Monostotic fibrous dysplasia: a case report with cone-beam computed tomography findings / Displasia fibrosa monostótica: relato de caso por meio de achados de tomografia computadorizada de feixe cônico

ABSTRACT Fibrous dysplasia is a benign fibrous-osseous lesion in which normal bone is replaced by fibrous connective tissue and immature bone, affecting only one (monostotic) or several bones (polyostotic) and mainly occurring in children and young adults. When present in facial bones, the maxilla is more frequently involved than the mandible, which can cause facial asymmetry in addition to dental complications. In the image exams, the main characteristic of fibrous dysplasia is its unpolished glass appearance. Computed tomography is the ideal method for evaluating this lesion and its relationship with adjacent structures. The use of conventional radiography, due to the overlapping of anatomical structures, makes it difficult to delineate the extension of the lesion. The present study is aimed at guiding dentist-surgeons on the main imaging characteristics of fibrous dysplasia by describing a case of a female 10-year-old patient presenting with this lesion in the maxilla.

RESUMO A displasia fibrosa é uma lesão fibro-óssea benigna em que o osso normal é substituído por tecido conjuntivo fibroso e osso imaturo, podendo afetar um único osso (monostótica) ou vários ossos (poliostótica), ocorrendo principalmente em crianças e adultos jovens. Quando presente nos ossos faciais, a maxila é envolvida com mais frequência que a mandíbula, podendo causar assimetria facial, além de complicações odontológicas. Nos exames por imagem a característica principal da displasia fibrosa é a aparência de vidro despolido. A tomografia computadorizada é o método ideal para avaliação dessa lesão e relação com estruturas adjacentes. A radiografia convencional, devido a sobreposição de estruturas anatômicas, torna difícil a delimitação da extensão da lesão. O presente estudo teve como objetivo apresentar o relato de caso de um paciente do sexo feminino, 10 anos de idade, com presença de displasia fibrosa na maxila, objetivando orientar os cirurgiões-dentistas com relação às principais características imaginológicas dessa lesão.

Micro-CT evaluation of the radioprotective effect of resveratrol on the mandibular incisors of irradiated rats

Abstract The purpose of this study was to perform a microcomputed tomographic evaluation of the radioprotective effect of resveratrol on the volume of mandibular incisors of irradiated rats. A second aim was to make a quantitative assessment of the effect of x-ray exposure on these dental tissues. Twenty adult male rats were divided into four groups: control, irradiated control, resveratrol, and irradiated resveratrol. The resveratrol groups received 100 mg/kg of resveratrol, whereas the irradiated groups were exposed to 15 Gy of irradiation. The animals were sacrificed 30 days after the irradiation procedure, and their mandibles were removed and scanned in a microcomputed tomography unit. The images were loaded into Mimics software to allow segmentation of the mandibular incisor and assessment of its volume. The results were compared by One-way ANOVA and Tukey's post hoc test, considering a 5% significance level. The irradiated groups showed significantly diminished volumes of the evaluated teeth, as compared with the control group (p < 0.05). The resveratrol group presented higher values than those of the irradiated groups, and volumes similar to those of the control group. High radiation doses significantly affected tooth formation, resulting in alterations in the dental structure, and thus lower volumes. Moreover, resveratrol showed no effective radioprotective impact on dental tissues. Future studies are needed to evaluate different concentrations of this substance, in an endeavor to verify its potential as a radioprotector for these dental tissues.

Comparison of palatal bone height in different facial morphological patterns by cone beam computed tomography

Abstract Aim: To evaluate the relationship between palatal bone height and facial types using cone beam computed tomography (CBCT) images. Methods: The study sample consisted of 110 CBCT images. Subjects aged 18 to 35 years old were classified as brachyfacial, mesofacial and dolichofacial, according to SN.GoGn angle, measured in cephalometric analysis with Nemotec 3D software. Three observers evaluated the bone height of the palate in the anterior region, at the level of the maxillary first premolars. The measurements were performed in sagittal and coronal views, in median and paramedian regions of the palate, also using Nemotec 3D software. Measurements were repeated after 15 days on 25% of the sample to analyse intra and interobserver agreements by CCI test. Analysis of variance was performed to calculate statistical differences between the bone heights of the three facial types, with a significance level of 5%. Results: The correlation level of intra-observer agreement was excellent. No significant differences were observed between the palatal bone height in the region of first premolars and the different facial types (p>0.05). Conclusions: Based on CBCT evaluations, there is no association between palatal bone height and facial morphological patterns.

