Validity of Nolla’s Method for Age Estimation for Children in Kurdish Iraqi Population - A Retrospective Study

Context: Radiographs have an essential role in Chronological Age (CA) estimation and are being used for dental age (DA) determination. Aims: Detecting the validity of Nolla’s method (NM) for the age assessment of Kurdish Iraqi children (KIC). Methods and Material: A retrospective study was performed using orthopantomographs (OPGs) of 354 subjects aged from 4 to 13 years (178 boys and 176 girls) and their recording files. Subjects were divided into nine study groups: 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13 years old. The chronological age (CA) was subtracted from the DA to find the validity of NM; the positive results indicated the overestimation of age, whereas the negative results indicated for underestimation. The data were recorded through a digitalised system using Microsoft Excel worksheet and analysed by Statistical Package for the Social Sciences (SPSS, version 25) programme using the dependent T?test and graphical analysis. The level of P value used in this study was set at < 0.05. Results: The DA is underestimated in ages 9 to 13 in boys and girls. The highest difference in DA–CA was at the age of 9 years (?0.146 ± 0.162). Conclusions: NM for age estimation was slightly overestimated in age groups of 4, 5, 6, 7, and 8 years in boys and girls without statistically significant differences. However, this method underestimated the ages of KIC ranging from 9 to 13 years significantly.

Accuracy of Nolla Method for Age Estimation of Northern Chinese Han Children / 法医学杂志

Objective To study the accuracy of Nolla method for age estimation of Northern Chinese Han children aged between 5.00 and 14.99 years based on original transformation tables and multiple regression model. Methods A total of 2 000 orthopantomographs （OPGs） were collected from the Hospital of Stomatology, Xi'an Jiaotong University, including 1 000 males and 1 000 females. Development stage of 7 left mandibular permanent teeth （except third molars） was assessed based on Nolla method, then age estimation was conducted through transformation tables and multiple regression model, respectively. Firstly, the development stage results of 7 permanent teeth were added up and the estimated age was obtained through the original transformation tables. Secondly, 80% of the samples （80 males and 80 females in each age group） were randomly selected from 2 000 OPGs as the train set. The chronological age of the selected patients was taken as the dependent variable, while gender and the development stage results of 7 permanent teeth were taken as the independent variable to establish multiple regression model. The remaining 20% of the samples were substituted into the model as the test set, to verify the accuracy of age estimation by multiple regression model. Results Mean chronological ages of males and females were 10.03±0.09 years and 10.01±0.09 years, respectively. The age estimated by original transformation tables showed an overestimation for males （0.18 years on average） and an underestimation for females （0.02 years on average）, with mean absolute error （MAE） of 0.94 years and 0.97 years, respectively. While the results by multiple regression model showed that males were overestimated by 0.06 years on average and females were underestimated by 0.02 years on average. The MAE was 0.66 years and 0.77 years, respectively. Conclusion The Nolla method is suitable for age estimation of Northern Chinese Han children. Compared with the original transformation tables method, the multiple regression model is more accurate for age estimation.

Comparación de tres métodos odontológicos para estimación de edad dental en niños hondureños / Comparison of three dental methods for estimating dental age in Honduran children

