O exame radiográfico da articulação temporomandibular

The limitations of TMJ radiographyc tecnics of examination and other conditions are studied in this paper.Os autores estudam o exame radiográficos da ATM, sob seus aspectos técnicos, dando ênfase as suas limitações, nas condições atuais de trabalho

Impacto da identificação do ponto anatômico e do erro padrão de mensuração na análise cefalométrica utilizando um modelo de simulação matemática

Objective: To assess, using a mathematical simulation model, the participation of each coordinate involved in the formation of cephalometric angles and to determine the extent to which errors in the identification of cephalometric landmarks can, individually and collectively, influence the measurement of these angles. Material and Methods: The reference values and standard errors of 13 landmarks obtained from the analysis of 30 cephalograms were used. For each landmark, 1000 observations were simulated using the Monte Carlo method. On the basis of linear regression models, equations designed to estimate measurement errors due to landmark identification errors were obtained and analysed. Results: The coordinates most involved in the formation of the angles SNA, SNB, ANB, FMA, PPL, DFC, and AEF were Ny, Ny, Ax, Goy, Poy, Poy, and Ptmx, respectively, and the standard measurement errors for these angles were 1.2, 0.9, 0.8, 1.6, 1.5, 1.5, and 1.4, respectively. Conclusion: The standard measurement error of the angle depends on the geometric impact coefficient and the standard error of the coordinates involved in the formation of the angles, and the geometric impact coefficient varies according to the angle analysed.Objetivos: Avaliar, empregando um modelo matemático de simulação, a participação de cada coordenada envolvida na formação de ângulos cefalométricos, assim como determinar a extensão da influência dos erros na identificação dos pontos cefalométricos, individual e coletivamente, na mensuração destes ângulos. Materiais e métodos: Foram utilizados os valores de referência e os erros padrão de 13 pontos anatômicos obtidos a partir da análise de 30 cefalogramas. Para cada ponto anatômico, foram simuladas 1000 observações utilizando o método de Monte Carlo. Com base em modelos de regressão linear, foram obtidas e analisadas equações destinadas a estimar os erros de medição devido a erros na identificação dos pontos cefalométricos. Resultados: As coordenadas mais envolvidas na formação dos ângulos SNA, SNB, ANB, FMA, PPL, DFC, e AEF foram Ny, Ny, Ax, Goy, Poy, Poy, e Ptmx, respectivamente, e os erros padrão de mensuração destes ângulos foram 1,2; 0,9; 0,8; 1,6; 1,5; 1,5 e 1,4, respectivamente. Conclusões: O erro padrão de mensuração de cada ângulo cefalométrico depende do coeficiente de impacto geométrico e do erro padrão das coordenadas dos pontos anatômicos envolvidos na formação dos mesmos, sendo que o coeficiente de impacto geométrico varia de acordo com o ângulo analisado

Buccal-lingual localization of the mandibular canal in relationship with the third molar using the lateral oblique technique

Aim: The aim of this study was to evaluate the use of lateral oblique radiography (LOR) at two different incidence angles for the bucco-lingual topographic localization of the mandibular canal with respect to the lower third molars. Materials And Method: A total of 24 dry jaws bearing at least one third molar were subject to LOR at vertical incidence angles of 0° and -30°. A trained and calibrated examiner measured the distance between the top of the mandibular canal to the most apical point of the third molar, using a digital calliper and individual light box for the radiographs. Based on the analysis of the two measurements (incidence angles of 0° and -30°) and considering the buccal object rule, the observer estimated the location of the mandibular canal, which was classified as lingual, central or buccal to the corresponding third molar. Results were compared with the computerized tomography images (gold standard). Results: The statistical analysis included sensitivity, specificity and accuracy tests. These results showed that LOR (0° e -30°) could be used to determine the bucco-lingual location of the mandibular canal with respect to the third molar. Conclusion: In spite of the magnification, LOR images demonstrated that the technique could be used for this study proposal

