Legal Med Research Articles

The influence of biological relatedness on sexual dimorphism and sex classification based on external morphology of the frontal bone.

The most significant sexual differences in the human skull are located in the upper third of the face (the frontal bone), which is a useful research object, mainly in combination with virtual anthropology methods. However, the influence of biological relatedness on sexual dimorphism and frontal bone variability remains unknown. This study was directed at sexual difference description and sex classification using the form and shape of the external surface of the frontal bones from a genealogically documented Central European osteological sample (nineteenth to twentieth centuries). The study sample consisted of 47 cranial CT images of the adult members of several branches of one family group over 4 generations. Three-dimensional virtual models of the frontal bones were analyzed using geometric morphometrics and multidimensional statistics. Almost the entire external frontal surface was significantly different between males and females, especially in form. Significant differences were also found between this related sample and an unrelated one. Sex estimation of the biologically related individuals was performed using the classification models developed on a sample of unrelated individuals from the recent Czech population (Čechová et al. in Int J Legal Med 133: 1285 1294, 2019), with a result of 74.46% and 63.83% in form and shape, respectively. Failure of this classifier was caused by the existence of typical traits found in the biologically related sample different from the usual manifestation of sexual dimorphism. This can be explained as due to the increased degree of similarity and the reduction of variability in biologically related individuals. The results show the importance of testing previously published methods on genealogical data.

THE PRESENCE OF FLUIDS IN THE PARANASAL SINUSES MIGHT COMPLEMENT OTHER POST-MORTEM DIAGNOSTIC METHODS TO CONFIRM OR REFUTE DROWNING AS THE CAUSE OF DEATH

da Trindade RQ, Vieira MG, Vieira RB, Vicentin-Junior CA, Damascena NP, Santiago BM, Martins-Filho PR, Machado CE. The role of paranasal sinus fluid in determining drowning as the cause of death: a systematic review and meta-analysis. J forensic Leg Med. 2023;12:102591. No funding was received for this review. Systematic review (SR) with meta-analysis (MA) of data.

The Influence of the Oral Microbiome on Oral Cancer: A Literature Review and a New Approach.

In our recent article (Smędra et al.: Oral form of auto-brewery syndrome. J Forensic Leg Med. 2022; 87: 102333), we showed that alcohol production can occur in the oral cavity (oral auto-brewery syndrome) due to a disruption in the microbiota (dysbiosis). An intermediate step on the path leading to the formation of alcohol is acetaldehyde. Typically, acetic aldehyde is transformed into acetate particles inside the human body via acetaldehyde dehydrogenase. Unfortunately, acetaldehyde dehydrogenase activity is low in the oral cavity, and acetaldehyde remains there for a long time. Since acetaldehyde is a recognised risk factor for squamous cell carcinoma arising from the oral cavity, we decided to analyse the relationship linking the oral microbiome, alcohol, and oral cancer using the narrative review method, based on browsing articles in the PubMed database. In conclusion, enough evidence supports the speculation that oral alcohol metabolism must be assessed as an independent carcinogenic risk. We also hypothesise that dysbiosis and the production of acetaldehyde from non-alcoholic food and drinks should be treated as a new factor for the development of cancer.

Patient Reported Impact of Symptoms in Spinal Bulbar Muscular Atrophy (PRISM-SBMA) (S33.007)

Patient Reported Impact of Symptoms in Spinal Bulbar Muscular Atrophy (PRISM-SBMA) (S33.007)

Spinraza in Adults with Spinal Muscular Atrophy (SAS) – 14 month results (S33.010)

Spinraza in Adults with Spinal Muscular Atrophy (SAS) – 14 month results (S33.010)

The Limb Girdle Muscular Dystrophy Health Index (S7.003)

The Limb Girdle Muscular Dystrophy Health Index (S7.003)

Valbenazine Decreases Disease Burden in Patients with Chorea Associated with Huntington Disease: Patient-Reported Huntington Disease Health Index (HD-HI) Results From the KINECT-HD Trial (P2-11.012)

Valbenazine Decreases Disease Burden in Patients with Chorea Associated with Huntington Disease: Patient-Reported Huntington Disease Health Index (HD-HI) Results From the KINECT-HD Trial (P2-11.012)

Use of third molar eruption based on Gambier's criteria in assessing dental age.

