Microestrutura da dentina observada sob diferentes condições clínicas empregando-se microscopia eletrônica e EDS

A proposta deste trabalho foi analisar qualitativa e semiquantitativamente, em M.E.V. - Tecnica Convencional, por Retroespalhamento de Eletrons (BSE) e por Espectroscopia de Dispersao de Raios-X (E.D.S.) - a microestrutura dentinaria de dentes em diferentes condicoes clinicas. Formaram-se 7 grupos, com 5 dentes cada grupo: I- inclusos jovens (IJ); II- higidos jovens (HJ); III- higidos adultos (HA); IV- com lesao cariosa oclusal (LCO); V- com lesao cariosa cervical (LCC); VI- com exposicao radicular (ER) e VII- com lesao cervical nao cariosa (LCNC). Apos as extracoes, os dentes foram imediatamente fixados em Karnovsky. As porcoes radiculares e o esmalte coronario foram seccionados, preservando-se o terco cervical dos dentes. Os especimes dentarios foram divididos em duas metades, ambas contendo as superficies vestibulares quanto as linguais, totalizando 70 especimes. Cuidado especial foi tomado nos grupos com LCO, LCC e LCNC, garantindo que as lesoes fizessem parte de suas duas seccoes. A analise morfologica foi realizada sobre area de dentina fraturada, em tres regioes: proximo a superficie externa, no terco medio e proximo a polpa. Os especimes foram desidratados em concentracao ascendente de etanol e secados em ponto critico. Metade dos especimes foi metalizada com ouro, para analise em M.E.V., e a metade homologa com carbono, para observacao em E.D.S. e BSE. Os grupos IJ e HJ nao mostraram alteracoes morfologicas, tanto na lingual quanto na vestibular. As dentinas peritubular e intertubular e os prolongamentos odontoblasticos (POs) estavam evidentes por toda a extensao dentinaria, assim como fibrilas de colageno margeando toda a superficie interna dos tubulos dentinarios (TDs), muitas vezes lembrando a lâmina limitans (LL). Os grupos LCC e LCO mostraram grande quantidade de cristais e estruturas tubuliformes (ETfs) na dentina abaixo das lesoes, alem das demais estruturas vistas no grupos anteriores. A face lingual das LCCs mostrou-se ausencia de estruturas...(AU) The purpose of this study was to analyze, qualitatively and semiquantitavely, with SEM, BSE and EDS, the dentin microstructure in teeth with different clinical conditions. The teeth were divided in 7 groups (n=5 each one): I- Young non erupted teeth (YNET), II- Young sound teeth (YST), III- Old sound teeth (OST), IV- Occlusal carious lesion (OCL), V- Cervical carious lesion (CCL), VI- Root exposure (RE) and VII- Non carious cervical lesion (NCCL). After extraction the teeth were immediately fixed in Karnovsky. Crows and root were cut off in such a way to preserve the cervical third for the purposes of this investigation. The cervical specimens were fractured in two halves, both containing the lingual and buccal cervical surfaces, totaling 70 specimens. Special care was taken with OCL, CCL and NCCL groups during the fracture to ensure that both fragments enclosed part of their respective lesions. The morphological analysis was performed on the fractured dentin surfaces of both fragments, in three regions: near the external surface, on the middle third and near the pulp chamber. The specimens were dehydrated in ascending series of ethanol concentrations and critical point dried. Half of the specimens were gold sputtered for SEM analysis and the homologous half carbon coated for BSE and EDS observation. The YNET and YST groups showed no morphological changes in both buccal and lingual surfaces. The PD and ID and the OPs were evident throughout the dentin extension. The collagen fibrils were observed layering the walls of dentin tubules in their entire length, resembling the LL. The CCL and OCL groups showed a great amount of Crs and TSs, together with the other same features seen in the previous groups. The lingual surface of the CCL was distinct from the buccal surface and the OPs were limited to the third near the pulp on both surfaces. The RE group did not reveal intratubular structures (ITS). However, on the same group, the diameter of the dentin tubules...(AU)