2D and 3D imaging of the relationship between maxillary sinus and posterior teeth

Aim: To compare the qualitative and quantitative information yielded by imaging modalities on the evaluation of the relationship between the maxillary sinus and the apices of posterior teeth. Methods: Three oral radiologists examined 109 panoramic radiographs and cone-beam computed tomography (CBCT) images obtained from a digital archive. A total of 1,875 apices were classified according to their topographic relationship in both imaging modalities. Agreements between the two imaging techniques were examined statistically. The evaluation was repeated in 25% of the sample to statistically evaluate the intraobserver agreement, with a 30-day interval. Results: The values found in the Kappa test for qualitative assessment and the intraclass correlation coefficient (ICC) for quantitative assessment showed nearly perfect and excellent correlation, respectively. Regarding the correlation between the two images, the Kappa test in the quality assessment showed a slight correlation between the palatal roots of the right first molars and second molars. Moreover, the quantitative evaluation by ICC showed poor agreement for the palatal roots of the left first molar and second molar, as well as for the buccomesial of the right second molars and for the buccodistal of the left second molars.Conclusions: There is low correlation between panoramic radiography and CBCT when roots are in contact or above the maxillary sinus floor. A high level of agreement was observed when roots are below the maxillary sinus floor.

Digital panoramic radiography for diagnosis of the temporomandibular joint: CBCT as the gold standard

Three-dimensional imaging modalities have been reported to be more accurate than panoramic radiographs (PR) for the assessment of bone components of the temporomandibular joint (TMJ). No exact prior information is available that demonstrates which specific limitations occur in terms of TMJ diagnosis when using PR for this purpose. This study aimed to assess the clinical validity of digital panoramic radiography (DPR) when diagnosing morphological disorders of the TMJ using cone-beam computed tomography (CBCT) images as the gold standard. A sample composed of TMJ images (N = 848), including 212 DPR and 212 CBCT images obtained from the same patient, was used to assess any morphological changes in the TMJ. Four appraisers diagnosed all of the DPR images, whereas the CBCT images were used to establish the gold standard. The reliability of each appraiser’s response pattern was analyzed using the Kappa test (κ), and diagnostic tests were performed to assess each appraiser’s performance using a significance level setting of 5% (α = 0.05). Reliability of each appraiser’s response pattern compared to the gold standard ranged from a slight-to-moderate agreement (0.18 ≤ κ ≤ 0.45); and among the different appraisers, the response pattern showed a fair agreement (0.22 ≤ κ ≤ 0.39). Diagnostic tests showed a wide range among the different possible morphological changes diagnosed. DPR does not have validity when diagnosing morphological changes in the TMJ; it underestimates the radiological findings with higher prevalence, and thus, it cannot be used effectively as a diagnostic tool for bone components within this region.

Aspectos tomográficos de ameloblastoma multicístico de células granulares: relato de caso / Computed tomography imaging features of multicystic granular cell ameloblastoma: a case report

O ameloblastoma multicístico é uma variante clínica do ameloblastoma, muitas vezes localmente agressivo, com significante aumento de morbidade e mortalidade. O ameloblastoma é frequentemente assintomático, sendo identificado incidentalmente durante exames odontológicos de rotina. Trata-se de uma lesão de crescimento lento e persistente, podendo ser notada, em alguns casos, uma expansão gradual da mandíbula, produzindo assimetria facial. Ameloblastomas raramente apresentam um comportamento maligno. A avaliação clínica inclui uma revisão cuidadosa da história clínica do paciente, bem como exame físico da cabeça e pescoço. Modalidades de imagens radiográficas são úteis para localizar a lesão, avaliar suas dimensões e os efeitos sobre as estruturas adjacentes. O manejo da lesão representa um desafio para todos os profissionais envolvidos na área de cirurgia de cabeça e pescoço. Assim, o objetivo deste trabalho foi descrever as características tomográficas de um ameloblastoma multicístico de células granulares em um paciente do sexo masculino, leucoderma, de 40 anos de idade...

