Forensic Age Assessment in Finland, and Dental Development of Somalis

Assessment of an individual’s age has important applications in forensics. From developing countries, the possibility to gather reliable reference data for forensic age estimation may be difficult. The aim was 1) to analyse the validity of the Greulich and Pyle method (1959), and other skeletal and dental methods; 2) to analyse forensic age assessments of asylum seekers in Finland, and the Finnish legislation; 3) to compare a created Somali dental development model (SM) on lower left permanent teeth (PT) from 31 to 37 with the Willems et al. model (WM; 2001); and 4) to study whether the addition of information on the development of third molars (TM) with PT increases the accuracy of age assessment of young Somalis. Dental and skeletal radiographic age-assessment methods were compared using Finnish child victim data (N=47). Information on forensic age assessment was collected from Finnish legislation texts, EU statistics, and public statistics by Immigration Authorities on asylum seekers in Finland. Analysis was made of forensic age assessments in Finland in 2015. The dental development of Somalis, born and living in Finland, was analysed, staging the PT according to Demirjian et al. (1973) and TM according to Köhler et al. (1994). First, both SM and WM on PT were validated on 635 Somalis, aged 4–18 years. Secondly, the age prediction performances of PT and TM development were tested separately and combined on 803 Somalis, aged 3–23 years, using a Bayesian approach. Of the compared dental and skeletal methods, development of PT showed the smallest deviation from the chronological age. In 2015, 149 asylum seekers, originating most often from Afghanistan, Iraq, and Somalia, were assessed for age using methods authorised by the Finnish legislation. Comparing the performances of the WM and SM, small but statistically significant differences in mean error were detected: -0.07 years in males and 0.16 years in females. The approach combining PT and TM predicted the age with the highest accuracy. In conclusion, dental methods, except using only TM, override skeletal methods in accuracy. The current Finnish legislation on forensic age assessment has been successfully implemented in Finland. In age assessment, the WM performs well for Somali children. The age prediction performance improves by combining the information of PT and TM, especially in 12- to 15-year-olds, when both PT and TM are still developing.Yksilön iän arvioinnilla on tärkeitä käyttöaiheita oikeuslääketieteessä. Oikeuslääketieteellistä iän arviointia käytetään vainajien tunnistamisvarmuuden lisäämiseen, turvapaikanhakijoiden henkilöllisyyden selvittämiseen sekä henkilörekisterimuutoksiin. Tutkimusmenetelminä käytetään yleisesti hampaiston ja luuston kehitystä selvittäviä menetelmiä, jotka edellyttävät useimmiten röntgenkuvausta. Hampaisto- ja luustoikä on aina arvio kronologisesta iästä. Turvapaikanhakijat ovat useimmiten lähtöisin kehitysmaista ja niistä voi olla haastavaa saada luotettavaa vertailuaineistoa ikäarvioita varten. Tutkimuksen tavoitteena oli 1) arvioida käden ja ranteen kehityksessä yleisesti käytettyä Greulich ja Pyle -atlasmenetelmää (1959), sekä verrata muita luusto- ja hampaistomenetelmiä keskenään, 2) tutkia turvapaikanhakijoiden oikeuslääketieteellisiä ikäarvioita Suomessa ja sitä koskevaa lainsäädäntöä, 3) vertailla tutkimuksessa luotua somalien hampaistokehitysmallia Willemsin menetelmään (2001) ja 4) tutkia nuorten somalien ikäarvioiden tarkkuutta yhdistämällä seitsemän pysyvän alahampaan (hampaat 31-37) ja viisaudenhampaiden kehityksestä saatava tieto. Suomalaisten vuoden 2004 Kaakkois-Aasian tsunamikatastrofissa menehtyneiden lasten röntgenkuvat (N=47) analysoitiin käyttäen eri hampaiston ja luuston kehitysmenetelmiä. Toinen tutkimus perustui suomalaisiin lakiteksteihin, EU- ja turvapaikanhakijatilastoihin ja vuoden 2015 oikeuslääketieteellisten ikäarvioiden analyysiin. Suomessa syntyneiden ja asuvien somalien hampaiston kehitys analysoitiin tutkimalla hampaiden 31-37 sekä viisaudenhampaiden kehitystä. Kolmannen tutkimuksen aineistona oli 635 4-18 -vuotiasta ja neljännessä tutkimuksessa 803 3-23 -vuotiasta somalinuorta, joiden tarkka kronologinen ikä tiedettiin. Kun hampaiston ja luuston kehityksen menetelmiä vertailtiin, muiden pysyvien kuin viisaudenhampaiden kehitys poikkesi vähiten kronologisesta iästä. Vuonna 2015 ikätutkimuksia tehtiin 149 turvapaikanhakijalle ja he olivat lähtöisin useimmiten Afganistanista, Irakista ja Somaliasta. Ikäarviotutkimuksia koskeva lainsäädäntö on otettu Suomessa hyvin vastaan. Tutkimus osoitti, että yleisesti käytetty Willemsin menetelmä toimii hyvin somalilapsilla. Yhdistämällä tieto pysyvien ja viisaudenhampaiden kehityksestä ikäarvioiden tarkkuus paranee etenkin ikäryhmässä 12-15 vuotta, kun molempien kehitys on vielä kesken

