Sigrid I. Kvaal

Age estimation of adults from dental radiographs

Previous studies have shown that with advancing age the size of the dental pulp cavity is reduced as a result of secondary dentine deposit, so that measurements of this reduction can be used as an indicator of age. The aim of the present study was to find a method which could be used to estimate the chronological age of an adult from measurements of the size of the pulp on full mouth dental radiographs. The material consisted of periapical radiographs from 100 dental patients who had attended the clinics of the Dental Faculty in Oslo. The radiographs of six types of teeth from each jaw were measured: maxillary central and lateral incisors and second premolars, and mandibular lateral incisors, canines and first premolars. To compensate for differences in magnification and angulation on the radiographs, the following ratios were calculated: pulp/root length, pulp/tooth length, tooth/root length and pulp/root width at three different levels. Statistical analyses showed that Pearsons correlation coefficient between age and the different ratios for each type of tooth was significant, except for the ratio between tooth and root length, which was, therefore, excluded from further analysis. Principal component analyses were performed on all ratios, followed by regression analyses with age as dependent variable and the principal components as independent variables. The principal component analyses showed that only the two first of them had significant influence on age, and a good and easily calculated approximation to the first component was found to be the mean of all the ratios. A good approximation to the second principal component was found to be the difference between the mean of two width ratios and the mean of two length ratios, and these approximations of the first and second principal components were chosen as predictors in regression analyses with age as the dependent variable. The coefficient of determination (r2) for the estimation was strongest when the ratios of the six teeth were included (r2 = 0.76) and weakest when measurements from the mandibular canines alone were included (r2 = 0.56). Measurement on dental radiographs may be a non-invasive technique for estimating the age of adults, both living and dead, in forensic work and in archaeological studies, but the method ought to be tested on an independent sample.

Dental Age in Adults — A Review of Estimation Methods

Time is a wicked thing. It has no tangible substance, and yet it has an extremely solid autonomy, advancing ever so constantly. And, most wickedly, its correlation to other things is often lamentably weak. This weak interdependence between time and many other natural phenomena is the cardinal reason for the difficulties which exist in human biology in assessing the two variables historic dating of human remains and age at death. In particular the problem of age estimation has been approached by many methods developed in the last decades — which illustrates that the existing techniques were always insufficient.

Methods of measuring morphological parameters in dental radiographs: Comparison between image analysis and manual measurements

Measurements of age-related changes in dental tissues are often used when estimating the age of an individual. With the new technology now available, the methods of measurement might be standardized and reproducible. The purpose of the present study was to compare the reliability of manual and computer-assisted measurements of morphological parameters in dental radiographs. Manual measurements were made conventionally using a pair of vernier callipers and a stereomicroscope with a measuring eyepiece. An image analysis software program was employed for the computer assisted measurements. Lengths and widths of tooth and pulp were measured both manually and with computer assistance on periapical radiographs from 40 patients, six teeth in each patient. Statistical analyses showed no significant intra- or inter-observer differences for the manual measurements. Statistically significant intra- and inter-observer differences were, however, found between the manual and computer-assisted measurements. The results implied that, despite advanced technology, conventional methods may be better suited for measuring linear morphological parameters in dental tissue.

EVALUATION OF PREPARATION, STAINING AND MICROSCOPIC TECHNIQUES FOR COUNTING INCREMENTAL LINES IN CEMENTUM OF HUMAN TEETH

Apposition of cementum occurs in phases resulting in two types of layers with different optical and staining properties that can be observed by light microscopy. Narrow, dark staining incremental lines are separated by wider bands of pale staining cementum. The distance from one line to the next represents a yearly increment deposit of cementum in many mammals, and counting these lines has been used routinely to estimate the age of the animals. Incremental lines in cementum have also been observed in sections of human teeth, and the object of the present investigation was to examine a number of methods for preparing and staining them for counting. Longitudinal and transverse sections, either ground or decalcified, were cut from formalin fixed human dental roots, paraffin embedded or frozen, and stained using several techniques. The cementum was investigated using conventional light, fluorescence, polarized light, confocal laser scanning, interference contrast, phase contrast, and scanning electron microscopy. Incremental lines in the cementum could be observed in ground sections and, following decalcification, in both frozen and paraffin embedded sections. Toluidine blue, cresyl violet, hematoxylin, or periodic acid Schiff (PAS) stained incremental lines allowing differentiation by conventional light microscopy. Contrast was best using fluorescence microscopy and excitation by green light since the stained cemental bands, but not the incremental lines, fluoresced after staining with cresyl violet, PAS or hematoxylin and eosin. The results with other microscopic techniques were unsatisfactory. Since incremental lines are not destroyed by acids and stain differently than the remaining cementum, it is likely that they possess an organic structure which differs from the cementum. Incremental lines in human dental cementum could be observed best using decalcified sections stained with cresyl violet excited by green light.

