Texture analysis in cone-beam computed tomographic images of medication-related osteonecrosis of the jaw.

Purpose: The aim of this study was to evaluate changes in the trabecular bone through texture analysis and compare the texture analysis characteristics of different areas in patients with medication-related osteonecrosis of the jaw (MRONJ). Materials and Methods: Cone-beam computed tomographic images of 16 patients diagnosed with MRONJ were used. In sagittal images, 3 regions were chosen: active osteonecrosis (AO); intermediate tissue (IT), which presented a zone of apparently healthy tissue adjacent to the AO area; and healthy bone tissue (HT) (control area). Texture analysis was performed evaluating 7 parameters: secondary angular momentum, contrast, correlation, sum of squares, inverse moment of difference, sum of entropies, and entropy. Data were analyzed using the Kruskal-Wallis test with a significance level of 5%. Results: Comparing the areas of AO, IT, and HT, significant differences (P<0.05) were observed. The IT and AO area images showed higher values for parameters such as contrast, entropy, and secondary angular momentum than the HT area, indicating greater disorder in these tissues. Conclusion: Through texture analysis, changes in the bone pattern could be observed in areas of osteonecrosis. The texture analysis demonstrated that areas visually identified and classified as IT still had necrotic tissue, thereby increasing the accuracy of delimiting the real extension of MRONJ.

Influence of Voxel Size on CBCT Images for Dental Implants Planning.

OBJECTIVE: This study was developed to evaluate the influence of voxel size on bone measurements for implant planning. MATERIALS AND METHODS: The research was performed by using edentulous synthetic human mandibles with different levels of bone resorption. For each mandible, height and bone thickness were measured with a digital caliper. The PaX-i3d device was used to acquire the volumes of the five mandibles, with 50kVp, 4 mA, and a voxel size of 0.08 mm. After the acquisition, the images were reconstructed in the software CS three-dimensional Imaging, with four different sizes of voxels: 0.1, 0.2, 0.3, and 0.4 mm. All volumes were analyzed by a single evaluator who performed measurements to obtain bone height and thickness, using the reference points that were considered in obtaining the gold standard. The data were analyzed by ANOVA with a significance level of 5%. RESULTS: There was no significant difference in the measurements obtained with different voxel sizes, both for bone height measurements and bone thickness. There was no statistically significant difference in measurements in thickness in comparison to the gold standard. CONCLUSION: When necessary, to measure height and bone thickness, it is possible to recommend voxel images of larger size (0.40 mm) without compromising the quality of the patient's clinical planning.

Influence of Low-Dose Protocols of CBCT on Dental Implant Planning.

PURPOSE: To evaluate the influence of low-dose protocols, with different numbers of basis images, on the precision of linear bone measurements in CBCT images. MATERIALS AND METHODS: Five polyurethane mandibles, with different levels of bone resorption, were used in this in vitro study. To obtain the reference standard, landmarks were made in the mandibular superior and buccal cortices, and then a digital caliper was used to measure the bone height and thickness at these regions. CBCT images were obtained with the PaX-i3D (Vatech) unit set at 50 kV, 4 mA, 0.2-mm voxel size and 50 × 50-mm field of view. Keeping these parameters fixed, each mandible was scanned twice, with different protocols: Low dose (L) had an acquisition time of 24 seconds and 720 basis images, and ultralow dose (UL) had an acquisition time of 15 seconds and 450 basis images. Then, measurements of bone height and thickness were performed on the images, using the previously determined landmarks as reference. The obtained data were submitted to statistical analysis, with a significance level of .05. Analysis of variance, Student t test, and intraclass correlation coefficient were employed. RESULTS: Regarding bone height, there were no significant differences between the measurements obtained with the L and UL protocols (P = .8648). Additionally, the L and UL protocols did not differ in relation to the reference standard (P = .8717 and P = .9928, respectively). Likewise, there were no significant differences between the measurements obtained with the L and UL protocols (P = .7969) for bone thickness, nor between these protocols and the gold standard (P = .7455). CONCLUSION: Considering the great demand for precise measurements in implantology, protocols of low-dose radiation can be used without compromising clinical planning.

Rare presentation of adenomatoid odontogenic tumor in a pediatric patient: a case report.

The adenomatoid odontogenic tumor (AOT) is a painless benign tumor with slow growth, usually asymptomatic. It has three variants: follicular, extrafollicular, and peripheral. In the follicular type, the tumor is associated with an impacted tooth, and maxillary canines are the most frequently affected. Association with primary teeth is very rare. Treatment consists essentially in a total lesion enucleation. The objective of this paper is to present the clinical case of a 7-year-old female patient with an adenomatoid odontogenic tumor associated with the crown of the left lower deciduous canine (73), dislodging it to the mandibular base and consequently shifting and also impacting the permanent lower canine (33). The lesion was treated with careful enucleation, preserving the permanent canine, which then had its eruption path released favoring its migration to an ideal position.

