In vitro inflammatory modulation of bioceramic endodontic sealer in macrophages stimulated by bacterial lipopolysaccharide.

AIM: To evaluate the effects of AH Plus (Dentsply), Sealer 26 (Dentsply), and Sealer Plus BC (Produtos Médicos e Odontológicos) on cytotoxicity and inflammation in macrophage cultures exposed to bacterial lipopolysaccharide (LPS). METHODOLOGY: After initial setting, the sealers were conditioned with serum-free culture medium for 24 h (1 ml/cm2 ). Macrophages from the RAW 264.7 strain were exposed to sealer extracts in a 1:16 ratio in a culture medium with or without LPS. Cell morphology, viability, mitochondrial activity, oxidative stress and gene expression of interleukin 1ß (IL-1ß) and tumour necrosis factor-alpha (TNF-α) were evaluated. Data on mitochondrial activity, oxidative stress and TNF-α were analysed using a two-way analysis of variance (anova) test, followed by the Student-Newman-Keuls post-test. IL-1ß data were analysed using one-way anova, followed by SNK, and the t-test was used for intragroup comparison. The significance level was set at 5%. RESULTS: In the absence of LPS, only AH Plus and Sealer 26 showed a reduction in cell density, while in the presence of LPS, Sealer 26 had the lowest density compared to the other groups. In terms of mitochondrial activity, at 24 and 48 h, Sealer Plus BC had significantly higher mean values than Sealer 26 and AH Plus (p < .05). Sealer 26 exhibited the lowest levels of oxidative stress and IL-1ß and TNF-α expression, regardless of the presence of LPS (p < .05). CONCLUSIONS: Although all sealers interfere with the response of macrophages to LPS, contact with epoxy resin-based sealers can impair cell activity in vitro, while bioceramic sealer seems to favour the inflammatory functions of these cells.

Knowledge, Perception, and Experience of Dentists About Teledentistry.

OBJECTIVES: This study aimed to evaluate the level of knowledge, perception, and experience of teledentistry amongst Brazilian dentists with the ongoing COVID-19 pandemic. METHODS: Between June and July 2020, an online questionnaire was used to collect information on the demographic and professional profiles of dentists and their levels of knowledge, perception, and attitudes towards teledentistry. Descriptive statistics were reported as percentages, and Chi-squared test was used to compare responses amongst general practitioners, specialists, and those with varying levels of professional experience. RESULTS: This study included 575 dentists, the majority of whom were from the southeast region of Brazil (73.4%) and had a specialist degree (70.4%). Approximately 42.4% of the study sample had graduated more than 10 years ago, 39.3% between 2 and 10 years ago, and 18.3% up to 2 years ago. In general, the majority of dentists exhibited only a superficial awareness of the resolution that regulates teledentistry in Brazil. A greater number of specialists were aware of the resolution (P = .007) and felt confident performing teledentistry (P = .000) compared to general practitioners, whilst those with more experience (graduated more than 10 years ago) exhibited greater knowledge (P = .012) and preparation (P = .000). More than 60% of the dentists, regardless of dental specialty and clinical experience, had no knowledge of providing prescriptions via teledentistry. The majority of general practitioners (89.5%) and specialists (81.4%) had no previous experience using teledentistry. CONCLUSIONS: The findings of this study suggest that Brazilian dentists are inadequately prepared for the implementation of teledentistry.

Low concentrations of caffeic acid phenethyl ester stimulate osteogenesis in vitro.

OBJECTIVE: The aim of this study was to evaluate the effects of caffeic acid phenethyl ester (CAPE) on osteoblast-like cell cultures (SAOS-2). METHODS: SAOS-2 were exposed to CAPE at 1 nM, 10 nM, 100 nM, 1 µM, and 10 µM. Non-exposed cultures were used as control. The following parameters were assayed: 1) cell viability at 1, 3, and 7 days; 2) alkaline phosphatase (ALP) activity at 5 and 10 days; 3) matrix mineralization at 14 days; and 4) Runt-related transcription factor 2 (RUNX2), ALP, osteopontin (SPP1), and osteocalcin (BGLAP) gene expression at 5 and 10 days. The data were analyzed by ANOVA two-way or Kruskal-Wallis (α = 5%). RESULTS: At day 1, cell viability was similar among all groups (p > 0.05). At days 3 and 7, cultures exposed to CAPE at 10 µM exhibited a significant reduction in cell viability compared with the others groups (p < 0.05). At day 5, ALP activity was similar among all experimental groups; at day 10, however, the stain intensity was higher in cultures exposed to CAPE at 100 nM and 10 nM in comparison with the other groups (p < 0.05). At days 5 and 10, RUNX2, ALP, SPP1, and BGLAP gene expression was greater in cultures exposed to CAPE in comparison with the control (p < 0.05). At day 14, matrix mineralization was similar in cultures exposed to CAPE at 1 nM and 10 nM (p > 0.05), but superior to those ones observed in the other experimental groups (p < 0.05). CONCLUSION: CAPE at low concentrations can positively module the osteogenesis in vitro.

