Comparison between cone-beam and multislice computed tomography for identification of simulated bone lesions.

There are many studies that compare the accuracy of multislice (MSCT) and cone beam (CBCT) computed tomography for evaluations in the maxillofacial region. However, further studies comparing both acquisition techniques for the evaluation of simulated mandibular bone lesions are needed. The aim of this study was to compare the accuracy of MSCT and CBCT in the diagnosis of simulated mandibular bone lesions by means of cross sectional images and axial/MPR slices. Lesions with different dimensions, shape and locularity were produced in 15 dry mandibles. The images were obtained following the cross sectional and axial/MPR (Multiplanar Reconstruction) imaging protocols and were interpreted independently. CBCT and MSCT showed similar results in depicting the percentage of cortical bone involvement, with great sensitivity and specificity (p < 0.005). There were no significant intra- or inter-examiner differences between axial/MPR images and cross sectional images with regard to sensitivity and specificity. CBCT showed results similar to those of MSCT for the identification of the number of simulated bone lesions. Cross sectional slices and axial/MPR images presented high accuracy, proving useful for bone lesion diagnosis.

Comparison between cone-beam and multislice computed tomography for identification of simulated bone lesions

There are many studies that compare the accuracy of multislice (MSCT) and cone beam (CBCT) computed tomography for evaluations in the maxillofacial region. However, further studies comparing both acquisition techniques for the evaluation of simulated mandibular bone lesions are needed. The aim of this study was to compare the accuracy of MSCT and CBCT in the diagnosis of simulated mandibular bone lesions by means of cross sectional images and axial/MPR slices. Lesions with different dimensions, shape and locularity were produced in 15 dry mandibles. The images were obtained following the cross sectional and axial/MPR (Multiplanar Reconstruction) imaging protocols and were interpreted independently. CBCT and MSCT showed similar results in depicting the percentage of cortical bone involvement, with great sensitivity and specificity (p < 0.005). There were no significant intra- or inter-examiner differences between axial/MPR images and cross sectional images with regard to sensitivity and specificity. CBCT showed results similar to those of MSCT for the identification of the number of simulated bone lesions. Cross sectional slices and axial/MPR images presented high accuracy, proving useful for bone lesion diagnosis.

Assessment of simulated mandibular condyle bone lesions by cone beam computed tomography.

There are many limitations to image acquisition, using conventional radiography, of the temporomandibular joint (TMJ) region. The Computed Tomography (CT) scan is a better option, due to its higher accuracy, for purposes of diagnosis, surgical planning and treatment of bone injuries. The aim of the present study was to analyze two protocols of cone beam computed tomography for the evaluation of simulated mandibular condyle bone lesions. Spherical lesions were simulated in 30 dry mandibular condyles, using dentist drills and drill bits sizes 1, 3 and 6. Each of the mandibular condyles was submitted to cone beam computed tomography (CBCT) using two protocols: 1) axial, coronal and sagittal multiplanar reconstruction (MPR); and 2) sagittal plus coronal slices throughout the longitudinal axis of the mandibular condyles. For these protocols, 2 observers analyzed the CBCT images independently, regarding the presence or not of injuries. Only one of the observers, however, performed on 2 different occasions. The results were compared to the gold standard, evaluating the percentage of agreement, degree of accuracy of CBCT protocols and observers' examination. The z test was used for the statistical analysis. The results showed there were no statistically significant differences between the 2 protocols. There was greater difficulty in the assessment of small-size simulated lesions (drill # 1). From the results of this study, it can be concluded that CBCT is an accurate tool for analyzing mandibular condyle bone lesions, with the MPR protocol showing slightly better results than the sagittal plus coronal slices throughout the longitudinal axis.

