Eruption times of third molars in young rural Nigerians

Third molar eruption in dental panoramic radiographs as a feature for forensic age assessment - new reference data from a German population

Forensic age assessment in the living can provide legal certainty when an individual's chronological age is unknown or when age-related information is questionable. An established method involves assessing the eruption of mandibular third molars through dental panoramic radiographs (PAN). In age assessment procedures, the respective findings are compared to reference data. The objective of this study was to generate new reference data in line with the required standards for mandibular third molar eruption within a German population. For this purpose, 605 PANs from 302 females and 303 males aged 15.04 to 25.99 years were examined. The PANs were acquired between 2013 and 2020, and the development of the mandibular third molars was rated independently by two experienced examiners using the Olze et al. staging scale from 2012. In case of disagreement in the assigned ratings, a consensus was reached through arbitration. While the mean, median and minimum ages were observed to increase with each stage of mandibular third molar eruption according to the Olze method, there was considerable overlap in the distribution of age between the stages. The minimum age for stage D, which corresponds to complete tooth eruption, was 16.1 years for females and 17.1 years for males. Thus, the completion of mandibular third molar eruption was found in both sexes before reaching the age of 18. In all individuals who had at least one tooth with completed eruption and who were younger than 17.4 years of age (n = 10), mineralization of the teeth in question was not complete. Based on our findings, the feature of assessing mandibular third molar eruption in PAN cannot be relied upon for determining age of majority.

Age estimation in the living: A scoping review of population data for skeletal and dental methods

Age estimation of living individuals has become a crucial part of the forensic practice, especially due to the global increase in cross-border migration. The low rate of birth registration in many countries, hence of identification documents of migrants, especially in Africa and Asia, highlights the importance of reliable methods for age estimation of living individuals. Despite the fact that a number of skeletal and dental methods for age estimation have been developed, their main limitation is that they are based on specific reference samples and there is still no consensus among researchers on whether these methods can be applied to all populations. Though this issue remains still unsolved, population information at a glance could be useful for forensic practitioners dealing with such issues. This study aims at presenting a scoping review and mapping of the current situation concerning population data for skeletal (hand-wrist and clavicle) and dental methods (teeth eruption and third molar formation) for age estimation in the living. Two hundred studies on the rate of skeletal maturation and four hundred thirty-nine on the rate of dental maturation were found, covering the period from 1952 and 2020 for a total of ninety-eight countries. For most of the western and central African countries there are currently no data on the rate of skeletal and dental maturation. The same applies to the countries of the Middle East, as well as the eastern European countries, especially as regard the skeletal development.

Third molar impaction in the Jazan Region: Evaluation of the prevalence and clinical presentation

Objective

To provide information on the prevalence and clinical features of impacted third molar teeth in the South-Western region of Saudi Arabia.

Material and methods

In this cross-sectional study, 1200 panoramic radiographs (50% males and 50% females) were retrieved from the electronic clinical records of patients at the College of Dentistry, Jazan University from December 2014 to December 2016, and impacted third molars were evaluated. Data on clinical and radiographic presentation were analyzed.

Results

Overall, there were 291 (24.3%) patients with impacted third molars among 1200 radiographs. The distribution of impacted third molars according to the number of impacted teeth was as follows: one impaction in 121 (41.6%); two impactions in 90 (30.9%); three impactions in 42 (14.4%); and four impactions in 38 (13.1%) patients. There was a high prevalence of all impaction types among females (54.5%). Maxillary vertical angulation was most common (50%) followed by mandibular mesioangular angulation (48.3%). The depth of impaction in maxillary teeth was higher than in mandibular teeth. Pain was uncommon (4.5% of patients).

Discussion

Clinically, vertical impaction in the maxilla was present in 50% of patients because of limited posterior space, and mesioangular angulation in the mandible was present in 48% of patients because of inadequate space between the ramus and the second molar. These findings are similar to other reports. Vertical impaction of the maxillary wisdom tooth is mostly related to the discrepancy between the mesiodistal size of the tooth crown and the limited retromolar space.

