Dental age estimation: development and testing of a reference data set for Qatari children, adolescents, and young adults aged between 5 and 25 years.

The purpose of this study is to establish and test a reference data set of dental development of Qatari subjects aged between 5 and 25 years. Radiographs of individuals aged between 5 and 25 years were re-used to establish a reference data set (RDS). A scheme comprising 8 tooth development stages (TDS) was used to assess all the teeth on the left side of the maxilla and mandible. The accuracy of dental age estimation (DAE) was tested with a separate sample of radiographs - the validation sample (VS) comprised 50 females and 50 males of known chronological age (CA). Dental panoramic tomographs (DPT) of 1,597 Qataris were assessed. The summary data for the individual TDS comprising the number (n-tds), mean ( x ¯ -tds), standard deviation (sd-tds), 0th%-ile (the minimum), 25th%-ile, 50th%-ile (the median), 75th%-ile, and 100th%-ile (the maximum) were used to estimate the age of the VS subjects using the simple average method (SAM). There is a significant difference in dental age of 4.8 months in the female group when compared to the CA. The difference in the male group is 4.5 months. This shows similar differences to assessments of other ancestral or ethnic groups.

Questions of logic in Atlas methods of dental age estimation.

PURPOSE: To review aspects of the underlying methodological procedures in Atlas Methods of Dental Age Estimation (DAE) research publications. Attention is paid to issues of Reference Data supporting the Atlases, details of analytic procedures in the development of the Atlases, the statistical reporting of results of Age Estimation (AE), the problems of expressing uncertainty, and the viability of conclusions in the reporting of DAE studies. METHODS: Research reports utilizing Dental Panoramic Tomographs for creating Reference Data Sets (RDS) were studied to unravel the processes of creating Atlases with a view to determining the appropriate procedures for developing numerical RDS and compiling them into an Atlas format to enable DAE of child subjects without birth records. RESULTS: The five different Atlases reviewed gave several different results in terms of AE. The possible causes of this were discussed - namely inadequate representation of Reference Data (RD) and lack of clarity in expressing uncertainty. It is suggested that the method of compiling Atlases needs to be more clearly defined. The yearly intervals described by some of the Atlases fails to take account of the Uncertainty of Estimates which is usually slightly greater than ±2½ years. CONCLUSION: The review of published Atlas design papers in the field of DAE shows a number of different study designs, statistical procedures, and presentational styles, particularly with regard to the statistical procedures and findings. These show that Atlas methods can only be accurate to what amounts to at best a year. RECOMMENDATIONS: Atlas methods lack the accuracy and precision of other methods of AE an example of which is the Simple Average Method (SAM).1 This inherent lack of accuracy must be taken into account when using Atlas methods for AE.

Dental age estimation: Development and validation of a reference data set for Kuwaiti children, adolescents, and young adults.

OBJECTIVES: This study was designed to establish a Reference Data Set for Dental Age Estimation of young Kuwaiti subjects. DESIGN: Dental Panoramic Tomographs of 1393 Kuwaiti children, adolescents, and young adults aged between 3 and 26 years were re-used to establish a Reference Data Set. The Tooth Development Stages described by Demirjian et al. in 1973 was used to assess all the teeth on the left side of the Maxilla and the Mandible. The Accuracy and Precision of Dental Age Estimation for Kuwaiti children and adolescents was investigated by calculating the age of children using 50 females and 50 males of known age separate from the main study sample. This was the Validation Sample. Summary data for the individual Tooth Development Stages, comprising the number, mean, and standard deviation were used to estimate the age of the subjects in the Validation Sample using the Simple Average Method to calculate the Dental Age. RESULTS: There was no statistically significant difference between the Chronological Age and the Dental Age in males with a mean difference of 0.14 years (1.75 months). The difference in females was significant at -0.33 years (-4.1 months). CONCLUSIONS: These data demonstrate that estimated Dental Age in Kuwaiti females is close, just over 4 months, and is very close, in males within 1.75 months of the Chronologic Age.

Deaths associated with GA for dentistry 1948 - 2016: the evolution of a policy for general anaesthesia (GA) for dental treatment.