The biological aspects of determining the dental age of subadults represent an important interdisciplinary scientific link with applications in criminal law and in forensic anthropology and dentistry. In criminal procedural law, it is necessary to determine the exact age of an undocumented person in view of the application of the provisions on juvenile offenders and minor victims. Chronological age can be estimated from the development of the third molars, as these are the only teeth that develop at the age of 18. The aim of this study was to verify the applicability of the Gambier method based on the eruption of the third permanent molars in the mandible and maxilla, to contribute to forensic age assessment. The analyzed group that met the criteria consisted of 811 orthopantomograms (OPGs) (339 females and 472 males) between the ages of 13 and 25years. The OPGs were retrospectively analyzed according to the method of Gambier et al. (Int J Legal Med 133:625-632, 29), which refers to the eruption stages of the third molar. Differences between eruption stages of maxillary and mandibular third molars were statistically significant in both biological sexes. Intersexual differences in mean age were significant only at stage 3 for any M3 tooth and at stage 1 for mandibular M3. There were no statistically significant differences between the left and right mandibular and maxillary third molars, respectively. Differences between mandibular and maxillary M3 were significant only for stage 1 in males on the left side and for stage 2 in both sexes and sides. The method used allowed the best classification of individuals into minor and adult groups (based on phase D-90.41% of individuals, based on the third stage of the mandibular left third molar-86.29%). Based on the results obtained, we can assume that the method cannot be used alone in the initial examination of living individuals, since all four third molars must be assessed and there are no additional findings from practice.

Anabolic-androgenic steroids: Considerations for forensic psychiatry, sports psychiatry, and the law

Anabolic-androgenic steroids: Considerations for forensic psychiatry, sports psychiatry, and the law

988 UNCLEAR SUDDEN DEATH IN THE YOUNG: DIFFERENT DISTRIBUTION AMONG THE ITALIAN REGIONS

Abstract Introduction Sudden death (SD) in the young due to cardiovascular diseases remains a focus of the public health system. It occurs unexpectedly in apparently healthy people. In addition, several of the diseases that cause sudden death in the young can be diagnosed and treated prior to the first lethal event; on the other hands, a post mortem approach, by the means of clinical autopsy and molecular autopsy, may clarify the underling disease to better develop futher prevention by a familial approach. The attention on this issue has greatly sensitized doctors and public opinion. Aim The aim of the manuscript was to evaluate the frequency of sudden deaths in Italy in the decade 2008-2017. Methods and Data sources The searches were carried out by consulting the database of the National Institute of Statistics (ISTAT). We counted in the ISTAT database all the deceased under the age of 40 due to unclear causes in the decade 2008-2017. Results We counted 7159 young patients with DS, unevenly distributed throughout the Italian territory. In detail, 10% (1373) were in the North-West, 14% (988) in the North-East, 13% (934) in the Center, 44% (3178) in the South and 10% (686) in the islands. The analysis showed how the unclear SD in Italy have decreased over time. Southern Italy had the highest number (357) of SD at the start of the observation which slightly dropped to 272 in 2017. Despite this significant reduction, the South remains the place where the largest number of unclear SD are counted. Most likely, the initial studies conducted in the Veneto region sensitized doctors to SD in young people and athletes, leading a wider screening through cardiological examination and electrocardiogram for prevention; furthermore a widespread recurrence to clinical autopsy, to reach a clear diagnosis, allows the awareness that other cases could occur in the same family. Grief coping approach and cultural competency may explain the regional difference. The new methods available to genetics, such as next generation sequency (NGS), have allowed an increase in diagnoses even in the deceased and have identified possible pathogenic genes in family members. Conclusions Sudden death in young people represents an important challenge, considering the number of events that occur in our country and the different distribution in the Italian regions. Medical community need to better address this issue, by implementing both prevention and post-mortem analysis, to reduce the sudden death burden, especially in southern region. Thiene G. Sudden cardiac death in the young: a genetic destiny? Clin Med (Lond). 2018 Apr 1;18(Suppl 2):s17-s23. Markwerth P, Bajanowski T, Tzimas I, Dettmeyer R. Sudden cardiac death-update. Int J Legal Med. 2021 Mar;135(2):483-495.Webster G, Carberry T, Berger S. Screening for prevention of sudden death in the young: what is new? Curr Opin Cardiol. 2020 Jan;35(1):80-86.

