Percorrer por autor "Pitschieller, Ricardo"
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- The effect of ceramic surface conditioning on bond strength of metallic brackets : an in vitro studyPublication . Ferreira, Rita; Pereira, Pedro Mariano; Pitschieller, Ricardo; Proença, Luís; Bugaighis, ImanObjective: To compare the shear bond strength (SBS) of brackets bonded to three different types of ceramic surfaces (feldspathic ceramic, lithium disilicate ceramic, and zirconia), conditioned with either hydrofluoric acid or sandblasting, using Assure® Plus All bonding agent. Materials and methods: A total of 72 monolithic CAD/CAM ceramic specimens were divided into six groups of 12 samples. Three groups (G1: feldspathic ceramic, G3: lithium disilicate ceramic, G5: zirconia surfaces) were conditioned with 9.6% hydrofluoric acid, while the remaining three (G2, G4, G6; with ceramic type in the same order as the previous three groups) were prepared with 50 μm aluminum oxide sandblasting. Premolar brackets were bonded using light-cured Assure® Plus All. The SBS and adhesive remnant index (ARI) were recorded and submitted to inferential analysis using one-way analysis of variance and Kruskal–Wallis tests, respectively. The significance level was set at 5% (P ≤ 0.05). Results: The mean SBS values for the three different ceramic groups conditioned with hydrofluoric acid (G1: 7.2 ± 1.5 MPa, G3: 9.3 ± 2.3 MPa, G5: 8.5 ± 2.0 MPa) were significantly higher than those obtained for the groups prepared by sandblasting before bonding (G2: 7.5 ± 1.8 MPa, G4: 4.4 ± 2.0 MPa, G6: 4.3 ± 2.8 MPa). Conclusions: The hydrofluoric acid treatment produced a favorable SBS for all three examined ceramic types before bracket bonding with Assure® Plus All. In comparison, sandblasting yielded a satisfactory SBS only with feldspathic surfaces. Furthermore, the ARI indicated a higher frequency of mixed-adhesive failures except for lithium disilicate conditioned with sandblasting. Therefore, using hydrofluoric acid is likely to be especially recommended when the clinician is not aware of the brand of ceramic restorative material.
- Neutrophils at the crossroads of oral microbiome dysbiosis and periodontal diseasePublication . Viana, João; Ferro, Tiago; Pitschieller, Ricardo; Machado, Vanessa; Su, Naichuan; Mendes, José João; Botelho, JoãoNeutrophils are the most abundant circulating leukocytes and essential components of innate immunity. Through mechanisms such as phagocytosis, reactive oxygen species (ROS) production, degranulation, and neutrophil extracellular trap (NET) formation, they play a crucial role in host defense. However, dysregulated neutrophil responses are linked to chronic inflammatory conditions, including periodontitis. This review summarizes current evidence on neutrophil biology in periodontal health and disease, focusing on functional mechanisms, recruitment pathways, the influence of dysbiosis, and their potential as biomarkers and therapeutic targets. Neutrophils display a dual role in periodontal tissues: while protecting against microbial invasion, their excessive or impaired activity contributes to tissue destruction. Altered chemotaxis, defective phagocytosis, and uncontrolled NET release perpetuate inflammation and alveolar bone loss. Neutrophil-derived enzymes, including myeloperoxidase, elastase, and matrix metalloproteinases, emerge as promising biomarkers for early diagnosis. In parallel, therapeutic strategies targeting oxidative stress, NET regulation, or neutrophil hyperactivity are being explored to preserve periodontal tissues. Neutrophils are central players in periodontal pathophysiology. Understanding their regulation and interaction with the oral microbiome may enable the development of novel diagnostic and therapeutic approaches, ultimately improving periodontal disease management.