Assessment of simulated mandibular condyle bone lesions by cone beam computed tomography

There are many limitations to image acquisition, using conventional radiography, of the temporomandibular joint (TMJ) region. The Computed Tomography (CT) scan is a better option, due to its higher accuracy, for purposes of diagnosis, surgical planning and treatment of bone injuries. The aim of the present study was to analyze two protocols of cone beam computed tomography for the evaluation of simulated mandibular condyle bone lesions. Spherical lesions were simulated in 30 dry mandibular condyles, using dentist drills and drill bits sizes 1, 3 and 6. Each of the mandibular condyles was submitted to cone beam computed tomography (CBCT) using two protocols: 1) axial, coronal and sagittal multiplanar reconstruction (MPR); and 2) sagittal plus coronal slices throughout the longitudinal axis of the mandibular condyles. For these protocols, 2 observers analyzed the CBCT images independently, regarding the presence or not of injuries. Only one of the observers, however, performed on 2 different occasions. The results were compared to the gold standard, evaluating the percentage of agreement, degree of accuracy of CBCT protocols and observers' examination. The z test was used for the statistical analysis. The results showed there were no statistically significant differences between the 2 protocols. There was greater difficulty in the assessment of small-size simulated lesions (drill # 1). From the results of this study, it can be concluded that CBCT is an accurate tool for analyzing mandibular condyle bone lesions, with the MPR protocol showing slightly better results than the sagittal plus coronal slices throughout the longitudinal axis.

Avaliação comparativa entre duas técnicas cirúrgicas empregada para remoção de tórus mandibular: relato de casos / Comparative evaluation of two surgical techniques applied to remove mandibular torus: case reports

Tórus são lesões não patológicas que acometem ossos maxilares. Sua remoção cirúrgica é indicada quando este se torna ulcerado por traumatismos locais insidiosos ou quando se configura um problema durante as reabilitações protéticas. Realizamos, neste estudo, uma avaliação comparativa entre duas técnicas cirúrgicas empregadas para remoção do tórus mandibulares com finalidade protética...

Tori are non pathological lesions that involve maxilary bones. Their surgical removal is indicated when this became ulcerated by insidious local trauma or when there is a problem during prosthetic rehabiblitation. The main goal of this study was to evaluate two different surgical technique applied to remove the mandibular...

Sorriso gengival: cirurgia ressectiva coadjuvante à estética dental / Gingival smile: resective surgery coadjuvant to the dental

Objetivo: relatar um caso de uma paciente que apresentou relação desarmônica entre o sorriso gengival - também causado pela presença da linha labial alta e, pela discrepância entre o comprimento curto das coroas clínicas dos dentes ântero-superiores. Descrição do caso: foram discutidas as vantagens, desvantagens, benefícios, indicações, contra-indicações, descrição da técnica de gengivectomia e a relação de harmonia entre estética dental e gengival. Conclusão: a cirurgia ressectiva gengival (gengivectomia) é um procedimento efetivo coadjuvante na adequação gengival em relação à estética dental, visando não apenas o resultado estético satisfatório, como também a manutenção salutar do periodonto.

Aim: report a case of the patient who presented relationship disharmonic between gingival smiles - also caused by presence of the high line lip - and discrepancy between the short lengths of the anterior superior teeth clinical crowns. Case description: the advantages, disadvantages, benefits, indications, contraindications, description of the gingivectomy technique and the harmony relationship between dental and gingival esthetics were discussed. Conclusion: gingival resective surgery (gingivectomy) is a co adjuvant effective procedure at the gingival conditioning reference to the dental esthetic, with purpose not only satisfactory esthetic results, how also the periodontal healthy maintenance.

Influence of dental metallic artifact from multislice CT in the assessment of simulated mandibular lesions.

OBJECTIVE: This study evaluated the influence of metallic dental artifacts on the accuracy of simulated mandibular lesion detection by using multislice technology. MATERIAL AND METHODS: Fifteen macerated mandibles were used. Perforations were done simulating bone lesions and the mandibles were subjected to axial 16 rows multislice CT images using 0.5 mm of slice thickness with 0.3 mm interval of reconstruction. Metallic dental restorations were done and the mandibles were subjected again to CT in the same protocol. The images were analyzed to detect simulated lesions in the mandibles, verifying the loci number and if there was any cortical perforation exposing medullar bone. The analysis was performed by two independent examiners using e-film software. RESULTS: The samples without artifacts presented better results compared to the gold standard (dried mandible with perforations). In the samples without artifacts, all cortical perforation were identified and 46 loci were detected (of 51) in loci number analysis. Among the samples with artifacts, 12 lesions out of 14 were recognized regarding medullar invasion, and 40 out of 51 concerning loci number. The sensitivity in samples without artifacts was 90% and 100% regarding loci number and medullar invasion, respectively. In samples with artifacts, these values dropped to 78% and 86%, respectively. The presence of metallic restorations affected the sensitivity values of the method, but the difference was not significant (p>0.05). CONCLUSIONS: Although there were differences in the results of samples with and without artifacts, the presence of metallic restoration did not lead to misinterpretation of the final diagnosis. However, the validity of multislice CT imaging in this study was established for detection of simulated mandibular bone lesions.