Suicide of a young woman using a kit containing sodium nitrite ordered on the internet

We report the case of a 13-year-old girl, found dead by her father, with a glass containing 15 g of white powder and a bottle containing 5 g of white powder with a moistened appearance. The autopsy was performed four days after the death. The anatomopathological study of the specimens was included in formaldehyde and prepared according to the Saffron Eosin Hematein technique. First of all, a post-mortem toxicological screening was performed on cardiac blood, peripheral blood, urine and gastric contents by high performance liquid chromatography coupled to high resolution mass spectrometry (HPLC-HRMS). Ethanol testing was performed by gas chromatography coupled to a flame ionization detector (GC-FID), and drug testing by liquid chromatography coupled to a mass spectrometer (LC-MS/MS, opiates, cocaine, amphetamine) or gas chromatography coupled to a mass spectrometer (GC-MS, cannabis). A rapid analysis of powders found near the body was carried out by RAMAN spectrometry, and confirmed by ion chromatography coupled with mass spectrometry and X-ray diffractometry. In order to establish the concentration of the substance found by those analyses in peripheral blood and gastric contents, we later used the saltzman reaction after addition of potassium ferrocyanide and zinc sulfate. External examination and autopsy revealed a non-specific asphyxia syndrome. This was confirmed by the anatomopathological study which showed signs of non-specific acute heart failure: diffuse visceral congestion (heart, lungs, spleen, liver, pancreas, kidneys, thyroid, stomach) and pulmonary haemorrhage. First of all, toxicological analyses revealed the presence of metoclopramide, in cardiac blood (0.37 mg/L), urines (0.20 mg/L), gastric contents (0.24 mg/L) and in peripheral blood at a concentration of 0.40 mg/L. However, no ethanol and presence of drugs of abuse (cannabinoids, opiates, cocaine, and amphetamines) were detected. Secondly, powders found close to the body were analysed by three different techniques, and revealed the presence of sodium nitrite in pure form. Finally, the analysis of gastric contents confirmed the presence of nitrites at a concentration of 30.9 mg/L. This analysis could not be performed on the blood samples due to colour interference. This young girl died of anoxia secondary to the ingestion of a suicide kit containing sodium nitrite. Diverted from their original use as euphoriants (poppers), nitrites are now used for suicidal purposes. Specific kits have emerged on the internet. They contain sodium nitrite, metoclopramide and antacid. NaN02 is presented in the form of a powder, similar to salt, which dissolves easily in a liquid to reconstitute a toxic drink (Durão C, J Forensic Leg Med, 2020;73:101989). The lethal dose of nitrites is estimated for an adult at 2.6 g (Hwang C, Forensic Sci Med Pathol, 2021;17(3):475–80). This dose seems variable since a fatal case is described in the literature for an ingestion of 1 g (Gowans WJ, Br J Gen Pract J R Coll Gen Pract, 1990;40(340):470–1) and one non-fatal case following ingestion of 6 g (Chui JSW, Anaesthesia, 2005;60(5):496–500). In our victim's case, metoclopramide was also detected, at a concentration of 0.40 mg/L in the peripheral blood. The metoclopramide's concentration is therapeutic between 0.05 and 0.15 mg/L and toxic from 0.2 mg/L (Schulz M, Crit Care,2012;16(4):R136). Such a concentration of metoclopramide is therefore potentially toxic and can cause extrapyramidal symptoms (tremors), drowsiness, impaired consciousness, confusion, hallucinations, even cardiorespiratory arrest (Vidal) and may have contributed to death. The alarming increase in the number of cases and the access facility to these suicide kits on the internet shows that it is essential to implement measures to regulate this substance to prevent its diversion and use.

Analysis of human insulin and its therapeutic analogs by LC-HRMS: 4 years feedback and perspectives

