Method Of Age Determination Research Articles

Evaluation of tooth coronal index bicervical diameter in mesiodistal direction & modified kvaals method for age and gender determination using digital panoramic radiographs: A retrospective study

Adequate Fluid and electrolyte balance in trauma patients is a task with complex decisions that are often complicated by coagulopathy and blood loss. An adequate volume of blood in the circulation is essential to maintain cerebral perfusion and vital function of the heart, kidneys, lungs, and other organs. Acute blood loss has been identified as one of the major causes of preventable deaths on arrival at hospital. The aim of fluid resuscitation should be to restore critical organ perfusion. This review discusses the availability of various options of Intravenous fluids and their co-relation with body’s demand in fluid management of trauma patients.

Applicability of the Greulich-Pyle Method in Assessing the Skeletal Maturity of Children in the Eastern Utter Pradesh (UP) Region: A Pilot Study.

BackgroundIn forensic proficiency, the distinct model applied for age estimation includes physical examination, i.e., evaluation of somatic maturity and post pubescence peculiarities, dental development, and radiological assessment of skeletal maturity usually of the hand and wrist. The Greulich and Pyle (GP) method of skeletal age (SA) determination is considered quicker and easier with a lower error percentage of prediction. The specificity and applicability of the GP atlas have been recapitulated in many studies. This study aims to assess the applicability and reproducibility of the GP atlas on a sample of the eastern Utter Pradesh (UP) population.ResultsConsidering the whole study population, the SA of the male subjects was retarded by 0.89 years or 9.03 months, whereas the SA of females were retarded by 0.36 years or 4.33 months than the chronological age, respectively.ConclusionAccording to this study, it is concluded that the GP atlas may not be applicable for both males and females in the eastern Uttar Pradesh region. The factors responsible for delayed skeletal growth and maturation may vary depending on demographics, ethnicity, and genetics. Further, a detailed study will be conclusive on a greater population size assessing more accurate and precise insights on the applicability and reproducibility of GP atlas.

Research Progress of Adult Age Determination with Imaging Methods

Adult age determination plays an important role in individual identification, criminal investigation and social welfare. The most popular adult age determination indicators are pubic symphysis, iliac auricular surface, costal cartilage, cranial sutures, teeth, laryngeal cartilage, etc. In recent years, with the progress of CT imaging and 3D reconstruction technology, the adult age determination study gradually has transferred from a time-consuming general observation of bones with complex pre-processing in the past to the non-destructive, convenient, time-saving and easy to store image analysis technology. To explore more accurate, rapid and convenient adult age determination methods, multiple imaging methods and artificial intelligence have been applied in adult age determination. This paper reviews the common methods and research progress of adult age determination at home and abroad, infers the development direction of adult age determination, in order to provide reference for the improvement and optimization of forensic adult age determination.

A systematic ageing method I: H ii regions D118 and D119 in NGC 300

ABSTRACT Accurately determining the age of H ii regions and the stars they host is as important as it is challenging. Historically, the most popular method has been isochrone fitting to Hertzsprung–Russell diagrams or colour–magnitude diagrams. Here, we introduce a different method for age determination using BPASS (Binary Population and Spectral Synthesis) and hoki . We infer the most likely ages of the regions D118 and D119 NGC 300 to be log(age/yr) = $6.86^{+0.05}_{-0.06}$ and we also deduce stellar mass and number counts by comparison with the BPASS models. We compare how our binary and single-star models perform and find that the latter are unable to predict 20 per cent (±10 per cent) of our sample. We also discuss how results obtained from isochrone fitting would differ. We conclude that ages could be underestimated by ∼0.2 dex and that the limitations of the isochrone method is not solely due to the lack of binary stars. We propose that the method presented here is more reliable and more widely applicable since it can be used on smaller samples. Alongside this study, we release new hoki features to allow easy implementation of this method.

Struggling with age: Common sawsharks (Pristiophorus cirratus) defy age determination using a range of traditional methods

Populations of sharks are declining globally, largely due to fishing pressure. There is a lack of fisheries-independent data on the demographics of many species, particularly those inhabiting deeper waters. The common sawshark (Pristiophorus cirratus) is a benthic-associated shark endemic to southeastern Australia that has been fished for over 90 years. Despite regular landings, little is known about their lifespan. To assess the age of P. cirratus, we first assessed their vertebral morphology to determine the best method for band pair elucidation. Based on morphology, vertebrae located in the post-branchial region were identified as the largest and least variable for band pair analysis. A total of eight different age-determination methods were then applied to shark vertebrae from this region to test the viability of traditional and nontraditional techniques in elucidating band pairs. Band pairs were indeterminable across all treatments. This research calls for further work into age validation and development of novel techniques to accurately age sawsharks.