Nanocellulose-collagen-apatite composite associated with osteogenic growth peptide for bone regeneration.

Despite advances in the field of biomaterials for bone repair/regeneration, some challenges for developing an ideal bone substitute need to be overcome. Herein, this study synthesized and evaluated in vitro a nanocomposite based on bacterial cellulose (BC), collagen (COL), apatite (Ap) and osteogenic growth peptide (OGP) or its C-terminal pentapeptide [OGP(10-14)] for bone regeneration purposes. The BC-COL nanocomposites were successfully obtained by carbodiimide-mediated coupling as demonstrated by spectroscopy analysis. SEM, FTIR and 31P NMR analyses revealed that in situ synthesis to apatite was an effective route for obtaining of bone-like apatite. The OGP-containing (BC-COL)-Ap stimulated the early development of the osteoblastic phenotype. Additionally, the association among collagen, apatite, and OGP peptides enhanced cell growth compared with OGP-containing BC-Ap. Furthermore, none of the nanocomposites showed cytotoxic, genotoxic or mutagenic effects. These promising results suggest that the (BC-COL)-Ap associated with OGP peptides might be considered a potential candidate for bone tissue engineering applications.

Osteopontin expression in co-cultures of human squamous cell carcinoma-derived cells and osteoblastic cells and its effects on the neoplastic cell phenotype and osteoclastic activation.

This study evaluated the temporal expression of osteopontin (OPN) in co-cultures of human osteoblastic cells (SAOS-2) and oral squamous cell carcinoma (OSCC)-derived cells (SCC9) and examined the effects of osteoblast-derived OPN on the neoplastic cell phenotype. Additionally, the effects of these co-cultures on subsequent osteoclastic activity were explored. SCC9 cells were plated on Transwell® membranes that were either coated or not coated with Matrigel and were then co-cultured with SAOS-2 cells during the peak of OPN expression. SCC9 cells exposed to OPN-silenced SAOS-2 cultures and SCC9 cells cultured alone served as controls. SCC9 cells were quantitatively evaluated for cell adhesion, proliferation, migration, and invasion into Matrigel. The impact of co-culturing SAOS-2 and SCC9 cells on the resorptive capacity of U-937-derived osteoclastic cells was also investigated. Furthermore, a reciprocal induction of SAOS-2 and SCC9 cells in terms of OPN expression over the co-culture interval was identified. SAOS-2-secreted OPN altered the SCC9 cell phenotype, leading to enhanced cell adhesion and proliferation and higher Matrigel invasion. This invasion was also enhanced, albeit to a lesser degree, by co-culture with OPN-silenced SAOS-2 cells. Cell migration was not affected. Co-culture with SAOS-2 cells-mainly during the period of peak OPN expression-promoted over-expression of IL-6 and IL-8 by SCC9 cells and enhanced the resorptive capacity of osteoclastic cells. Taken together, these results suggest that osteoblast-derived OPN affects the interactions among OSCC-derived epithelial cells, osteoblasts, and osteoclasts, which could contribute to the process of bone destruction during bone invasion by OSCC.

Changes in actin and tubulin expression in osteogenic cells cultured on bioactive glass-based surfaces.