To prove the involvement of insulins in intoxication is challenging in postmortem cases. Two insulins assays were developed and validated, quantitatively in blood and qualitatively in tissues. The aim is to share feedback from 4 years of these methods’ application, in clinical and forensic contexts. This retrospective study focused on cases for which insulins analysis was requested in these last 4 years. The studied parameters were: context of the request, samples transfer and analysis intervals, type and concentration results. For postmortem cases, samples were collected during autopsy according to a homemade protocol consisting in cardiac and peripheral blood, liver, kidney, muscle, injection site (IS). For clinical cases, samples were serum collected during hospitalization. Assay allows detection of human insulin and analogs: aspart, glulisine, lispro, detemir, degludec, glargine and M1. Blood samples assay consisted in 3 steps: protein precipitation, filtration and immunopurification before analysis on LC-HRMS (Bottinelli. Talanta 2021:225). Steps of cutting and ultrasonication in acidic ethanol were added for tissue samples (Bottinelli. Int J Legal Med 2021;135:1813–22). Sixty-six cases were analyzed between January 2018 and March 2022: 59 were postmortem cases for which insulin use was suspected (history of diabetes, insulin material found at corpse discovery place…) and 7 were clinical cases for which insulins analysis was requested for a diagnosis of severe hypoglycemia. Treatment by insulins was known in 23 cases and 13 cases were not diabetic. A total of 10 clinical sera, 94 postmortem bloods ( n = 53 peripheral; n = 41 cardiac), 16 IS, 20 muscles, 33 livers and 33 kidneys were analyzed. At least one insulin was identified in 29 cases (43%) corresponding to 8 positive sera (80%), 10 IS (62%), 7 muscles (35%), 12 cardiac bloods (29%), 11 peripheral bloods (21%), 7 kidneys (21%), and 4 livers (12%). In 7 cases, insulin administration was characterized by analysis of tissues as blood analysis was negative. In most postmortem cases, insulins were detected when postmortem interval was less than 72 h. Moreover, 50% of samples were positive when blood is centrifuged and freeze less than 24 h after sampling. All insulins were identified at least one time, but aspart (27%) and glargine/M1 (11%) were the most represented. For aspart, postmortem blood concentrations ranged from < 1.0 ng/mL (LOQ) to 432 ng/mL (mean: 50.1 ng/mL), with the highest measured for two non-diabetic people. Insulins intoxications are underestimated as underlined by numerous authors. Since the application of the new LC-HRMS methods, numerous cases of insulins use and intoxication were revealed. Preparation of postmortem samples is the crucial point requiring several steps with specific material. The expensive and time-consuming methods lead to a non-systematic perform, but only when data from autopsy or enquiries suggest possible insulin administration. Initially not dedicated to clinical cases, methods allowed to elucidate origins of severe hypoglycemia in various situations: Münchausen, degludec spontaneous release, suicide attempt, self-medication. The major detection of aspart and glargine is consistent with the prescription trends in France. More degludec detection was expected but was limited either because it was less implicated in intoxications or due to matrix effects. Autopsy realization within 72 h after death, centrifugation/freezing of blood samples within 24 h after sampling and analyses of several matrices including blood and tissues, seem to be crucial conditions to maximize chances for highlighting presence of insulins in postmortem cases. Even if the “simple” detection of an insulin is informative in numerous cases, interpretation of concentration would be relevant. However, insulins displayed a large range concentrations as numerous parameters could have an influence such as diabetes status, type of analog, metabolism, hemolysis… Define a therapeutic or toxic range seems complex and further studies are required. This could be possible with the increase of interest for this problematic in medico-legal research teams.

Evaluation of the effect of impaction on the mineralization of mandibular third molars and forensic age estimation in a sample of south Indian children.

Assessment of third molar mineralization is a basic forensic odontological method available for age estimation in children and adolescents. Due to their protracted development into the late adolescence, their development has become the subject of interest and acquired great forensic importance. It is clearly evident in the literature that impaction factor has an influence on the rate of maturation of the third molars. In this regard, the present study was undertaken to test the relationship between impaction and its concomitant effect on the mineralization of the third molar and forensic age estimation. A total of 520 digital orthopantomograms (OPG) of 260 males and 260 females of south Indian origin were assessed retrospectively. Maturation of the third molars (I3M) was assessed using the method of Cameriere et al. (Int J Leg Med 122 (6):493-497, 2008). Impaction status was determined according to the position of lower right and left third molars in relation to the long axis of the second molars. Out of the total sample, 68.1% of lower left third molars and 71.2% of lower right molars were impacted. Statistical measures for I3M were calculated in the males and females for both impacted and non-impacted third molars. It was ascertained that the mean age and I3M values were higher in impacted third molars, indicating the slower rate of maturation than non-impacted ones. The sensitivity and specificity of the test (I3M < 0.08) was 96.2% and 72.4% for non-impacted third molars and 46.2% and 87% for impacted third molars, respectively. Our findings indicate that the cut-off value of I3M < 0.08 resulted in greater number of age misclassifications (false negatives) for impacted molars, highlighting the need for new cut-off value of I3M to meet the legal standards. It was concluded that the mineralization of impacted third molars was slower compared to non-impacted ones in south Indian males and females. Further studies are warranted to validate these findings among a larger and more diverse sample.