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.

Forame retromolar: sua repercussão clínica e avaliação de 35 mandíbulas secas / The retromolar foramen - the clinical implication and evaluation of 35 dry mandibles

Introdução: O forame retromolar, assim como o canal retromolar, são considerados variações anatômicas pouco frequentes, que se localizam na região de trígono retromolar. Seu conteúdo é derivado do nervo alveolar inferior juntamente com arteríolas e vênulas. Objetivo: Chamar a atenção dos Cirurgiões-Dentistas quanto à importância clínica do forame retromolar e seu canal, por meio da avaliação de sua incidência em mandíbulas secas. Material e método: Foram analisadas 35 mandíbulas quanto à presença do forame retromolar e a sua relação com o terceiro molar ou o último dente da arcada, o lado do forame e a distância entre este e a língula, o trajeto do canal, a dimensão do trígono retromolar e outras mensurações. Resultado: Das 35 mandíbulas incluídas no estudo, o forame retromolar foi encontrado em seis (17%), sendo que, em duas mandíbulas, o forame foi encontrado bilateralmente, totalizando oito forames retromolares. A presença desse forame não está relacionada com o último dente do arco, apesar da sua proximidade com essa região (8,99 mm); note-se que a média encontrada entre a distância do forame retromolar e a língula foi de 15,24 mm. Conclusão: Este estudo demonstra que o forame retromolar e o canal retromolar podem ser encontrados ocasionalmente na rotina clínica do Cirurgião-Dentista, explicando assim possíveis falhas nas técnicas anestésicas de bloqueio do nervo alveolar inferior, hemorragias durante procedimentos cirúrgicos e alterações sensoriais nessa região no pós-operatório.

Background: The retromolar foramen as well as the retromolar canal are considered rare anatomical variations and are located in the region of retromolar area and their content is derived from the inferior alveolar nerve?s arterioles and venules. Objective: The aim of this work is to request the attention of dentists regarding the clinical importance of the retromolar foramen and retromolar canal through the evaluation of their presence in dry mandibles. Material and method: Thirty-five mandibles were analyzed for the presence of the retromolar foramen and its relationship with  the third  or last  molar  tooth  of the arch. In addition, the distance between  foramen and  lingula,  the canal  route,  and the size of the  retromolar were evaluated, and other measurements were made. Result: In all mandibles included  in this study, the  retromolar  foramen  was found in  6 (17%). In two mandibles, the foramen was found bilaterally, totaling 8 retromolar foramen. The presence of this foramen is not related to the last tooth arch despite its proximity with this region (8.99 mm); the average distance between the retromolar foramen and lingula was 15.24 mm. Conclusion: This study demonstrates that retromolar foramen and retromolar canal can be found occasionally in routine dental surgery and could explain failures in block anesthesia of inferior alveolar nerve, bleeding during surgical procedures and sensory changes in this region in the postoperative period.

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.

A relação entre os hábitos parafuncionais e a posição do disco articular em pacientes sintomáticos para disfunção têmpero-mandibular / The relationship between parafunctional habits and disc position in symptomatic patients with temporomandibular dysfunction

Os hábitos parafuncionais são descritos como os principais fatores etiológicos da disfunção temporomandibular (DTM). A fim de relacioná-los com tal patologia nas articulações têmporomandibulares, foram selecionados 30 pacientes sintomáticos submetidos a exame clínico e a exame de imagem por ressonância magnética. Após realizados os exames, observou-se que a posição do disco mais prevalente foi o deslocamento com redução bilateral (26,66%), tendo como principal parafunção o apertamento dental, seguido do bruxismo. Com base nesses dados, conclui-se haver concordância entre a presença de hábitos parafuncionais e a presença de sinais e sintomas da DTM, uma vez que essa relação se mostrou presente em 90% dos pacientes examinados

Relaçäo entre as variaçöes de posicionamento do plano sagital mediano e a assimetria mandibular em radiografias panorâmicas / Relation between the positioning variations of midsagittal plane and the mandibular asymetry in panoramic radiographys

O presente trabalho teve como finalidade avaliar o grau de assimetria mandibular produzido por alteraçöes de posicionamento em radiografias panorâmicas. Para tanto, crânios macerados foram posicionados, alterando-se o Plano Sagital Mediano em relaçäo ao feixe central de luz do aparelho panorâmico, sendo realizadas as seguintes alteraçöes: desvio lateral em 2, 4, 6, 8, 10mm; inclinaçäo em 2, 4, 6, 8, 10 graus; e por fim, giro em 2, 4, 6, 8, 10 graus. Os crânios foram classificados quanto ao seu grau de assimetria mandibular quando do posicionamento correto e quando das alteraçöes de posicionamento. Além disso, foi realizada uma análise subjetiva, que teve como finalidade avaliar a capacidade de profissionais em identificar a presença e tipos de erros. Tendo como base os resultados, pode-se concluir que o desvio lateral do Plano Sagital Mediano proporcionou um maior aumento no índice de assimetria mandibular e na avaliaçäo da análise subjetiva, a concordância entre os examinadores foi classificada como leve, de acordo com o teste de Kappa

