Journal of Research in Dental

Background and Aim: Cone beam computed tomography (CBCT) produces high-quality data in periodontal diagnosis and treatment planning. The aim of this study was to compare the accuracy of CBCT with intraoral digital and conventional radiography in the measurement of periodontal bone defects. 

Methods and Materials: In this diagnostic research, two hundred and eighteen artificial osseous defects (buccal and lingual infra-bony, inter proximal, horizontal, crater, dehiscence and fenestration defects) were shaped in 13 dry mandibles. CBCT  and intraoral radiography with parallel technique by conventional film and digital sensor were compared with the standard reference (digital caliper). Inter and intra observer agreement were assessed using Intra class correlation co-efficient and Pearson correlation. Paired T-Test was applied for the comparison of absolute differences of conventional and digital intraoral radiography and CBCT measurements with the gold standard. All statistical analyses were performed using SPSS® v13.0 statistical software.
Results: Inter and intra observer agreement were both high for CBCT (ICC: α=0/88) but moderate for intraoral conventional radiography (ICC: α=0/54) and digital radiography (ICC: α=0/73). No significant differences were detected between the observers for all the techniques (P> 0.05). According to Paired T-test, mean difference for CBCT technique (0.01mm) was lower than digital radiography (0.47mm) and conventional radiography (0.63mm). CBCT allowed the measurement of all lesion types, but intraoral radiography did not allow the measurement of buccal and lingual defects. 
Conclusion: The results of this study showed that the studied radiographic modalities are useful in identifying the periodontal bone defects. CBCT technique showed the highest accuracy in the measurement of periodontal bone defects compared with digital and conventional intraoral radiography.

Background and aim: Mental nerve injury is one of the challenges of implant surgeries in the anterior mandibular region, which leads to complications such as paresthesia of the lip and chin. The present study aimed to evaluate the prevalence of the Inferior Alveolar Nerve's (IAN) anterior loop and mandibular incisive canal by use of  CBCT.

Materials and Methods: In this descriptive study, 200 high resolution CBCT images of the patients referring to a private oral and maxillofacial radiology center were evaluated. The images were obtained by NewTom Giano unit and were measured in NNT viewer software. Reconstructed panoramic-like images were prepared, and upon the detection of the anterior loop, cross sectional slices were made and dimensions of the anterior loop were calculated by counting the cross sections. In addition, the maximum diameter of the incisive canal was measured, and the location of this diameter was determined on the cross sections relative to dental roots. Data were analyzed by Chi-Square test.

Results: In the 200 evaluated subjects, the prevalence of the anterior loop, with the minimum length of 3mm, was estimated to be 19% and the prevalence of the incisive canal was valued to be 87.5%. No significant correlation was detected between the presence of the anterior loop and age, gender, dental status and side of the jaw. Also, no significant association was detected between the presence of the incisive canal and age, gender and dental status (p=0/597,p=0/492,p=0/643) respectively. The maximum diameter of the incisive canal was 5.3 mm which was located between the first and second premolars.

Conclusion: Considering the results, it seems that evaluation and measurement of the length of the IAN's anterior loop and the diameter of the incisive nerve by CBCT are necessary steps to prevent nerve injuries during surgical procedures in the anterior mandibular region.