DSpace Collection:

Veracidade do escaneamento intraoral em reabilitações implantossuportadas de arco total: efeito da esterilização de scanbodies e dos marcadores de posicionamento

Tue, 28 Jul 2026 00:00:00 GMT

Title: Veracidade do escaneamento intraoral em reabilitações implantossuportadas de arco total: efeito da esterilização de scanbodies e dos marcadores de posicionamento Abstract: Understanding and controlling variables that affect the trueness of intraoral scanning is essential for improving the predictability of full-arch digital workflows. The overall objective of this thesis was to evaluate factors influencing the trueness of intraoral scanning in full-arch implant-supported rehabilitation. Three specific objectives were investigated. Specific objective 1: to evaluate the effect of repeated autoclave sterilization cycles on the dimensional stability, surface deviation, and marginal fit of scanbodies manufactured from different materials. Specific objective 2: to describe and clinically apply a digital workflow using 3D-printed positioning markers for bimaxillary full-arch implant-supported rehabilitation. Specific objective 3: to evaluate the effect of mucosa-supported positioning markers on the trueness of intraoral scanning in edentulous mandibles rehabilitated with full-arch implant-supported prostheses, as well as their influence on clinical procedure time and patient satisfaction. Based on the findings of these studies, it was observed that repeated autoclave sterilization cycles promoted greater surface deviation in polyetheretherketone (PEEK) scanbodies than in titanium scanbodies, although all evaluated components remained within clinically acceptable limits. The clinical application of 3D-printed positioning markers proved feasible and facilitated digital dataset alignment during complete-arch implant rehabilitation. Furthermore, the use of mucosa-supported positioning markers significantly improved the trueness of intraoral scanning when compared with conventional impressions and digital scanning without markers. Digital workflows required less clinical time and resulted in higher patient satisfaction than conventional impression techniques. The incorporation of positioning markers did not increase procedure time and did not negatively affect patient acceptance. It may be concluded that the trueness of intraoral scanning for full-arch implant-supported rehabilitation is influenced by both scanbody-related factors and scanning strategies.

Saúde bucal no sistema prisional: estudo sobre a estrutura e o acesso de pessoas privadas de liberdade

Tue, 04 Aug 2026 00:00:00 GMT

Title: Saúde bucal no sistema prisional: estudo sobre a estrutura e o acesso de pessoas privadas de liberdade Abstract: Ensuring healthcare for people deprived of liberty is essential to uphold human dignity and the right to health, while also contributing to disease prevention and the protection of public health. In this context, oral healthcare within the Brazilian prison system constitutes a strategic field for examining health inequities, given the numerous challenges involved in ensuring comprehensive care in correctional settings. Therefore, this thesis aimed to analyze the implementation of the National Policy for Comprehensive Healthcare for Persons Deprived of Liberty (PNAISP) and to understand the pathways followed by incarcerated individuals in their search for oral healthcare. To explore this issue, three studies were conducted. The first study employed a qualitative approach and involved men serving sentences in a state prison operating under a closed regime in the state of Minas Gerais, Brazil. For these individuals, barriers to accessing oral healthcare stem from State neglect, manifested through prison overcrowding and a shortage of qualified healthcare professionals. This context gives rise to a micropolitics of access that undermines the principle of equity. The second study, quantitative and cross-sectional in design, analyzed trends in dental services provided within the Brazilian prison system between 2014 and 2022. The findings revealed that the growth of the incarcerated population has not been accompanied by a proportional increase in the number of dentists, while a considerable rise in tooth extraction procedures was observed. Finally, the third study adopted a retrospective ecological design using data from the Primary Health Care Information System. Data from all municipalities reporting the productivity of Prison Primary Healthcare Teams between 2017 and 2022 were analyzed. The study compared the productivity of prison oral healthcare teams during the COVID-19 pandemic (2020–2022) with that observed in the preceding three-year period (2017–2019). The results revealed marked regional inequalities, with the productivity of several municipalities approaching or reaching zero. Emergency procedures and tooth extractions predominated over restorative and periodontal treatments. In summary, this thesis demonstrated that the implementation of PNAISP has neither expanded healthcare coverage nor reduced inequalities in access to care. These findings raise concerns about the effectiveness of the policy and highlight the need to strengthen its implementation, with an emphasis on expanding service provision and improving access to oral healthcare within the prison system, thereby overcoming the institutional barriers experienced by incarcerated individuals.

Impacto da radioterapia de cabeça e pescoço nos tecidos dentários: alterações estruturais e efeito de dentifrícios fluoretados

