Acceptance and awareness of southeastern and western private practice pediatric dentists of fluoride-free toothpastes: a survey study.

The American Academy of Pediatric Dentistry (AAPD) affirms that the use of fluoride, as an adjunct in the prevention of caries, is safe and effective. The AAPD encourages dentists, other healthcare providers, and parents to optimize fluoride exposures to reduce the risk of caries and to enhance the remineralization of affected teeth. However, there is resistance amongst patients towards fluoride overexposure and despite there being research on other effective remineralizing agents, most pediatric dentists primarily cater their practice to fluoride-based products.

Biological effects of Ni(II) on monocytes and macrophages in normal and hyperglycemic environments.

Corrosion and release of nickel ions from biomedical alloys are well documented, but little is still known about the effects of released nickel ions on cellular function with recurrent inflammatory challenges. Evidence suggests Ni(II) ions amplify LPS-induced secretion of several pro-inflammatory cytokines from monocytes. Exacerbating the inflammatory response, hyperglycemic conditions also affect monocytic function.

Inherent physical characteristics and gene expression differences between alveolar and basal bones.

Objectives: The objective of this study was to evaluate the baseline differences between alveolar and basal areas of the rat mandible.

Study Design: Rat mandibular alveolar and basal bones were evaluated using histology and micro-computed tomography to compare osteocyte number as well as bone density and architecture and polymerase chain reaction to measure gene expression levels.

Results: Micro-computed tomography data indicated that basal bone is denser and less porous than alveolar bone.

Blue light activates phase 2 response proteins and slows growth of a431 epidermoid carcinoma xenografts.

Background: Recent studies suggest that light in the UVA range (320-400 nm) activates signaling pathways that are anti-inflammatory, antioxidative and play a critical role in protection against cancer. These effects have been attributed to NF-E2-related factor (NRF2)-mediated up-regulation of 'phase 2' genes that neutralize oxidative stress and metabolize electrophiles. We had previously shown that small doses of blue light (400-500 nm) had selective toxicity for cultured oral tumor cells and increased levels of peroxiredoxin phase 2 proteins, which led to our hypothesis that blue light activates NRF2 signaling.

Human periodontal ligament fibroblast responses to compression in chronic periodontitis.

Aim: Test whether human periodontal ligament fibroblasts (PDLFs) retain homeostatic responses to a physiological compressive force during chronic periodontitis.

Material And Methods: Six cell lines were established from periodontally healthy individuals (H-PDLFs) and another six were cultured from patients diagnosed with chronic periodontitis (D-PDLFs). Compressive force at 150 psi was applied to H-and D-PDLFs for 3 h on 2 consecutive days.

Cytotoxicity of endodontic sealers after one year of aging in vitro.

The in vitro cytotoxic response to endodontic sealers was assessed for one year. AH-Plus (AHP), Epiphany (EPH), EndoRez (ER), Guttaflow (GF), InnoEndo (IN), and Pulp Canal Sealer (PCS) were exposed to mouse osteoblasts and human monocytes after curing, 52 weeks of aging, and after resurfacing post-aging; cellular response was estimated by succinate dehydrogenase (SDH) activity. The effect of materials on TNFα secretion from activated (LPS) and inactivated monocytes also was measured.

Effects of an experimental calcium aluminosilicate cement on the viability of murine odontoblast-like cells.

Introduction: Quick-setting calcium aluminosilicate cement with improved washout resistance is a potential substitute for calcium silicate cements in endodontics. This study examined the effect of an experimental calcium aluminosilicate cement (Quick-Set; Primus Consulting, Bradenton, FL) on the viability of odontoblast-like cells.

Methods: The biocompatibility of Quick-Set and white ProRoot MTA (WMTA; Dentsply Tulsa Dental Specialties, Tulsa, OK) cements and their eluents was evaluated using a murine dental papilla-derived odontoblast-like cell line (MDPC-23); 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to examine the effects of the 2 hydraulic cements on mitochondrial metabolic activity.

Quaternary ammonium silane-functionalized, methacrylate resin composition with antimicrobial activities and self-repair potential.

The design of antimicrobial polymers to address healthcare issues and minimize environmental problems is an important endeavor with both fundamental and practical implications. Quaternary ammonium silane-functionalized methacrylate (QAMS) represents an example of antimicrobial macromonomers synthesized by a sol-gel chemical route; these compounds possess flexible Si-O-Si bonds. In present work, a partially hydrolyzed QAMS co-polymerized with 2,2-[4(2-hydroxy 3-methacryloxypropoxy)-phenyl]propane is introduced.

