الفهرس 
introductlonOnly 14 pages are availabe for public view
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Abstract
A total of 118 CBCT digital records of orthodontic patients were found to fulfill the criteria of selection from the digital archive. 90 CBCT digital records were selected randomly and were grouped according to age. Each group contains 30 CBCT digital records as follows:
group A: with age from 14 years old to 18 years old.
group B: with age from 19 years old to 23 years old.
group C: with age from 24 years old to 28 years old.
Evaluation of quantitative bone characteristics of the mandibular buccal shelf of bone:
A) vestibular cementoenamel junction was identified.
B) Evaluation of buccal bone thickness. Total bone thickness = the cortical bone plus the medullary bone (mm). This measurement was taken on two horizontal reference lines apically located.
• 1st horizontal reference line at 6 mm apically from cementoenamel junction.
• 2nd horizontal reference line at 11 mm apically from cementoenamel junction.
C) Evaluation of Apico-coronal bone depth. Total depth = cortical bone plus medullary bone (mm). Cortical depth = the cortical bone alone (mm). These measurements were taken on two vertical reference lines buccally located.
• 1st vertical reference line was located at 4 mm buccal to cementoenamel junction.
• 2nd vertical reference line was located at 6 mm buccal to cementoenamel junction.
Conclusion:
• No statistically significant differences between all age groups at all the sites except at the mesial root of the Right second molar Total bone thickness at 6 mm apical to the cementoenamel junction, the mesial root of the left second
Summary and Conclusion
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molar Total bone depth at 4 mm buccal to the cementoenamel junction and the distal root of the left second molar at 6 mm buccal to the cementoenamel junction.
• Mandibular Buccal Shelf offers optimal sites for the insertion of Mini Screw Implants according to its osseous characteristics.
• The mandibular Buccal Shelf’s insertion site with the optimal anatomic characteristics is the buccal bone lateral to the second molar’s distal root, with screw insertion located 4 mm buccal to the cementoenamel junction.
• Mini Screw Implants insertion sites should always be evaluated individually because of anatomical variation among individuals.
• Pre-drilling is recommended to avoid high insertion torque, according to the mandibular Buccal Shelf’s cortical bone thickness.