Knee Bone Age using MRI: Validation of a Novel Method to Reduce Hand Bone Age Radiographs

Objectives:Determining bone age in skeletally immature patients is critical for proper management and surgical planning. Pennock et al. recently created and validated a bone age atlas using the ossification pattern of the knee on MRI in pediatric patients, obfuscating the need for a hand radiograph and its associated cost, radiation exposure, and clinical inefficiency. This aim of this study was to create and validate a shorthand method of bone age determination using knee MRI.Methods:We identified patients who underwent both knee MRI and hand bone age radiograph within a ninety-day period. From the findings of Pennock et al., a stepwise algorithm for predicting bone age on knee MRI was developed for males and females separately, in collaboration with a pediatric musculoskeletal radiologist. Six raters at varying levels of training used the algorithm to assign a bone age to each knee MRI. Intraclass correlation coefficient (ICC) was used to compare each rater’s predicted knee bone age to the Greulich and Pyle (G&P) hand bone age and validate the shorthand algorithm. Inter- (two-way random, absolute agreement) and intra-rater (two-way mixed, absolute agreement ) reliability were also calculated using ICC.Results:Thirty-eight patients (44.7% females) underwent a knee MRI at a mean age of 12.8 years (range 9.3-15.7). The mean time between hand bone age x-ray and knee MRI was 20.2 days (range 0-88). The inter-rater reliability for the application of our shorthand algorithm was 0.81 (95% CI: 0.72 – 0.88), indicating good inter-observer agreement. The shorthand algorithm was also shown to be a reliable predictor of hand bone age across level of training, as medical students (ICC 0.77, 95% CI 0.60-0.88), residents (ICC 0.80, 95% CI 0.65-0.89), and attending physicians (ICC 0.80, 95% CI 0.63-0.89) all achieved strong correlation between predicted knee bone age and G&P hand bone age. All respondents also demonstrated consistency, with intra-rater ICCs between 0.85-0.93.Conclusion:This shorthand algorithm is a consistent, reliable and valid way to determine skeletal maturity using knee MRI in patients aged 10 to 15 and can be utilized across different levels of orthopaedic and radiographic expertise. We believe this method is readily applicable in a clinical setting and may reduce the need for routine hand bone age radiographs.Figure 1.Table 1.Correlation between knee MRI bone age and hand radiograph bone age (G&P) for each rater, as determined using intraclass correlation coefficients (ICC). Note: Intra-rater reliability has not been competed for “Resident 2” at this time. Validity of MRI Knee Bone Age and Hand Bone Age Intra-Rater Reliability Rater ICC 95% CI ICC 95% CI Student 10.750.57-0.860.930.79-0.97Student 20.730.53-0.860.930.87-0.97Resident 10.730.54-0.850.850.73-0.92Resident 20.780.60-0.88--Attending 10.740.54-0.850.860.70-0.93Attending 20.800.63-0.890.860.72-0.93

Age determination using Nolla’s Method- A Radiographic Study

Background: Tooth development shows less variability in relation to chronological age. Tooth development is widely used to assess maturity and predict age. So, dental tissues can be used as a better aid for estimating age. Radiography plays an important role in humane age determination. There are five common methods to determine age using radiographs: Gleiser and Hunt (1955); Demijiran et al (1973); Gustafson and Koch (1974); Harris and Nortje (1984); Kullman et al (1992). Nolla’s method (1960) was one of the various method used in age determination using radiographs. The aim is to estimate the age using Nolla’s method of forensic age estimation. Materials and Method:The present study was conducted on 20 selected individuals(10 males and 10 females) between age 9-17. Dental age assessment was done using OPG. The radiograph were compared with the Nolla’s chart (fig-1) and dental age was assessed using age norms for upper and lower teeth including third molars proposed by Nolla. The chronological age and dental age obtained using Nolla’s method was later subjected to statistical analysis. Results: There is no significant difference between chronological age and estimated age with Nolla’s method both in males and females i;e is ‘p’ value is not significant in both males and females (.161 in females and .757 in males). Conclusion: Nolla’s method of age determination was accurate in both males and females.No statistical significance was found between chronological age and estimated age for males and females. Hence Nolla’s method can also be used in forensic dentistry.

