The effect of different exposure parameters on proximal caries detection using the Kodak 9000 3D CBCT system / Efeito de diferentes parâmetros de exposição na detecção de cáries proximais usando o sistema Kodak 9000 3D TCFC

ABSTRACT Objective: The objective of study was to evaluate the diagnostic quality of CBCT images for caries lesions detection using different exposure parameters. Methods: Sixty extracted human teeth were selected and scanned using Kodak 9000 3D CBCT system, with the following exposure parameters combinations: 74 kV, 10mA; 74 kV, 12mA; 74 kV, 8 mA; 70 kV, 10 mA; 70kV, 12 mA; 70 kV e 8 mA; 70 kV, 6.3 mA. Two observers evaluated the images for caries presence using CS 3D Imaging Software. Each observer scored the proximal surfaces of each tooth on a 5-point scale. The scores were compared to histological sections used as gold standard. Accuracy for caries lesion detection was assessed for each exposure parameter combination and evaluated by means of ROC curve analysis. Results: The mean values for the areas under the ROC curves for each exposure parameter combination varied from 0.35 to 0.60. There was no statistical significant difference among protocols 1, 2, 4, 6 and 7. However, protocols 3 and 5 differed from all protocols. Conclusion: Although the highest dose protocol was the most efficient for proximal caries detection, the lowest dose protocol should be chosen based on the ALADA principle.

RESUMO Objetivo: Avaliar a qualidade de diagnóstico de imagens de TCFC para detecção de lesões de cárie utilizando parâmetros de exposição diferentes. Métodos: Sessenta dentes humanos extraídos foram selecionados e digitalizados usando o sistema Kodak 9000 3D TCFC, com as seguintes combinações de parâmetros de exposição: 74 kV, 10 mA; 74 kV, 12 mA; 74 kV, 8 mA70 kV, 10 mA; 70 kV, 12 mA; 70 kV e 8 mA; 70 kV, 6,3 mA. Dois observadores avaliaram as imagens para a presença de cárie utilizando o CS 3D Imaging Software. Cada observador pontuou as superfícies proximais de cada dente em uma escala de 5 pontos. Os escores foram comparados com cortes histológicos, utilizados como padrão-ouro. A precisão para detecção de lesões de cárie foi analisada para cada combinação de parâmetros de exposição e avaliada por meio de análise da curva ROC. Resultados: Os valores médios para as áreas sob as curvas ROC para cada combinação de parâmetro de exposição variou de 0,35-0,60. Não houve diferença estatística significativa entre os protocolos 1, 2, 4, 6 e 7. No entanto, os protocolos 3 e 5 diferem de todos os protocolos. Conclusão: Embora o protocolo de dose mais elevada foi o mais eficiente para a detecção da cárie proximal, o protocolo de dose mais baixa deverá ser escolhido com base no princípio ALADA.

Relationship between articular eminence inclination and alterations of the mandibular condyle: a CBCT study

Abstract This study aimed at verifying the correlation among angulation of the articular eminence (AE), shape of the condyle and its degenerative bone diseases (DBDs), according to age and sex, through Cone Beam Computed Tomography (CBCT). Five hundred and twenty-eight temporomandibular joints (TMJ) were evaluated. The condyles were classified as: flat, convex, angled and rounded, and the AE angulation was measured. The DBDs evaluated were osteophytes, flattening, erosion, subcortical cysts and spinal sclerosis. There was no difference in the mean angulations in relation to age group (p>0.05). In age groups of 60-69 years (p=0.003) and 70 years or over (p=0.021), the angulation was higher in males. There was an association between DBD and sex (p=0.047), in that the prevalence was higher in females. Differences in AE angles were not observed in condyles with one or no DBDs (p>0.05). However, the presence of two or more DBDs led to a decrease in the angle (p<0.05). Angled condyles showed higher AE angulations than the flat and convex types (p<0.01). In conclusion, the AE inclination is influenced by DBD and condyle shape; an association of two or more bone diseases in the condyle, or its flat or convex anatomy, results in a decrease in the angulation.

Fusão incomum de distomolar com terceiro molar avaliado por tomografia computadorizada de feixe cônico / Unusual fusion of a distomolar with a third molar assessed by cone-beam computed tomography

Os dentes supranumerários são uma anomalia e podem ser vistos em todos os quadrantes dos maxilares, com maior incidência na maxila. Quando os dentes supranumerários ocorrem distalmente ao terceiro molar, eles são denominados de dentes distomolares. Os distomolares ocorrem mais comumente unilateralmente na maxila de pessoas negras e afetam 2.2% da população. Por outro lado, a fusão ocorre pela união de dois germes dentários separados, desenvolvendo um único dente unido pela dentina e/ou pelo esmalte. A frequência de fusão de dentes permanentes e supranumerários é menor do que 0.1%, e normalmente envolve dentes anteriores da maxila. Radiografias periapicais são rotineiramente utilizadas em endodontia para o diagnóstico e planejamento pré-operatório, bem como durante o trans e pós-operatório. Entretanto, limitações relacionadas à bidimensionalidade dessa modalidade de imagens podem impedir a visualização adequada da anatomia dos canais radiculares dos dentes com variações anatômicas. O objetivo do presente relato foi descrever um caso raro de fusão por meio da tomografia computadorizada de feixe cônico...

Supernumerary teeth are teeth that occur in addition to the normal series. They can be observed in all quadrants of the jaw, with highest incidence in the maxilla. When a supernumerary tooth is distal to the most posterior molar, it is called a distomolar. Distomolars are more common unilaterally, in the maxilla and in black people and affect 2.2% of the population. In contrast, fusion is the result of the union of two separate tooth germs, forming a single tooth joined by dentin and/ or enamel, and fusion of a permanent tooth with a supernumerary accounts for fewer than 0.1% of cases, usually involving anterior maxillary teeth. Periapical radiographs are routinely used for endodontic diagnosis and preoperative planning, for transoperative guidance and for postoperative follow-up. However, the two-dimensional nature of this imaging technique can impose limitations on the ability to determine the anatomy of root canals in teeth with anatomical variations. The objective of this case report is to describe a rare case of fusion of a distomolar with a third molar, assessed using cone-beam computed tomography (CBCT)...

