Biomedical subjects

Lucy Di Silvio

Publications and source records attributed to Lucy Di Silvio.

5 recordsLinked to original sources

PubMed2006

The safety of nickel containing dental alloys.

Nickel is a constituent of many dental alloys. This paper reviews mainly papers published after 1985 with regards to biological reactions to nickel in dentistry. Nickel is an allergen, but there is no evidence that individual patients are at a significant risk of developing sensitivity solely due to contact with nickel-containing dental appliances and restorations. Hypersensitivity reactions to nickel are only likely to occur with prior sensitization from non-dental contacts and even these are rare. Clinical evidence has been presented to show that small doses of nickel, e.g. from dental appliances, may induce tolerance to this allergen. The papers reviewed report low rates of release of nickel from dental alloys. Some nickel compounds, which are mildly cytotoxic, have been implicated as carcinogens by inhalation in industrial settings, but these compounds are not present in dentistry-related operations, including dental technology procedures. Nickel-containing alloys and compounds have not been associated with increased cancer risk by oral or dermal routes of exposure. It is concluded that, subject to use according to established techniques, nickel-containing dental alloys do not pose a risk to patients or members of the dental team.

Carcinogens↗

PubMed2006

A novel ex vivo culture system for studying bone repair.

Repair of large bony defects still remains a challenge for surgeons. Hydroxyapatite (HA) is well known for its biocompatibility and osseoconduction properties in the osseous environment. In this study the biofunctionality of a newly developed scaffold comprising of collagen and HA, with variable macropores was examined. The biological response was evaluated using primary human osteoblast cells (HOBs). Cell infiltration, proliferation and differentiation were assessed. The results showed that HOBs were able to migrate from the collagen into the HA pores with greater cell migration and infiltration observed in those scaffolds with larger pores. Furthermore, it was shown that Alkaline Phosphatase, a differentiation marker for HOBs was enhanced as the average macropore size increased. This in vitro model provides a more relevant method of testing the biofunctionality and migration ability of cells at a trauma site following implantation in bone and cartilage.

Bone Diseases↗

PubMed2006

Can mesenchymal stem cells survive under normal impaction force in revision total hip replacements?

Impaction allograft as a scaffold for bone-forming cells is a tissue-engineering approach for filling bone defects that are commonly encountered during revision total joint replacement (THR). The purpose of this in vitro study is to assess the viability of mesenchymal stem cells (MSC) grown on allograft following impaction using forces similar to those measured during revision total hip replacements. Impaction forces of 0, 3, 6, and 9 kN were used representing normal and high impact. The results showed that the viability in the 3 and 6 kN groups was not significantly reduced compared with that of the 0 kN group, while the survival of the MSCs was significantly reduced after 9 kN impaction force. This study suggests that the addition of MSCs to the allograft scaffold will survive normal impaction force in revision THR.

Animals↗

PubMed2006

The effect of a commercially available chlorhexidine mouthwash product on human osteoblast cells.

Chlorhexidine mouthwash (CMW) is used for decontamination of tooth, implant or prosthetic surfaces to treat or prevent local infection. A cell culture model was used to investigate cytotoxicity of CMW employing an MTT assay to record cell activity. Human osteoblast-like cells (HOS TE 85) were seeded. Dilutions of CMW (1:1 to 1:128) were made up with culture medium. Positive and negative controls were prepared. Cells were incubated, exposed to CMW, for 5 min to 4 h. Diluted tetrazolium salt solution was added. Plates were incubated for a further 4 h. Medium was removed, dimethylsulphoxide was added, and absorbance at 570nm read. Undiluted CMW caused total cytotoxicity, similar to positive control. Progessive dilution of CMW was associated with elevated cell survival. Cytotoxicity increased with longer time exposures. It was concluded that CMW can be cytotoxic in high concentrations and when applied for long time periods. Work is needed to determine effects on other cell types and clinical significance of these findings.

Analysis of Variance↗

PubMed2002

Optimizing HAPEX topography influences osteoblast response.

HAPEX (hydroxyapatite-reinforced polyethylene composite) is a second-generation orthopedic biomaterial designed as a bone analog material, which has found clinical success. The use of topography in cell engineering has been shown to affect cell attachment and subsequent response. Thus, by combining bioactivity and enhancing osteoblast response to the implant surface, improved tissue repair and implant life span may be achieved. In this study a primary human osteoblast-like cell model has been used to study the influence of surface topography and chemistry produced by three different production methods. Scanning electron microscopy, fluorescence microscopy, and confocal scanning laser microscopy have been used to study cell adhesion; tritiated thymidine uptake has been used to observe cell proliferation; and the reverse transcriptase-polymerase chain reaction and biochemical methods have been used to study phenotypic expression. Transmission electron microscopy has also been used to look at more long-term morphology. The results show that topography significantly influences cell response, and may be a means of enhancing bone apposition on HAPEX.

Alkaline Phosphatase↗