Influence of dental metallic artifact from multislice CT in the assessment of simulated mandibular lesions

OBJECTIVE: This study evaluated the influence of metallic dental artifacts on the accuracy of simulated mandibular lesion detection by using multislice technology. MATERIAL AND METHODS: Fifteen macerated mandibles were used. Perforations were done simulating bone lesions and the mandibles were subjected to axial 16 rows multislice CT images using 0.5 mm of slice thickness with 0.3 mm interval of reconstruction. Metallic dental restorations were done and the mandibles were subjected again to CT in the same protocol. The images were analyzed to detect simulated lesions in the mandibles, verifying the loci number and if there was any cortical perforation exposing medullar bone. The analysis was performed by two independent examiners using e-film software. RESULTS: The samples without artifacts presented better results compared to the gold standard (dried mandible with perforations). In the samples without artifacts, all cortical perforation were identified and 46 loci were detected (of 51) in loci number analysis. Among the samples with artifacts, 12 lesions out of 14 were recognized regarding medullar invasion, and 40 out of 51 concerning loci number. The sensitivity in samples without artifacts was 90 percent and 100 percent regarding loci number and medullar invasion, respectively. In samples with artifacts, these values dropped to 78 percent and 86 percent, respectively. The presence of metallic restorations affected the sensitivity values of the method, but the difference was not significant (p>0.05). CONCLUSIONS: Although there were differences in the results of samples with and without artifacts, the presence of metallic restoration did not lead to misinterpretation of the final diagnosis. However, the validity of multislice CT imaging in this study was established for detection of simulated mandibular bone lesions.

Osteochondroma of the temporomandibular joint: a case report.

Osteochondroma of the mandibular condyle has been found in the oral and maxillofacial region rarely. This paper describes a case of osteochondroma of the mandibular condyle in a 20-year-old woman, who was referred to our service with facial asymmetry, prognathic deviation of chin, cross-bite to the contralateral side, changes in condylar morphology, limited mouth opening, and malocclusion. Computed tomography (CT) was performed for better evaluation to the pathological conditions on the temporomandibular joint. Based on the clinical examination, patient history, and complementary exams, the hypothesis of osteochondroma was established. Condylectomy was performed using a preauricular approach with total removal of the lesion. After 3 years of postoperative follow up and orthodontic therapy, the patient is symptom-free, and has normal mouth opening with no deviation in the opening pattern.

Osteochondroma of the temporomandibular joint: a case report

Osteochondroma of the mandibular condyle has been found in the oral and maxillofacial region rarely. This paper describes a case of osteochondroma of the mandibular condyle in a 20-year-old woman, who was referred to our service with facial asymmetry, prognathic deviation of chin, cross-bite to the contralateral side, changes in condylar morphology, limited mouth opening, and malocclusion. Computed tomography (CT) was performed for better evaluation to the pathological conditions on the temporomandibular joint. Based on the clinical examination, patient history, and complementary exams, the hypothesis of osteochondroma was established. Condylectomy was performed using a preauricular approach with total removal of the lesion. After 3 years of postoperative follow up and orthodontic therapy, the patient is symptom-free, and has normal mouth opening with no deviation in the opening pattern.

Osteocondroma de côndilo mandibular é raro na região craniofacial. Este artigo descreve um caso de osteocondroma de côndilo mandibular em uma mulher de 20 anos que foi encaminhada ao nosso serviço apresentando assimetria facial, desvio de mento, mordida cruzada para o lado contralateral, alterações na morfologia condilar, limitação de abertura bucal e maloclusão. Tomografia computadorizada foi realizada para melhor avaliação da condição patológica da ATM. Devido à base no exame clínico, histórico do paciente e exames complementares, foi estabelecida uma hipótese de osteocondroma. Um procedimento de condilectomia utilizando abordagem preauricular com uma total remoção da lesão foi executado. Após três anos de acompanhamento pós-operatório e ortodôntico, o paciente está livre dos sintomas e tem uma abertura normal sem desvio de padrão durante a abertura.

