Research Information System
Thesis Type: Doctorate
Institution Of The Thesis: Gazi University, Sağlık Bilimleri Enstitüsü, AĞIZ, DİŞ VE ÇENE RADYOLOJİSİ ANABİLİM DALI, Turkey
Approval Date: 2019
Thesis Language: Turkish
Student: BERRİN ÇELİK
Supervisor: Cemile Özlem Üçok
Abstract:
Changes in dimentional measurements due to malpositioning of patients are possible. This
condition leads measurement errors on the images in clinical practice. The aim of this study is to
compare the buccal and lingual bone thickness of human dry mandible with the measurements
obtained on CBCT images and to evaluate the effects of various head positioning on CBCT. We
also aimed to determine the differences between actual physical measurements and CBCT
measurements in terms of tooth type (anterior-premolar-molar) and jaw side (right-left). In the
present study reference points were indicated by gutta percha in 26 human dry mandibles. The
CBCT images of the mandibles were obtained in the anteroposterior and right-left directions (100
angle). The average buccal and lingual cortical bone thickness on dry mandibles and radiologic
images were individually measured and the mean difference between actual and radiologic
measurements was obtained. The measurements were performed by two observers and 15 days
later 15% of the measurements were repeated. Obtained data were statistically analysed. Data
distribution was analyzed using Shapiro-Wilk test and normality graphs. The measurements were
evaluated by the mean ± standard deviation (mean ± sd) and median (range: R). Data were
analyzed by ANOVA test. The consistency of the measurements between two approaches and the
intra-observer, inter-observer agreement were examined by intra-class correlation coefficient
(ICC). Statistical significance was considered as p < 0.05. It was shown that there was a
statistically significant difference between the measurements performed on dry mandibles and
CBCT images. Mean differences for buccal and lingual cortical bone thickness were found between
0.005-0.203 mm and 0.004-0.183 mm respectively. CBCT results were higher in the anterior and
premolar region and lower in the molar region compared to the values of physical measurements.
No statistically significant difference was indicated between right and left jaws in terms of teeth
position. High intra-observer and inter-observer compatibility was observed. Head positioning had
no effect on the accuracy and reliability of CBCT measurements. It was concluded that there was a
statistically significant difference in CBCT measurements compared to physical measurements but
this difference corresponds to less than or equal to 0.2 mm and is considered to be in clinically
acceptable limits. It is also concluded that CBCT is accurate enough to evaluate buccal and lingual
cortical bone thickness.
Key Words : CBCT, cortical bone thickness, head positioning, mandible