Pneumatic pressure bioreactor for cyclic hydrostatic stress application: mechanobiology effects on periodontal ligament cells.

A bioreactor system was developed to provide high-amplitude cyclic hydrostatic compressive stress (cHSC) using compressed air mixed commercially as needed to create partial pressures of oxygen and carbon dioxide appropriate for the cells under investigation. Operating pressures as high as 300 psi are achievable in this system at cyclic speeds of up to 0.2 Hz.

Dysregulation of monocytic cytokine secretion by endodontic sealers.

Recent studies have reported that sealers may alter the secretion of specific cytokines from THP1 monocytic cells in vitro. In this study, a cytokine array was used to determine if endodontic sealers changed secretion of 42 cytokines. White mineral trioxide aggregate (WMTA), MTA preparation (CS), AH-Plus (AHP), and Pulp Canal Sealer (PCS) were mixed, allowed to set for 72 h, then "aged" in buffered-saline for 12 weeks.

Cytotoxic response of three cell lines exposed in vitro to dental endodontic sealers.

The in vitro cytotoxicity of five endodontic sealers was measured >8-12 weeks using L929 mouse fibroblasts, osteoblastic cells (ROS) 17/2.8 rat osteoblasts, and MC3T3-E1 mouse osteoblasts. Discs (n = 6) of AH-plus Jet (AHP), two versions of Endo Rez (ER, ERx), Epiphany (EPH), and Pulp Canal Sealer (PCS) were prepared.

In vitro osteogenic potential of an experimental calcium silicate-based root canal sealer.

Objective: This in vitro study compared the cytotoxicity and osteogenic potential of an experimental calcium silicate-based sealer with an epoxy resin-based sealer (AH Plus; Dentsply Caulk, Milford, DE) and a zinc oxide-eugenol-based sealer (Pulp Canal Sealer; SybronEndo, Orange, CA).

Methods: Disks prepared from the respective sealer and from Teflon (negative control) were placed in direct contact with a MC3T3-E1 osteogenic cell line at 6 weekly intervals after immersion in a culture medium. Succinic dehydrogenase activities were evaluated using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay.

Periodontal ligament fibroblasts sustain destructive immune modulators of chronic periodontitis.

Background: In healthy periodontal tissue, innate immune responses effectively confine and suppress a bacterial insult. However, a disruption of the host-bacterial equilibrium may produce an overexpression of cytokines and lead to permanent, host-mediated tissue damage. Although such periodontal destruction primarily results from activated immune mechanisms, the site-specific damage suggests that local tissues participate in these pathologic changes.

Cytotoxicity, calcium release, and pH changes generated by novel calcium phosphate cement formulations.

Few published studies describe the biological properties of calcium phosphate cements (CPCs) for dental applications. We measured several biologically relevant properties of 3 CPCs over an extended (8 wk) interval. Monocalcium phosphate, calcium oxide, and synthetic hydroxyapatite were combined with either modified polyacrylic acid, light-activated modified polyalkenoic acid, or 35% w/w polymethyl vinyl ether maleic acid to obtain Types I, II, and III CPCs, respectively.

Corrosion of phosphate-enriched titanium oxide surface dental implants (TiUnite) under in vitro inflammatory and hyperglycemic conditions.

Endosseous dental implants use is increasing in patients with systemic conditions that compromise wound healing. Manufacturers recently have redesigned implants to ensure more reliable and faster osseointegration. One design strategy has been to create a porous phosphate-enriched titanium oxide (TiUnite) surface to increase surface area and enhance interactions with bone.

Titanate particles as agents to deliver gold compounds to fibroblasts and monocytes.

Titanates are inorganic compounds with high affinity for specific metal ions or metal compounds, including gold. We have previously demonstrated that both monosodium titanate (MST) and amorphous peroxo-titanate (APT) alone do not suppress cellular metabolism of several cell types, and we have shown that MST and APT adsorb and release gold compounds in biological salt solutions. In the current study, we extend this work and show that MST and APT loaded with two gold compounds deliver sufficient levels of these compounds to alter the metabolism of mammalian cells.

Corrosion of machined titanium dental implants under inflammatory conditions.