The present study evaluated whether the changes in the labeling pattern of cytoskeletal proteins in osteogenic cells cultured on bioactive glass-based materials are due to altered mRNA and protein levels. Primary rat-derived osteogenic cells were plated on Bioglass® 45S5, Biosilicate®, and borosilicate (bioinert control). The following parameters were assayed: (i) qualitative epifluorescence analysis of actin and tubulin; (ii) quantitative mRNA and protein expression for actin and tubulin by real-time PCR and ELISA, respectively, and (iii) qualitative analysis of cell morphology by scanning electron microscopy (SEM). At days 3 and 7, the cells grown on borosilicate showed typical actin and tubulin labeling patterns, whereas those on the bioactive materials showed roundish areas devoid of fluorescence signals. The cultures grown on bioactive materials showed significant changes in actin and tubulin mRNA expression that were not reflected in the corresponding protein levels. A positive correlation between the mRNA and protein as well as an association between epifluorescence imaging and quantitative data were only detected for the borosilicate. SEM imaging of the cultures on the bioactive surfaces revealed cells partly or totally coated with material aggregates, whose characteristics resembled the substrate topography. The culturing of osteogenic cells on Bioglass® 45S5 and Biosilicate® affect actin and tubulin mRNA expression but not the corresponding protein levels. Changes in the labeling pattern of these proteins should then be attributed, at least in part, to the presence of a physical barrier on the cell surface as a result of the material surface reactions, thus limiting fluorescence signals.

Chemical and Morphological Changes of Primary Teeth Irradiated with Nd:YAG Laser: An Ex Vivo Long-Term Analysis.

OBJECTIVE: The aim of this study was to assess any long-term chemical and morphological Nd:YAG laser modifications on irradiated primary enamel. BACKGROUND DATA: Previous studies on irradiated primary human enamel employed methodologies that evaluated the short-term effects only. METHODS: One hundred and eighty-six irradiated (with and/or without fluoride) primary enamel teeth from high-caries-risk children, which were exfoliated over a 1-year period, were collected, and the sample surface area was submitted for scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray energy-dispersive spectrometry (EDS). The subsurface was analyzed by Knoop microhardness and light microscopy (LM). Data were analyzed by one way ANOVA and Tukey tests (α=0.05) and Kruskall-Wallis and Tukey tests (α=0.05). RESULTS: FTIR analysis revealed a higher concentration of phosphate and carbonate in the irradiated (0.987±0.064) and lower concentration in the control groups (1.477±0.310). SEM analysis showed that the control samples exhibited a slightly smoother surface than the irradiated groups. The EDS analysis did not show any differences in the amount of calcium, phosphorus, or fluoride among the groups. The microhardness analysis revealed that sealant (249.86±7.15) and laser irradiation (262.44±22.69) led to higher hardness values than the negative control group (128.35±25.19). LM indicated significantly reduced caries formation in the laser (5.35±5.38%) and the laser plus acidulated phosphate fluoride (APF) groups (10.35±0.88%) compared with the negative control group (72.56±12.86%). CONCLUSIONS: Even with the limitations of the present study, these results suggest that Nd:YAG irradiation clinically modified the chemical composition of the enamel surface regardless of fluoride concentration, which successfully inhibited demineralization of primary tooth enamel over a 1-year period without significant morphological changes.

Nd:YAG laser in occlusal caries prevention of primary teeth: a randomized clinical trial.

Dental caries is still the most prevalent chronic disease affecting human populations. Among the preventive treatments performed, it has been reported that laser irradiation combined with topical fluoride can induce an even greater increase in enamel caries resistance. The aim of this study was to evaluate the Nd:YAG laser, with or without fluoride, in occlusal caries prevention of the primary dentition. A double-blind split-mouth study design was used. Fifty-two children with high caries risk (7.6 ± 1.4 years) were selected and received the following: G1--the first molar was a negative control, and the second received a resin sealant; G2--the first molar was a negative control, and the second received laser irradiation (50 mJ, 10 Hz, 0.5 W); G3--the first molar received only acidulate phosphate fluoride (APF), and the second received APF + laser; G4--fisrt molar received only fluoride varnish, and the second received fluoride varnish + laser. Patients were followed up to 12 months to evaluate the presence of white-spot lesions and/or caries cavities by three calibrated observers. Thirty-five patients completed the study. Significant differences were found between the treatment and control groups (p < 0.05). The laser-alone and resin sealant resulted in statistically lower caries formation than the negative control group (p < 0.05). Nd:YAG laser irradiation in primary teeth effectively prevented occlusal caries in pits and fissures when used alone with lower energy over a 1-year period.