Bulk-fill resin-based composite restorative materials: a review.

Resin-based composite (RBC) materials are increasingly being used for the restoration of posterior teeth. The increasing demand for aesthetic, tooth-coloured restorations coupled with the patient's concerns regarding the use of mercury containing restorations, has driven a surge in the use of RBC materials. With the Minamata Convention in 2013 calling for the phase-out of dental amalgam and dental schools increasingly teaching techniques for RBC restorations in posterior teeth, it is likely that the dental profession's reliance upon RBC for the restoration of posterior teeth will only increase. In order to simplify and speed-up the placement of large posterior RBCs, manufacturers have produced a range of materials which can be placed in single or deeper increments, known as bulk-fill RBCs. Over a relatively short period of time many bulk-fill RBCs have been marketed quoting increment depths between 4-10 mm. The placement of these larger increments of RBC may reduce the time needed when placing posterior restorations and thereby reduce technique sensitivity. This article aims to review the properties and handling characteristics of the bulk-fill RBC materials currently available, while advising the optimal techniques of placement.

Intracortical haematogenous osteomyelitis.

We present an unusual case of haematogenous osteomyelitis in the diaphysis of the tibia of an adult leading to a subacute presentation with an extracortical abscess. Fluid from the abscess grew methicillin resistant Staphylococcus aureus (MRSA) on culture; MRSA with the same antibiogram had been grown from the patient's blood seven years earlier following a bowel resection. Drainage of the abscess and curettage of the bone lesion together with appropriate antibiotic therapy led to resolution of the osteomyelitis.

NICE or not so NICE?

This article provides an opinion on the NHS NICE guidance on wisdom tooth removal introduced in 2000. Guidelines should support clinical decision-making by providing recommendations based on sound evidence but the wisdom tooth guidelines were published without any research evidence. General dentists and oral surgeons in England and Wales are under pressure to comply with this guidance but what have been the implications for patient care? There is growing evidence that patients have not been best served, with significant numbers developing caries in an adjacent tooth before consideration of wisdom tooth assessment.

Learning curves in orthopaedic surgery: a case for super-specialisation?

INTRODUCTION: The objective of this study was to assess if there is a significant learning curve in the treatment of developmental dysplasia of the hip. PATIENTS AND METHODS: We followed up cases of developmental dysplasia of the hip treated by a single surgeon over a 12-year period. There were 96 cases, 56 treated by open reduction and 40 treated by closed reduction. Assessment was made of the incidence and degree of avascular necrosis in the treated hips, as a radiological outcome measure. RESULTS: Plotting the cumulative percentage of satisfactory outcomes demonstrated an increasingly high percentage of satisfactory results with increasing number of procedures performed, i.e. as the surgeon progressed up the 'learning curve'. CONCLUSIONS: This study demonstrates a learning curve in the treatment of developmental dysplasia of the hip. It may be possible to draw parallels to other treatments, and also support for the growing trend to specialisation.

Pressure characteristics of pelvic binders.

We present a study of the pressures developed at the bony prominences (greater trochanter, iliac crest and sacrum) when a pelvic binder was applied to 10 healthy individuals. The pressures developed between the pelvic binder and the skin over the prominences were all greater than the pressure recommended at interfaces to avoid the development of pressure sores. This suggests that patients with pelvic fractures who are treated with temporary pelvic binders are at risk of developing pressure sores. This should be recognised and the skin inspected if the binder is to be in place for a prolonged period.

Alcohol and radiographs in the accident and emergency department.

OBJECTIVE: To investigate the contribution of alcohol ingestion to the radiological workload of an inner city accident and emergency (A&E) department. METHODS: A prospective survey of patients presenting to A&E who required radiographs was performed over a seven day period. The A&E clinician questioned patients about alcohol intake during the six hours before the onset of the presenting complaint or injury, and made an objective assessment of signs of alcohol ingestion or intoxication. An assessment was made also of the relative contribution of alcohol as a cause of patients' injuries. RESULTS: A total of 419 patients who had radiography fulfilled the inclusion criteria, and a questionnaire was completed for 351 (84%). Forty (11%) of 351 were found to have ingested alcohol. Thirty five (87%) of 40 patients who had ingested alcohol were radiographed for trauma, as compared with 171 (55%) of the 311 who had not (p<0.001). Alcohol was considered to have been causative of injury in 30% and a contributory factor in an additional 58%. Radiographs of the skull, face and jaw accounted for 18 (33%) of 55 radiographs from trauma patients who had ingested alcohol compared with 20 (9%) of 212 radiographs from those who had not (p<0.001). There was no significant difference in the proportion of abnormal radiographs between these two groups (27% of radiographs from trauma patients who had ingested alcohol compared with 23% of radiographs from those who had not, p>0.2). CONCLUSION: Patients with alcohol related injuries requiring radiography have a significant impact on the radiological workload of an A&E department, although the prevalence of alcohol ingestion detected in this study was less than expected from previous studies.

The characterization of novel, dual ErbB-2/EGFR, tyrosine kinase inhibitors: potential therapy for cancer.

The type I receptor tyrosine kinases constitute a family of transmembrane proteins involved in various aspects of cell growth and survival and have been implicated in the initiation and progression of several types of human malignancies. The best characterized of these proteins are the epidermal growth factor receptor (EGFR) and ErbB-2 (HER-2/neu). We have developed potent quinazoline and pyrido-[3,4-d]-pyrimidine small molecules that are dual inhibitors of ErbB-2 and EGFR. The compounds demonstrate potent in vitro inhibition of the ErbB-2 and EGFR kinase domains with IC(50)s <80 nM. Growth of ErbB-2- and EGFR-expressing tumor cell lines is inhibited at concentrations <0.5 microM. Selectivity for tumor cell growth inhibition versus normal human fibroblast growth inhibition ranges from 10- to >75-fold. Tumor growth in mouse s.c. xenograft models of the BT474 and HN5 cell lines is inhibited in a dose-responsive manner using oral doses of 10 and 30 mg/kg twice per day. In addition, the tested compounds caused a reduction of ErbB-2 and EGFR autophosphorylation in tumor fragments from these xenograft models. These data indicate that these compounds have potential use as therapy in the broad population of cancer patients overexpressing ErbB-2 and/or EGFR.

Indazolylamino quinazolines and pyridopyrimidines as inhibitors of the EGFr and C-erbB-2.

Described herein is the design and synthesis of indazolylaminopyridopyrimidines and quinazolines as inhibitors of the class 1 tyrosine kinase receptor family. Data is presented for N(4)-(1-benzyl-1H-indazol-5-yl)-N(6),N(6)-dimethylpyrido[3,4-d]pyrimidine-4,6-diamine 3B. This compound inhibited EGFr and c-erbB-2 enzymes selectively over other kinases. It inhibited the proliferation of a range of tumour cell lines in vitro and the growth of BT474 xenografts in SCID mice.

Sodium channel beta1 and beta2 subunits parallel SNS/PN3 alpha-subunit changes in injured human sensory neurons.

Voltage-gated sodium channels consist of a pore-containing alpha-subunit and one or more auxiliary beta-subunits, which may modulate channel function. We previously demonstrated that sodium channel SNS/PN3 alpha-subunits were decreased in human sensory cell bodies after spinal root avulsion injury, and accumulated at injured nerve terminals in pain states. Using specific antibodies for immunohistochemistry, we have now detected sodium channel beta1 and beta2 subunits in sensory cell bodies within control human postmortem sensory ganglia (78% of small/medium (< or = 50 microm) and 68% of large (> or = 50 microm) cells); their changes in cervical sensory ganglia after avulsion injury paralleled those described for SNS/PN3 alpha-subunits. Our results suggest that alpha- and beta-subunits share common regulatory mechanisms, but present distinct targets for novel analgesics.

Virological Methods for the Generation and Characterization of Influenza Viruses with Reduced Sensitivity to 4-Guanidino-Neu5Ac2en.