Multicystic ameloblastoma is a clinical variant of ameloblastoma. It is often locally aggressive with significant impact on patient morbidity and mortality. Ameloblastoma is often asymptomatic and is usually detected as an incidental finding during routine dental examinations. It presents slow and persistent growth; in some cases a gradual expansion of the jaw producing facial asymmetry may be noticed . Although the occurrence is rare, ameloblastomas can exhibit malignant behavior and metastasize. Clinical evaluation includes careful review of the patient's medical history and physical examination of the head and neck region. Radiographic imaging techniques are useful for locating the lesion, estimating its dimensions and assessing its effects on adjacent structures. Management of ameloblastoma is a challenge for all involved in the field of head and neck surgery. The aim of this paper was therefore to describe the tomographic features of a multicystic granular cell ameloblastoma in a 40-year-old white male patient...

Oblique or orthoradial CBCT slices for preoperative implant planning: which one is more accurate?

AIM: To assess which slice inclination would be more accurate in measuring sites for implant placement: the oblique or the orthoradial slice. METHODS: Five regions of eight edentulous mandibles were selected (incisor, canine, premolar, first molar and second molar). The mandibles were scanned with a Next Generation i-CAT CBCT unit. Two previously calibrated oral radiologists performed vertical measurements in all the selected regions using both the oblique and orthoradial slices. The mandibles were sectioned in all the evaluated regions in order to obtain the gold standard. The Wilcoxon signed rank test compared the measurements obtained in the oblique and orthoradial slices with the gold standard. RESULTS: The bone height measurements for the first and second molar regions using the orthoradial slices were statistically different from the gold standard. CONCLUSIONS: Using the orthoradial slices to obtain cross-sectional images may offer insufficient accuracy for implant placement in the posterior region...

Radioprotective Effect of Vitamin E in Parotid Glands: a Morphometric Analysis in Rats

The aim of this study was to evaluate the radioprotective effect of vitamin E on rat parotid glands by morphometric analysis. Sixty male rats were divided into 5 groups (n=6): control, in which animals received olive oil solution; olive oil/irradiated, in which animals received olive oil and were irradiated with a dose of 15 Gy of gamma radiation; irradiated, in which animals were irradiated with a dose of 15 Gy gamma radiation; vitamin E, which received α-tocopherol acetate solution; vitamin E/irradiated, which received α-tocopherol acetate solution before irradiation with a dose of 15 Gy gamma rays. Half of the animals were euthanized at 8 h, and the remaining at 30 days after irradiation. Both parotid glands were surgically removed and morphometric analysis of acinar cells was performed. Data were subjected to two-way ANOVA and Tukey's test (α=0.05). Morphometric analysis showed a significant reduction in the number of parotid acinar cells at 30 days in olive oil/irradiated and irradiated groups. In groups evaluated over time a significant reduction was shown at 30 days in olive oil/irradiated and irradiated groups, indicating that ionizing radiation caused tissue damage. The vitamin E/irradiated group presented more acinar cells than the irradiated group, but no statistically significant difference was observed (p>0.05). In conclusion, vitamin E seems to have failed as a radioprotective agent on acinar cells in rat parotid glands.