The effects of hyperglycemia, altered cell function, or inflammatory mediators on implant corrosion are not well studied; yet, these effects are critical to implant biocompatibility and osseointegration. Because implant placement is burgeoning, patients with medically compromising systemic conditions such as diabetes are increasingly receiving implants, and the role of other inflammatory diseases on implant corrosion also needs investigation. In the current study, the corrosion properties of commercially available, machined titanium implants were studied in blood, cultures of monocytic cells, and solutions containing elevated dextrose concentrations.

Brushing-induced surface roughness of nickel-, palladium-, and gold-based dental casting alloys.

Statement Of Problem: Alloys with high nickel content have been increasingly used for dental prostheses. These alloys have excellent hardness, elastic modulus, and strength, yet have high corrosion rates when exposed to chemical or physical forces that are common intraorally.

Purpose: The purpose of the current study was to measure the susceptibility of several types of nickel-based alloys to brushing abrasion relative to gold- and palladium-based alloys.

Ni(II) ions dysregulate cytokine secretion from human monocytes.

Nickel-containing alloys are used in dentistry because of their low cost, but poor corrosion behavior increases their risk of causing adverse biological responses. Intraorally, nickel-containing alloys accumulate bacterial plaque that triggers periodontal inflammation via toxins such as lipopolysaccharide (LPS). Recent evidence suggests that in monocytes, Ni(II) amplifies LPS-induced secretion of several cytokines that mediate periodontal destruction.

Interactions between stainless steel, shear stress, and monocytes.

Angioplasty with stent placement is commonly used to treat coronary atherosclerosis. However, 20-40% of stainless steel stents restenose within 6 months via a prolonged inflammatory response mediated by monocytic infiltration and cytokine secretion. In the current study, we tested a hypothesis that blood flow and monocytes interact to alter stent corrosion.

Effect of mercury(II) on Nrf2, thioredoxin reductase-1 and thioredoxin-1 in human monocytes.

Objectives: Human blood levels of mercury are commonly 10nM, but may transiently reach 50-75nM after dental amalgam placement or removal. Controversy persists about the use of mercury because the effects of these 'trace' levels of mercury are not clear. Concentrations of mercury > or =5000nM unequivocally alter redox balance in blood cells including monocytes.

In vitro cytotoxic response to lithium disilicate dental ceramics.

Objectives: The use of lithium disilicate dental ceramics is increasing in dentistry and previous reports have suggested that they may have greater biological risks than previously thought. We tested a hypothesis that composition and processing influence the biological properties of these ceramics.

Methods: The cytotoxicity of two machined and three pressed lithium disilicate materials (n=6) were tested in vitro using mouse fibroblasts in direct contact with the materials for 72h.

Ni(II) activates the Nrf2 signaling pathway in human monocytic cells.

Nickel is a component of biomedical alloys that is released during corrosion and causes inflammation in tissues by as yet unknown mechanisms. Recent data show that Ni(II) at concentrations of 10-50 microM amplifies lipopolysaccharide-triggered, NFkappaB-mediated cytokine secretion from monocytes. In the current study, we tested the hypothesis that Ni(II) amplifies cytokine secretion by activating the Nrf2 antioxidant pathway rather than by enhancing activity of the NFkappaB signaling pathway.

Attachment of human epithelial cells and periodontal ligament fibroblasts to tooth dentin.

A goal of treatment in periodontal therapy is to regenerate a new fibroblastic attachment rather than to repair lost attachment with a long junctional epithelium. To date, there is no evidence that fibroblastic attachment formed during regeneration is stronger or less susceptible to periodontal breakdown than a long junctional epithelial attachment. We measured the rate and strength of attachment of epithelial cells (NHEK) and periodontal ligament fibroblasts (PDLF) cultured individually and cocultured to dentin surfaces to determine which cell type has a faster attachment rate and greater adhesive strength to human dentin, and whether the cell types attach independently.

Sublethal concentrations of diverse gold compounds inhibit mammalian cytosolic thioredoxin reductase (TrxR1).

Unlabelled: Thioredoxin reductase (TrxR) reduces thioredoxin (Trx), thereby contributing to cellular redox balance, facilitating the synthesis of deoxy-ribose sugars for DNA synthesis, and regulating redox-sensitive gene expression. Auranofin is a gold compound that potently inhibits TrxR. This inhibition is one suspected mechanism of auranofin's therapeutic benefit in the treatment of rheumatoid arthritis.