Exfoliative cytology and titanium dental implants: A pilot study

Background: Oral exfoliative cytology is a diagnostic method that involves the study of cells exfoliated from the oral mucosa. Ions/particles released from metallic implants can remain in the peri-implant milieu. The aim of the present study is to assess the presence of metal particles in cells exfoliated from peri-implant oral mucosa around titanium dental implants. Methods: The study comprised 30 patients carrying titanium dental implants, who had neither a metallic prosthesis nor metal restorations in neighboring teeth. Individuals undergoing orthodontic therapy and those who had oral piercing were also excluded from the study. The study sample included patients with and without peri-implantitis. Cytologic samples of the peri-implant area were collected. Samples of the marginal gingiva on the contralateral side of the implant were taken from the same individuals to serve as control. Cytologic analysis was performed using light microscopy. Titanium concentration was determined using inductively coupled plasma-mass spectrophotometry. Results: Metal-like particles were observed inside and outside epithelial cells and macrophages in cytologic smears of peri-implant mucosa of both patients with and without peri-implantitis. No particles were found in the control cytologic samples. The concentration of titanium was higher in the peri-implantitis group compared with the group without peri-implantitis; no traces of titanium were observed in controls. Conclusions: Regardless of an inflammatory response, ions/particles are released from the surface of the implant into the biologic milieu. Exfoliative cytology is a simple technique that may be used to detect metal particles in cells exfoliated from the peri-implant mucosa.Fil: Olmedo, Daniel Gustavo. Universidad de Buenos Aires. Facultad de Odontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nalli, Gabriela. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Verdú, Sergio. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Paparella, María Luisa. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Cabrini, Rómulo L.. Universidad de Buenos Aires. Facultad de Odontología; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Departamento de Radiobiología; Argentin

Titanium dental implant-related pathologies: A retrospective histopathological study

Objectives: To perform a retrospective, descriptive, histopathological study of peri-implant tissue pathologies associated with titanium dental implants (TDI), and to evaluate the presence of metallic particles in samples from a single diagnostic center. Methods: Sixty-eight cases of TDI-associated lesions were retrieved from the Surgical Pathology Laboratory archives, School of Dentistry, University of Buenos Aires (UBA) (1990?2018). The study included re-examining the histopathological features of the biopsy samples, analyzing the inflammatory infiltrate, and examining the samples to detect metallic particles whose chemical composition was determined spectrophotometrically (EDS). Available clinical and radiographic data were also reviewed. Results: The retrieved cases ranged from lesions of inflammatory origin to neoplastic lesions. Metallic particles were observed in 36 cases (52.9%), all of which showed inflammation. Particle length ranged from 2 to 85µm. EDS analysis of the particles/deposits observed in the tissues showed the presence of aluminum, titanium, iron, and nickel, among other elements. Conclusions: A significant number of TDI-associated lesions, including cases not reported to date and diagnosed at a single diagnostic center, are shown here. Cases showing particles exhibited an inflammatory response, irrespective of the histopathological diagnosis. The role of metallic particles in the development of TDI-associated lesion is yet to be established.Fil: Paparella, María Luisa. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Domingo, Mariela Gisele. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Puia, Sebastián Ariel. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Jacobi Gresser, Elisabeth. No especifíca;Fil: Olmedo, Daniel Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Odontología; Argentin

Impairing squamous differentiation by Klf4 deletion is sufficient to initiate tongue carcinoma development upon K-Ras activation in mice

Oral squamous cell carcinoma (SCC) is among the most prevalent cancers in the world and is characterized by high morbidity and few therapeutic options. Like most cancers, oral SCC arises from a multistep process involving alterations of genes responsible for balancing proliferation and differentiation. Among these, Krupsilonppel-like factor 4 (Klf4) suppresses cell proliferation and promotes differentiation and thus helps to maintain epithelial homeostasis. However, the prevailing role of Klf4 in maintenance of normal homeostasis in oral epithelium has not been established in vivo. Here, we used an inducible oral-specific mice model to selectively ablate Klf4 in the oral cavity. We generated K14-CreERTam/Klf4 f/f mice that survived to adulthood and did not present overt phenotype. However, histologically these mice showed dysplastic lesions, increased cell proliferation and abnormal differentiation in the tongue 4 months after induction, supporting a homeostatic role of Klf4 in the oral epithelia. Furthermore, by breeding these mutants with a transgenic line expressing at endogenous levels K-ras G12D, we assessed the role of disrupting differentiation gene programs to the carcinogenesis process. The K14-CreERTAM/K-ras G12D/Klf4 - /- mice rapidly develop oral SCC in the tongue. Thus, our findings support the emerging notion that activation of differentiating gene programs may represent a barrier preventing carcinogenesis in epithelial cells harboring oncogenic mutations, and thus that molecules acting upstream and downstream of Klf4 may represent components of a novel tumor-suppressive pathway.Fil: Abrigo, Marianela. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; ArgentinaFil: Alvarez, Romina Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; ArgentinaFil: Paparella, María Luisa. Universidad de Buenos Aires. Facultad de Odontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Calb, Diego E.. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología; ArgentinaFil: Bal, Elisa Dora. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gutkind, J. Silvio. National Institutes of Health; Estados UnidosFil: Raimondi, Ana Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Biokinetics and tissue response to ultrananocrystalline diamond nanoparticles employed as coating for biomedical devices

Although Ultrananocrystalline diamond (UNCD) has been proposed as a coating material for titanium biomedical implants, the biological effects and toxicity of UNCD particles that could eventually detach have not been studied to date. The biokinetics and biological effects of UNCD compared to titanium dioxide (TiO2) nanoparticles was evaluated in vivo using Wistar rats (n = 30) i.p. injected with TiO2, UNCD or saline solution. After 6 months, blood, lung, liver, and kidney samples were histologically analyzed. Oxidative damage by membrane lipidperoxidation (thiobarbituric acid reactive substances-TBARS), generation of reactive oxygen species (superoxide anion- O2 -), and antioxidant enzymes (superoxide dismutase-SOD, catalase-CAT) was evaluated in lung and liver. Histologic observation showed agglomerates of TiO2 or UNCD in the parenchyma of the studied organs, though there were fewer UNCD than TiO2 deposits. In addition, TiO2 caused areas compatibles with foci of necrosis in the liver and renal hyaline cylinders. Regarding UNCD, no membrane damage (TBARS) or mobilization of enzymatic antioxidants was observed either in lung or liver samples. No variations in O2 - generation were observed in lung (Co: 35.1 ± 4.02 vs. UNCD: 48 ± 9.1, p > 0.05). Conversely, TiO2 exposure caused production of O2 - in alveolar macrophages and consumption of catalase (p < 0.05). The studied parameters suggest that UNCD caused neither biochemical nor histological alterations, and therefore may prove useful as a surface coating for biomedical implants.Fil: Tasat, Deborah Ruth. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Universidad de Buenos Aires. Facultad de Odontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bruno, Marcos E.. Universidad de Buenos Aires. Facultad de Odontología; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Domingo, Mariela Gisele. Universidad de Buenos Aires. Facultad de Odontología; Argentina. Consejo Interuniversitario Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gurman, Pablo. University of Texas; Estados UnidosFil: Auciello, Orlando. University of Texas; Estados UnidosFil: Paparella, María Luisa. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Evelson, Pablo Andrés. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Guglielmotti, Maria Beatriz. Universidad de Buenos Aires. Facultad de Odontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Olmedo, Daniel Gustavo. Universidad de Buenos Aires. Facultad de Odontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin