Incidental findings in patients evaluated with cone beam computed tomography for orthodontic treatment / Achados incidentais em tomografia computadorizada de feixe cônico em pacientes avaliados para tratamento ortodôntico

ABSTRACT Objective: The aim of this retrospective study was to determine and quantify incidental findings in CBCT scans taken exclusively for orthodontic purposes. Methods: A total of 202 scans were evaluated by two examiners and classified into five different groups. Results: A total of 227 incidental findings were found in a sample of patients aged 5-58 years old. The highest number of findings was of dental origin (n = 157), followed by airway (N = 46), skull (N = 16) and ATM (n = 8). Scans with no incidental finding accounted for 20% of the examinations. Subjects having lower mean age were found in the group of airway findings. The prevalence of incidental findings in the current study was consistent with the literature, thus corroborating their high frequency. Orthodontists who make use of CBCT are responsible for assessment of all data. Conclusion: The precise evaluation of incidental findings may help in the early diagnosis, treatment and patient monitoring. Further studies should be conducted to assess the influence of these findings on the orthodontic treatment.

RESUMO Objetivo: Investigar e quantificar achados incidentais em exames de tomografia computadorizada de feixe cônico realizadas unicamente para fins ortodôntico. Métodos: Foram incluídos os exames de tomografia de feixe cônico com finalidade de diagnóstico ortodôntico no período de novembro de 2011 a abril de 2014 (n=202) avaliados por dois examinadores e os dados coletados classificados em cinco grupos diferentes. Foi realizada análise exploratória dos dados através do cálculo de média, desvio padrão, frequência e porcentagem. A associação entre o local do achado e o gênero foi verificada através do teste exato de Fisher. Resultados: Foi encontrado um total de 227 achados; o grupo com maior número de achados foi o de origem dental (n=157), seguido do grupo de vias aéreas (n=46), de crânio (n=16) e de ATM (n=8). Exames sem nenhum achado representaram 20% do total. Os sujeitos com menores médias de idade foram encontrados no grupo de vias aéreas. A prevalência de alterações tomográficas incidentais em pacientes ortodônticos é alta. Conclusão: Um cuidadoso diagnóstico das imagens de tomografia de feixe cônico além da região de interesse ortodôntica é indispensável para prevenir patologias ocultas. Estudos adicionais podem ser realizados para avaliar qual a influência desses achados no tratamento ortodôntico.

Volumetric study of sphenoid sinuses: anatomical analysis in helical computed tomography.

PURPOSE: The sphenoid sinus is the most inaccessible part of the face, being inside the sphenoid bone and closely related to numerous vital neural and vascular structures. The objective of this study was to analyze and evaluate the variation of anatomy and the volume of the sphenoid sinus using helical computed tomography and medical imaging software. MATERIALS AND METHODS: A total of 47 helical CT scans of sinuses of male and female individuals aged 18-86 years were selected. The images were formatted using ITK-SNAP software, consisting of three steps: (1) segmentation; (2) volumetric analysis and (3) 3D reconstruction. The sphenoid sinuses were also classified according to Hammer, i.e., in conchal, pre-sellar, sellar and post-sellar types. A single investigator, who is specialist in dental radiology and was trained and calibrated, performed the volume and image analysis. After 15 days, the segmentations were repeated. RESULTS: The Dunn's multiple comparison test revealed significant differences in the volume rankings between the right and left sides (P = 0.0002), with the post-sellar type presenting the greatest volume on the right side compared to pre-sellar and sellar types. In the left sphenoid sinuses, the post-sellar type showed the greatest volume. The Lin's correlation coefficient showed excellent reproducibility values. CONCLUSIONS: According to the applied methodology, it was found that the volume of the sphenoid sinus was influenced by neither age nor gender (P > 0.005). There was difference in the volumes of sphenoid sinus on the right and left sides and in the anatomical classification.

Validation of cone-beam computed tomography as a predictor of osteoporosis using the Klemetti classification.

This study aimed at evaluating the validity of cone-beam computed tomography (CBCT) for assessing mandibular bone quality using the Klemetti classification. The morphology of the endosteal mandibular cortex of 30 (60 hemi-mandibles) postmenopausal women between the ages of 45 and 80 years was evaluated based on the Klemetti classification in panoramic radiographs used as reference images. Afterwards, panoramic reconstruction and cross-sectional slices of CBCT examinations of these patients were analyzed and categorized according to the same classification. All the images were assessed by two oral radiologists. The McNemar-Bowker test compared the agreement between the CBCT images and the reference images. No differences were found between the diagnostic results based on panoramic radiography and panoramic reconstruction. However, the mean scores for the cross-sectional evaluation were higher, and the results, statistically different from the others. Based on the disagreement found between the panoramic radiographs and the CBCT cross-sectional slices, the Klemetti classification is not an adequate means of assessing bone quality with CBCT. On the other hand, the higher values found for the cross-sectional slices could be associated with better visibility on the CBCT images.

