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Dental age estimation plays an important role in the field of clinic medicine and forensic medicine. The Demirjian and Nolla methods are common scoring methods for dental age estimation but there was no research about the comparison of accuracy of these two methods in northeastern Chinese children. Hence, in this study, we compared the accuracy of these two methods to explore more suitable method for our studied population. We collected 535 orthopantomograms from northern Chinese children aged from 6 to 15 years and divided them into training dataset and testing dataset according to the ratio of 7:3. The dental age of training dataset were estimated using Demirjian and Nolla methods, respectively. The results suggested that the mean differences of these two methods were 0.24 and −0.40 years, and mean absolute difference were 0.65 and 0.59 years. Then to further improve the accuracy of dental age assessment, the new improved formulas and dental age conversion tables were established after analyzing the relationship between the sum scores based on Nolla method and chronology age in training dataset. According to the new method used in testing dataset, the minimum value of mean difference (0.00) and mean absolute difference (0.49) were obtained, which are largely smaller than that of Demirjian and Nolla methods. The new developed method and dental age conversion scales may be more suitable dental age estimation method for northeastern Chinese children. We collected 535 orthopantomograms from northern Chinese children aged from 6 to 15 years and divided them into training dataset and testing dataset according to the ratio of 7:3. The mean differences of Demirjian and Nolla methods in training dataset were 0.24 and −0.40 years, and mean absolute difference were 0.65 and 0.59 years. The new improved formulas and dental age conversion tables were established after analyzing the relationship between the sum score based on Nolla method and chronology age in training dataset. According to the new method used in testing dataset, the minimum value of mean difference (0.00) and mean absolute difference (0.49) were obtained, which are largely smaller than that of Demirjian and Nolla methods. [ABSTRACT FROM AUTHOR]

Feto-fetal transfusion syndrome (FFTS) severely affects monochorionic (MC) multiple pregnancies and affects 1 in 1600 pregnancies overall. The number of increasing disputed obstetrics cases in China is related to unavailability of prompt diagnosis of FFTS. We present here a woman with a MC triplet pregnancy with intrauterine fetal death at 33 weeks of gestation due to FFTS. Subsequent pathological anatomy showed that the MC placenta contained vascular anastomoses, including arterio-arterial anastomosis and arterio-venous anastomosis. These anastomoses led to unidirectional blood flow with the absence of adequate compensatory counter-transfusion and bi-directional flow. When encountering such challenging conditions, medical practitioners should discreetly compare the fetuses’ characteristics with features of placental blood vessels and consult morphological and pathological findings. Furthermore, they should perform ultrasound examinations, particularly focussing on fetal size differences and the maximum vertical pocket in the diagnosis of FFTS, especially in MC multiple pregnancies with abdominal symptoms. [ABSTRACT FROM PUBLISHER]

Dental age estimation plays an important role in the field of clinic medicine and forensic medicine. The Demirjian and Nolla methods are common scoring methods for dental age estimation but there was no research about the comparison of accuracy of these two methods in northeastern Chinese children. Hence, in this study, we compared the accuracy of these two methods to explore more suitable method for our studied population. We collected 535 orthopantomograms from northern Chinese children aged from 6 to 15 years and divided them into training dataset and testing dataset according to the ratio of 7:3. The dental age of training dataset were estimated using Demirjian and Nolla methods, respectively. The results suggested that the mean differences of these two methods were 0.24 and -0.40 years, and mean absolute difference were 0.65 and 0.59 years. Then to further improve the accuracy of dental age assessment, the new improved formulas and dental age conversion tables were established after analyzing the relationship between the sum scores based on Nolla method and chronology age in training dataset. According to the new method used in testing dataset, the minimum value of mean difference (0.00) and mean absolute difference (0.49) were obtained, which are largely smaller than that of Demirjian and Nolla methods. The new developed method and dental age conversion scales may be more suitable dental age estimation method for northeastern Chinese children., Competing Interests: No potential conflict of interest was reported by the authors., (© 2023 The Author(s). Published by Taylor & Francis Group on behalf of the Academy of Forensic Science.)