O objetivo neste estudo foi avaliar o efeito radioprotetor da vitamina E sobre glândulas parótidas de ratos por meio de análise morfométrica. Sessenta ratos machos foram divididos em cinco grupos: controle, no qual os animais receberam solução de óleo de oliva; óleo de oliva irradiado, em que os animais receberam óleo de oliva e foram irradiados com uma dose de 15 Gy de radiação gama; irradiado, em que os animais foram irradiados com uma dose de 15 Gy de radiação gama; vitamina E, no qual receberam solução de acetato α-tocoferol; vitamina E irradiado, os quais receberam solução de acetato de α-tocoferol antes da irradiação com uma dose de 15 Gy de radiação gama. Metade dos animais foi eutanasiada em 8 h, e o restante aos 30 dias após a irradiação. Ambas as glândulas parótidas foram removidas cirurgicamente e análise morfométrica das células acinares foi realizada. Os dados foram submetidos à Análise de Variância com 2 fatores e teste de Tukey (α=0,05). A análise morfométrica mostrou uma redução significativa no número de células acinares da glândula parótida aos 30 dias nos grupos óleo irradiado e irradiado. Nos grupos avaliados ao longo do tempo uma redução significativa foi mostrada aos 30 dias nos grupos óleo irradiado e irradiado, indicando que a radiação ionizante causou danos teciduais. O grupo vitamina E/irradiado apresentou mais células acinares que o grupo irradiado, mas diferença estatisticamente significante não foi observada. Em conclusão, a vitamina E parece ter fracassado como um agente radioprotetor nas células acinares das glândulas parótidas de ratos.

Gray scale inversion in digital image for measurement of tooth length

The aim of this study was to assess the applicability of gray scale inversion in performing digital linear endodontic measurements. Standardized digital images were taken of 40 extracted human permanent single-rooted teeth with K-files size 15 placed at different lengths in the root canal, using the CDR Wireless® digital system. All images were treated with Positive, a digital tool that inverts the grayscale value. Eight radiologists measured the distance between the lower limit of the rubber stop and the tip of the file on both original and positive images. After 15 days, they repeated this procedure in 50% of the image samples. The intra- and inter-examiner agreement was analyzed by intraclass correlation test, and the comparison between the two image groups and the actual lengths by the Student's t-test (α=0.05). Intra- and inter-examiner evaluation showed high reproducibility (r>0.95) of both original and positive images. No statistically significant differences (p>0.05) were found between measurements performed on original and positive images, but both differed significantly from the actual lengths (p<0.05). Gray scale inversion has low applicability in measuring endodontic files, since it did not improve the accuracy of measurements.

O objetivo deste estudo foi avaliar a aplicabilidade da inversão da escala de cinza na realização de mensurações endodônticas lineares digitais. Quarenta dentes unirradiculares humanos extraídos foram radiografados com limas K tamanho 15 posicionadas no canal radicular em diferentes comprimentos, usando o sistema digital CDR Wireless®. Todas as imagens foram tratadas com Positive, uma ferramenta digital que inverte os valores da escala de cinza. Oito radiologistas mediram a distância entre o limite inferior do stop de borracha e a ponta da lima endodôntica nas imagens originais e positivas. Após quinze dias, eles repetiram esse procedimento em 50% da amostra. A concordância intra- e interobservador foi analisada pelo teste de correlação intraclasse e a comparação entre os dois grupos de imagem e os valores reais, pelo teste t-Student (α=0,05). A análise intra- e interobservador apresentou elevada reprodutibilidade (r>0,95) das imagens original e Positive. Não foi encontrada diferença (p>0,05) entre as medidas realizadas nas imagens original e positiva, mas ambas diferiram dos valores reais (p<0,05). A inversão da escala de cinza tem baixa aplicabilidade na realização de mensuração endodôntica, considerando que as medidas não se apresentaram mais acuradas.

Radioprotective effect of sodium selenite on bone repair in the tibia of ovariectomized rats

This studyevaluated protection by selenium (Se) in the bone repair process in ovariectomized rats after irradiation. For such purpose, 80 ovariectomized female Wistar rats were randomly divided into 4 experimental groups: ovariectomized (Ov), Ov/Se, Ov/irradiated (Irr) and Ov/ Se/Irr. A bone defect was created on the tibia of all animals 40 days after ovariectomy. Two days after surgery, only the Ov/Se and Ov/Se/Irr rats received 0.8 mg Se/kg. Three days after surgery, only the Ov/Irr and Ov/Se/Irr rats received 10 Gy of x-rays on the lower limb region. The animals were euthanized at 7, 14, 21 and 28 days after surgery to assess the repair process, which was evaluated by analysis of trabecular bone number (Masson Trichrome) and birefringence analysis (Picrosirius). It was possible to observe a delay in the bone repair process in the ovariectomized/irradiated group and similarity between the ovariectomized, Ov/Se and Ov/Se/Irr groups. In conclusion, sodium selenite exerted a radioprotective effect in the bone repair of tibia of ovariectomized rats without toxicity.