Digital radiographic evaluation of the midpalatal suture in patients submitted to rapid maxillary expansion.

Aims: To analyze the density of the midpalatal suture by means of digital radiographs three months after retention to evaluate if this period of retention is really sufficient for bone repair. Materials and Methods: This prospective study consisted of 31 patients (11 girls and 20 boys) in the mixed or permanent dentition stage, treated using a tooth-tissue borne expanders (Haas). Occlusal digital radiographs were taken at three stages: prior to rapid maxillary expansion (Stage I); immediately after desired maxillary expansion (Stage II); and after three months of retention (Stage III). Radiographs were taken on a dental X-ray machine, set at 70 kVp and 7 mA with an exposure time of 0.04 s. A phosphor storage plate system, imaging plate size n. 2 (35 × 45 × 1.6 mm), was used. Three regions (A, B and C) measured 0.02 mm² were selected for optical density analysis. The difference between the measurements was evaluated with the paired t-test. Results: The optical density was reduced at Stages II and III compared with Stage I. Between-stage comparison showed statistically significant changes for all variables (P < 0.05), with the highest mean optical density at Stage I and the lowest at Stage II, in all groups. Actually, there was an increase in optical density between Stages II and III, but they are reduced compared with Stage I. Conclusion: The results strongly suggest that bone formation did not occur as expected, and that a longer retention period for bone repair may be necessary.

Comparative study of linear measurements performed in magnetic resonance and computed tomography images with the aid of an image realignment software / Estudo comparativo de medidas realizadas em imagens por ressonância magnética e por tomografia computadorizada com auxílio de um software de realinhamento de imagens

The aim of this study was to compare linear measurements of implant sites performed in magnetic resonance and computed tomography images with the aid of an image alignment software. Four patients from the Dental Implant Research and Teaching Center of Universidade Federal de Santa Catarina, Florianópolis, Brazil, were submitted to both computed tomography and magnetic resonance scans. An image realignment software was used to allow measuring the exact same sites on the images of both modalities. A total of eighty linear measuremensts of the posterior regions and twelve linear measurement of the anterior regions were performed with each modality. Measurements were carried out by one calibrated observer. Observer's reproducibility was higher than 97% (Dalberg's error). Student's t-test was used to compare the results of the height of the alveolar process in the computed tomography and magnetic resonance images. There was no statistically significant differences between the measurements performed in the computed tomography and magnetic resonance images (p = 0.4136). with a strong correlation between them (r = 0.8346). Similarly, there was no statistically significant differences between the measurements produced by the two modalities when the analysis discriminated the anterior and posterior regions (p = 0.7801 and p = 0.4381, respectively), with a strong correlation between the measurements in the posterior region of the jaws (r = 0.8547), and a weak correlation in the anterior region (r = 0.5472). Linear measurements of the alveolar process obtained from magnetic resonance and computed tomography images are comparable.

Condições de radioproteção dos consultórios odontológicos / Radioprotection in dentistry offices

Em 1998, o Ministério da Saúde estabeleceu as Diretrizes de Proteção Radiológica em Radiodiagnóstico Médico e Odontológico, visando garantir a qualidade nos procedimentos prestados à população e assegurar a proteção radiológica aos profissionais da saúde. O objetivo desta pesquisa foi verificar a situação dos consultórios odontológicos quanto às especificações técnicas preconizadas e às medidas de proteção adotadas, utilizando-se um questionário com itens sobre equipamentos, técnicas e proteção radiológica. O universo foi composto pelos cirurgiões-dentistas do município de Aracaju, Sergipe, que executam o exame radiográfico como rotina, sendo a amostra final de 103 profissionais. Dentre os resultados encontrados, destacam-se o alto índice de profissionais que desconhecem as normas atuais (64,1 por cento) e as especificações técnicas de seus equipamentos (51,5 por cento desconhecem a quilovoltagem e 57,3 por cento, a miliamperagem), como também aqueles que utilizam o método visual de revelação (67 por cento). Como condutas positivas, 62,1 por cento dos pesquisados fazem uso da técnica do paralelismo e 98,1 por cento utilizam a proteção plumbífera no paciente. Com isso, conclui-se que apesar de uma minoria conhecer as Diretrizes de Proteção, algumas medidas estão sendo corretamente adotadas; todavia, uma melhor conscientização se faz necessária.

In 1998, the Brazilian Ministry of Health established the Guidelines for Protection in Medical and Odontological Radiography, aimed at ensuring the quality of radiological procedures provided to the population as well as radiological protection for the health professionals. The purpose of this study was to verify the current situation in the dental offices with regard to the technical specifications and the adopted protective measures, using a questionnaire including questions about equipments, techniques and radiological protection. The investigated universe consisted of the surgeon dentists of the city of Aracaju using radiographic examination as a routine, resulting in a final sample of 103 professionals. The results showed that a high percentage of these professionals ignore the current norms (64,1 percent) as well as the technical specifications of their equipment (51,5 percent ignored the peak kilovoltage and 57,3 percent the milliamperage of their equipment), besides examining the radiographs visually (67 percent) As positive behaviors, the paralleling technique was preferred by 62,1 percent and the lead apron was used by 98,1 percent. We conclude that, despite the limited knowledge about the Guidelines, some measures are being correctly adopted but that the dentists have to be more aware of the necessary protective measures.