Conclusion

Noiseless presentation of an impacted third molar requires raising the population’s awareness about the need for diagnosis and treatment of the problem to avoid any further complications. The study can be to guide surgical procedures. This study documented the prevalence, pattern, and clinical features of impacted third molars in South Western region of Saudi Arabia.

Dental age estimation using radiographic assessment of third molar eruption among 10-20-year-old Ugandan population

Aim

This study aimed at establishing the age for third molar eruption among Ugandans aged 10-20 years.

Materials and Methods

This was a cross-sectional study comprising 471 male and 541 female patients attending Mulago Dental Clinic. Patients' orthopantomographs were assessed for third molar eruption as described by Olze et al. Age was summarized using means/SD. Jaw and sex differences were assessed using Student's t-test.

Results

Complete eruption (Stage D) ranged between 13 and 20 years. The mean age at complete eruption for girls and boys was 17.5-18 years and 18.2-18.6 years, respectively. Mean age was statistically significantly (P < 0.05) lower among girls compared to boys for all third molar teeth (#18, #28, #38, and #48). The difference in mean eruption times between girls and boys was -0.62 (95% confidence interval: 0.2-1.0, P = 0.006). At 18 years, 40% or 41% maxillary and 52% or 53% mandibular molars were completely erupted. There were statistically significant differences in eruption between the sexes and jaws for all teeth (P < 0.05).

Conclusions

Given the fact that the percentage of erupted third molars by age 18 was found to be <50% on an average in this Ugandan population, we should reconsider the use of third molar eruption as a definitive tool for age estimation in this population.

Association between skeletal morphology and agenesis of all four third molars in Japanese orthodontic patients

The purpose of this study was to clarify differences in skeletal morphologies between male and female orthodontic patients with and without agenesis of all four third molars. A total of 64 patients (32 males and 32 females) with agenesis of all four third molars without agenesis of other teeth were selected as the third molars agenesis group (group 1). In addition, 64 patients (32 males and 32 females) with all these teeth were selected as controls (group 2). Lateral cephalograms taken between the ages of 14 and 30 years were used to compare skeletal morphology between groups 1 and 2 and between sexes. Maxillary length (P < 0.001), lower facial height (P < 0.05), gonial angle (P < 0.001) and mandibular plane angle (P < 0.001) were significantly smaller in group 1 than in group 2. Irrespective of the presence or absence of all four third molars, males had significantly smaller lower facial height (P < 0.01) and mandibular plane angle (P < 0.001) and significantly greater total mandibular length (P < 0.001), mandibular body length (P < 0.001) and mandibular ramus height (P < 0.001) than females. Japanese orthodontic patients with agenesis of all four third molars had significantly small maxillary length, lower facial height, gonial angle and mandibular plane angle.

Predictive values derived from lower wisdom teeth developmental stages on orthopantomograms to calculate the chronological age in adolescence and young adults as a prerequisite to obtain age-adjusted informed patient consent prior to elective surgical procedures in young patients with incomplete or mismatched personal data