Esse estudo avaliou a proteção do selênio no processo de reparação óssea em ratas ovariectomizadas após irradiação. Para isso, 80 ratas Wistar foram divididas aleatoriamente em 4 grupos experimentais: ovariectomizado, ovariectomizado/selênio, ovariectomizado/irradiado e ovariectomizado/selênio/irradiado. Foi realizado um defeito ósseo na tíbia de todos os animais 40 dias após ovariectomia. Dois dias após essa cirurgia, os animais dos grupos ovariectomizado/selênio e ovariectomizado/selênio/irradiado receberam 0,8 mg Se/kg. Três dias após a cirurgia, os animais dos grupos ovariectomizado/irradiado e ovariectomizado/selênio/irradiado receberam 10 Gy de radiação X na região de membros inferiores. Os animais foram sacrificados 7, 14, 21 e 28 dias após a cirurgia para avaliação do processo de reparo ósseo, que foi realizado pela análise do número de trabéculas ósseas (coloração Tricrômico de Masson) e pela análise de birrefringência (coloração de Picrosirius). Foi observado atraso no processo de reparo ósseo no grupo ovariectomizado/irradiado e semelhança entre os grupos ovariectomizado, ovariectomizado/selênio e ovariectomizado/selênio/irradiado. Foi possível concluir que o selenito de sódio exerceu efeito radioprotetor no processo de reparação de tíbias em ratas ovariectomizadas sem toxicidade.

Displasia ectodérmica: relato de dois casos clínicos / Ectodermal dysplasia: report of two clinical cases

A Displasia ectodérmica é uma doença rara de origem congênita, caracterizada pelo comprometimento de estruturas derivadas do ectoderma. Os indivíduos portadores de Displasia ectodérmica apresentam como sinais clínicos: hipotricose, hipohidrose e anormalidades cranianas. As manifestações orais mais frequentes são a oligodontia ou anodontia, atraso na erupção e anomalias de formas dentárias, além de hipoplasia de esmalte e deficiência no desenvolvimento do processo alveolar. O objetivo neste artigo é relatar dois casos de displasia ectodérmica, enfatizando suas características clínicas e radiográficas, bem como suas principais implicações odontológicas

The ectodermal dysplasia is a rare congenital disease characterized by the involvement of structures derived from ectoderm. Individuals who have ectodermal dysplasia have the following clinical signs: hypotrichosis, hypohidrosis and cranial abnormalities. The most common oral lesions are oligodontia or anodontia, delayed eruption and morphologic abnormality, as well as enamel hypoplasia and deficiency in the development of the alveolar process. The aim of this article is to report two cases of dysplasia, emphasizing their clinical and radiographic features, as well as their main dental implications

Diagnosis of secondary caries in esthetic restorations: influence of the incidence vertical angle of the X-ray beam

The aim of this study was to evaluate the accuracy on the diagnosis of secondary caries-like lesions simulated on esthetic restorations of different materials, changing the incidence vertical angle (IVA) of the x-ray beam. Twenty human teeth received MOD inlay preparations. In the experimental group (n=10), a round cavity was made in the floor of the proximal box to simulate the caries-like lesion. All teeth were restored with 3 composite resins (Charisma, Filtek-Z250 and TPH-Spectrum) at 3 moments. Two radiographic images were acquired with 0º and 10º IVA. Ten observers evaluated the images using a 5-point confidence scale. Intra- and interobserver reliability was analyzed with the Interclass Correlation Coefficient and the diagnostic accuracy was evaluated using the area under the ROC curve (Az), Friedman test and Wilcoxon test (α=0.05). Higher accuracy values were obtained with 10º IVA (Az=0.66, Filtek-Z250>Az=0.56, TPH-Spectrum) compared to 0º (Az=0.55, Charisma>Az=0.37, TPH-Spectrum), though without statistically significant difference (p>0.05). The detection of secondary caries-like lesions simulated on esthetic restorations of different materials suffered no negative influence by changing the IVA of the x-ray beam.

