Cone beam computed tomography (CBCT) is increasingly seen in UK dental practices, but there is no published information regarding how it is used. The aim of the study was to obtain such information using a survey. Materials and Methods:A survey on aspects of justification, optimisation and training was distributed to all dental practices having CBCT equipment and a contract with Dental X-ray Protection Services (DXPS). Results:Seventy-one completed surveys were received (49% response rate). A wide range of CBCT equipment was in use. The number of scans reported as being carried out was typically low. One third of respondents had acquired their CBCT machine within the last year. The clinical use was overwhelmingly in adult patients and related to implant dentistry. Small or medium field of view scans were most commonly used.Only 19.7% of respondents could provide detailed exposure factors. Patient protective shielding for patients was almost never used. The dentist always or mainly performed the CBCT reporting in 88.7% of practices. Conclusions:The survey provided no evidence of excessive use of CBCT in UK dental practices.The typical reported use was of small field of view scans for implant dentistry. Only 8.4% of practices performed examinations on children and young people. Some concerns were raised regarding respondents' knowledge about exposure factors and the clinical evaluation of images. IN BRIEF Presents an overview of the current use of CBCT in UK dental practices  Suggests that most CBCT examinations are small field of view scans for adult patients in the context of implant dentistry  Raises some questions about knowledge of exposure factors and the training for clinical evaluation of CBCT images

Background and objective: Extraction of an impacted mandibular third lower molar tooth is one of the common surgical procedures that may lead to the damage of inferior alveolar nerve due to roots proximity to the mandibular canal. This study aimed to know the relative relationship and proximity of the mandibular third molar roots to the inferior alveolar canal in relation to gender, age, depth of impaction, relation with ramus, and type of angulation of the impacted tooth in Kurdistan population. Methods: A sample of 366 digital panoramic radiographs of patients with impacted mandibular third molar was studied. Panoramic radiographic signs images were evaluated for the presence of root contact with the superior border of the mandibular canal, darkening of the roots apex, deflected roots, narrow root, superimposition of the canal, interruption of the white line, diversion of the inferior alveolar canal, and narrowing of the inferior alveolar canal. The depths of impaction, relation with ramus, and type of angulation were also studied. Results: Significant relation of the proximity of the mandibular third molar roots to the inferior alveolar canal with the gender (P = 0.001) and age (P <0.001) were seen. A significant relation of the proximity of the mandibular third molar roots to the inferior alveolar canal with the depth of impaction (P <0.001), relation with the ramus (P = 0.004), and angulation of impaction were also seen (P <0.001). Conclusion: Significant relation of the proximity of the mandibular third molar roots to the inferior alveolar canal with gender, age, depth of impaction, relation with the ramus, and angulation of impaction were seen.

Objectives: The evidence for diagnostic accuracy using cone beam computed tomography (CBCT) for dental applications depends heavily on ex vivo research, but there is little knowledge of whether the model used affects the diagnostic accuracy results. The objective of this study was to determine the impact of different designs of anthropomorphic models on diagnostic accuracy for the specific task of dental root fracture detection. Methods: Horizontal or oblique root fracture was induced in 24 of 48 permanent maxillary incisors. The 48 teeth were scanned by CBCT using standard clinical exposure factors on five occasions, each with a different model design. Scans were viewed by five dental and maxillofacial radiologists, who each made a forced diagnosis of fracture or no fracture in each root and a judgment on root fracture using a five-point confidence scale. Sensitivity (Se), specificity (Sp) and areas under receiver operating characteristic (ROC) curve (Az) were calculated for each observer for each model. Results: There were no significant differences between the diagnostic accuracy measurements recorded using different models. There were, however, numerous significant differences between observers using the same anthropomorphic model. Conclusions: Despite the differences in X-ray attenuation between the five model designs, the results suggest that the anthropomorphic model does not affect the results of diagnostic accuracy studies on root fracture using this CBCT machine at standard clinical exposures. This provides some confidence in the previously published evidence. The interobserver diagnosis differences indicate that research using only two observers could provide misleading results.