Dental age estimation in Somali children using the Willems et al. model

AimThe aim of the current study was to retrospectively collect dental panoramic radiographs from Somali children living in Finland, to use the radiographic data to develop a new age estimation model based on the model established by Willems et al. (J Forensic Sci 46(4):893-895, 2001), and to compare the age prediction performances of the Willems et al. model (WM) and the newly developed model.Material and methodsDental panoramic radiographs from 808 healthy Somalis born in Finland were selected. The development of the seven left mandibular permanent teeth, from the central incisor to the second molar, was staged according to Demirjian et al. (Hum Biol 45(2):211-227, 1973). Radiographs with all listed permanent teeth completely developed were excluded. The studied sample consisted of 635 subjects (311 females, 324 males) ranging in age from 4 to 18years. Kappa and weighted Kappa statistics were used to quantify intra- and inter-observer agreement in stage allocation. The collected dataset was used to validate the WM, constructed on a Belgian Caucasian reference sample, and to establish a Somali-specific age estimation model (SM) based on the WM. Both models were validated and their age prediction performances quantified using mean error (ME), mean absolute error (MAE) and root mean squared error (RMSE).ResultsThe SM resulted in a slight underestimation of age when the sex groups were analysed separately or combined, with ME varying between 0.04 (standard deviation (SD) 1.01) and 0.05 (SD 1.04) years, MAE between 0.77 and 0.80years and RMSE between 1.01 and 1.04years. The WM statistically significantly underestimated the age of females, with an ME of 0.20 (SD 1.01) years (p=0.0006). For males, and for females and males combined, no statistically significant ME was observed.ConclusionThe WM and SM were similar in their age prediction performances, and the use of the WM in dental age assessment in the Somali population is justified.Peer reviewe

Forensic age assessment of asylum seekers in Finland

In Finland, forensic age assessment is strictly regulated by legislation. According to the Aliens Act (301/2004) and the amendment of the Act (549/2010), the police authorities, the frontier guard authorities, and the immigration authorities have the right to refer asylum seekers to the University of Helsinki, Department of Forensic Medicine, for age assessment. These assessments are especially performed to solve if the person is of major age, the cutoff being 18 completed years. The forensic age assessment is largely based on dental development, since the special permit of the Radiation and Nuclear Safety Authority (STUK) to the Department of Forensic Medicine of the University of Helsinki, allowing the use of ionizing radiation for non-medical purposes, includes dental and hand X-rays. Forensic age assessment is always performed by two forensic odontologists. In 2015, the total number of forensic age assessment examinations was 149, and the countries of origin of the asylum seekers were most commonly Iraq, Afghanistan, and Somalia. The current legislation on forensic age assessment has been well received and approved. Radiological and other examinations can be performed in different parts of Finland, but the forensic odontologist at the University of Helsinki is always involved in the process and ensures joint quality standards for the forensic age assessment.Peer reviewe

Dental age estimation in Somali children and sub-adults combining permanent teeth and third molar development

Estimation of an individual's age has important applications in forensics. In young individuals, it often relies on separate evaluations of permanent teeth (PT) and third molars (TM) development. Here, we analysed the age prediction performance of combined information from PT and TM in an unusual sample of healthy Somalis, born and living in Finland. PT development was staged according to Demirjian et al. (Hum Biol, 1973) and TM development according to Kohler et al. (Ann Anat, 1994), using panoramic radiographs from 803 subjects (397 males, 406 females) aged 3-23years. A sex-specific Bayesian age-estimation model for the multivariate distribution of the stages conditional on age was fitted on PT, TM and PT and TM combined. The age-estimation performances were validated and quantified. The approach combining PT and TM only overestimated age with an ME of -0.031years in males and -0.011years in females, indicating the best age prediction performance.Peer reviewe

Suunterveys

Luku teoksessa: Skogberg Natalia, Mustonen Katri-Leena, Koponen Päivikki, Tiittala Paula, Lilja Eero, Ahmed Haji Omar Awa, Snellman Olli, Castaneda Anu E (toim.). Turvapaikanhakijoiden terveys ja hyvinvointi: Tutkimus Suomeen vuonna 2018 tulleista turvapaikanhakijoist

Dental age estimation in Somali children and sub-adults combining permanent teeth and third molars development

Estimation of an individual’s age has important applications in forensics. In young individuals, it often relies on separate evaluations of permanent teeth (PT) and third molars (TM) development. Here we analysed the age prediction performance of combined information from PT and TM in an unusual sample of healthy Somalis, born and living in Finland. PT development was staged according to Demirjian et al. (Hum Biol, 1973) and TM development according to Köhler et al. (Ann Anat, 1994), using panoramic radiographs from 803 subjects (397 males, 406 females) aged 3-23 years. A sex-specific Bayesian age-estimation model for the multivariate distribution of the stages conditional on age was fitted on PT, TM, and PT and TM combined. The age-estimation performances were validated and quantified. The approach combining PT and TM provided the overall best age prediction performance.status: publishe

Dental age estimation in Somali children and sub-adults combining permanent teeth and third molar development

Estimation of an individual’s age has important applications in forensics. In young individuals, it often relies on separate evaluations of permanent teeth (PT) and third molars (TM) development. Here we analysed the age prediction performance of combined information from PT and TM in an unusual sample of healthy Somalis, born and living in Finland. PT development was staged according to Demirjian et al. (Hum Biol, 1973) and TM development according to Köhler et al. (Ann Anat, 1994), using panoramic radiographs from 803 subjects (397 males, 406 females) aged 3-23 years. A sex-specific Bayesian age-estimation model for the multivariate distribution of the stages conditional on age was fitted on PT, TM, and PT and TM combined. The age-estimation performances were validated and quantified. The approach combining PT and TM only overestimated age with an ME of -0.031 years in males and -0.011 years in females, indicating the best age prediction performance.status: Published onlin

Dental age estimation in Somali children combining permanent teeth and third molars development

status: publishe

Comparison of permanent tooth development in Finnish and Somali children and subadults

status: publishe