hrvatski

Validation of tooth cement annulations for assessing dental age in humans

Introduction: Currently published research suggests that tooth cement annulations can be used for assessing dental age in humans. For the regular use in forensic practice the method should be properly validated. The purpose of this study was to examine the inter- and intra-rater agreement in the measurement of tooth cement annulations thickness.Materials and Methods: The study sample consisted of 82 donor teeth of both sexes of which 26 were measured 10 months apart (two episodes (2E)) and 56 were measured during the same episode (1E). Additionally, 11 (of 82) teeth were randomly selected during the second episode by the second rater. The teeth used were extracted because of periodontal disease or for orthodontic or prosthetic reasons. The excluding criterion was the presence of tooth root lesions. Donors’ age ranged from 20 to 69 years at the time of tooth extraction. Each tooth was embedded in a quick- setting autoacrylate, and the roots were cut with transverse incisions on an ISOMET 1000 cutter in the apical, middle and cervical third of the tooth’s root. The thickness of each incision ranged from 0.3 to 0.5 µm. Cement thickness measurements were made with a light microscope and an Olympus EP50 camera, Version: V3_20190202. The microscope was calibrated separately for each episode according to same specifications. The first rater was blinded for the measurements done during the first episode and measured the adjacent cuts in all three root thirds. The second rater was blinded for the measurements done by first rater. The correlation between the achieved estimated dental age, and chronological age was calculated using the Spearman correlation coefficient. Agreement between first and second episode measurements (inter-rater) was calculated using the coefficient of concordance (CC) with 95% confidence interval (CI), a for intra-rater agreement using a kappa test. Data was also presented using Bland-Altman plots. Results: Statistically significant lower agreement level of the tooth cement thickness was found for adjacent cuts when they were measured in separate episodes (intra-rater agreement) compared to the agreement of same measures done in one episode: adjacent apical cuts, CC2E=0.32 (95% CI 0-0.59) vs CC1E=0.84 (95% CI 0.75-0.90) ; adjacent middle cuts CC2E=0.38 (95% CI 0.08-0.61) vs CC1E=0.86 (95% CI 0.76-0.91) ; and adjacent cervical cuts, CC2E=0.48 (95% CI 0.27-0.65) vs CC1E=0.91 (95% CI 0.86-0.94). Almost perfect agreement was found (mean whole root cement thickness, apical and middle third, kappa >0.86 ; cervical third cement thickness, kappa=0.815) for inter-rater agreement, yielding a very small measurement error of 0.89% (95% CI -0.21 do 1.98%). Conclusion: Conducted validation of the measures of tooth cement annulations used in estimating the dental age of humans showed that there is a very high level of inter-rater agreement yielding a very small measurement error. Intra-rater agreement testing showed that the error could most probably be due to the error in microscope calibration which can be prevented by quality control measure using the measurement of standard tooth.

forensic stomatology ; age assessment ; tooth cement thickness ; transverse sections ; validation

Acknowledgments: The research was funded by the Croatian Science Foundation through the project: Tooth Analysis in Forensic and Archaeological Research, IP-2020-02-9423.

engleski

Validation of tooth cement annulations for assessing dental age in humans

Introduction: Currently published research suggests that tooth cement annulations can be used for assessing dental age in humans. For the regular use in forensic practice the method should be properly validated. The purpose of this study was to examine the inter- and intra-rater agreement in the measurement of tooth cement annulations thickness.Materials and Methods: The study sample consisted of 82 donor teeth of both sexes of which 26 were measured 10 months apart (two episodes (2E)) and 56 were measured during the same episode (1E). Additionally, 11 (of 82) teeth were randomly selected during the second episode by the second rater. The teeth used were extracted because of periodontal disease or for orthodontic or prosthetic reasons. The excluding criterion was the presence of tooth root lesions. Donors’ age ranged from 20 to 69 years at the time of tooth extraction. Each tooth was embedded in a quick- setting autoacrylate, and the roots were cut with transverse incisions on an ISOMET 1000 cutter in the apical, middle and cervical third of the tooth’s root. The thickness of each incision ranged from 0.3 to 0.5 µm. Cement thickness measurements were made with a light microscope and an Olympus EP50 camera, Version: V3_20190202. The microscope was calibrated separately for each episode according to same specifications. The first rater was blinded for the measurements done during the first episode and measured the adjacent cuts in all three root thirds. The second rater was blinded for the measurements done by first rater. The correlation between the achieved estimated dental age, and chronological age was calculated using the Spearman correlation coefficient. Agreement between first and second episode measurements (inter-rater) was calculated using the coefficient of concordance (CC) with 95% confidence interval (CI), a for intra-rater agreement using a kappa test. Data was also presented using Bland-Altman plots. Results: Statistically significant lower agreement level of the tooth cement thickness was found for adjacent cuts when they were measured in separate episodes (intra-rater agreement) compared to the agreement of same measures done in one episode: adjacent apical cuts, CC2E=0.32 (95% CI 0-0.59) vs CC1E=0.84 (95% CI 0.75-0.90) ; adjacent middle cuts CC2E=0.38 (95% CI 0.08-0.61) vs CC1E=0.86 (95% CI 0.76-0.91) ; and adjacent cervical cuts, CC2E=0.48 (95% CI 0.27-0.65) vs CC1E=0.91 (95% CI 0.86-0.94). Almost perfect agreement was found (mean whole root cement thickness, apical and middle third, kappa >0.86 ; cervical third cement thickness, kappa=0.815) for inter-rater agreement, yielding a very small measurement error of 0.89% (95% CI -0.21 do 1.98%). Conclusion: Conducted validation of the measures of tooth cement annulations used in estimating the dental age of humans showed that there is a very high level of inter-rater agreement yielding a very small measurement error. Intra-rater agreement testing showed that the error could most probably be due to the error in microscope calibration which can be prevented by quality control measure using the measurement of standard tooth.

forensic stomatology ; age assessment ; tooth cement thickness ; transverse sections ; validation

Acknowledgments: The research was funded by the Croatian Science Foundation through the project: Tooth Analysis in Forensic and Archaeological Research, IP-2020-02-9423.