Photodynamic treatment of oral lichen planus

OBJECTIVES The aim of this study was to examine the clinical behavior and response to topical methyl 5-aminolevulinate (MAL) photodynamic therapy (PDT) of oral lichen planus and to describe the buildup and biodistribution of photoactive porphyrins in normal and lichen planus-affected oral mucosa after MAL application. STUDY DESIGN The difference in clinical expression in 14 patients with buccal oral lichen planus was compared before and after treatment. MAL-induced photoactive porphyrins were monitored using noninvasive in situ fluorescence measurements. Microfluorometry was used to study the biodistribution. RESULTS The absorption and conversion of protoporphyrin IX (PpIX) in epithelial and subepithelial T cells was demonstrated in histologic sections. As a result of 1 treatment session, there was a significant improvement of oral lichen planus after 6 months (P = 0.02) and during a 4-year follow-up period. CONCLUSIONS MAL is absorbed and converted to PpIX in T cells. Oral lichen planus treated with MAL-PDT showed lasting improvement after a single treatment.

A dental study comparing age estimations of the human remains from the Swedish warship Vasa

The great Swedish warship Vasa capsized and sank in Stockholm harbour on her maiden voyage in 1628. The ship was raised from the seabed in 1961 and skeletal remains were recovered from at least 25 individuals, with teeth and jaws from 17 of them. The skeletal material was odontologically examined, including dental radiographs. Teeth lost both ante-mortem and post-mortem were recorded and variations in tooth anatomy noted. Acquired changes were recorded including enamel hypoplasia, attrition, dental caries and periodontal recession. Age estimations based on a separate odontological study, osteological changes and tooth attrition had been made in 1989. Ages were estimated additionally by three non-destructive dental methods based on (a) the length of the apical translucent zone, (b) selected measurements both on intact teeth and from ratios on dental radiographs and (c) ratios of the length and width measurements on dental radiographs from selected teeth. Several sources of post-mortem changes had been observed, among them vivianite in 33 teeth from four individuals. The results of the dental examination showed that few teeth had been lost ante-mortem, there was a low caries rate and little loss of periodontal attachments. With few exceptions, there is fairly good agreement between the different methods of estimating age. Age estimates based on dental attrition were, however, significantly different from the other dental methods and age estimates calculated from apical translucency ought to be regarded with scepticism due to post-mortem changes. The chronological ages of the victims will never be known, but age estimates based on all the age-markers available will probably reach a fairly close approximation. Copyright

Inter-examiner variation in the assessment of age-related factors in teeth.

