Survival rates and complication types for single implants provided at the Melbourne Dental School.

BACKGROUND: Single implants and implant-supported single crowns (ISSCs) have become popular treatment modalities for single tooth replacement. Studies have identified high implant survival rates, but also many complications. The aim of this five-year retrospective study was to assess the survival rates, complication types and occurrences for single implants and ISSCs at the Melbourne Dental School (MDS) in Victoria, Australia. METHODS: A search of the Royal Dental Hospital of Melbourne (RDHM) database was conducted for data on all implant treatment and reported complications during the period between 1 January 2005 and 31 December 2009. Complications were categorized into surgical, biological and restorative types. RESULTS: A total of 622 implant fixtures and 444 ISSCs were inserted into 406 patients. Seventeen implants failed during the mean follow-up time of 2.18 years, yielding a 2.7% failure rate and an estimated one- and five-year survival rate of 98.8% and 93.9%, respectively. The cumulative surgical, biological and restorative complication incidences were 11.9%, 17.6% and 14.1%, respectively. CONCLUSIONS: This study confirmed that single tooth replacement using implant therapy within a teaching environment had a high survival rate. However, complications frequently occurred. This article only provides a descriptive analysis. Correlation analysis between variables would provide greater insight into the causes of complications.

Identification and characterization of a murine receptor for galactose-terminated glycoproteins.

The asialoglycoprotein receptor, the hepatic binding lectin for galactose-terminated glycoproteins, has been isolated and characterized from human, rabbit and rat liver. Several recent studies have shown the existence of the same receptor in murine liver. However, the biochemical structure of the receptor in murine liver has not been resolved. In this paper, we describe the identification and purification of the receptor for asialoglycoproteins from murine liver. The purified receptor has three polypeptides with apparent molecular weights of 42,000, 45,000 and 51,000, respectively, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Furthermore, our studies suggest that the receptor from murine liver is very similar to its counterpart in rat liver, although some potential interesting differences have also been observed. Initial studies indicate that this receptor is well conserved in different mouse strains.

N-Linked oligosaccharides of the H-2Dk histocompatibility protein heavy chain influence its transport and cellular distribution.

The H-2K and H-2D proteins encoded by the K and D region of the major histocompatibility complex of the mouse were isolated by immunoprecipitation with specific antisera and resolved by two-dimensional gel electrophoresis. Of these two polypeptides, the H-2Dk glycoproteins isolated from macrophages of C3H/HeHa mice exhibit distinct cell surface and cytoplasmic forms although they share a strong degree of homology in the polypeptide backbone. Structurally they differ in their oligosaccharide structures. The structure of the oligosaccharides on the intracellular forms is of the high mannose type while the same structures on the cell surface forms are of the complex type. In the absence of all three oligosaccharide side chains, the unglycosylated polypeptides are expressed on the cell surface. In contrast, polypeptides containing one, two, or all three oligosaccharide side chains of the high mannose type are not transported to the cell surface. Cell surface expression of these glycoproteins requires processing of the oligosaccharide side chains from the high mannose form to the complex type. However, not all oligosaccharide antennae have to be terminally modified since H-2Dk glycoproteins synthesized in the presence of oligosaccharide-processing enzyme inhibitors such as swainsonine or monensin are also transported to the cell surface. H-2Dk glycoproteins containing oligosaccharide structures of the complex type but lacking terminal sialic acids are found on the cell surface, suggesting that sialylation is not required for transport. These results indicate that the oligosaccharide structures of the H-2Dk glycoproteins act to influence their cellular distribution.