The aims of this study will be:

1. To investigate the relationships between mandibular second molar calcification stages and skeletal maturity in Egyptian population, and
2. To evaluate whether the mandibular second molar calcification stages can be used as a reliable diagnostic tool to assess skeletal maturity in Egyptian population.

This cross-sectional study will include 106 Egyptian subjects with age range between 9 and 18 years old, who will present to outpatient clinic of Orthodontic department, Faculty of Dentistry, Cairo University, and will be classified according to their gender into two groups (males and females). Radiographs (panorama and cephalogram) will be collected from all study participants who meet inclusion criteria for data analysis. The inclusion criteria will be as follows:

• Chronological age ranging from 9 to 18 years
• No serious illness
• Normal overall growth and development
• Absence of abnormal dental conditions, such as impaction, transposition, and congenitally missing teeth
• Absence of previous history of trauma or disease to the face and neck
• Absence of orthodontic treatment
• No permanent teeth extracted

We will obtain panoramic and lateral cephalometric radiographs of 106 Egyptian subjects from the pretreatment records of patients attending clinics for orthodontic treatment.

All radiographic assessments will be performed in a darkened room. Any radiograph that shows motion dullness or has poor contrast will be discarded. A single radiologist will expose and develop all radiographs.

Inclusion Criteria:

• • Chronological age ranging from 9 to 18 years

  • No serious illness
  • Normal overall growth and development
  • Absence of abnormal dental conditions, such as impaction, transposition, and congenitally missing teeth
  • Absence of previous history of trauma or disease to the face and neck
  • Absence of orthodontic treatment
  • No permanent teeth extracted

Exclusion Criteria:

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212 Egyptian subjects with their age ranging between 9 and 18 years old, who will present to outpatient clinic of Orthodontic department, Faculty of Dentistry, Cairo University.