La estimación de la edad dental reviste de vital importancia en el ámbito forense por sus amplias aplicaciones en los procesos de identificación y su aplicación para estimar la edad cronológica especialmente en personas vivas, en las que no se dispone de pruebas válidas de su fecha de nacimiento. Se compararon los métodos de Dermirjian, Moorees y Nolla para estimación de la edad dental con fines de aplicación forense, para lo cual se seleccionaron 114 radiografías panorámicas de pacientes hondureños por nacimiento, de ambos sexos (57 femeninos y 57 masculinos), con edades cronológicas entre cinco y 17 años que acudieron al Servicio de Ortodoncia del Hospital Odontológico Monseñor Agustín Hombach de la Universidad Católica de Honduras en Tegucigalpa; los pacientes se seleccionaron sin agenesias dentales en la hemiarcada inferior izquierda, ni alteraciones en el desarrollo dental; sin tratamientos de apicoformación y sin extracción prematura de primeras o terceras molares. Los estadios de maduración se asignaron de acuerdo a la metodología propuesta por Demirjian, Moorrees y Nolla. La edad cronológica se obtuvo de los expedientes, se determinó la exactitud de cada método, calculando la diferencia de las medias entre la edad cronológica y la edad dental estimada por los tres métodos mediante una prueba de Wilcoxon, debido a que la muestra no presentó una distribución normal. Morrees (0.31, DE = 1.14) y Nolla (0.1, DE = 1.23) sobreestiman la edad en el sexo femenino y la subestiman en los masculinos (0.3/-0.2, DE = 1.32/1.35), mientras que el método de Demirjian subestima la edad en ambos sexos (-0.4/-0.4, DE = 1.23/1.31). Se evidenció que en la muestra estudiada no hay diferencias entre la edad cronológica y la edad dental estimada por los métodos de Demirjian, Moorees y Nolla...(AU)

Comparación de los métodos de Nolla, Demirjian y Moorrees en la estimación de la edad dental con fines forenses / Comparison of Nolla, Demirjian and Moorrees methods for dental age calculation for forensic purposes

RESUMEN: Objetivo: El propósito de este estudio fue comparar tres métodos de estimación de la edad dental (ED) con fines forenses. Material y métodos: Se seleccionaron 512 radiografías panorámicas de sujetos de Maracaibo, estado Zulia, Venezuela, de ambos sexos (272 hembras y 240 varones), con edades cronológicas (EC) entre 6-18 años. Se asignaron los estadios de maduración propuestos por Nolla, Moorrees et al y Demirjian et al a siete dientes mandibulares permanentes del lado izquierdo, la ED fue calculada de acuerdo con la metodología de cada autor. Se obtuvo la EC en la cual se observaron los diferentes estadios de maduración, así como las diferencias de media entre la EC y la ED estimada por cada método mediante un test de Student para muestras relacionadas. Resultados: En general, las hembras alcanzaron los estadios de maduración a edades más tempranas que los varones. Se evidenció en el total de la muestra, una sobreestimación de la edad para el método de Demirjian et al (-0.14 ± 1.45), mientras que para el de Nolla y Moorrees et al se observó una subestimación, esta subestimación fue mayor para el método de Moorrees et al (2.63 ± 2.09) que para el de Nolla (0.42 ± 1.38), siendo que las diferencias encontradas entre la EC y la ED fueron estadísticamente significativas. Conclusión: Se determinó que para el total de la muestra, el método de Demirjian et al fue el más preciso.

ABSTRACT: Objective: The purpose of the present study was to compare three methods for calculation of dental age (DA) to be used for forensic purposes. Material and methods: 512 panoramic X-rays of subjects of both genders living in Maracaibo, State of Zulia, Venezuela were selected (272 females, 240 males). Selected subjects were in the 6-18 years chronological age (CA) range. Maturation stages of Nolla, Moorrees et al and Demirjian et al were assigned to seven permanent teeth of the left side, and DA was calculated according to methodology of each author. CA was obtained where different stages of maturation were observed, as well as mean difference between DA and CA as calculated with each method were obtained with a t student test for related samples. Results: In general, females reached maturation stages at earlier ages than males. The total sample revealed age over-estimation for the Demirjian method (-0.14 ± 1.45), whereas, a sub-calculation was observed for the Nolla and Moorrees et al method. This under-estimation was greater for the Moorrees at al method (2.63 ± 2.09) when compared to Nolla method (0.42 ± 1.38) and differences between DA and CA were found to be statistically significant. Conclusion: In the total studied sample, it was determined that Demirjian et al method was the most accurate.

