molar index (I3M) was tested with Pearson's correlation coefficient. The I3M, the age and the gender of the subjects were used as predictive variable for age estimation. The small F-value for the gender (F = 0.042, p = 0.837) reveals that this factor does not affect the growth of the third molar. Adjusted R(2) (AdjR(2)) was used as parameter to define the best fitting function. All the regression models (linear, exponential, and polynomial) showed a similar AdjR(2). The polynomial (2nd order) fitting explains about the 78% of the total variance and do not add any relevant clinical information to the age estimation process from the third molar. The standard deviation and relative error increase with the age. The I3M has its minimum in the younger group of studied individuals and its maximum in the oldest ones, indicating that its precision and reliability decrease with the age.