Journal of Research in Dental

Background and aim: Considering the widespread development of implants in dental treatment plans, linear measurements on panoramic radiography are of especial importance. In the present study we investigated the effect of head misalignment up to 15° around vertical and horizontal axes on the magnification rate of digital panoramic radiography in each part of upper and lower jaws.

Materials and methods: In this in vitro experimental study, five edentulous human skulls were used. Steel globes with 4mm diameter were placed inside each dental socket. Each skull was exposed twice at standard panoramic position and at 5, 10 and 15° upward, downward, left and right deviated positions with NewTom GIANO radiographic system with the least amount of kVp and mAs. All 50 images were saved in true size and the maximum horizontal and vertical diameter of each globe was measured by an oral and maxillofacial radiologist using linear measurement software. Data were statistically analyzed by Chi- square and ANOVA tests.

Results: At standard panoramic position, linear measurements in both horizontal and vertical dimensions showed magnification and the results indicated 12-13% magnification in vertical dimension in all parts of both jaws. The least rate of horizontal magnification was seen in the molar area of both jaws (6%). (p<0.05)

At lateral head rotation, linear measurements in vertical dimension were less affected. (p>0.05) Linear measurements in horizontal dimension showed the highest variations especially in the posterior parts of the jaws. (p>0.05)

At upward and downward chin rotations, vertical measurements showed magnification rate comparable with that of standard panoramic position while horizontal measurements showed increased magnification at upward rotation and decreased magnification during downward rotation. (p>0.05)

Conclusions: Vertical and horizontal linear measurements show magnification at standard panoramic position and also at lateral head rotation around Y-axis and at upward and downward rotations. Furthermore, even at deviations up to 15°, no minimized measurements were recorded in the obtained panoramic radiographs.

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.

Background and Aim: Considering the significance of the detection of proximal caries and the limited information available on the diagnostic value of digital radiography after the use of enhancement filters, this in-vitro study sought to compare the diagnostic value of digital radiography with and without the use of the edge enhancement (EE) filter in the detection of proximal enamel caries in premolars.

Materials and Methods: This in-vitro study was conducted on 80 extracted intact human premolars. Every two teeth were mounted in a single block using putty impression material and every two blocks were placed in articulation. Digital bitewing radiographs were taken and saved twice, once in their original form and once after the application of the EE filter. Afterwards, a cavity was prepared on the proximal surface of one of the teeth (chosen randomly) in each block using a bur and then, the tooth was put back in the block. Digital bitewing radiographs were taken again with the same exposure settings. The 80 final images were printed on radiographic films and were evaluated by three oral and maxillofacial radiologists. The results were compared with the gold standard (the cavities formed by a bur). The data were statistically analyzed by Chi-square test.

Results: The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were 75%, 87.5%, 85.7%, 77.7% and 81.2%, respectively in the original digital radiographs and 80%, 95%, 94.1%, 82.6% and 87.5%, respectively in the enhanced images. The difference between the two groups was not statistically significant (P=0.7, P=0.3, P=0.3, P=0.7, P=0.3).

Conclusion: Application of the EE filter does not improve the diagnostic accuracy of radiographs in the detection of proximal enamel caries.

Background: The calcifying odontogenic cyst (COC) is a rare cystic lesion, mainly affecting the anterior aspect of the jaws. It is usually discovered in unexpected settings and can be clinically observed as a painless and well-defined lesion. The COC may be associated with other odontogenic tumors, such as odontomas. Nearly 50% of COCs are associated with an unerupted tooth, most often a canine. The most unique features of this pathology are histopathological features, including a cystic lining with characteristic ghost epithelial cells with a tendency for calcification. Radiological examinations often reveal a radiolucent and unilocular lesion, sometimes associated with radiopaque lesions. Pathological assessments are required for the final diagnosis. Management is through complete excision with annual radiographic monitoring for five years.
Case Presentation: Here, we report a classic case of COC in the left mandibular region associated with an extremely displaced impacted canine in a 16-year-old girl.
Conclusion: Although uncommon, COCs are frequently associated with impacted teeth. The radiolucencies associated with impacted teeth have different effects on the surrounding structures and require different treatment plans, depending on the type of the lesion.