The compound 4-guanidino-Neu5Ac2en (zanamivir) has been described as a selective inhibitor of the influenza virus neuraminidase (NA) (1). Viruses that are less sensitive to this inhibitor can be isolated after several passages in MDCK cells in the presence of the inhibitor. Variants isolated so far have had mutations predominantly in the hemagglutinin (HA) gene (2). Many of these mutations appear to lower the affinity of the HA for the cellular receptor, so that there is less requirement for significant NA activity for the newly synthesized progeny virus to elute. There are three reports of a mutation in the NA gene, all at the same conserved site, glu 119 (3-5). In this chapter, the authors describe methods for the isolation of the mutants, and for their characterization in cell culture based assays.

Isolation and characterisation of a prenylated p-terphenyl metabolite of Aspergillus candidus possessing potent and selective cytotoxic activity; studies on mechanism of action.

We describe the discovery and properties of a prenylated p-terphenyl metabolite of the fungus Aspergillus candidus. The compound (1) possesses potent cytotoxic activity against a range of tumour and other hyper-proliferative cell lines. Cell cycle analysis shows that in mouse keratinocyte (BALB/MK) cells treated with 1, the cell cycle is arrested in early S phase, indicative of an antimetabolite effect. Furthermore, cellular cytotoxicity can be reversed by addition of exogenous pyrimidine but not purine nucleosides to the cell culture medium. It is therefore likely that compound 1 selectively inhibits pyrimidine biosynthesis, and it is this property which accounts for its potent cytotoxic properties.

Fifth metacarpal stress fracture in a female softball pitcher.

PURPOSE: This article describes a previously unreported fifth metacarpal stress fracture. CASE SUMMARY: A female softball pitcher presented with gradual development of dorsal pain in her pitching hand. A radioisotope scan showed increased uptake in the fifth metacarpal. This supported a clinical diagnosis of a stress fracture, and the patient was treated with a period of relative rest. At 6 weeks, the patient was able to return to pitching with technique modification. DISCUSSION: Seven cases of metacarpal stress fractures have been reported, yet none involved the fifth metacarpal. The causes of a fifth metacarpal stress fracture differ from those of other metacarpals and may be a combination of extrinsic forces from the ball and intrinsic forces from muscle pull. Although treatment involves the standard rest period, technique must be assessed and appropriately adjusted. RELEVANCE: Metacarpal stress fractures should be considered in athletes with persistent hand pain where repetitive grip function is used.

Molecular mechanisms of cell and tissue interactions during early tooth development.

BACKGROUND: Morphogenesis and cell differentiation during the development of all organs, including the tooth, are regulated by interactions between cells and tissues. The developing tooth is one of the organs in which the molecular mechanisms of such interactions are starting to be elucidated. RESULTS: Homotypic cell interactions take place between cells of the same developmental history, and they are a central mechanism in the formation of mesenchymal cell condensates during the bud stage of tooth development. Syndecan-1, a cell surface heparan sulfate proteoglycan, is transiently expressed in the dental mesenchyme and may regulate dental mesenchymal cell condensation. It binds tenascin, a matrix glycoprotein abundant in dental mesenchyme, suggesting involvement of cell-matrix interactions. Syndecan also binds growth factors, and its association with cell proliferation in the dental mesenchyme suggests roles in the regulation of cell number in the condensing cells. Inductive interactions between the epithelial and mesenchymal tissues regulate tooth development at all stages. In the early dental mesenchyme, the expression of several molecules, including syndecan and tenascin, are regulated by the epithelium. There is evidence that growth factors act as diffusible signals mediating these interactions. BMP-2 and BMP-4 (bone morphogenetic proteins), which belong to the TGF beta superfamily, are expressed in the early dental epithelium, and their effects on the dental mesenchyme mimic those of the epithelium. In particular, BMPs induce the expression of the homeobox-containing transcription factors Msx-1 and Msx-2 in the dental mesenchyme. CONCLUSIONS: Based on current knowledge about the molecular changes accompanying tooth development and the results of experimental studies, we present a model for molecular regulation of early tooth development.

