Clinical , Histological and Radiological Aspects regarding the Influence of Some External Factors on the Pulp - Dentin Complex

The present study aimed at assesssing – by clinical, histological and radiological investigations – the influence of some external factors on the pulp-dentin complex, and at providing a causal interpretation of the structural changes observed. Materials and methods. Clinical and radiological exams were performed on 65 old patients with ages between 60-75, and also on 40 young patients with ages between 20-35, presenting different dental-periodontal pathologies. The pulp-dentin complex was submitted to a morphopathological examination, to highlight the structural changes observed at microscopic level. Fragments of dental pulp were imersed in a 4% formaldehyde solution with phosphate buffer 0.1 M., pH 7.2, for 12 -14 hours, at a temperature of 4oC, and 3-5 μm thick slices were prepared. The slices were coloured with hematoxylin-eosine (HE), by the trichromic technique – Masson. Photographies were taken with a Zeiss microscope, with Kodak 200 ASA. Results. Significant differences were observed, between the two groups of patients, as to the external factors that produce structural changes on pulp-dentin organ. In the group of young patients dental caries and coronal fillings prevailed, while the group of old patients was mostly associated with atrition and chronic marginal periodontitis. Out of the 40 young patients, 30 presented chronic dental caries (75%), while, among the 65 old patients, only 24 presented dental caries (36.9%). The percentages of coronary fillings between the two study groups were close, which could be considered as one of the causes producing changes in the pulp-dentin organ, following aggresive preparation of cavities, the action of materials used for the protection of pulp-dentin complex or of the materials used for coronry fillings. Conclusions. Dental pulp has a remarkable ability to counteract the action of harmful factors, producing a mineral barrier and stimulating the reparatory processes. Changes in the endodontic space can be produced in both experimental groups, but more intensely and more frequently in the old patients. The endodontic space is modified, both physiologically and pathologically, including deposition of secondary or tertiary dentin (reactionary or reparative dentin), as well as pulp reactions, such as: inflammation, fibrosis, calcium degeneration or vacuolisis. At cell level, microsocopic images showed a decrease of the odontoblasts number and sizes, as well as a reduced fibroblasts/fibrocytes ratios. These changes are associated with progressive vascular and nervous changes, that can be considered both theis cause and effect. These pathological transformations are related with a more difficult preparation of the endodontic space and can be considered as having a major role in the failure of endodontic therapy.