Forensic age estimation based on magnetic resonance imaging of the proximal humeral epiphysis in Chinese living individuals.

Forensic age estimation in living individuals is mainly based on radiological features, but direct radiography and computed tomography lead to a rise in ethical concerns due to radiation exposure. Thus, the contribution of magnetic resonance imaging (MRI) to age estimation of living individuals is a subject of ongoing research. In the current study, MRIs of shoulder were retrospectively collected from a modern Chinese Han population and data from 835 individuals (599 males and 236 females) in the age group 12 to 30years were obtained. A staging technique based on (Schmidt et al. Int J Legal Med 121(4):321-324, 2007) and (Kellinghaus et al. Int J Legal Med 124(4):321-325, 2010) was used and all images were evaluated with T1-wieghted turbo spin echo (T1-TSE) sequence and T2-weighed fat suppression (T2-FS) sequence. One-sided images were assessed because data from both sides were considered coincidental, as no significant differences were found (P > 0.05). Two MRI sequences were evaluated separately and subsequently compared. Regression models and supportive vector classification (SVC) models were established accordingly. The intraobserver and interobserver agreement levels were good. Compared with T1-TSE sequence, the R2 values of T2-FS sequence were generally higher, while the mean absolute deviation (MAD) values were slightly lower. For T2-FS sequence, the MAD value was 1.49years in males and 2.19years in females. With two MRI sequences incorporated, the SVC model obtained with 85.7% correctly classified minors and 96.2% correctly classified adults in males, while 83.3% and 98.0% respectively in females. In conclusion, T2-FS sequence may slightly outperform the T1-TSE sequence in shoulder MRI analysis for age estimation, while shoulder MRIs could be a reliable prediction indicator for the 18-year threshold and two MRI sequences incorporated are encouraged.

Pair-Matching Digital 3D Models of Temporomandibular Fragments Using Mesh-To-Mesh Value Comparison and Implications for Commingled Human Remain Assemblages.

The mesh-to-mesh value comparison (MVC) method developed by Karell et al. (Int J Legal Med 130(5):1315-1322, 2016) facilitates the digital comparison of three-dimensional mesh geometries obtained from laser-scanned or computed tomography data of osteological materials. This method has been employed with great success to pair-matching geometries of intact skeletal antimeres, that is, left and right sides. However, as is frequently the case for archaeological materials, there are few circumstances which proffer complete skeletal remains and fewer still when considering contexts of commingling. Prior to the present research, there existed a paucity of sorting techniques for the diverse taphonomic conditions of skeletal materials found within commingled assemblages, especially regarding fragmentary remains. The present chapter details a study in which the MVC method was adapted to encompass comparisons of isolated components of bone in lieu of entire bone geometries in order to address this dearth. Using post-mortem computed tomography data from 35 individuals, three-dimensional models of 70 mandibular fossae and 69 mandibular condyles were created and then compared using Viewbox 4, to produce numerical mesh-to-mesh values which indicate the geometrical and spatial relationship between any two given models. An all-to-all comparison was used to determine if the MVC method, using an automated Trimmed Iterative Closest Point (TrICP) algorithm, could be utilized to (1) match corresponding bilateral pairs of condyles and fossae and (2) match same-sided articular correlates. The pair-matching of both the condyles and the fossae generally produced high sensitivity and specificity rates. However, the articulation results were much poorer and are not currently recommended.

The Future of LTC: The Continuing Evolution of the SNF

The Future of LTC: The Continuing Evolution of the SNF

Preliminary analysis testing the accuracy of radiographic visibility of root pulp in the mandibular first molars as a maturity marker at age threshold of 18years.