Establishment of age determination method and their resource biology research for Pacific saury, <i>Cololabis saira</i>

Establishment of age determination method and their resource biology research for Pacific saury, <i>Cololabis saira</i>

Conserved in-ovo cranial ossification sequences of extant saurians allow estimation of embryonic dinosaur developmental stages

Dinosaur embryos are among the rarest of fossils, yet they provide a unique window into the palaeobiology of these animals. Estimating the developmental stage of dinosaur embryos is hindered by the lack of a quantitative method for age determination, by the scarcity of material, and by the difficulty in visualizing that material. Here we present the results of a broad inquiry, using 3D reconstructions from X-ray computed tomography data, into cranial ossification sequences in extant saurian taxa and in well-preserved embryos of the early branching sauropodomorph dinosaur Massospondylus carinatus. Our findings support deep-time conservation of cranial ossification sequences in saurians including dinosaurs, allowing us to develop a new method for estimating the relative developmental percentage of embryos from that clade. We also observe null-generation teeth in the Massospondylus carinatus embryos which get resorbed or shed before hatching, similar to those of geckos. These lines of evidence allow us to confidently estimate that the Massospondylus carinatus embryos are only approximately 60% through their incubation period, much younger than previously hypothesized. The overall consistency of our results with those of living saurians indicates that they can be generalized to other extinct members of that lineage, and therefore our method provides an independent means of assessing the developmental stage of extinct, in-ovo saurians.

MRI KNEE BONE AGE: A NOVEL SHORTHAND APPROACH TO REDUCE BONE AGE RADIOGRAPHS IN CHILDREN

Background:Determining bone age in skeletally immature patients is critical for proper management and surgical planning. Pennock et al. recently created and validated a bone age atlas using the ossification pattern of the knee on MRI in pediatric patients, obfuscating the need for a hand radiograph and its associated cost, radiation exposure, and clinical inefficiency.Hypothesis/Purpose:We sought to validate and demonstrate reliability of a novel shorthand method of bone age determination using knee MRI across multiple levels of medical training.Methods:We identified patients who underwent knee MRI and hand bone age radiograph within a ninety-day period. In collaboration with a pediatric musculoskeletal radiologist, stepwise algorithms for predicting bone age on knee MRI were developed- one for males and one for females. Six raters at varying levels of training used the algorithm to assign a bone age for each patient. Intraclass correlation coefficient (ICC) was used to compare each rater’s predicted knee bone age to the Greulich and Pyle (G&P) hand bone age and validate the shorthand algorithm. Inter-rater reliability was also calculated using ICC.Results:Thirty-eight patients (44.7% female) underwent a knee MRI at a mean age of 12.8 years (range 9.3-15.7). The mean time between hand bone age x-ray and knee MRI was 20.2 days (range 0-88). The inter-rater reliability for the application of our shorthand algorithm was 0.81 (95% CI: 0.72 – 0.88), indicating good inter-observer agreement. The shorthand methos was shown to be a good predictor of G&P hand bone age, both for each individual rater (ICC range: 0.73 – 0.80) and the mean knee MRI bone age across all raters (ICC 0.81; 95% CI 0.65 – 0.90). It was also shown to be a consistent predictor of hand bone age across level of training, as medical students (ICC 0.77, 95% CI 0.60-0.88), residents (ICC 0.80, 95% CI 0.65-0.89), and attending physicians (ICC 0.80, 95% CI 0.63-0.89) all achieved strong correlation between predicted knee MRI bone age and G&P hand bone age.Conclusions:This novel shorthand algorithm is a reliable and valid way to determine skeletal maturity using knee MRI. It can be utilized clinically across different levels of radiographic and orthopaedic expertise and reduces the need for hand bone age radiographs and consequential radiation exposure in children.Figure 1.Shorthand Algorithm for Knee Bone Age Using MRI for MalesFigure 2.Shorthand Algorithm for Knee Bone Age Using MRI for FemalesTable 1.Correlation between knee MRI bone age and hand radiograph bone age (G&P) for each rater, as determined using intraclass correlation coefficients (ICC). Rater ICC 95% CI Student 10.750.57 – 0.86Student 20.730.53 – 0.86Resident 10.730.54 – 0.85Resident 20.780.60 – 0.88Attending 10.740.54 – 0.85Attending 20.800.63 – 0.89Mean0.830.68 – 0.91