Evaluation of simulated bone lesion in the head of the mandible by using multislice computed tomography.

UNLABELLED: Conventional radiography has shown limitation in acquiring image of the ATM region, thus, computed tomography (CT) scanning has been the best option to the present date for diagnosis, surgical planning and treatment of bone lesions, owing to its specific properties. OBJECTIVE: The aim of the study was to evaluate images of simulated bone lesions at the head of the mandible by multislice CT. MATERIAL AND METHODS: Spherical lesions were made with dental spherical drills (sizes 1, 3, and 6) and were evaluated by using multislice CT (64 rows), by two observers in two different occasions, deploying two protocols: axial, coronal, and sagittal images, and parasagittal images for pole visualization (anterior, lateral, posterior, medial and superior). Acquired images were then compared with those lesions in the dry mandible (gold standard) to evaluate the specificity and sensibility of both protocols. Statistical methods included: Kappa statistics, validity test and chi-square test. Results demonstrated the advantage of associating axial, coronal, and sagittal slices with parasagittal slices for lesion detection at the head of the mandible. RESULTS: There was no statistically significant difference between the types of protocols regarding a particular localization of lesions at the poles. CONCLUSIONS: Protocols for the assessment of the head of the mandible were established to improve the visualization of alterations of each of the poles of the mandible's head. The anterior and posterior poles were better visualized in lateral-medial planes while lateral, medial and superior poles were better visualized in the anterior-posterior plane.

Evaluation of simulated bone lesion in the head of the mandible by using multislice computed tomography

Conventional radiography has shown limitation in acquiring image of the ATM region, thus, computed tomography (CT) scanning has been the best option to the present date for diagnosis, surgical planning and treatment of bone lesions, owing to its specific properties. OBJECTIVE: The aim of the study was to evaluate images of simulated bone lesions at the head of the mandible by multislice CT. MATERIAL AND METHODS: Spherical lesions were made with dental spherical drills (sizes 1, 3, and 6) and were evaluated by using multislice CT (64 rows), by two observers in two different occasions, deploying two protocols: axial, coronal, and sagittal images, and parasagittal images for pole visualization (anterior, lateral, posterior, medial and superior). Acquired images were then compared with those lesions in the dry mandible (gold standard) to evaluate the specificity and sensibility of both protocols. Statistical methods included: Kappa statistics, validity test and chi-square test. Results demonstrated the advantage of associating axial, coronal, and sagittal slices with parasagittal slices for lesion detection at the head of the mandible. RESULTS: There was no statistically significant difference between the types of protocols regarding a particular localization of lesions at the poles. CONCLUSIONS: Protocols for the assessment of the head of the mandible were established to improve the visualization of alterations of each of the poles of the mandible's head. The anterior and posterior poles were better visualized in lateral-medial planes while lateral, medial and superior poles were better visualized in the anterior-posterior plane.

Quantitative CT analysis of the glabellar and anterior nasal spine regions for the placement of implants for nasal prosthesis retention.

OBJECTIVES: The aim of this study was to determine the precision of the measurements of 2 craniometric anatomic points--glabella and anterior nasal spine--in order to verify their possibility as potential locations for placing implants aimed at nasal prostheses retention. METHODS: Twenty-six dry human skulls were scanned in a high-resolution spiral tomography with 1-mm axial slice thickness and 1-mm interval reconstruction using a bone tissue filter. Images obtained were stored and transferred to an independent workstation containing e-film imaging software. The measurements (in the glabella and anterior nasal fossa) were made independently by 2 observers twice for each measurement. Data were submitted to statistical analysis (parametric t test). RESULTS: The results demonstrated no statistically significant difference between interobserver and intraobserver measurements (P > .05). The standard error was found to be between 0.49 mm and 0.84 mm for measurements in bone protocol, indicating a high level of precision. CONCLUSIONS: The measurements obtained in anterior nasal spine and glabella were considered precise and reproducible. Mean values of such measurements pointed to the possibility of implant placement in these regions, particularly in the anterior nasal spine.

3-D volume rendering maxillofacial analysis of angular measurements by multislice CT.

