Avaliação histológica e histomorfométrica da regeneração óssea guiada sob membranas biológicas não reabsorvíveis em ratas osteoporóticas com e sem tratamento com ácido zoledrônico

• Ano de defesa: 2015
• Autor(a) principal: Busetti, Juliano
• Orientador(a): Figueiredo, José Antonio Poli de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Pontifícia Universidade Católica do Rio Grande do Sul
• Programa de Pós-Graduação: Programa de Pós-Graduação em Odontologia
• Departamento: Faculdade de Odontologia
• País: Brasil
• Palavras-chave em Português: ODONTOLOGIA; ENDODONTIA; REGENERAÇÃO ÓSSEA; REGENERAÇÃO TECIDUAL GUIADA; OSTEOPOROSE; EXPERIMENTAÇÃO ANIMAL
• Área do conhecimento CNPq: CIENCIAS DA SAUDE::ODONTOLOGIA
• Link de acesso: http://tede2.pucrs.br/tede2/handle/tede/6501

Regeneration of lost tissues can be obtained in a predictable way by using the Guided Bone Regeneration (GBR) concept. The development of such concept is based on the observation that to regenerate a certain type of tissue, specific cells with the ability to reconstruct such kind of tissue must repopulate the wound. GBR was applied to heal different type of bone defects and the isolation of it by using resorbable and nonresorbable membranes resulted in a predictable healing through the formation of new bone. Nowadays the GBR concept is used for the treatment of multiple clinical situations in dentistry, even with dental implants. Osteoporosis is the most common chronic bone disease and may interfere in the healing of regenerative procedures. The increase in life expectancy results in a larger number of elderly patients referred for bone regeneration and dental implants. Osteoporosis is associated with aging, menopause and chronic use of some types of drugs. Regenerative protocols must be postulated taking into account this category of patients. Limited scientific evidence suggests that osteoporosis can negatively influence bone healing as well as the osseointegration of dental implants. In addition to disease, the use of drugs for its prevention and treatment may affect healing of GBR procedures. Bisphosphonates (BP) are the most frequently used drugs for treatment and prevention of osteoporosis. The drug acts mainly in the inhibition of bone resorption by its action on osteoclasts. Among the commercially prescribed BP, zoledronic acid (ZA) is known to be the most potent of all. In the first paper of this thesis osteoporosis was induced in rats and these animals were submitted to regenerative procedures comparing samples with and without osteoporosis as well as with and without the use of ZA. To assess GBR, critical size defects (CSD) were made in the animals’ calvarial bone. Microporous non-resorbable PTFE (polytetrafluorethylene) membranes were used to promote GBR in healthy, osteoporotic and osteoporotic animals treated with ZA. Forty-eight Wistar rats with 6 months of age were included in the study. Experimental osteoporosis was induced by ovariectomy (OVX) associated with hipocalcic diet in 32 animals. Sixteen OVX rats received a single dose of ZA (OZ) while the other 16 osteoporotic rats received no treatment (O). The remaining 16 animals were SHAM operated; the ovaries were exposed but not removed, being considered the control group (C). Six weeks after osteoporosis induction, each animal from the OZ group received a single dose of ZA. One week latter (7 weeks after baseline) two 5-mm CSD were performed bilaterally in the parietal bones and one of these defects was treated with two membranes, one located internally, in contact to the Dura, and the other was placed on top of the defect. GBR healing periods were 30 and 60 days for each group. Evaluation of new bone formation (NBF) was done by qualitative and quantitative histological analysis. Differences in means between groups (O, OZ and C), the use of membranes as well as the observation period (days 30 and 60) were analyzed by ANOVA for each variable. When a statistically significant difference was identified between the averages, the Bonferroni post hoc test was used. The results showed that treatment with ZA (p = 0.001) and the use of membranes (p = 0.000) significantly increased the amount of regenerated bone tissue and the presence of osteoporosis may have reduced NBF (p = 0.028).