Topographic relationship of impacted third molars and mandibular canal: correlation of panoramic radiograph signs and CBCT images

is study evaluated the proximity and relation of impacted lower third molars and mandibular canal on panoramic radiography. Methods: Radiographic signals associated with proximity of structures and Pell & Gregory and Winter classifications of 78 impacted teeth were analyzed and compared with CBCT images (gold standard). The associations between the findings were tested with Pearsons chi-square. Results: Direct contact between structures was observed in 85% of cases of radiolucent band over roots. Conclusions: Radiolucent band over roots is the image more associated with direct contact between structures and the one that indicates lingual positioning of the canal more consistently. Some categories of Pell & Gregory and Winter classifications suggested signs of the topographic location of the mandibular canal

Accuracy of detecting and measuring buccal bone thickness adjacent to titanium dental implants-a cone beam computed tomography in vitro study

OBJECTIVES: The aim of this study was to assess the accuracy of detecting and measuring buccal bone thickness (BBT) adjacent to titanium implants in cone beam computed tomography (CBCT) images. STUDY DESIGN: Titanium implants (1, 2, or 3), abutments, and metal-ceramic crowns were inserted into 40 bone blocks with various BBTs. CBCT images were acquired in various settings: Voxel sizes (0.2 and 0.13 mm) and reconstruction section thicknesses (2.0 and 5.0 mm) were assessed by 3 examiners. True BBT was measured in digital photographs of the bone blocks. Buccal bone detection was evaluated by sensitivity and specificity. BBT was evaluated by 1-way analysis of variance (ANOVA) between the true and the CBCT measurements and by calculating the difference between the true measurement and the CBCT measurement (Di-BBT). RESULTS: Detection of buccal bone exhibited high sensitivity (0.86-1) and low specificity (0.14-1). More implants in the field of view, large voxel size, and thick image reconstruction sections had a negative impact on buccal bone detection. ANOVA showed statistically significantly larger BBT for the CBCT measurements in all settings (1.07-1.21 mm) compared with the true measurements (0.85 mm). Di-BBT was mostly within 0.5 mm. CONCLUSIONS: BBT adjacent to titanium implants is overestimated when evaluated on CBCT cross-sectional images

Alteraciones de la mucosa bucal causadas por la asociación entre el tabaco y los colutorios bucales con una concentración de alcohol del 26,9 % Alterations of the oral mucous membrane caused by the association between tobacco and the mouthwashes with an alcohol concentration of 26.9 %

Se analizaron el epitelio y la capa de queratina de la mucosa oral de 15 ratas que durante 45 días fueron sometidas a una aplicación tópica de picadura de tabaco y de colutorio bucal con una concentración de alcohol del 26,9 %. Tras ese período, se extrajeron las mucosas y se les realizó un análisis histológico. Se observó una significativa disminución del espesor del epitelio y de la capa de queratina, lo que indica que la picadura asociada con colutorios bucales con alta concentración de alcohol, provoca la reducción del espesor de la capa de queratina y del epitelio de la boca.<br>The epithelium and the keratin layer of the oral mucous membrane of 15 rats that were subjected to a topical application of cut tobacco and mouthwashes with an alcohol concentration of 26.9 % during 45 days were analyzed. After that period, the oral mucous membranes were removed and a histological analysis was made. It was observed a significant decrease of the thickness of the epithelium and of the keratin layer, which shows that cut tobbaco associated with collutories with a high concentration of alcohol causes the reduction of the thickness of the keratin layer and of the mouth epithelium

Alteraciones de la mucosa bucal causadas por la asociación entre el tabaco y los colutorios bucales con una concentración de alcohol del 26,9 %

Se analizaron el epitelio y la capa de queratina de la mucosa oral de 15 ratas que durante 45 días fueron sometidas a una aplicación tópica de picadura de tabaco y de colutorio bucal con una concentración de alcohol del 26,9 %. Tras ese período, se extrajeron las mucosas y se les realizó un análisis histológico. Se observó una significativa disminución del espesor del epitelio y de la capa de queratina, lo que indica que la picadura asociada con colutorios bucales con alta concentración de alcohol, provoca la reducción del espesor de la capa de queratina y del epitelio de la boca