O objetivo deste estudo foi avaliar a precisão no diagnóstico de lesões iguais-à-cárie secundárias simuladas em restaurações estéticas de materiais diferentes, mudando o ângulo vertical de incidência (AVI) do feixe de raios-x. Vinte dentes humanos foram submetidos a preparo cavitário inlay MOD. No grupo experimental (n=10), no soalho da caixa de proximal, foi confeccionada uma cavidade esférica para simular lesões iguais-a-cárie. Todos os dentes foram restaurados com 3 resinas compostas (Charisma, Filtek-Z250, TPH-Spectrum), em três tempos diferentes. Duas imagens radiográficas foram adquiridas com 0 e 10 graus de AVI o feixe de raios-x. Dez observadores avaliaram as imagens usando uma escala de confiança de 5-pontos. A reprodutibilidade intra- e inter- observador foi analisada com o coeficiente de correlação interclasse e a precisão do diagnóstico foi avaliada usando a área sob a curva ROC (Az), o teste de Friedman e de Wilcoxon (α=0,05). Os mais altos valores de precisão (p>0,05) foram observados com o AVI em 10º (Filtek-Z250 Az=0,66>TPH-Spectrum Az=0,56) comparado com 0º (Charisma Az=0,55>TPH-Spectrum Az=0,37), porém, sem diferenças estatisticamente significantes (p>0,05). A detecção de lesões iguais-à-cárie secundárias simulada em restaurações estéticas de diferentes materiais não foi influenciada pela mudança de AVI do feixe de raios-x.

Carcinoma adenoide cístico em uma localização incomun / Adenoid cystic carcinoma in an uncommon site

O carcinoma adenoide cístico é uma massa de crescimento lento e indolor, com propensão a invadir nervos periféricos e apresenta uma alta taxa de recorrência, com metástase em outros órgãos. A ocorrência do carcinoma adenoide cístico é relativamente rara, representando 10% a 15% das neoplasias de glândulas salivares maiores e cerca de 12.3% das neoplasias de glândulas salivares menores. A frequência relatada em língua é de 19.8%, sendo que, em 85% dos casos, a região afetada é a base da língua. Relatamos um caso de carcinoma adenoide cístico em paciente do gênero feminino, 66 anos de idade, localizado em dorso de língua e descrevemos os seus achados ultrassonográficos.

The adenoid cystic carcinoma is a slow growing and painless mass, with a tendency to invade peripheral nerves and produce metastasis, and also presenting a high rate of recurrence. Adenoid cystic carcinoma is relatively rare condition, accounting for 10% to 15% of all major salivary gland neoplasms and approximately 12.3% of minor salivary glands neoplasms. The tongue is involved in 19.8% of the cases, and in 85% of these cases the affected region is the base of the tongue. We report a case of adenoid cystic carcinoma in a 66-year-olf female patient, located in the dorsum of the tongue, and describe its ultrasound characteristics.

Dens invaginatus: a cone beam computed tomography case report / Dens invaginatus: relato de um caso por tomografia computadorizada de feixe cônico

One of the most common dental anomalies is dens invaginatus. As the name indicates, it is an invagination of the coronary or root surface, bounded by enamel, which can be so profound as to simulate the appearance of a tooth inside another. Usually occurs in permanent maxillary lateral incisors, followed by maxillary central incisors, premolars, canines and less frequently molars. In this article we will describe the cone beam computed tomography features of a type III dens invaginatus.

Uma das anomalias dentárias mais comuns é o dens invaginatus. Assim como o nome indica, é uma invaginação da superfície coronária ou radicular, delimitada por esmalte, que pode ser tão profunda a ponto de simular a aparência de um dente dentro do outro. Normalmente ocorre em incisivos laterais superiores permanentes, incisivos centrais superiores, pré-molares, caninos e, menos frequentemente, molares. Neste artigo será descrito os achados por tomografia computadorizada de feixe cônico de um dens invaginatus tipo III.

