Regeneração óssea de defeitos alveolares usando um cimento odontológico bioativo contendo nano-hidroxiapatita, quitosana, óxido de zinco nanoparticulado e doxiciclina in vivo

Abstract

Oral rehabilitation of patients can be affected by the small amount of bone tissue present in the oral cavity. Bone loss is associated with tooth extractions, periodontal diseases, infections, trauma and congenital diseases. In order to achieve ideal characteristics for the gain and / or recovery of lost bone tissue, bone cements are being used in the treatment of these injuries due to their biocompatibility and osteoconduction properties, contributing to the patients' aesthetic and functional recovery. This study aimed to research the effects of the application of a new dental cement containing nano-hydroxyapatite, nanoparticulate zinc oxide, chitosan, with doxycycline (DHCZ) and without doxycycline (HCZ) on bone regeneration of alveolar defects. Forty six-week-old male Wistar rats, weighing an average of 175 grams, were used. An alveolar bone defect was made after extraction of the left upper first molar, and were randomly filled in four groups: G1: DHCZ cement, G2: HCZ cement, G3: bovine demineralized bone matrix (MODB) and G4: blood clot control. At the end of each experimental time, 14 days (T1) and 28 days (T2) the animals were euthanized and the dissected jaws were kept in 10% formaldehyde for 48 hours. After descaling, the tissues were subjected to histological evaluation with Hematoxylin / Eosin (HE) staining and Masson's trichrome staining and histomorphometric analyzes. Histologically, differences were observed in relation to the degradation of the biomaterial, being greater in DHCZ cement. Newly formed bone trabeculae were present in all groups, but the number and size of the medullary spaces and the number of blood vessels present in them varied between groups. Osteocytes were observed dispersed in the bone matrix within smaller gaps in T2 than in T1 in all groups, and the bone matrix was more organized. The presence of collagen fibers was verified in Masson's trichrome staining in all groups. Histomorphometric analyzes showed that all groups filled with biomaterial had new bone formation above 37%, being higher in the group filled with DHCZ (55%). In T2, the groups filled with biomaterial had a fill above 67%, being higher in MODB (80%), however the results of the DHCZ group had a similar response 77%. Histomorphometric data were submitted to the Kruskal Wallis non-parametric statistical test with a level of significance of (p <0.05). The results showed that when comparing the DHCZ bone cement in T1 with all groups in T2 there was no statistically significant difference indicating that it took less time to reach the same level reached in T2 by all groups. Based on the results obtained, it is possible to conclude that the dental cement containing doxycycline, proposed in the present study, promoted an excellent response in the regeneration of the alveolar defect in rats with respect to the area of filling in the first 14 days being significantly larger.