OBJECTIVE: This study was designed to determine the precision and accuracy of angular measurements using three-dimensional computed tomography (3D-CT) volume rendering by computer systems. STUDY DESIGN: The study population consisted of 28 dried skulls that were scanned with a 64-row multislice CT, and 3D-CT images were generated. Angular measurements, (n = 6) based upon conventional craniometric anatomical landmarks (n = 9), were identified independently in 3D-CT images by 2 radiologists, twice each, and were then performed by 3D-CT imaging. Subsequently, physical measurements were made by a third examiner using a Beyond Crysta-C9168 series 900 device. RESULTS: The results demonstrated no statistically significant difference between interexaminer and intraexaminer analysis. The mean difference between the physical and 3-D-based angular measurements was -1.18% and -0.89%, respectively, for both examiners, demonstrating high accuracy. CONCLUSION: Maxillofacial analysis of angular measurements using 3D-CT volume rendering by 64-row multislice CT is established and can be used for orthodontic and dentofacial orthopedic applications.

Validation of computed tomography protocols for simulated mandibular lesions: a comparison study.

Computed tomography is the choice technique to assess oral and maxillofacial osseous lesions because it provides hard and soft tissues visualization in one examination without superimposition of surrounding structures. This examination offers a significant advance in maxillofacial lesions detection with an excellent anatomic resolution. The aim of this research was to evaluate the validity of two protocols, in axial sections, in simulated mandibular lesions. Two CT protocols were obtained in dry mandibles in which perforations were done simulating lesions. Two observers, previously calibrated, evaluated the images according to different parameters. The results indicated that the sensitivity and specificity in lesion detection were 100% for both protocols, but the detection of loci number of multilocular lesions and the location and detection of medullar invasion obtained reduced validity values, which were influenced by the acquisition protocol. We concluded that thinner axial slices and reconstructions were more effective in detecting early medullar invasion and loci number. Thicker protocols were not considered appropriate to detect multilocular lesions and early stages of medullar invasion.

Aplicação de medidas cefalométricas em 3D-TC / Application of cephalometric measurements in 3D-TC

OBJETIVO: o objetivo desta pesquisa foi avaliar a precisão e acurácia (validade) de medidas cefalométricas lineares em imagens reconstruídas em terceira dimensão (3D), pela técnica de volume, a partir da tomografia computadorizada (TC) multislice. METODOLOGIA: o material da pesquisa consistiu de 10 (dez) crânios secos, previamente selecionados, sem distinção de etnia ou gênero, os quais foram submetidos à TC multislice 16 cortes com 0,5mm de espessura por 0,3mm de intervalo de reconstrução. Posteriormente, os dados obtidos foram enviados para uma estação de trabalho independente, contendo o programa Vitrea®. Os pontos cefalométricos (n=13) foram localizados e as respectivas medidas ósseas lineares (n=15) foram realizadas por 2 examinadores, previamente treinados, medindo cada um duas vezes, independentemente, em 3D. As medidas físicas foram obtidas por um terceiro examinador, utilizando um paquímetro digital. A análise dos dados foi realizada mediante um estudo comparativo entre as medidas inter e intra-examinadores, em 3D-TC, e entre estas e as medidas físicas obtidas diretamente nos crânios, utilizando ANOVA (análise de variância). RESULTADOS: não foram encontradas diferenças estatisticamente significantes entre os valores das medidas inter e intra-examinadores, nem entre as medidas físicas e em 3D, com p>0,6 para todas as medidas. O erro percentual foi de 2,05 por cento para as medidas interexaminadores e de 2,11 por cento para as medidas intra-examinadores. A média do erro percentual entre as medidas físicas e em 3D variou de 0,96 por cento a 1,47 por cento. CONCLUSÃO: todas as medidas cefalométricas lineares foram consideradas precisas e acuradas utilizando a técnica de volume em 3D por meio da TC multislice.