Wed, 15 Jul 2026 00:00:00 GMT

Title: Impacto da radioterapia de cabeça e pescoço nos tecidos dentários: alterações estruturais e efeito de dentifrícios fluoretados Abstract: Radiotherapy is one of the main therapeutic modalities used in the treatment of head and neck cancer. However, it may lead to complex oral complications. Radiation-related caries (RRC) is characterized by a more rapid and aggressive progression than conventional dental caries, typically initiating with enamel cracking and delamination, followed by dentin exposure to the oral environment. The direct effects of ionizing radiation on dental tissues include changes in microhardness, disruption of the collagen network, and obliteration of dentinal tubules, making the management of this condition particularly challenging and highlighting the importance of preventive strategies. Although the efficacy of fluoride is well established, evidence regarding the effects of different fluoride concentrations on irradiated dental substrates remains limited. The aim of this thesis was to evaluate the structural alterations induced by radiotherapy in dental tissues and to investigate the effects of toothpastes containing different fluoride concentrations on irradiated tissues through complementary studies, encompassing structural and crystallographic changes as well as the response of dental tissues to fluoride-based preventive strategies. To achieve this, three in vitro laboratory studies were conducted, presented as Chapters 1, 2, and 3. Chapter 1 aimed to correlate the mechanical and solubility properties of enamel with radiation-induced crystallographic changes, considering the proximity to the dentino-enamel junction (DEJ). The methodologies included two-dimensional synchrotron radiation X-ray microdiffraction (SR-µXRD), Vickers microhardness, fracture toughness, and citric and lactic acid solubility tests. The irradiated enamel exhibited lower microhardness values and greater acid solubility than the non-irradiated enamel. Furthermore, SR-µXRD revealed changes in the crystallographic parameters and texture of irradiated hydroxyapatite. Chapter 2 investigated the effects of radiation on the surface properties of demineralized human dentin following pH cycling and toothpaste treatment. Knoop microhardness, Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM) were employed. Under the in vitro conditions of this study, irradiated and non-irradiated dentin showed similar behavior regarding microhardness and surface roughness after being subjected to the same pH-cycling protocol and treatment with fluoride toothpastes. Chapter 3 evaluated the effects of toothpastes containing different fluoride concentrations on the mechanical and surface properties of irradiated and non-irradiated dentin after pH cycling. The same methodologies described in Chapter 2 were used. The results demonstrated that different fluoride concentrations produced distinct responses in irradiated dentin. The toothpaste containing 5,000 ppm fluoride resulted in higher microhardness values and lower surface roughness than the fluoride-free toothpaste and the 1,450 ppm fluoride toothpaste. In conclusion, head and neck radiotherapy promotes significant structural changes in dental tissues, as evidenced by crystallographic alterations in enamel hydroxyapatite. Furthermore, fluoride toothpastes demonstrated the potential to mitigate the deleterious effects of ionizing radiation on dentin.

Evolução da terapia com Fibrina Rica em Plaquetas (PRF) na prática odontológica: tubos plásticos sem aditivos como alternativa na produção de PRF, biofuncionalização de hidroxiapatita sintética com Protocolo Progressivo PRO-PRF e uma série de casos

Fri, 16 Jan 2026 00:00:00 GMT

Title: Evolução da terapia com Fibrina Rica em Plaquetas (PRF) na prática odontológica: tubos plásticos sem aditivos como alternativa na produção de PRF, biofuncionalização de hidroxiapatita sintética com Protocolo Progressivo PRO-PRF e uma série de casos Abstract: Platelet-Rich Fibrin (PRF) has emerged as a promising autologous biomaterial in tissue engineering and the biofunctionalization of synthetic materials, particularly in regenerative bone procedures. This thesis aimed to investigate key aspects related to the preparation, characterization, and clinical application of PRF, with emphasis on the use of plastic tubes without additives and the biofunctionalization of synthetic hydroxyapatite (HA) using the third-generation Progressive PRF (PRO-PRF) protocol. In Chapter 1, the density of the fibrin network, platelet aggregates, and cellular morphology of three PRF protocols obtained in glass or plastic tubes, with or without silica coating, were evaluated. Eight volunteers (n = 8) participated in the study, from whom nine blood samples were collected per individual. The samples were divided into three groups according to tube material and centrifuged using the following protocols: Leukocyte- and Platelet-Rich Fibrin (L-PRF – 700 g/12 min), Advanced Platelet-Rich Fibrin (A-PRF – 200 g/14 min), and Advanced Platelet-Rich Fibrin Plus (A-PRF+ – 200 g/8 min). The membranes were analyzed by light microscopy (LM) to assess fibrin and platelet density and by transmission electron microscopy (TEM) for qualitative evaluation of cellular morphology. Membranes obtained from plastic tubes without additives exhibited significantly lower fibrin network density in the L-PRF (p < 0.019) and A-PRF (p < 0.001) protocols. A significantly higher percentage of platelets was observed in membranes produced in plastic tubes without additives, regardless of the protocol used (p < 0.005). Ultrastructural morphology and cellular integrity were preserved in all groups. In Chapter 2, the distribution pattern of HA biofunctionalized with three protocols was investigated: L-PRF, GM350, and PRO-PRF. The study included eight participants (n = 8), with approximately 48 mL of blood collected in six plastic tubes without additives at three different time points. The tubes were divided into three groups according to the centrifugation protocol: L-PRF, GM350 (350 g/15 min), and PRO-PRF (60 g/5 min, 200 g/5 min, and 700 g/5 min). The fluid material was aspirated and transferred to glass containers (5 mL) containing 0.25 g of HA. After polymerization, the clots were compressed to form blocks. Density analysis by micro-computed tomography revealed no significant differences among L-PRF (37.95 ± 0.40), GM350 (39.13 ± 2.29), and PRO-PRF (34.62 ± 4.05; p = 0.132). The PRF/HA ratio, assessed by LM, was significantly lower in PRO-PRF compared with L-PRF (55.14 ± 1.65; p = 0.033) and GM350 (57.10 ± 4.66; p = 0.014). Scanning electron microscopy (SEM) revealed a dense three-dimensional fibrin network integrated with HA. Chapter 3 described a series of four clinical cases involving the application of HA biofunctionalized with PRO-PRF in maxillary sinus floor elevation procedures. Preliminary clinical and tomographic outcomes demonstrated significant vertical bone gain after 120 days (mean: 8.07 mm), and no postoperative complications observed, suggesting that HA biofunctionalization with PRO-PRF represents a safe and promising strategy to enhance tissue repair.