Re-investigating Miocene age control and paleoenvironmental reconstructions in western Amazonia (northwestern Solimões Basin, Brazil)

The modern Amazonian rainforest has a great fascination and global significance, but our knowledge of past landscape changes is still limited due to sparse data and the lack of radiometric age constrains. Precise dating in records older than the late Pleistocene are difficult to obtain and often regionally confined, therefore biostratigraphic correlations are used to estimate depositional ages across sedimentary basins. Aiming for a better understanding of the Neogene changes in western Brazil, we studied palynology and ostracod assemblages from the Solimões Formation, a key site for paleoenvironmental models to discuss the biotic changes in Amazonia. Further, we compare the biostratigraphic information of both groups with radiometric maximum deposition ages constrained by U/Pb measurements on detrital zircon grains.Down to the depth of ~95 m, zircon populations show a maximum deposition age of 11.42 ± 0.66 Ma documenting Tortonian (late Miocene) or younger ages for the top of the Solimões Formation. Palynological biostratigraphy show the Psilatricolporites caribbiensis zone (latest Miocene–Pliocene) down to a depth of 181.8 m, where the Grimsdalea magnaclavata zone suggests a late middle Miocene to early late Miocene age. In comparison, ostracod biostratigraphy indicates the Cyprideis cyrtoma zone (late Miocene) down to 176.0 m and the Cyprideis minipunctata (late middle to late Miocene) for the bottom of the section. Thus, both biostratigraphic concepts suggest ages close to the maximum ages indicated by the detrital zircons. This comparison of the biozonations with U/Pb maximum deposition ages represents the first independent calibration of these widely used methods for age determination in the Solimões Basin.Palynological and ostracod data illustrate dynamic environments varying from fluvial settings with wetland forests and swamps to lakes and/or abandoned channels with temporary slightly saline conditions. Instead of a slow evolution of Neogene Amazonian environments, our results show migrating rivers and waterbodies surrounded by rainforest during the period recorded by the base and top of the studied core material, separated by a phase of more extensive lakes and swamps (core depth 90–120 m). Indicators for slightly elevated salinity are found until the topmost sample and thus persisted during the late Miocene.This highlights the importance of new age control to improve the regional biostratigraphic timescale and reconstructed environmental changes.

Evaluation of chronological age based on third-molar development in the Serbian population

Background/Aim. Persons identification and their age assessment is necessary in vast number of cases and there are different methods used for such purposes. Numerous studies indicate that the third molar development could play a crucial role in identifying an individual`s age. The aim of this study was to determine the possibility for estimating the chronological age based on the third molar development stages in children and young adults in the Serbian population. Methods. A total of 570 Serbian patients aged 6?27 years were included in this study. Out of the total number of subjects, there were 248 males with an average age of 12.21 ? 3.91 years, and 332 females with an average age of 12.88 ? 4.06 years. Stages of dental formation were determined on orthopantomograms by comparing with standard Demirjian radiographic appearances. Results. Third molars mineralization occured more rapidly in males than in females. Most of the persons with third molar (the stage H development according to the Demirjian method) were older than 18 years. Conclusion. ?hird molar mineralization stages determination on orthopantomograms is useful additional method for determination of chronological age in living individuals. This finding might be important for forensic studies, focusing on the determination of the legally important ages. Variability among different ethnic groups has to be taken into consideration when applying this method. It is necessary to carry out extensive surveys on a larger sample in order to determine the norms for assessing the dental and chronological age of Serbian population.

AGE DETERMINATION OF A SEDIMENT SAMPLE BY OPTICALLY STIMULATED LUMINESCENCE

Luminescence dating is an important method for age determination that is based on studying the luminescence characteristics of quartz and feldspar as the most common minerals in sediments and artifacts. The greatest advantage of this dating method is its wide dynamic range, starting from 10 years to 500000 years and its ability to be applied on many different materials and to a range of grain sizes, from fine slit to medium sand. Measurements in this paper are done on sediment samples by optically stimulated luminescence technique, including sample preparation and analysis of results.