Forensic age estimation, after completion of third molar mineralization, regressive features such as apposition of secondary dentin, which is seen as narrowing of the pulp space in the radiographs, can be used as an alternative. In the present study, we explored the radiographic visibility of the root pulp of mandibular first molars using stage classification of Olze et al. (Int J Legal Med 124(3):183-186, 2010) in a sample of 901 orthopantomograms (404 males and 497 females) of south Indian origin with age ranging from 14 to 22years. Descriptive statistics for the stages according to age was performed for both sexes separately. The strength and direction of the relationship between the chronological age and pulp visualization stages was tested using spearman's rho correlation statistics. The relationship between age and stage attainment showed statistical significance for both sexes. A strong, positive correlation was seen between the stage and chronological age. All males and females presenting stage 0 of root pulp visibility were younger than 18years. If stage 1 is determined, it is highly possible that an individual regardless of sex is younger than 18years. Stage 2 was attained in 79.6% males and 83.1% females who were at least 18years. One hundred percent males and 92.8% females with stage 3 were at least 18years. The accuracy of this method in mandibular first molars for estimating age threshold of 18years ranged from moderate to high. However, it is recommended to use this method in conjunction with other age estimation methods.

The suitability of Synbone® as a tissue analogue in ballistic impacts

Knowledge of material behaviour under impact is of key importance to understand ballistic impact events on tissue. Bone—with its complex underlying microstructure—is no exception; the microstructural network in bone is not only crucial to its integrity, but also provides a pathway for energy dispersion upon impact (Piekarski in J Appl Phys 41:215–225, 1970). Synbone®, a Swiss-made polyurethane bone simulant, has been considered as a potential bone analogue, particularly for cranial structures (Smith et al. in Leg Med 17(5):427–435, 2015; Riva et al. in Forensic Sci Int 294: 150–159, 2019). This study focused on long bone models and cylinders available from Synbone®, with the aim of determining their efficacy for use in ballistic testing and recreation. Comparisons were made between porcine bone and multiple Synbone® models regarding projectile energy loss and damaged surface area using high-speed video and high-resolution photography. CT and reverse ballistics techniques were also used as diagnostic tools. A significant correlation was made between real bone and Synbone®’s ballistic cylinders in all aspects of this study; however, it was observed that osteoporotic cylinders and anatomical models differ significantly in their reaction to impact. Consequently, the use of Synbone® as a ballistic target simulant—particularly when legal or practical accuracy is essential—will need to be treated carefully, giving due attention to these limitations.

Accuracy of the cutoff value of the third molar maturity index: an Egyptian study

BackgroundThis study aimed to test the sensitivity and specificity of the third molar maturity index (I3M) cutoff value to discriminate between individuals above and below 18 years of age in an Egyptian sample.Material and methodsDigital images of 247 orthopantographs (97 boys and 150 girls) were evaluated. The cutoff value of I3M obtained from the results of Cameriere et al. (Int J Legal Med 122:493–497, 2008) was evaluated in both girls and boys.ResultsSensitivity (the proportion of individuals being 18 years of age or older) was 95% and 73% in boys and girls, respectively. Meanwhile, specificity (the proportion of individuals younger than 18) was 100% in boys and 97% in girls. The proportion of correctly classified boys was 97% while it was 59% in girls.ConclusionIt can be concluded that the third molar maturity index can discriminate between individuals who are 18 years and over and those under 18 with higher accuracy in boys.

Root Pulp Visibility as a mandibular maturity marker at the 18-year threshold in the Maltese population.

The determination of age of majority (the 18-year-old threshold) using the popular Demirjian tooth staging method is unreliable, so other maturity markers are required. This study examines whether the Root Pulp Visibility (RPV) of the mandibular third molar is a useful indicator of age. One thousand six dental panoramic radiographs (DPTs) were examined and the left mandibular third molar assessed according to the RPV stages using the method of Olze et al. (Int J Legal Med 124:183-186, 2010) as modified by Lucas et al. (Forensic Sci Int 270:98-102, 2017). Six hundred sixty-two DPTs, 288 males and 374 females, satisfied the inclusion criteria. Individuals who had reached stages RPV-A and RPV-B were represented in a wide range of ages spanning the 18-year-old threshold. Individuals who had reached stages RPV-C and RPV-D were all above the 18-year-old threshold. It was not possible to analyse a large number of DPTs for various reasons. Individuals whose mandibular third molar exhibited stages RPV-C and RPV-D may be deemed to have reached the age of majority. These results are consistent with other published studies. Variation in the rate of development of the third molar limits the applicability of this method. RPV staging is an accurate method of determining the 18-year-old threshold. Substitute methods are required in a large number of cases.