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OBJECTIVE: This study aimed to evaluate the dose-response effects of ionizing radiation (IR) on alveolar bone repair and bone strength after tooth extraction. MATERIALS AND METHODS: A total of 32 male Wistar rats were used in the study, 28 animals were included in the final analysis, and n = 7 for each experimental group. Mandibular first molars were extracted. After 7 days, the animals were randomly divided into four groups according to single-dose irradiation: NIr, control group; Ir15, irradiated at 15 Gy; Ir20, irradiated at 20 Gy; and Ir30, irradiated at 30 Gy. The tooth extraction sites were subjected to micro-computed tomography (micro-CT), histological, histomorphometric, and biomechanical analyses 14 days after extraction. Data were analyzed using one-way ANOVA followed by Tukey's post hoc test (α = 0.05). RESULTS: Micro-CT analysis revealed that IR led to lower values of bone volume (BV, in mm3) (0.68 ± 0.08, P < 0.001) and bone volume fraction, ratio of the segmented bone volume to the total volume of the region of interest (BV/TV, in %) (44.1 ± 8.3, P < 0.001) for the Ir30 group compared to the control group. A significantly lower amount of newly formed bone was observed in the Ir30 (P = 0.005) than in the Ir15 group. The histomorphometric results of quantification of bone matrix neoformation and the micro-CT were in agreement, demonstrating greater damage to the Ir30 group. IR30 cells showed a lower percentage of densely packed collagen than control cells. No significant differences were found in the biomechanical parameters. CONCLUSION: IR affects alveolar bone repair. A dose of 30 Gy reduced the bone healing process owing to a smaller amount of newly formed bone and a lower percentage of densely packed collagen. Therefore, a dose of 30 Gy can be used to successfully establish an animal model of an irradiated mandible that mimics the irradiated clinical conditions. CLINICAL RELEVANCE: Radiotherapy can lead to severe side effects and tooth extraction is a major risk factor. A proper understanding of the pathological mechanisms of radiation in alveolar bone repair requires the establishment of a suitable animal model of clinical conditions.

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Objetivo: Analisar a associação do acesso a ações preventivas em saúde bucal e do tratamento mutilador, ofertado pelos serviços públicos de grandes municípios brasileiros, com as suas características sociais e a composição orçamentária. Metodologia: Realizou-se um estudo ecológico com dados secundários de 323 municípios brasileiros com mais de 100 mil habitantes. As variáveis selecionadas para estudo foram os indicadores sociais (desigualdade social, renda, trabalho, escolaridade, infraestrutura sanitária), indicadores orçamentários (capacidade arrecadatória, dependência de recursos federais) e indicadores de saúde bucal (cobertura de equipes básicas de saúde bucal, acesso a ações preventivas e acesso a tratamento mutilador). Os dados dos indicadores de saúde bucal foram dicotomizados entre municípios com maior e menor acesso às ações preventivas ou ao tratamento mutilador. A associação das variáveis dependentes foi testada por meio de testes bivariados e regressão logística. Resultados: Um maior acesso às ações preventivas foi observado nos municípios com melhores condições sociais e orçamentárias. Por outro lado, um maior acesso ao tratamento mutilador foi observado em municípios com condições sociais orçamentárias inferiores. Conclusão: Apenas a infraestrutura sanitária e cobertura de equipes básicas de saúde bucal se mantiveram associados ao acesso às ações preventivas, enquanto o indicador de desigualdade social manteve-se associado ao tratamento mutilador. Descritores: indicadores sociais; disparidades nos níveis de saúde; mensuração das desigualdades em saúde; financiamento governamental.Associação de fatores sociais e orçamentários ao acesso ao cuidado em saúde bucal de grandes municípios brasileiros: um estudo ecológico

Aim: To analyze the correlation of access to preventive oral health measures and mutilating treatment, offered by the public health system of large Brazilian municipalities, considering social conditions and budgetary compositions. Methods:An ecological study was carried out with secondary data from 323 Brazilian municipalities with more than 100,000 inhabitants. The variables selected for the study were social indicators (social inequality, income, work, education, sanitary infrastructure); budget indicators (collection capacity, dependence on federal resources); and oral health indicators (coverage of basic oral health teams, access to preventive actions, and access to mutilating treatment). Oral health indicators were dichotomized between municipalities with higher and lower access to preventive oral health measures and mutilating treatment. The association of dependent variables was tested using bivariate tests and logistic regression. Results: Higher access to preventive measures was observed in municipalities with better social and budgetary conditions. By contrast, higher access to mutilating treatment was observed in municipalities with lower social budgetary conditions. Conclusion: Only health infrastructure and coverage of basic oral health teams remained associated with access to preventive actions, while the indicator of social inequality remained associated with mutilating treatment.

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