BACKGROUND: Following the inception of the National Health Service in 1948 dental treatment under General Anesthesia (GA) became easily available. An unexpected consequence of this was a disconcerting number of deaths associated with GA. Over the decades since 1948 there have been a number of specialist medical society, royal college, and government working parties deliberating on the appropriateness of GA being conducted in general dental practice and community dental practice. METHODS: The figures for the number of general anaesthetics per annum in England and Wales were obtained from the general dental services board, the community dental service, and records from hospital inpatient episodes. The number of deaths per annum were obtained from coroners' enquiries and dental protection societies. FINDINGS: Prior to 2001 there is a strong correlation between the number of GA's per annum and deaths. Since 2001, when the UK government directed that all GAs for dentistry must be administered in a hospital with Intensive Care facilities the number of deaths per annum has reduced to nil. INTERPRETATION: The change in the arrangements under which GA for dentistry are administered was coincident with improved training and knowledge of GA for dentistry. This has led to a cessation of deaths associated with GA for dentistry. The incidence rate is now estimated at less than 1 death per 3.5 million GAs.

Expressing Uncertainty in Dental Age Estimation: A Comparison between Two Methods of Calculating the "Average" Standard Deviation.

The expression of uncertainty is defined by the standard deviation and is usually expressed in multiples of the standard deviation (±1sd, ±2sd, and ±3sd). The objective was to use weighting of the sd calculation by the number or count of subjects for each tooth development stage. A comparison shows the difference between the range of uncertainty using the unweighted sd and the weighted sd. The range of uncertainty related to Dental Age Estimation is statistically significantly greater (p < 0.001) for the weighted sd compared to the unweighted sd. It is concluded that the number of subjects for each Tooth Development Stage in the Reference Data set should be included in the calculation for a single Dental Age Estimation using the Simple Average Method when presenting the uncertainty associated with the point estimate of the "mean" for Dental Age Estimation of a single subject of unknown age.

Dental Age Estimation: Pattern Recognition of Root Canal Widths of Mandibular Molars. A Novel Mandibular Maturity Marker at the 18-Year Threshold.

The final stage of third molar development is used to assign a subject to above the 18-year threshold. Some subjects exhibiting this final stage are less than 18 years. Radiographs from 1000 females and 1000 males age 16.00-25.99 years were examined. Each half-year age band comprised 50 females and 50 males. Three categories of root canal widths (RCW) of the LL6, LL7, and LL8 [FDI 36, 37, and 38] were defined. Reproducibility was achieved by re-assessing the same subjects 12 months apart. For females, the minimum value for RCW-A was 16.33 years, RCW-B 17.23 years, and RCW-C 18.45 years. For males, the minimum values were RCW-A 17.16 years, RCW-B 18.29 years, and RCW-C 18.16 years. The presence of RCW-C in a female, and the presence of RCW-B or RCW-C in a male is compelling evidence that the subject is above the 18-year threshold.

Dental age estimation: periodontal ligament visibility (PLV)-pattern recognition of a conclusive mandibular maturity marker related to the lower left third molar at the 18-year threshold.

The purpose of this study was to explore the applicability of periodontal ligament visibility (PLV) at the 18-year threshold. This mandibular maturity marker is graded into four separate age related stages, PLV-A, PLV-B, PLV-C, and PLV-D. These are discernible on a dental panoramic tomograph (DPT). The sample comprised a total of 2000 DPTs evenly divided into half yearly age bands from 16.00 to 25.99 years with 50 females and 50 males in each age band. It was found that PLV-A and PLV-B had minimum values below the 18-year threshold. PLV-C and PLV-D in females had minimum values of 18.08 and 18.58 years, respectively. In males, the minimum values for PLV-C was 18.10 years and PLV-D was 18.67 years. It was concluded that the presence of PLV-C or PLV-D indicates that a subject is over 18 years with a very high level of probability.

Dental Age Estimation-Root Pulp Visibility (RPV) patterns: A reliable Mandibular Maturity Marker at the 18 year threshold.

The purpose of this paper was to explore the potential application of Root Pulp Visibility (RPV) to determine whether or not a subject of unknown date of birth is under or over the 18year threshold. PATIENTS, MATERIALS AND METHODS: Two thousand Dental Panoramic Radiographs comprising equal numbers of females and males evenly distributed between the ages of 16 and 26 years were examined. All third molars were scored using the Anglo-Canadian 8 Stage Tooth Development system [1]. The Lower Left Third Molar was censored to avoid redundant data being included in the data array for the Age at Attainment of Stage H, the final stage of tooth development (Roberts et al., 2015 [2]). A filter cascade was applied to the data to select the data array for 1. Teeth in the final stage of development, 2. Female or male gender, 3. The definitive stage of RPV: RPV-A, RPV-B, RPV-C, or RPV-D. RESULTS: The summary data for each of these stages was derived and the minimum value for each was used to determine the relationship of the minimum value of A, B, C or D to the 18 Year threshold. It was found that for both females and males the minimum value for RPV-A and RPV-B indicated that subjects displaying this could be under 18 years old. For RPV-C and RPV-D, the minimum values show unequivocally that for both females and males the subject was over 18 years old. CONCLUSION: RPV has an important role in unambiguously determining whether a subject is below or above the 18year threshold.