Automatic Bone Age Determination Using Wrist MRI Based on FIFA Grading System for Athletes: A Deep Learning Approach

Background: Young athletes need to comply with fair play principles including age-specific rules for each category of matches (1). Although birth certificates are considered the main document indicating the age of players, in some regions of the world, the registration of birth is subject to variation, which makes the certificates unreliable. Therefore, FIFA has tried to use imaging methods without ionizing radiation to find out the bone age as the basis for fair play confirmation. FIFA has developed a grading system consisting of I - VI levels, which can be used in teenage athletes (2). The grading system is currently used as the standard bone age determination method in football players (3,4). All national and club matches are obliged to follow screening procedures strictly like anti-doping procedures. Objectives: The purpose of this study was to evaluate the performance of a deep learning-based automatic system that provides FIFA grades upon receiving DICOM images of the MRI study to facilitate and speed up the bone age determination. Methods: The FIFA bone age determination system consists of six grades starting from a totally unfused epiphyseal plate (Grade I) to a completely fused plate (Grade VI) where variable progressive degrees of fusion are considered the basis for Grade II to V. The protocol includes nine slices in the coronal plane with 3 mm gaps between the slices. The recommended MR sequence is T1. Since the middle image in the nine-picture dataset is considered the most informative slice containing the largest image of the distal radius, the study was done using this single slice as the basic source of grading. Then, another volumetric set of slices 4, 5, and 6 was used as the second group. A convolutional neural network was designed in four convolutional layers including pooling, ReLU, and fully connected layers (Figure 1). Next, 55 teenage football players of the national U17 team were examined using a 1.5 Siemens Avanto Machine. The studies were interpreted by an MSK radiologist member of the AFC panel of radiologists who was aware of the FIFA scoring and grading system, as the ground truth. Thirty-six cases were used for training and 19 cases for testing of the CNN. To increase the number of training images, augmentation was performed by rotating and moving the original images. Therefore, a total number of 613 images were obtained for training and 267 images for testing. Results: Images introduced to the neural network resulted in sequential layers of meaningful output (Figure 2). The final outcome of the network, as the FIFA grade of the case, was compared with the interpretation of the radiologist (Table 1). The findings indicated high accuracy of a single slice dataset while the accuracy approached 100% when the volumetric three slice sets were used. Conclusion: The findings of this research indicated that CNN could be used for automatic bone age determination and FIFA grading of wrist MRI by reasonably high accuracy.

Last deglaciation in the central Balkan Peninsula: Geochronological evidence from the Jablanica Mt. (North Macedonia)

Several studies applied numerical age determination methods to examine glacial phases of the central Balkan Peninsula. However, the resulting datasets are contradictory, meaning that further discussion is needed. This study provides 10Be cosmic ray exposure (CRE) ages of a succession of glacial landforms in the Jablanica Mt. (North Macedonia), aiming at a better understanding of Late Pleistocene glacier development in the area. On the basis of the mapped glacial landforms, six glacial stages were identified and their mean equilibrium line altitudes (ELAs) were estimated. The CRE ages of five glacial stages - from the second oldest to the youngest - were determined between 16.8+0.8/−0.5 ka and 13.0+0.4/−0.9 ka. Accordingly, the most extensive glaciation in the Jablanica Mt. occurred before ~17 ka. The average ELA of the glaciers was 1792 ± 18 m a.s.l. during the largest ice extent, and 2096 ± 18 m during the last phase of the deglaciation.Independent reconstructions of key climatic drivers of glaciological mass balance suggest that glacial re-advances during the deglaciation were associated to cool summer temperatures before ~15 ka. The last glacial stillstand apparently resulted from a modest drop in summer temperature coupled with increased winter snow accumulation. In the study area no geomorphological evidence for glacier advance after ~13+0.4/−0.9 ka could be found. On the basis of independent climate proxies we propose that the last glacier advance occurred no later than ~13 ka, and glaciers were withdrawing during the Younger Dryas when low temperatures were combined with dry winters.

Radiocarbon dating of groundwater from a PZ-2 piezometer located in the foreground of Wieliczka Salt Mine, Poland

Abstract A comparison of two methods of radiocarbon age determination of groundwater is presented. The simplest Pearson model and the “user-defined” option of the NETPATH program were considered. Both methods were used to determine the age of water from a PZ-2 piezometer that is situated in the foreground of chamber Z-32 in Wieliczka Salt Mine. Results of these calculations clearly demonstrate that 14C ages obtained by the Pearson model can be significantly overestimated in comparison with those determined by the NETPATH code. Without additional data, such as the stable isotope composition of the water, conclusions on the age of the groundwater based solely on the Pearson model may be highly inadequate.

