O objetivo deste estudo foi avaliar a capacidade de identificação de prematuridades oclusais por meio de imagens obtidas de cortes paraxiais de tomografias computadorizadas de feixe cônico. Para este fim, realizou-se um estudo piloto em que 16 pacientes jovens assintomáticos foram submetidos ao exame clínico, incluindo análise oclusal criteriosa, e em seguida foram confeccionados dispositivos desprogramadores individuais (“JIG de Lucia”). Mediante manipulação mandibular e marcação interoclusal com papel carbono (Accufilm) identificou-se clinicamente o contato prematuro em relação cêntrica (RC) de cada paciente. Posteriormente estes dispositivos foram ajustados na posição de contato cêntrico e utilizados durante os exames tomográficos para que se pudessem obter imagens tomográficas na posição de relação cêntrica. Após o processamento das imagens, estas foram analisadas com o intuito de identificar prematuridades oclusais nas imagens visualizadas por 30 profissionais divididos de acordo com as áreas de atuação (Oclusão, Clínica Geral e Radiologia, n=10 para cada área) e tempo de exercício profissional (<5; entre 5 e 10; e >10 anos). Mediante comparação entre os contatos prematuros identificados na análise clínica oclusal e as imagens tomográficas apontadas pelos profissionais como áreas de contatos prematuros, foram calculados os índices de concordância entre essas duas variáveis. Os dados obtidos foram analisados estatisticamente pela Análise de Variância ANOVA e teste de Scott-Knott (α=0,05). Os resultados deste estudo demonstraram que a identificação de prematuridades oclusais por meio de cortes paraxiais de tomografias computadorizadas de feixe cônico mostrou-se como um método de confiabilidade média.

The aim of this study was to evaluate the ability to identify occlusal prematurity by images from paraxial slices of cone-beam computed tomography (CBCT). For such purpose, a pilot study was performed in which 16 asymptomatic young patients were subjected to a clinical examination, including a careful occlusal analysis and then individual deprogrammer devices (“Lucia's JIG”) were fabricated. Premature contacts were clinically identified in centric relation (CR) for each patient by jaw manipulation and interocclusal marking with articulating paper (Accufilm). Subsequently, these devices were adjusted in CR and used during the tomographic exams in such a way that CBCT in CR could be obtained. After routine processing, the images were analyzed in order to identify occlusal prematurity on the displayed images by 30 professionals divided according to areas of activity (occlusion specialist, general practitioner and radiologist; n=10 per area) and time of professional experience (less than 5, between 5 and 10, and over 10 years). By comparing the premature contacts identified in the clinical analysis and CBCT images, an agreement index between these two variables was calculated. Data were analyzed statistically by ANOVA and Scott-Knott test (α=0.05). The results showed that the identification of occlusal prematurity by paraxial CBCT slices was proven to be a method of average reliability.

The magnitude of occasional discrepancies between the centric relation and maximal intercuspation positions remains a controversial subject. This study quantitatively evaluated the possible discrepancies in the condyle/mandibular fossa relationship between these positions using cone-beam computed tomography. Twenty young and asymptomatic volunteers were distributed equally into normal occlusion and Angle Class I, II and III malocclusion groups. They were submitted to one tomographic scan in maximal intercuspation and one in centric relation. Measurements were performed on lateral and frontal cuts of the patients' temporomandibular joints, and the data collected were compared using Student's t test at a significance level of 5%. The results showed that there were no statistically significant differences between the centric relation and maximal intercuspation positions in young and asymptomatic patients with practically intact dentitions using cone-beam computed tomography.

This research consisted of a quantitative assessment, and aimed to measure the possible discrepancies between the maxillomandibular positions for centric relation (CR) and maximum intercuspation (MI), using computed tomography volumetric cone beam (cone beam method). The sample of the study consisted of 10 asymptomatic young adult patients divided into two types of standard occlusion: normal occlusion and Angle Class I occlusion. In order to obtain the centric relation, a JIG device and mandible manipulation were used to deprogram the habitual conditions of the jaw. The evaluations were conducted in both frontal and lateral tomographic images, showing the condyle/articular fossa relation. The images were processed in the software included in the NewTom 3G device (QR NNT software version 2.00), and 8 tomographic images were obtained per patient, four laterally and four frontally exhibiting the TMA's (in CR and MI, on both sides, right and left). By means of tools included in another software, linear and angular measurements were performed and statistically analyzed by student t test. According to the methodology and the analysis performed in asymptomatic patients, it was not possible to detect statistically significant differences between the positions of centric relation and maximum intercuspation. However, the resources of cone beam tomography are of extreme relevance to the completion of further studies that use heterogeneous groups of samples in order to compare the results.