M.Sc Thesis

M.Sc StudentKhatib Hiba
SubjectThe Effect of Radiation Dose on CBCT Measurements of
Gingival Thickness and their Correlation with
Direct Actual Measurements
DepartmentDepartment of Medicine
Supervisors CKINICAL PROFESSOR E Eli Machtei
DR. Jacob Horwitz


Objectives: 1. To measure buccal gingival thickness (GT) clinically and on CBCT cross sections. 2. To compare radiographic GT between different CBCT exposure doses. 3. To compare radiographic GT between two different CBCT scan systems. Methods: 8 fresh pig maxillae were utilized for each of two CBCT scan systems (A and B). Eight disposable dental needles were inserted into the gingival tissue of each jaw until reaching resistance from the underlying bone. A mark on each needle at its entrance point into the soft tissue was created using a permanent marker. Jaws were scanned twice, using low (L) and high (H) exposure times. The needles were extruded, and an electronic caliper was used to measure the length of the penetrated portion of the needle in mm (Cli). Radiographic gingival thickness in mm was measured on cross sectional images, produced in the 3D location of the needles (Rad). Descriptive statistics and paired 2 sample t-tests were performed. Significance was set at 5%. Results: Clin (A) 2.23mm±0.54mm; Rad H (A) 2.21mm±0.48mm; Rad L (A) 2.14mm±0.51mm. Clin (B) 2.28mm±0.54mm; Rad H(B): 2.14mm±0.50mm; Rad L (B) 2.17mm±0.49mm. t-tests between Clin (A) and Rad (A) were not statistically significant, while those between Clin (B) and Rad (B) were statistically significant, albeit not clinically of significance. t-tests between Rad (H)and Rad (L) in both systems were not statistically significant. Conclusions: Lower radiation doses do not negatively affect the accuracy of linear measurement of gingival thickness.