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.

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.

Accuracy in the diagnosis of the mental nerve loop: a comparative study between panoramic radiography and cone beam computed tomography / Precisión en el diagnóstico del bucle del nervio mental: estudio comparativo entre radiografía panorámica y tomografía computadorizada de haz cónico

Dental implant and chin osteotomy are executed on the mandible body and the mental nerve is an important anatomical limit. The aim of this research was to know the position of the mental nerve loop comparing result in panoramic radiography and cone beam computed tomography. We analyzed 94 hemimandibles and the patient sample comprised female and male subjects of ages ranging from 18 to 52 years (mean age, 35 years) selected randomly from the database of patients at the Division of Oral Radiology at Piracicaba Dental School State University of Campinas; the anterior loop (AL) of the mental nerve was evaluated regarding the presence or absence, which was classified as rectilinear or curvilinear and measurement of its length was obtained. The observations were made in the digital panoramic radiography (PR) and the cone beam computed tomography (CBCT) according to a routine technique. The frequencies of the AL identified through PR and CBCT were different: in PR the loop was identified in 42.6% of cases, and only 12.8% were bilateral. In contrast, the AL was detected in 29.8% of the samples using CBCT, with 6.4% being bilateral; Statistical comparison between PR and CBCT showed that the PR led to false-positive diagnosis of the AL in this sample. According to the results of this study, the frequency of AL is low. Thus, it can be assumed that it is not a common condition in this population.

Implantes dentales y la osteotomía de mentón son realizadas en el cuerpo mandibular y el nervio mental es un importante limite anatómico. El objetivo de esta investigación es conocer la posición del bucle del nervio mental comparando resultados entre radiografia panorámica y tomografía computadorizada de haz cónico (TCHC). Fueron analizadas 94 hemimandíbulas; la muestra de pacientes de sexo feminino y masculino con edades fluctuando entre 18 y 52 años (edad media, 35 años) seleccionados de la base de datos de pacientes de la División de Radiología de la Facultad de Odontología de Piracicaba, Universidad Estadual de Campinas; el bucle anterior (BA) del nervio mental fue evaluado según su presencia o ausencia, el cual fue clasificado como rectilíneo o curvilíneo obteniéndose el largo total del bucle; las observaciones fueron realizadas en radiografías panorámicas digitales (RP) y en TCHC de acuerdo a técnicas de rutina. La frecuencia de identificación del BA en RP y TCHC fue diferente: en la PR, el BA se identificó en un 42,6% de los casos y solo el 12,8% fue bilateral. En contraste, el BA fue detectado en el 29,8% de la muestra utilizando TCHC, con un 6,4% bilateral; la comparación estadística entre RP y TCHC muestra que la RP lleva a diagnósticos falsos positivos de la muestra de BA. De acuerdo con los resultados de este estudio, la frecuencia de BA es baja. Por este motivo se puede asumir que esta es una condición anatómica poco frecuente en la población estudiada.

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.