Dental Age Estimation: A Test of the Reliability of Correctly Identifying a Subject Over 18 Years of Age Using the Gold Standard of Chronological Age as the Comparator.

This study was designed to test the reliability of using the third molars to demarcate between child and adult status. A total of 2000 dental panoramic tomographs were used for assessment of the calculated age using the 8-stage system of tooth development and applied to all four third molars. The LL8 was also assessed using this 8-stage system. For each tooth development stage, the Normal distribution and percentile summary data were estimated. The calculated dental age compared with the chronological age was statistically significantly different (p < 0.001) for both females and males giving underestimates of the true age. Comparison of single tooth dental age and chronological age was only slightly different. The most important finding is that the assignment to above or below the 18-year threshold, in the age range 17 years to 19 years, could be wrong on up to 50% of occasions.

Dental Age Estimation (DAE): Data management for tooth development stages including the third molar. Appropriate censoring of Stage H, the final stage of tooth development.

INTRODUCTION: The final stage of dental development of third molars is usually helpful to indicate whether or not a subject is aged over 18 years. A complexity is that the final stage of development is unlimited in its upper border. Investigators usually select an inappropriate upper age limit or censor point for this tooth development stage. MATERIALS AND METHODS: The literature was searched for appropriate data sets for dental age estimation and those that provided the count (n), the mean (x¯), and the standard deviation (sd) for each of the tooth development stages. The Demirjian G and Demirjian H were used for this study. Upper and lower limits of the Stage G and Stage H data were calculated limiting the data to plus or minus three standard deviations from the mean. The upper border of Stage H was limited by appropriate censoring at the maximum value for Stage G. RESULTS: The maximum age at attainment from published data, for Stage H, ranged from 22.60 years to 34.50 years. These data were explored to demonstrate how censoring provides an estimate for the correct maximum age for the final stage of Stage H as 21.64 years for UK Caucasians. CONCLUSION: This study shows that confining the data array of individual tooth developments stages to ± 3sd provides a reliable and logical way of censoring the data for tooth development stages with a Normal distribution of data. For Stage H this is inappropriate as it is unbounded in its upper limit. The use of a censored data array for Stage H using Percentile values is appropriate. This increases the reliability of using third molar Stage H alone to determine whether or not an individual is over 18 years old. For Stage H, individual ancestral groups should be censored using the same technique.

The Weighted Average Method 'WAM' for dental age estimation: a simpler method for children at the 10 year threshold: "it is vain to do with more when less will suffice" William of Ockham 1288-1358.".

The mathematical principle of weighting averages to determine the most appropriate numerical outcome is well established in economic and social studies. It has seen little application in forensic dentistry. This study re-evaluated the data from a previous study of age assessment at the 10 year threshold. A semiautomatic process of weighting averages by n-td, x-tds, sd-tds, se-tds, 1/sd-tds, 1/se-tds was prepared in an Excel worksheet and the different weighted mean values reported. In addition the Fixed Effects and Random Effects models for Meta-Analysis were used and applied to the same data sets. In conclusion it has been shown that the most accurate age estimation method is to use the Random Effects Model for the mathematical procedures.

Dental age estimation: the role of probability estimates at the 10 year threshold.