Dental maturation assessment of Nanjing children aged 3 -16 years / 实用口腔医学杂志

[Abstract ]Objective:To estimate dental maturation norms of permanent dentition in a group of Nanjing children using Nolla's tech-nique.Methods:549 cases of panoramic radiographs (279 males and 270 females)of Nanjing children at the age range of 3 to 16 years were collected for the study.All permanent mandibular teeth on the left side (except for the third molars)were scored according to Nolla's method,and data were presented in tables and used to plot dental maturation curves for the Nanjing boys and girls.Results:Females were found to be more advanced in the degrees of dental development.Dental maturation is significantly associated with chron-ological age (for males and females:r =0.959,P <0.001 and r =0.953,P <0.001,respectively).The mathematical model of them was established,and then the fitting equation was obtained.Conclusion:The dental maturation curve and chronology of permanent dentition can provide the growth norms of permanent teeth for Nanjing children and facilitate the way for dentists to assess the growing children during diagnosis and treatment planning.

Characterization of stem cells from the pulp of unerupted third molar tooth.

Context: Dental pulp stem cells (DPSCs) are the most diagnosed type of stem cells isolated from dental tissues. Previous studies demonstrate that tissues in earlier stages of development could be better stem cell resources for tissue engineering. Aims: In this study, aiming at finding younger stem cell resources, we chose the pulp of human unerupted third molar teeth when the crown was completely formed and the roots had not begun their development, Nolla's 6 th developmental stage (N6 th ). Materials and Methods: Surgical removal of the third molar was performed by aseptic technique with minimal trauma. The tissues were digested enzymatically and the resulted single cells were cultured. Immunophenotypic characterization of the cells was done via immunocytochemistry, immunofluorescence, and flow cytometry assays. Adipogenic and osteogenic differentiation potential of these cells was examined and confirmed by histochemical staining and reverse transcription-polymerase chain reaction analysis. Statistical Analysis Used: This study is descriptive. Results: N6 th -unerupted dental pulp cultured cells expressed DPSC markers: Vimentin, CD73, CD90, CD105, CD166, CD44, CD146, and STRO-1, but did not express hematopoietic cell markers: CD14, CD34, CD45, HLA-DR and were also negative for dentin sialoprotein negative showing an undifferentiated preodontogenic state. Adipocytes differentiated from N6 th -DPSCs were positively stained with Oil-Red-O and expressed both early and late adipocyte specific genes. Formation of Alizarin-red positive condensed calcium-phosphate nodules accompanied by strong expression of two osteogenic mRNAs, exhibited osteogenic differentiation. Conclusion: Based on the results of this study, we suggest that N6 th -DMSCs are a viable choice for cryo-banking and future usage in regenerative therapies; however, more investigations are necessary before clinical application can commence.

Edad dental según los métodos Demirjian y Nolla en niños peruanos de 4 a 15 años / Dental age according to Demirjian and Nolla methods in peruvian children of 4 to 15 years old

Objetivo. Determinar qué método, Demirjian o Nolla, es más preciso en la determinación de la edad en niños peruanos de 4 a 15 años. Material y métodos. Se evaluaron 59 radiografías panorámicas, 25 del sexo masculino y 34 del femenino; se determinó la edad dental según los métodos mencionados, y posteriormente se comparó esta con la edad cronológica. Resultados. Se encontró una diferencia significativa entre la edad dental y la edad cronológica determinada con método Demirjian; la edad fue sobrestimada en 0.94 años. Con el método Nolla no se encontró una diferencia significativa entre ambas edades; la edad fue subestimada en -0.24 años. Conclusiones. El método Nolla es más preciso para estimar la edad dental, según la muestra de estudio empleada, por no haber diferencias significativas entre la edad dental y la edad cronológica.

Objective. To determine which method, Demirjian or Nolla, is more accurate in determining the age in peruvian children of 4 to 15 year old. Materials and methods. 59 panoramic radiographs were evaluated, 25 of male and 34 of female; dental age was determined according to both methods, and then compared this one with chronological age. Results. When using the Demirjian method a significant difference between dental age and chronological age was found, the age was overestimated in 0.94 years. With the Nolla method we found no significant difference between the two ages, age was underestimated -0.24 years. Conclusions. The Nolla method is more accurate to estimate the dental age, according to the study sample used, there is no significant difference between dental age and chronological age.