Age determination for uranium standard samples by 231Pa/235U radiochronometer

Developing different model age determination methods of uranium sample could get more information on insight into source and suspected use in nuclear forensic investigation. A procedure for the determination of model age of uranium sample using 231Pa/235U radiochronometer was reported. The 233Pa spike used in the procedure of 231Pa–235U model age determination was separated from in-house 237Np stock solution by using two TRU resin columns and three silica gel columns and calibrated by CRM U100. Model ages of CRM U010 and IRMM-1000b were presented. The model age of IRMM-1000b using 231Pa/235U radiochronometer were older than the literature reported results by 230Th/234U radiochronometer by amounts exceeded the expanded uncertainty.

Chronostar: a novel Bayesian method for kinematic age determination. I. Derivation and application to the β Pictoris moving group

Abstract Gaia DR2 provides an unprecedented sample of stars with full 6D phase-space measurements, creating the need for a self-consistent means of discovering and characterising the phase-space overdensities known as moving groups or associations. Here we present Chronostar, a new Bayesian analysis tool that meets this need. Chronostar uses the Expectation-Maximisation algorithm to remove the circular dependency between association membership lists and fits to their phase-space distributions, making it possible to discover unknown associations within a kinematic data set. It uses forward-modelling of orbits through the Galactic potential to overcome the problem of tracing backward stars whose kinematics have significant observational errors, thereby providing reliable ages. In tests using synthetic data sets with realistic measurement errors and complex initial distributions, Chronostar successfully recovers membership assignments and kinematic ages up to ≈100 Myr. In tests on real stellar kinematic data in the phase-space vicinity of the β Pictoris Moving Group, Chronostar successfully rediscovers the association without any human intervention, identifies 15 new likely members, corroborates 43 candidate members, and returns a kinematic age of 17.8 ± 1.2 Myr. In the process we also rediscover the Tucana-Horologium Moving Group, for which we obtain a kinematic age of $36.3^{+1.3}_{-1.4}$ Myr.

Bomb Radiocarbon Age Validation of Warsaw Grouper and Snowy Grouper

Current stock assessments for both the Warsaw Grouper Hyporthodus nigritus and the Snowy Grouper H. niveatus are based on age‐structured population models determined using traditional otolith‐based aging techniques. However, recent studies using bomb radiocarbon validation have shown that many deepwater fishes live much longer than previously estimated when relying on conventional age determination methods. In this study, we conducted bomb radiocarbon age validations of Warsaw Grouper and Snowy Grouper from the Gulf of Mexico. Radiocarbon age validation supported annual growth increment formation for all Warsaw Grouper size classes and medium‐sized Snowy Grouper. Conversely, ages of larger, older Snowy Grouper were greatly underestimated due to difficulty in discriminating annuli. This bomb radiocarbon analysis validates a minimum 56‐year longevity for both Warsaw Grouper and Snowy Grouper, increasing the currently published longevities of 41 and 54 years, respectively.

Aging steller sea lions by growth layer groups in teeth

ABSTRACTAccurate age determination of individuals is crucial in estimating age structure in populations as well as age‐specific rates of reproduction and survival. We examined growth layer groups (GLGs) in the canine, incisor, and postcanine teeth of Steller sea lions (Eumetopias jubatus) to find the optimal method to determine their age using 18 known‐age animals, from data collected in Hokkaido, Japan, 1995–2011. After checking to determine if the pulp cavity was open, nearly closed, or closed, teeth were sectioned and stained. Occlusion of the canine pulp cavity occurred at older ages than with the incisor and postcanine teeth. Initially, the number of GLGs in both dentin and cementum was compared with actual ages to confirm the age determination method. Dentin GLGs appeared clearly in all of the canines, incisors, and postcanines. The number of GLGs was consistent with the actual age, with the exception of teeth with a closed pulp cavity. With respect to cementum, appearance of GLGs was rather obscure and no GLG was detectable at ages of 0 and 1 year. Thus, the number of GLGs in cementum could be assigned as age when the value 1 year was added. We examined the accuracy and precision of the tested methods using an independent reader, who did not know the actual ages. By conducting readings 3 times, we used coefficient of variation (CV) to determine precision. The most precise CV was obtained in dentin canine (6.7%). Accuracy was calculated as proportion of estimates without error. The greatest accuracy in dentin was observed in canines (0.83, n = 18), whereas that of cementum was in postcanines (0.36, n = 11). We concluded that canine dentin provided the most precise and accurate ages for Steller sea lions. Once closure of the pulp cavity in canines has occurred at the age of 15–16 years in males and 11–12 years in females, we recommend postcanine cementum be used. © 2019 The Wildlife Society.