INTRODUCTION: The use of probability at the 18 year threshold has simplified the reporting of dental age estimates for emerging adults. The availability of simple to use widely available software has enabled the development of the probability threshold for individual teeth in growing children. MATERIALS AND METHODS: Tooth development stage data from a previous study at the 10 year threshold were reused to estimate the probability of developing teeth being above or below the 10 year thresh-hold using the NORMDIST Function in Microsoft Excel. The probabilities within an individual subject are averaged to give a single probability that a subject is above or below 10 years old. To test the validity of this approach dental panoramic radiographs of 50 female and 50 male children within 2 years of the chronological age were assessed with the chronological age masked. Once the whole validation set of 100 radiographs had been assessed the masking was removed and the chronological age and dental age compared. The dental age was compared with chronological age to determine whether the dental age correctly or incorrectly identified a validation subject as above or below the 10 year threshold. RESULTS: The probability estimates correctly identified children as above or below on 94% of occasions. Only 2% of the validation group with a chronological age of less than 10 years were assigned to the over 10 year group. CONCLUSIONS: This study indicates the very high accuracy of assignment at the 10 year threshold. Further work at other legally important age thresholds is needed to explore the value of this approach to the technique of age estimation.

Dental age assessment (DAA): a study of a Caucasian population at the 13 year threshold.

UNLABELLED: The purpose of this study was to develop a Reference Data Set for Dental Age Assessment at the 13 year old threshold in Caucasian children. PATIENTS, MATERIALS AND METHODS: The Reference Data Set comprised 5187 re-used Dental Panoramic Tomographs (DPTs) between the ages of 11-15 years, from both the Eastman Dental Hospital and King's College Dental Hospital archives. Tooth Development Stages were recorded for the left maxillary and mandibular teeth and all four permanent third molars (Demirjian et al., 1973, Demirjian 1978). A separate Study Sample of DPTs, comprising 50 males and 50 females aged between 10 and 16 years was collected to test the accuracy of the method. Summary Data was generated for the individual Tooth Development Stages which consisted of the number (n-tds), mean (x), standard deviation (sd) and the standard error (se). By using the mathematical techniques of meta-analysis, this data was used to estimate the age of each subject in the Study Sample. The estimated Dental Age derived was compared to the gold standard of Chronological Age. RESULTS: The mean difference between the Chronological Age and Dental Age was determined to be -0.1 years (-1.2 months) for males and 0.05 years (-0.6 months) for females. CONCLUSION: Dental Age was reliably estimated at the 13 year threshold.

Dental age assessment of adolescents and emerging adults in United Kingdom Caucasians using censored data for stage H of third molar roots.

The root of the third permanent molar is the only dental structure that continues development after completion of growth of the second permanent molar. It is claimed that the lack of a clearly defined end point for completion of growth of the third permanent molar means that this tooth cannot be used for dental age assessment. The aim of this study was to estimate the mean age of attainment of the four stages (E, F, G, and H) of root development of the third molar. The way in which the end point of completion of stage H can be identified is described. A total of 1223 dental panoramic tomographs (DPTs) available in the archives of the Eastman Dental Hospital, London, were used for this study. The ages of the subjects ranged from 12.6 to 24.9 years with 63 per cent of the sample being female. Demirjan's tooth development stages (TDSs), for the first and second molars, were applied to the third molars by a single examiner. For each of stages E, F, and G and for stage H censored data, the mean ages of the males and females were compared, separately within each tooth morphology type using the two sample t-test (P < 0.01). The same test was used to compare the mean ages of the upper and lower third molars on each side, separately for each gender. The mean age of attainment and the 99 per cent confidence interval (CI) for each TDS were calculated for each third molar. The final stage H data were appropriately censored to exclude data above the age of completion of root growth. The results showed that, for each gender, the age in years at which individuals attained each of the four TDSs was approximately normally distributed. The mean age for appropriately censored data was always lower than the corresponding mean age of the inappropriately censored data for stage H (male UR8 19.57, UL8 19.53, LL8 19.91, and LR8 20.02 and female UR8 20.08, UL8 20.13, LL8 20.78, and LR8 20.70). This inappropriately censored data overestimated the mean age for stage H. The appropriately censored data for the TDSs of the third molar may be used to estimate the age of adolescents and emerging adults assuming average growth and development and recent attainment of stage H.

Dental age assessment (DAA): reference data for British children at the 10-year-old threshold.