Validation of cone-beam computed tomography as a predictor of osteoporosis using the Klemetti classification

Abstract This study aimed at evaluating the validity of cone-beam computed tomography (CBCT) for assessing mandibular bone quality using the Klemetti classification. The morphology of the endosteal mandibular cortex of 30 (60 hemi-mandibles) postmenopausal women between the ages of 45 and 80 years was evaluated based on the Klemetti classification in panoramic radiographs used as reference images. Afterwards, panoramic reconstruction and cross-sectional slices of CBCT examinations of these patients were analyzed and categorized according to the same classification. All the images were assessed by two oral radiologists. The McNemar-Bowker test compared the agreement between the CBCT images and the reference images. No differences were found between the diagnostic results based on panoramic radiography and panoramic reconstruction. However, the mean scores for the cross-sectional evaluation were higher, and the results, statistically different from the others. Based on the disagreement found between the panoramic radiographs and the CBCT cross-sectional slices, the Klemetti classification is not an adequate means of assessing bone quality with CBCT. On the other hand, the higher values found for the cross-sectional slices could be associated with better visibility on the CBCT images.

Influência de terceiros molares não erupcionados em fratura de ângulo e côndilo / Influence of unerupted third molars on angle and condyle fracture

Condylar and angle fractures are the most common types of mandibular injuries. There is evidence in the literature suggesting that the presence of unerupted lower third molars increases the risk of angle fracture and reduces the chance of condyle fracture. The present paper reports on a case of a 19-year-old Caucasian man who had bilateral angle fracture associated with the two lower unerupted third molars. No other fracture was detected on the panoramic radiograph. This case suggests that unerupted lower third molars increase the risk of angle fracture whereas preventing condyle fracture. Reduction of the bone mass of the angle in the presence of third molars and disruption of the oblique ridge with partially erupted molars support our findings. As the treatment of condyle fracture is more complex, it might not be appropriate to strengthen the mandibular angle, making the mandible more vulnerable to condylar fractures by means of prophylactic extraction of asymptomatic unerupted third molars.

Côndilo e ângulo são os locais onde as fraturas mandibulares ocorrem com maior frequência. Há evidências na literatura sobre a propensão para fratura de ângulo mandibular na presença de terceiros molares inferiores não-erupcionados, bem como redução da respectiva probabilidade de fratura em côndilo. O caso relatado envolve um homem branco, de 19 anos de idade, que teve fratura bilateral do ângulo em associação com os dois terceiros molares inferiores não-erupcionados. Nenhuma outra fratura foi detectada na radiografia panorâmica. Os achados deste caso ilustram a evidência de que terceiros molares inferiores não irrompidos aumentam o risco de fratura de ângulo, reduzindo, porém, o risco de fratura em côndilo. Algumas teorias sobre essa associação envolvem a redução da massa óssea do ângulo na presença do terceiro molar, além da ruptura da linha oblíqua quando eles estão parcialmente erupcionados. Como a fratura do côndilo tem um tratamento mais complexo, a exodontia profilática de terceiros molares não-erupcionados assintomáticos pode não ser apropriada, por fortalecer o ângulo mandibular e tornar a mandíbula mais vulnerável às fraturas condilares.

Morphodigital study of bone quality in the mandibular angle in patients with third molar impacted.

The aim of this study was to analyze if the presence of impacted third molars, and their positions in the mandibular angle, can change the bone quality in this area, considering the measure of the cortical thickness in this region as representative or not for mandible fracture risk. Software was used to analyze 50 digital images from panoramic radiographs of patients who had one or two impacted third molars in the mandible, and 30 digital images of patients with agenesis of the mandibular third molar. The thickness of the cortical region of the mandible was measured; it was possible to draw a parallel line to the posterior portion of the mandible and a parallel line to the body of this bone on each side of the image. At the intersection of these lines near the distal portion of the second molar, another line was set up to serve as reference in the cortical thickness measurement. It could be concluded that the cortical thickness of the mandibular angle in male patients without impacted third molars was greater than the thickness in patients with these teeth, and no difference in thickness was found for the female group.