Evaluation of marginal and internal fit of ceramic crown copings.

OBJECTIVES: (1) To measure the marginal and internal adaptation of different prosthetic crowns infrastructures (IS); (2) to analyze two types of methodologies (replica and weight technique) used to evaluate the adaptation of indirect restorations. METHODS: Ceramic IS were fabricated using CAD/CAM technology and slip-casting technique, and metal IS were produced by casting (n=10). For each experimental group, the adaptation was evaluated with the replica (RT) and the weight technique (WT), using an impression material (low viscosity silicon) to simulate the luting agent. Cross-sectional images of the silicon replica were obtained and analyzed with Image J software to measure the low viscosity silicon layer thickness at pre-determined points. The silicon layer was also weighted. Results were statistically analyzed with ANOVA and Tukey's test (α=0.05). Pearson correlation was used to analyze the relation between the two types of evaluation methods. RESULTS: All IS evaluated showed clinically acceptable internal and marginal adaptation. Metal IS showed the best adaptation, irrespective of the measuring technique (RT and WT). The IS produced by CAD-CAM showed greater gap values at the occlusal area than at other evaluated regions. The IS produced by the dental laboratory technician showed similar gap values at all evaluated regions. There is no correlation between RT and WT (p>0.05). SIGNIFICANCE: Different levels of adaptation were found for the different experimental groups and for the different evaluation methods. However, all IS evaluated showed clinically acceptable values of marginal and internal adaptation.

Relação diagnóstica entre folículo pericoronário e cisto dentígero / Diagnostic relationship between pericoronal follicle and dentigerous cyst

Objetivo: Relacionar os diagnósticos histopatológico e radiográfico para casos de folículo pericoronário e cisto dentígero de terceiros molares inferiores. Métodos: Foram selecionadas, em arquivos, as lâminas histológicas e as respectivas radiografias panorâmicas dos casos diagnosticados como folículo pericoronário e cisto dentígero. Obteve-se uma amostra de 62 casos elegíveis: 45 folículos pericoronários e 17 cistos dentígeros. Para confirmação do diagnóstico histopatológico foram reavaliadas as informações clínicas dos pacientes e as lâminas histológicas. No exame radiográfico foi realizada a mensuração das imagens radiolúcidas pericoronárias, sendo que medidas iguais ou maiores do que 2,5mm foram utilizadas como parâmetro para o diagnóstico de cistos dentígeros. A comparação entre os resultados dos diagnósticos histopatológico e radiográfico, atribuídos aos 62 casos apurados, foi feita pelos testes de sensibilidade, especificidade e valor preditivo. Resultados: Os resultados mostraram que a medida de 2,5mm para o halo radiolúcido pericoronário foi pouco sensível no diagnóstico de cisto dentígero. Conclusão: O diagnóstico diferencial das imagens radiolúcidas pericoronárias deve ser esclarecido pela soma de dados clínicos, radiográficos e histopatológicos.

Objective: Associate the histopathological and radiographic diagnoses of cases of pericoronal follicle and dentigerous cyst of the mandibular third molars. Methods: Histological slides and the respective panoramic radiographs of cases diagnosed as pericoronal follicle and dentigerous cyst were selected from files. A sample of 62 eligible cases was obtained: 45 pericoronal follicles and 17 dentigerous cysts. In order to confirm the histopathological diagnosis, the clinical information and histological slides of the patients were reassessed. The pericoronal radiolucent images in the radiographs were measured and those equal to or greater than 2.5 mm were used as parameter for the diagnosis of dentigerous cysts. The comparison between the results of the histopathological and radiographic diagnoses attributed to the 62 cases was done by sensitivity and specificity tests and by predictive value. Results: The results showed that a size of 2.5 mm for the pericoronal radiolucent halo was not very sensitive for the diagnosis of dentigerous cyst. Conclusion: The differential diagnosis of the pericoronal radiolucent images must be clarified by the sum of clinical, histopathological and radiographic data.