The purpose of this work was to develop a reference dataset for dental age assessment at the 10-year-old threshold. Dental panoramic radiographs of children aged between 9 and 11 years were reused to determine the age of attainment of tooth development stages relevant to the 10-year threshold. These data were used to test the accuracy of the dental age assessment (DAA) on a separate study sample of known chronological age. The study sample comprised 100 radiographs (50 female, 50 male) of known chronological age that did not form part of the reference dataset. For each subject in the study sample, the mathematical procedure used in meta-analysis was applied to all teeth that were still developing. The weighted average of all the developing teeth in a given child was assigned as the dental age for that individual. This was compared to the gold standard of chronological age. Three thousand six hundred sixty-two radiographs comprised the reference sample. The mean difference between the chronological age and dental age estimated for the sample of female subjects was 0.12 years (1.44 months) and for the males was 0.33 years (3.96 months). A method comparison technique was used to evaluate the difference between the chronological age and estimated dental age for each study subject. This showed a good agreement for both females and males. DAA using meta-analysis provides a simple method of estimating the age of subjects of unknown birth date at the 10-year threshold. This is, presently, the most accurate method of age assessment for individuals of unknown date of birth.

Dental and skeletal growth in early fossil hominins.

Early fossil hominins have often been assigned a chronological age on the basis of modern human data for tooth eruption. Better data and more sophisticated methods are now available to estimate their chronological age from modern human standards for stages of mineralization of individual teeth developing within the jaws. However, while comparisons with modern human dentitions are interesting, they can also be misleading as early hominin teeth and dentitions did not grow like modern human teeth. Chronological age can also be estimated using the microanatomy of tooth enamel and root dentine. Counts of incremental markings in enamel predict much younger ages at death for early fossil hominins than those based on modern human radiographic standards of dental development. Comparative evidence from the skeleton suggests that a greater proportion of adult body mass and stature was achieved earlier in the growth period of fossil hominins than it is in modern humans. The combined skeleto-dental evidence provides the basis for a hypothesis that the earliest hominins grew more like modern great apes, but that Homo erectus had a slightly more prolonged period of growth, and which was still not totally modern human-like in its pattern or timing.

Dental age assessment (DAA): reference data for British caucasians at the 16 year threshold.

UNLABELLED: The purpose of this study was to determine reference data for dental age assessment (DAA) for the 16 year threshold in British caucasians. PATIENTS, MATERIALS AND METHODS: One thousand seven hundred and twenty-two Dental Panoramic Radiographs of individuals aged between 4 and 24 years were re-used to establish reference intervals using the tooth development stages (TDSs) previously described [A. Demirjian, H. Goldstein, J.M. Tanner, A new system of dental age, assessment, Human Biology 45 (1973) 221-227]. All teeth present in the left maxilla and mandible, and the third permanent molars were assessed. In addition, to test the accuracy of DAA, the radiographs of a study sample of 50 children of known chronological age (CA) were assessed in the same manner as the reference population. These were aged between 15 and 17 years and separate from the database. For each subject in the study sample a new method of mathematical manipulation based on meta-analysis was applied to all teeth that were still developing [G.J. Roberts, S. Parekh, A. Petrie, V.S. Lucas, Dental age assessment (DAA): a simple method for children and emerging adults, British Dental Journal 204(4) (2008) 192-193]. The estimated calculated average of all the teeth present on the radiograph of each individual generated by the meta-analysis was assigned to each individual as the dental age. For each test subject this was then compared to the gold standard of chronological age. RESULTS: The average difference between dental age and chronological age for individuals in the test sample was 0.27 years (3.24 months) in females and 0.23 years (2.76 months) in males. CONCLUSION: Dental age assessment obtained by calculation of tooth development stages using meta-analysis provides estimates of age around the 16 year threshold.

Prevalence, intensity and nature of bacteraemia after toothbrushing.

OBJECTIVE: To estimate the prevalence, intensity and microbial identity of bacteraemia associated with toothbrushing. METHODS: A total of 141 children and adolescents, aged between 3 and 17 years, having dental treatment under general anaesthesia at the Eastman Dental Hospital were recruited. Six millilitre of blood was taken before toothbrushing (baseline) with (1) Oral B 30 toothbrush or (2) Braun or (3) Sonicare electric toothbrush or (4) dental handpiece and rubber cup. A second 6-ml sample was taken 30s after toothbrushing. All blood samples were processed using lysis filtration and bacteria were identified to species level. RESULTS: There was a significantly greater prevalence of bacteraemia following the dental handpiece only (p=0.02). There was a significantly greater aerobic and anaerobic intensity of bacteraemia following brushing with both the Sonicare (p=0.03 and p=0.05) and the dental handpiece (p=0.001 and p=0.005). CONCLUSIONS: Toothbrushing causes a bacteraemia that is often statistically significantly greater than baseline. Toothbrushing is an important contributory factor in cumulative dental bacteraemia.