Cementoblastoma benigno: relato de caso / Benign cementoblastoma: a case report

Cementoblastoma benigno é uma neoplasia odontogênica relativamente rara caracterizada, pela formação de uma massa de tecido semelhante ao cemento, em conexão com a raiz do dente. Radiograficamente está aderido à porção apical ou lateral da raiz e se apresenta como uma massa radiopaca densa, bem delimitada e circundada por um halo radiotransparente fino e uniforme. Neste artigo, os achados clínicos e radiográficos de um caso de Cementoblastoma benigno são apresentados.

Benign cementoblastoma is a relatively rare odontogenic neoplasm characterized by the formation of a mass of cementum-like tissue, connected to the root of the tooth. Radiographically, it is attached to the apical or lateral root and presents as a well-defined, dense radiopaque mass, surrounded by a thin and uniform radiolucent halo. In this article, the clinical, radiographic and therapeutic features of a case of benign cementoblastoma are presented.

Comparative evaluation among different materials to replace soft tissue in oral radiology studies

OBJECTIVE: The aim of this study was to establish which materials afford better simulation of soft tissues in Oral Radiology studies. MATERIAL AND METHODS: The sample was composed of four materials in eleven different thicknesses to simulate the soft tissues of the face. The mean values of the relative amounts of radiographic contrast of the materials were determined and compared to a gold standard value, which was obtained from 20 patients who were referred to have periapical radiographs taken of the left mandibular molars. Data were subjected to statistical analysis with Dunnett's test (p<0.05). RESULTS: The mean value of the relative amounts of contrast encountered in the patients was 0.47, with a range between 0.36 and 0.64 for all 44 material/thickness combinations. The majority of the tested materials showed values close to those of the patients' tissues, without statistically signifcant differences among them. The values of only three materials/thickness combinations differed statistically from those of the patients' tissues. CONCLUSIONS: Based on the results of the present study, it may be concluded that except for utility wax (4 mm and 8 mm) and water (4 mm), all materials tested at different thickness could be used as soft tissue substitute materials in Oral Radiology studies.

Evaluation of the panoramic image formation in different anatomic positions

The aim of this study was to determine size, shape and position of the image layer by evaluation of the radiographic image formation in different anatomic positions. A customized phantom was made of a rectangular acrylic plate measuring 14 cm² and 0.3 cm thick, with holes spaced 0.5 cm away and arranged in rows and columns. Each column was separately filled with 0.315 cm diameter metal spheres to acquire panoramic radiographs using the Orthopantomograph OP 100 unit. The customized phantom was placed on the mental support of the device, with its top surface kept parallel to the horizontal plane, and was radiographed at three different heights from the horizontal plane, i.e., the orbital, occlusal and mandibular symphysis levels. The images of the spheres were measured using a digital caliper to locate the image layer. The recorded data were analyzed statistically by the Student'-t test, ANOVA and Tukey' test (?=0.05). When the image size of spheres in horizontal and vertical axes were compared, statistically significant differences (p<0.05) were observed in all areas, portions of the image layer and heights of horizontal plane evaluated. In the middle portion of the image layer, differences in the image size of spheres were observed only along the horizontal axis (p<0.05), whereas no differences were observed along the vertical axis (p>0.05). The methodology used in this determined the precise size, shape and position of the image layer and differences in magnification were observed in both the horizontal and vertical axes.

O objetivo na presente pesquisa foi determinar o tamanho, forma e posição da camada de imagem por meio da avaliação da formação da imagem radiográfica em diferentes posições anatômicas. Foi construído um phantom constituído por uma placa acrílica de 14 cm² e 0,3 cm de espessura, com sua superfície contendo perfurações a cada 0,5 cm dispostas em linhas e colunas. O phantom foi posicionado no local do apoio de mento do aparelho panorâmico, com sua superfície paralela ao plano horizontal. Esferas metálicas de 0,315 cm foram inseridas nas perfurações, e executadas radiografias panorâmicas. Cada coluna de cada quadrante foi individualmente preenchida pelas esferas para a execução das radiografias, em três planos horizontais diferentes: alturas orbital, oclusal e mentual. As imagens das esferas foram medidas com o uso de um paquímetro digital e a camada de imagem localizada. Os dados foram analisados estatisticamente utilizando-se o teste T Student, ANOVA e teste de Tukey (?=0,05). Quando o tamanho das esferas nos eixos horizontal e vertical foi comparado, diferenças estatisticamente significativas (p<0,05) foram observadas em todas as áreas da camada de imagem, porções e alturas do plano horizontal avaliado. Na porção central da camada de imagem diferenças no tamanho das esferas foram observadas somente no eixo horizontal (p<0,05), enquanto que no eixo vertical nenhuma diferença foi observada (p>0,05). A metodologia utilizada determinou com precisão o tamanho, forma e posição da camada de imagem, e diferenças de ampliação foram observadas tanto no eixo horizontal quanto vertical.

