title: Correlation between Chronological Age, Dental Age and Skeletal Age among Monozygoyic and Dizygotic Twins.
abstract: BACKGROUND
  Chronological age, dental development, height and weight measurements, sexual maturation characteristics and skeletal age are some biological indicators that have been used to identify time of growth. Many researchers have agreed that skeletal maturity is closely related to the craniofacial growth, and bones of hand and wrist are reliable parameters in assessing it. The complete hand and wrist radiograph involves 30 bones and assessment of these bones is one elaborate task. The present study is therefore, undertaken to assess the correlation between the chronological age, dental age and skeletal ages among different types of twins.
  
  
  METHODS
  The study consisted of 60 subjects (30 twins) aged 8 to 16 years, divided into group of 10 monozygotic, 10 dizygotic and 10 mixed sex twins. The sample was selected from Twin Survey- 2008 conducted by Department of Orthodontics and Dentofacial Orthopaedics, Sree Balaji Dental College and Hospital, Chennai. Their zygosity was determined by sex, blood groups and by the parent. The chronological age was measured by the date of birth given by the parents. Panoramic and hand wrist x-rays were taken. Dental age was assessed by Demerjian et al method and skeletal age by Greulich and Pyle method. The correlation among twins in dental and skeletal ages with the chronological age was assessed using Correlation Coefficient and Student's't' Test.
  
  
  RESULTS
  The obtained data was fed into the computer and statistical analysis was done for the same using the SPSS version 10.0. Statistical significance was tested at P<0.05 level. Mean and Standard Deviation, Correlation Coefficient, Student's't' Test statistical methods were employed. The result showed highly significant 'p' value as <0.001 in all the correlations except for mixed pairs. Descriptive statistics in most of the areas demonstrated a non-significant result between zygosity groups.
  
  
  CONCLUSIONS
  There is a correlation existing between the individual's chronological age, dental age and skeletal age and correlation also exists in the twin pairs of the same zygosity and among each pair but no correlation exists between different zygotic twins. How to cite this article: Gupta M, Divyashree R, Abhilash P R, Bijle M N A, Murali K V. Correlation between Chronological Age, Dental Age and Skeletal Age among Monozygoyic and Dizygotic Twins. J Int Oral Health 2013; 3(1):16-22.
authors.affiliation: Department of Orthodontics, New Horizon Dental College, Bilaspur, Chhattisgarh, India.
authors.forename: Mohit
authors.initials: M
authors.lastname: Gupta
authors.forename: R
authors.initials: R
authors.lastname: Divyashree
authors.forename: Pr
authors.initials: P
authors.lastname: Abhilash
authors.forename: Mohammed Nadeem
authors.initials: MN
authors.lastname: A Bijle
authors.forename: Kv
authors.initials: K
authors.lastname: Murali
keywords: Chronological Age; Dental Age; Skeletal Age; Twin Study