AIM: To test the precision and accuracy of conventional linear cephalometric measurements in 3D reconstructed images using a multislice CT. METHODS: The study population consisted of 10 dry skulls, previously selected, without distinction of ethnic group and sex, which were submitted to a multislice CT 16 slices using 0.5mm of slice thickness and 0.3mm of interval of reconstruction. Subsequently the data was sent to an independent workstation. Conventional craniofacial landmarks (n=13), usually applied to facial orthopedic and orthodontic treatment planning, were localized and linear measurements (n=15) were obtained by 2 radiologists, twice each, independently, in 3D-CT images. In total 600 measurements were made. The correspondent physical measurements were obtained by a third examiner using a digital caliper. Statistical evaluation of the measurements was carried out regarding to inter and intra-examiner, in 3D-CT, and between image and physical measurements from dry skulls, using analysis of variance. RESULTS AND CONCLUSIONS: There were no statistically significant differences between inter and intra-examiner measurements or between imaging and physical measurements. The results also showed an inter-examiner variability error of 2.05 percent, and an intra-examiner variability error of 2.11 percent. There were also no statistically significant differences between imaging and physical measurements with p>0.6 for all measurements. The mean difference was from 0.96 percent to 1.47 percent for all measurements. The validity of linear cephalometric measurements was established using 3D volume rendering from a multislice CT with high precision and accuracy.

Validation of computed tomography protocols for simulated mandibular lesions: a comparison study

Computed tomography is the choice technique to assess oral and maxillofacial osseous lesions because it provides hard and soft tissues visualization in one examination without superimposition of surrounding structures. This examination offers a significant advance in maxillofacial lesions detection with an excellent anatomic resolution. The aim of this research was to evaluate the validity of two protocols, in axial sections, in simulated mandibular lesions. Two CT protocols were obtained in dry mandibles in which perforations were done simulating lesions. Two observers, previously calibrated, evaluated the images according to different parameters. The results indicated that the sensitivity and specificity in lesion detection were 100 percent for both protocols, but the detection of loci number of multilocular lesions and the location and detection of medullar invasion obtained reduced validity values, which were influenced by the acquisition protocol. We concluded that thinner axial slices and reconstructions were more effective in detecting early medullar invasion and loci number. Thicker protocols were not considered appropriate to detect multilocular lesions and early stages of medullar invasion.

A tomografia Computadorizada é a técnica de escolha no exame de lesões ósseas orais e maxilo-faciais porque proporciona a visualização de tecidos duros e moles em aquisição única e sem sobreposição de estruturas adjacentes. Este exame oferece um avanço significativo na detecção de lesões maxilo-faciais, com excelente resolução anatômica. O objetivo desta pesquisa foi avaliar a validade de dois protocolos, em secções axiais, em lesões simuladas de mandíbula. Dois protocolos de TC foram obtidos em mandíbulas secas em que foram feitas perfurações, simulando lesões. Dois observadores previamente calibrados avaliaram as imagens seguindo parâmetros diversos. Como resultados pudemos observar que a sensibilidade e a especificidade foram de 100 por cento para detecção de lesões para ambos os protocolos, mas a detecção do número de lojas das lesões multiloculares e a localização e detecção de invasão medular obtiveram valores reduzidos em sua validade, o que foi influenciado pelo protocolo de aquisição. Concluiu-se que secções axiais e reconstruções mais finas foram mais efetivas na detecção de invasão medular precoce e de lojas tumorais. Protocolos mais espessos não foram considerados apropriados para a detecção de lesões multiloculares e estágios iniciais de invasão medular.

CT-based analysis of malignant tumor volume and localization: a preliminary study

O propósito desta pesquisa foi correlacionar medidas volumétricas de lesões malignas em reconstruções tridimensionais (TC-3D) com a resposta ao tratamento e verificar o grau de envolvimento ósseo dessas lesões, aplicando-se protocolos de imagem específicos associados à computação gráfica. Foram estudados 17 indivíduos portadores de lesões malignas maxilofaciais que haviam sido submetidos à tomografia computadorizada espiral (TC-2D). Os dados originais foram transferidos para uma estação de trabalho independente, utilizando um programa para imagens volumétricas, com o qual dois observadores obtiveram medidas de área e volume das lesões, independentemente, 3 vezes cada um, no pré e pós-tratamento. O protocolo de segmentação foi aplicado para avaliação do comprometimento ósseo. A diferença entre os valores obtidos na análise da TC e no padrão ouro não foi considerada significante (p > 0,05). Considerando o envolvimento ósseo, obtiveram-se três falsos-negativos em análise das reconstruções multiplanares (TC-RMP) e nenhum falso-negativo em análise da TC-3D por meio do protocolo de segmentação. A utilização de recursos como reconstrução em TC-3D pode ser um fator diferencial e de grande valia para aumentar opções quanto a localização, dimensões e esclarecimento de componentes de diversas lesões.