The relationship between temporomandibular dysfunction and head and cervical posture

OBJECTIVE: This study aimed to evaluate the possibility of any correlation between disc displacement and parameters used for evaluation of skull positioning in relation to the cervical spine: craniocervical angle, suboccipital space between C0-C1, cervical curvature and position of the hyoid bone in individuals with and without symptoms of temporomandibular dysfunction. MATERIAL AND METHODS: The patients were evaluated following the guidelines set forth by RDC/TMD. Evaluation was performed by magnetic resonance imaging for establishment of disc positioning in the temporomandibular joints (TMJs) of 30 volunteer patients without temporomandibular dysfunction symptoms and 30 patients with symptoms. Evaluation of skull positioning in relation to the cervical spine was performed on lateral cephalograms achieved with the individual in natural head position. Data were submitted to statistical analysis by Fisher's exact test at 5%significance level. To measure the degree of reproducibility/agreements between surveys, the kappa (K) statistics was used. RESULTS: Significant differences were observed between C0-C1 measurement for both symptomatic (p=0.04) and asymptomatic (p=0.02). No statistical differences were observed regarding craniocervical angle, C1-C2 and hyoid bone position in relation to the TMJs with and without disc displacement. Although statistically significant difference was found in the C0-C1 space, no association between these and internal temporomandibular joint disorder can be considered. CONCLUSIONS: Based on the results observed in this study, no direct relationship could be determined between the presence of disc displacement and the variables assessed.

Estudo da mineralização dentária em crianças da região metropolitana de Recife / Study of the dental mineralization in children of the Recife metropolitan region

Com o propósito de estudar a mineralização dentária de crianças da região metropolitana de Recife, foram utilizadas 1.352 radiografias panorâmicas de indivíduos do sexo masculino e 1.346 do sexo feminino, distribuídas entre faixas etárias variando de 4 a 15 anos. Em cada radiografia, foram avaliados os estágios de mineralização dos incisivos, caninos, pré-molares e molares tanto da maxila como da mandíbula. Para esta avaliação, utilizou-se um diagrama de oito estágios de mineralização preconizado por Nicodemo e Demirjian et al. Foram obtidas, para cada faixa etária, as médias e os desvios padrões dos estágios de mineralização de cada um dos dentes estudados para ambos os sexos. Para verificar a existência de diferença estatisticamente significativa no desenvolvimento dentário entre os sexos feminino e masculino, foi aplicado o teste t de Student. Verificou-se que, de maneira geral, a mineralização dentária ocorreu primeiro no sexo feminino, indicando precocidade do desenvolvimento dentário nas meninas. Os resultados possibilitaram correlacionar a idade cronológica com as diversas fases de formação dentária, o que permitiu traçar um panorama do desenvolvimento da dentição permanente para a população da região de Recife.

Osteocondrite dissecante da articulação temporomandibular: imagem em radiografia panorâmica / Osteochondritis dissecans of the temporomandibular joint: panoramic radiography features

Relatamos um caso de um paciente de 62 anos, do sexo masculino, apresentando osteocondrite dissecante (OD), estádio 4, na articulação temporomandibular (ATM) do lado esquerdo. Também salientamos a importância da radiografia panorâmica no diagnóstico da OD nos seus estádios 3 e 4, e recomendamos sua inclusão no protocolo de abordagem por imagem para casos de OD.