title: Age estimation based on pulp chamber volume of first molars from cone-beam computed tomography images.
abstract: OBJECTIVE
  To establish a method that can be used for human age estimation on the basis of pulp chamber volume of first molars and to identify whether the method is good enough for age estimation in real human cases.
  
  
  METHODS
  CBCT images of 373 maxillary first molars and 372 mandibular first molars were collected to establish the mathematical model from 190 female and 213 male patients whose age between 12 and 69 years old. The inclusion criteria of the first molars were: no caries, no excessive tooth wear, no dental restorations, no artifacts due to metal restorative materials present in adjacent teeth, and no pulpal calcification. All the CBCT images were acquired with a CBCT unit NewTom VG (Quantitative Radiology, Verona, Italy) and reconstructed with a voxel-size of 0.15mm. The images were subsequently exported as DICOM data sets and imported into an open source 3D image semi-automatic segmenting and voxel-counting software ITK-SNAP 2.4 for the calculation of pulp chamber volumes. A logarithmic regression analysis was conducted with age as dependent variable and pulp chamber volume as independent variables to establish a mathematical model for the human age estimation. To identify the precision and accuracy of the model for human age estimation, another 104 maxillary first molars and 103 mandibular first molars from 55 female and 57 male patients whose age between 12 and 67 years old were collected, too. Mean absolute error and root mean square error between the actual age and estimated age were used to determine the precision and accuracy of the mathematical model. The study was approved by the Institutional Review Board of Peking University School and Hospital of Stomatology.
  
  
  RESULTS
  A mathematical model was suggested for: AGE=117.691-26.442×ln (pulp chamber volume). The regression was statistically significant (p=0.000<0.01). The coefficient of determination (R(2)) was 0.564. There is a mean absolute error of 8.122 and root mean square error of 5.603 between the actual age and estimated age for all the tested teeth.
  
  
  CONCLUSIONS
  The pulp chamber volume of first molar is a useful index for the estimation of human age with reasonable precision and accuracy.
authors.affiliation: Department of Oral and Maxillofacial Radiology, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Zhi-pu
authors.initials: ZP
authors.lastname: Ge
authors.affiliation: Department of Oral and Maxillofacial Radiology, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Ruo-han
authors.initials: RH
authors.lastname: Ma
authors.affiliation: Department of Oral and Maxillofacial Radiology, Peking University School and Hospital of Stomatology, Beijing, China. Electronic address: kqgang@bjmu.edu.cn.
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Forensic Pathology and Anthropology, Institute of Forensic Sciences, Ministry of Public Security P.R.C., Beijing, China.
authors.forename: Ji-zong
authors.initials: JZ
authors.lastname: Zhang
authors.affiliation: Department of Oral and Maxillofacial Radiology, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Xu-chen
authors.initials: XC
authors.lastname: Ma
mesh_terms: D000293:Adolescent; D000328:Adult; D000366:Age Determination by Teeth / Q000379:methods*; D000368:Aged; D002648:Child; D002681:China; D054893:Cone-Beam Computed Tomography; D003782:Dental Pulp / Q000000981:diagnostic imaging*; D005260:Female; D005553:Forensic Dentistry; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D008963:Molar / Q000000981:diagnostic imaging*; D055815:Young Adult
keywords: Age estimation; Cone-beam CT; First molar; Forensic anthropology population data; Pulp chamber volume