Inter-observer variations in the registration of dental age-related characteristics have not previously been studied. Examination and registration were made by 6 dentists with varying experience in age estimation. A total of 13 age-related dental characteristics in 30 teeth extracted from adults were assessed macroscopically, by stereomicroscope and from radiographs. The measurements were analysed in a microcomputer, using the SPSS/PC+ statistical package. The results showed that, except for the score on surface roughness, significant differences were found between some of the observers for all types of measurements, when a pairedt-test analysis was made. The correlation coefficients between the observers varied and were rather weak for the surface roughness score. The study revealed systematic differences among the observers as well as differences in interpreting the definitions of the scores for the different parameters. Thus age estimation using statistical methods is seen to be dependent upon the experience of the individual observer and interpretation. Care should therefore be taken not to rely too much upon the results of an odontological age estimation. The possible implications of these results for forensic work are also discussed.ZusammenfassungSubjektiv bedingte Bewertungsunterschiede zwischen verschiedenen Untersuchern bei altersabhängigen Zahnveränderungen sind bisher noch nicht untersucht worden. Die Untersuchungen und Aufzeichnungen wurden von sechs verschiedenen Zahnärzten mit unterschiedlicher Erfahrung in der Altersbestimmung durchgeführt. Dreizehn altersabhängige Kriterien wurden an 30 extrahierten Zähnen von Erwachsenen makroskopisch, stereomikroskopisch und radiographisch untersucht. Die Meßwerte wurden mit einem Mikrocomputer unter Anwendung des Statistikprogramms SPSS/PC+ analysiert. Die Ergebnisse zeigen, daß außer für den Wert der Oberflächenrauheit, signifikante Unterschiede zwischen den Meßwerten der einzelnen Untersucher, ermittelt mit Hilfe des gekoppeltent-Tests, auftraten. Die Korrelationskoeffizienten zwischen den Ergebnissen der einzelnen Untersucher variierten und waren beim Wert der Oberflächenrauheit am geringsten. Die Studie zeigte Differenzen in der Systematik der verschiedenen Untersucher und in der Interpretation der Definitionen altersabhäginger Parameter. Somit ist die Altersbestimmung mit Hilfe statistischer Methoden stets von der Erfahrung und Interpretation einzelner Untersucher abhängig. Daher sollte der Wert einer odontologischen Altersbestimmung nicht überschätzt werden. Konsequenzen dieser Studie für die forensische Praxis werden diskutiert.

Age estimation in adults by dental imaging assessment systematic review

IMPORTANCE The need to rely on proper, simple, and accurate methods for age estimation in adults is still a world-wide issue. It has been well documented that teeth are more resistant than bones to the taphonomic processes, and that the use of methods for age estimation based on dental imaging assessment are not only less invasive than those based on osseous analysis, but also have shown similar or superior accuracy in adults. OBJECTIVES To summarise the results of some of the recently most recently cited methods for dental age estimation in adults, based on odontometric dental imaging analysis, to establish which is more accurate, accessible, and simple. EVIDENCE REVIEW A literature search from several databases was conducted from January 1995 to July 2016 with previously defined inclusion criteria. CONCLUSION Based on the findings of this review, it could be possible to suggest pulp/tooth area ratio calculation from first, upper canines and other single rooted teeth (lower premolars, upper central incisors), and a specific statistical analysis that considers the non-linear production of secondary dentine with age, as a reliable, easy, faster, and predictable method for dental age estimation in adults. The second recommended method is the pulp/tooth width-length ratio calculation. The use of specific population formulae is recommended, but to include data of individuals from different groups of population in the same analysis is not discouraged. A minimum sample size of at least 120 participants is recommended to obtain more reliable results. Methods based on volume calculation are time consuming and still need improvement.

Determining the effectiveness of adult measures of standardised age estimation on juveniles in a Western Australian population

The estimation of chronological age through assessment of dental radiographs is well-established and a useful method to assist in the identification of persons in forensic and anthropological scenarios. The objective of our investigation was twofold: (i) to validate the Kvaal et al. age-estimation method on a sample of Western Australian subjects, and (ii) to increase the range of chronological ages to which the Kvaal et al. method can be applied. Our sample size included panoramic radiographs from 74 subjects (aged 12–28 years). A set of ratios were calculated and then used to apply different statistical models of linear regression, in order to generate a final formula to estimate age. The most accurate estimations were obtained from the models generated by the mandibular canine measurement (SEE ± 3.708 years), and for the three mandibular teeth (SEE ± 3.388 years). The results indicate that inclusion of juveniles did not affect final results, and the method still produced estimates acceptable in a forensic framework.

Orthodontic Treatment: Real Risk for Dental Age Estimation in Adults?

Dental age estimation becomes a challenge once the root formation is concluded. In living adults, one dental age indicator is the formation of secondary dentine, also associated with orthodontic treatment as well as root shortening. The aim of this study was to establish whether these secondary effects of orthodontic treatment could generate a statistically significant difference in dental age estimations when using Kvaals method. The study sample included 34 pairs of pre‐ and postorthodontic panoramic radiographs, from different individuals with exactly the same age and sex distribution. Females 65%, median age 17.5 years, and males 35%, median age 22.5 years, were included. After data collection, dental age was estimated per tooth using formulae previously published. The risk of obtaining over‐estimation of age was calculated. (RR = 1.007). The changes caused by orthodontic treatment do not have any significant effect on age estimation when Kvaal et al.s method is applied on panoramic radiographs.