Caracterização química e morfológica da cárie relacionada à radiação

Abstract

Among the adverse effects of radiotherapy in the treatment of malignant neoplasms in the head and neck region, radiation-related caries is considered one of the most worrying, since it constitutes a form of caries with great destructive potential and rapid progression, which can lead to total amputation of the crown and complete loss of the dentition, interfering in the quality of life of these patients. It has as its etiology the combination of indirect effects of radiotherapy (hyposalivation, changes in the composition and pH of saliva, mucositis, changes in diet and oral hygiene habits), together with the direct effects on dental structure. Knowing this, studies should be done in order to better understand this change, prevent and treat it. This work involved 3 objectives. Objective 1: to evaluate the literature seeking to condense information on the use of FTIR in the chemical characterization of enamel, dentin and bone. Identifying in this way, spectrum peaks and their attributions related to the diagnosis of alterations and pathologies of mineralized tissues. Objective 2: to investigate the effect of ionizing radiation and salivary flow rateon dentin susceptibility to caries by means of a microcosm biofilm model. Objective 3: to compare a sound dentin to a carious affected dentin of pre-radiotherapy patients and patients submitted to head and neck radiotherapy. Through the literature review, carried out in objective 1, it can be concluded that Fourier transform infrared spectroscopy (FTIR) can provide fundamental information on the molecular structure of organic and inorganic of dental enamel, dentin and bone. It is one of the most versatile analytical techniques for the non-destructive, chemical characterization of samples. Moreover, it is able to detect alterations and pathologies of mineralized tissues, such as dental caries. Objective 2 showed that the microcosm biofilm model promoted demineralization, exposed and altered the organic matrix of dentin. With reduced salivary flow, the mineral alterations were more detectable. Ionizing radiation also promoted changes in the inorganic and organic matrix and the mineral density of dentin. Finally, in the objective 3, dental caries and ionizing radiation led to a hydroxyapatite demineralization and protein degradation. However, caries related to radiation exhibited more pronounced changes, with a diffuse demineralization pattern.