Avaliaçäo no desempenho de acadêmicos durante tomadas radiográficas periapicais, pela técnica da bissetriz, realizada na Faculdade de Odontologia da Universidade Norte do Paraná (Unopar) / Evaluation of dental students'performance in taking periapical radiographic using the bisectrix technique at Faculdade de Odontologia of the Universidade do Norte do Paraná (Unopar)

Foram feitas a análise e classificaçäo da qualidade dos exames radiográficos realizados por estudantes do terceiro ano de graduaçäo da Faculdade de Odontologia da Unopar. Foi examinado no período de um ano um total de mil radiografias pelos professores da disciplina de radiologia, os quais as classificaram como: ótima - 9,9 por cento; boas - 40,85 por cento, regulares - 40,75 por cento e insatisfatória - 8,5 por cento. Constatou-se que 90,1 por cento dos exames radiográficos apresentaram algum tipo de erro, seja de técnica, seja de processamento. Os erros encontrados em virtude de processamento incorreto tiveram grande expressäo (46,6 por cento); ângulo vertical incorreto (21 por cento) e enquadramento inadequado (19,5 por cento) também foram considerados altos. Os autores constataram que, com o passar do tempo, houve um aumento gradativo no número de radiografias ótimas, observando, assim, uma melhora dos alunos com a prática

Estudo comparativo de diferentes sistemas e recursos radiográficos digitais em mensuraçöes endodônticas / Comparative study of different systems and digital radiographic tools in endodontic measurements

O objetivo do presente trabalho foi avaliar, por meio de mensuraçÖes endodônticas, a eficiência dos recursos digitais, "3D", "negativo" e "cor" verificando o desempenho destes numa análise intra e inter sistemas. Os objetos de estudo se constituíram de 11 dentes uniradiculares extraídos que foram radiografados com limas 6 e com lima 10. Os sistemas empregados foram o CDR (Schick Technologies Inc., NY, EUA), Digora (Soredex Orion Corporation, Helsink, Finlândia) e DenOptix (Gendex Dental Systems, EUA). Cinco foram os examinadores que realizaram as mensuraçöes por emio de réguas digitais. Os dados foram submetidos à análise de variância e ao teste de Tukey. A diferença entre as médias das mensuraçöes realizadas e as medidas reais, apresentou-se estatisticamente significante entre os recursos avaliados para o mesmo sistema (p<0, 01), e para o mesmo recurso entre sistemas diferentes (p<0, 01). No estudo intra sistema, os resultados näo mostraram diferença estatísticano CDR e no Digora para as três ferramentas digitais empregadas, ao contrário do DenOptix onde a "cor" apresentou-se com mais fraco desempenho. Na avaliaçäo inter sistema todos os três recursos estudados foram mais eficientes no digora. Quanto às limas empregadas, o único sistema que mostrou diferença estatística foi o DenOptix

Estudo da eficiência de diferentes sistemas radiográficos nas mensuraçöes endodônticas / Study on the efficiency of different radiographic systems in endodontic measurements

O objetivo do presente trabalho foi avaliar comparativamente a eficiência de diferentes sistemas radiográficos nas mensuraçöes endodônticas, analisando ainda se os resultados alcançados com os dois diâmetros de limas empregados apresentam-se diferentes entre si. Os objetos de estudo foram 11 dentes unirradiculares extraídos e limas endodônticas nos tamanhos 6 e 10. Os sistemas digitais utilizados foram o CDR (Schick Technologies Inc., NY, EUA), o Digora (Soredex Orion Corporation, Helsink, Finlândia) e o DenOptix (Dentsply International/Gendex Dental X-Ray Division, Des Plaines, IL), além do filme E-speed, no sistema filme-base. Cinco foram os examinadores que efetuaram as mensuraçöes. Os dados coletados foram submetidos a análise de variância; encontrou-se diferença estatística (p < 0,01) entre as médias das diferenças das medidas efetuadas e as medidas reais para os diferentes sistemas e limas empregados. Os resultados apontaram o Digora como o sistema de melhor desempenho, tendo-se, na sequência, o filme, o CDR e o DenOptix. As medidas obtidas com limas tamanho 6 e 10 foram estatisticamente diferentes entre os sistemas empregados. Em um mesmo sistema, as medidas obtidas com limas 6 apresentaram diferença estatística em relaçäo às obtidas com limas 10, somente no sistema DenOptix. Assim, foi possível concluir que diferentes sistemas têm tendência a apresentar diferentes níveis de eficiência no que se refere a mensuraçöes endodônticas