Introduction: Surgical procedures require informed patient consent, which is mandatory prior to any procedure. These requirements apply in particular to elective surgical procedures. The communication with the patient about the procedure has to be comprehensive and based on mutual understanding. Furthermore, the informed consent has to take into account whether a patient is of legal age. As a result of large-scale migration, there are eventually patients planned for medical procedures, whose chronological age can't be assessed reliably by physical inspection alone. Age determination based on assessing wisdom tooth development stages can be used to help determining whether individuals involved in medical procedures are of legal age, i.e., responsible and accountable. At present, the assessment of wisdom tooth developmental stages barely allows a crude estimate of an individual's age. This study explores possibilities for more precise predictions of the age of individuals with emphasis on the legal age threshold of 18 years. Material and Methods: 1,900 dental orthopantomograms (female 938, male 962, age: 15-24 years), taken between the years 2000 and 2013 for diagnosis and treatment of diseases of the jaws, were evaluated. 1,895 orthopantomograms (female 935, male 960) of 1,804 patients (female 872, male 932) met the inclusion criteria. The archives of the Department of Diagnostic Radiology in Dentistry, University Medical Center Hamburg-Eppendorf, and of an oral and maxillofacial office in Rostock, Germany, were used to collect a sufficient number of radiographs. An effort was made to achieve almost equal distribution of age categories in this study group; 'age' was given on a particular day. The radiological criteria of lower third molar investigation were: presence and extension of periodontal space, alveolar bone loss, emergence of tooth, and stage of tooth mineralization (according to Demirjian). Univariate and multivariate general linear models were calculated. Using hierarchical multivariate analyses a formula was derived quantifying the development of the four parameters of wisdom tooth over time. This model took repeated measurements of the same persons into account and is only applicable when a person is assessed a second time. The second approach investigates a linear regression model in order to predict the age. In a third approach, a classification and regression tree (CART) was developed to derive cut-off values for the four parameters, resulting in a classification with estimates for sensitivity and specificity. Results: No statistically significant differences were found between parameters related to wisdom tooth localization (right or left side). In univariate analyses being of legal age was associated with consecutive stages of wisdom tooth development, the obliteration of the periodontal space, and tooth emergence, as well with alveolar bone loss; no association was found with tooth mineralization. Multivariate models without repeated measurements revealed imprecise estimates because of the unknown individual-related variability. The precision of these models is thus not very good, although it improves with advancing age. When calculating a CART-analysis and a receiver operating characteristics - area under the curve of 78% was achieved; when maximizing both specificity and sensitivity, a Youden's index of 47% was achieved (with 73% specificity and 74% sensitivity). Discussion: This study provides a basis to help determine whether a person is 18 years or older in individuals who are assumed to be between 15 and 24 years old. From repeated measurements, we found a linear effect of age on the four parameters in the individuals. However, this information can't be used for prognosis, because of the large intra-individual variability. Thus, although the development of the four parameters can be estimated over time, a direct conclusion with regard to age can't be drawn from the parameters without previous biographic information about a person. While a single parameter is of limited value for calculating the target age of 18 years, combining several findings, that can be determined on a standard radiography, may potentially be a more reliable diagnostic tool for estimating the target age in both sexes. However, a high degree of precision can't be achieved. The reason for persistent uncertainty lies in the wide chronological range of wisdom tooth development, which stretches from well below to above the 18th life year. The regression approach thus seems not optimal. Although sensitivity and specificity of the CART-model are moderately high, this model is still not reliable as a diagnostic tool. Our findings could have impact, e.g. on elective surgeries for young individuals with unknown biography. However, these results cannot replace social engagement, in particular thorough physical examination of patients and careful registration of their histories. Further studies on the use of this calculation method in different ethnic groups would be desirable.

Timing of clinical eruption of third molars in a Jordanian population

OBJECTIVES

This study aimed at providing the first standards on the timing of third molar eruption in Jordanians.

METHODS

A total of 571 healthy Jordanian adolescents and young adults aged 15-27 years (275 males and 296 females distributed into one-year age groups) were clinically examined for third molar eruption. Presence of four clinical eruption stages from crown emergence to full eruption were counted and expressed each as a frequency relative to the total of participants within a given age group. Using probit regression, median ages at each of the eruption stages were calculated for the whole sample and for both genders.

RESULTS

In the whole sample, maxillary and mandibular third molars were found to emerge at 20 and 20.6 years and to reach full eruption at 22.7 and 23.5 years respectively. At all of the four clinical eruption stages, third molars of males and lower jaw slightly preceded those of females and upper jaw respectively. However, none of the differences were statistically significant.

CONCLUSIONS

The first data on the timing of clinical eruption of third molars in a Jordanian population have been provided to be utilized in various clinical and research fields of orthodontics, dental pathology, oral surgery, paleodontology, forensic dentistry and police sciences. As the clinical duration of third molar eruption ranges from 20 to 24 years, the responsibility for providing care of third molar eruption problems is shifted from secondary schools to tertiary education, governmental and private work bodies.

Timing of human mandibular third molar formation

BACKGROUND

Population differences in tooth formation using radiographs can be determined if the entire developmental sequence of a single tooth is studied. The only developing tooth visible radiographically from initiation to root completion is the third molar or wisdom tooth.

AIM

The timing of mandibular third molar formation was documented for two groups of children in England and two in South Africa.

SUBJECTS AND METHODS

Panoramic radiographs of White and Bangladeshi children from London and Black African and Cape Coloured children from South Africa were examined (age 5-24). Mean age of entering third molar stages (crypt appearance to root completion) was calculated using logistic regression and compared between sex and group using a t-test.

RESULTS

Average age of third molar stages was significantly (p < 0.001) later in three groups for almost all stages of the third molar compared to Black children. The average age of entering initial mineralization ranged from 7.97 to 9.74 years while average age of apex closed was 19.27-20.88.

CONCLUSION

These results show for the first time a significant difference in the timing of maturation of the mandibular third molar between groups with South African Black children being earlier than other groups.

Studies of the Chronological Course of Wisdom Tooth Eruption in a Black African Population

The importance of forensic age estimation in living subjects has grown over the last few years. In dental age estimation, tooth eruption is a parameter of developmental morphology that can be analyzed by either clinical examination or by evaluation of dental X-rays. In the present study, we determined the stage of wisdom tooth eruption in 410 male and 106 female Black South African subjects of known age (12-26 years) based on radiological evidence from 516 conventional orthopantomograms. Four eruption stages were determined (no emergence, alveolar emergence, gingival emergence, complete emergence). Statistical scores were determined for the individual stages separately for both sexes. The data presented here can be utilized for forensic estimation of the minimum and most probable ages of investigated persons.

Mineralization of the mandibular third molar: A study of American blacks and whites

The tempo of tooth mineralization is under significant genetic control, and the orderly progression of morphological changes-in concert with the long span during growth in which teeth form-makes "dental age" a useful measure of a person's degree of biological maturity. The third molar is of particular interest because (1) it is the last and most variable tooth to form and (2) it is the only tooth to complete formation after puberty, which has made it attractive in forensic and legal circles as an estimator of adulthood. Age standards are described here for mandibular third molar formation stages in a cross-sectional sample of 4,010 persons (age range: 3-25 years), with proportionate sample sizes of American blacks and whites and males and females. Formation was scored against the 15-grade ordinal scheme of Moorrees, and descriptive statistics were computed using proportional hazards survival analysis. Blacks achieved each formation stage significantly ahead of whites, but not in a uniform manner. Instead, there was an enhanced advancement in blacks during crown formation and during late stages of root formation. In both races formation proceeded faster in males, which is unique for the third molar, as prior studies suggest. Sample variance increases with the stage of formation, such that 95% confidence limits span 8 or more years for root formation stages. Consequently, the third molar provides a rough gauge of an individual's chronological age, but the considerable variability precludes any precise estimate, particularly in late adolescence where most forensic interest has focused.

Forensic age diagnostics of living individuals in criminal proceedings

Age estimations of living individuals are increasingly important in criminal matters. If doubts arise regarding the age of a person suspected of a criminal offense, forensic age estimation is prompted by the need to ascertain whether the person concerned has reached the age of criminal responsibility and whether general criminal law in force for older juveniles or adults is to be applied. According to the recommendations of the Arbeitsgemeinschaft für Forensische Altersdiagnostik (study group for forensic age diagnostics), age estimates in criminal proceedings should be based on the general physical examination, the X-ray examination of the hand and the odontological examination by a dentist, including dental status and orthopantomogram. In order to improve diagnostic reliability, these methods should always be used in combination, ensuring that each part is performed by forensically trained and experienced experts of the relevant disciplines. In order to demonstrate that the proband has reached the age of 21, an additional X-ray examination or CT scan of the clavicles is recommended. Future research projects should assess the variation for a combination of the above methods, quantify the impact of socio-economic status and ethnicity on the examined development systems and review the suitability of non-ionizing imaging methods of age estimation.