Murine MLP: cloning and expression in the embryonic head.

Differential display reverse transcription polymerase chain reaction (DD RT-PRC) was used to isolate cDNA clones of mRNA expressed in particular compartments of the developing murine head. One clone has been characterized and found to be the murine homologue of the MLP genes. In other species the LIM-domain containing MLPs are expressed specifically in muscle. In situ hybridization and RT-PCR have confirmed that the murine gene is expressed during both cardiac and skeletal myogenesis. Our data show that DD RT-PCR is a valuable technique to clone cDNA clones from minute tissue samples by virtue of the gene's expression pattern rather than by a process of library screening by homology.

Migrating to learn and learning to migrate: a study of the experiences and intentions of international student migrants.

"The research reported here evaluates whether students come to the UK mainly for educational reasons, and therefore perceive their stay as temporary, or whether emigration for study is being used as part of a conscious strategy by people intending to become future labour migrants.... The simplest interpretation of the results appears to be that migration, experienced as a result of international moves for study purposes, does not influence planning of further migration moves. But the research also indicates that migration for education is closely tied to other types of population redistribution and should be treated by population geographers as an integral part of international migration systems." Data were collected by questionnaire survey from 349 engineering students at Hong Kong universities and 82 Hong Kong students studying engineering in the UK.

The British who are not British and the immigration policies that are not: the case of Hong Kong.

"While 'closed-door' immigration policies are adopted by most countries, 'exceptionalist' legislation is often made to permit entry of special immigrant groups. An example is the British Nationality (Hong Kong) Act 1990, which was passed in the run-up to the change in sovereignty of Hong Kong in 1997. Britain's increasingly restrictive immigration policies prior to 1990 [have] resulted in the majority of Hong Kong citizens having British nationality (as British Dependent Territories citizens) but without the right of abode in the U.K. The 1990 Act conferred full British citizenship status on 50,000 heads of households in Hong Kong." The authors conclude that "in a world of marked global inequalities, immigration pressure will become even more extreme and is likely to produce an increasing number of cases of exceptionalist immigration legislation in countries with both ¿open' and 'closed'-door policies.'

Discourse on migration and ethnic identity: interviews with professionals in Hong Kong.

"This paper has revealed a complex set of relationships between migration, place and ethnic identity [in Hong Kong]. On the one hand, ethnic identity is shaped by the places where people have lived, particularly the places where they have spent the early years of their life; on the other [hand], places--being the context for socialization--provide the milieux where people learn who and what they are and how to act...." The authors note that "while legislation clearly regulates levels of immigration, international migration is also self-regulated by potential migrants in relation to interpretations of their ethnic identities and their perceptions of 'other' places."

Sialylation of terminal saccharides of glycoconjugates expressed by murine molar tooth germs developing in vitro and in vivo.

During development of the mammalian tooth germ the pattern of terminal saccharides of glycoconjugates changes, with many structures losing lectin reactivity in a consistent pattern. This study investigated whether the epitopes are lost or become masked by terminal sialylation, using a combination of neuraminidase treatment of sections and sialic acid-reactive lectins. The results suggested that most of the terminal galactosamine and fucose sites in the epithelial enamel organ were removed during morphogenesis. Conversely, during condensation of the dental mesenchyme, masked peanut agglutinin (PNA)-reactive galactose epitopes appeared. During differentiation and organisation of the mesenchyme into odontoblasts and a subodontoblastic layer the PNA-reactive sites became masked again. These regions also specifically expressed sialylated glucosamine. However, at the proliferating epithelial cervical loop galactose sites appeared to be masked. This was more pronounced during in vitro development when abnormal expression of PNA-reactive sites was found at the cervical loop. Additionally, fucosylated sites persisted in the enamel organ, further indicating that the expression of terminal saccharides was disrupted during development in the organ culture system. These data suggest that loss of terminal galactose and galactosamine is related to differentiation of the cells. However, whether this loss occurs by removal or sialic acid masking is not dependent either on the origin of the cells or the epitope being lost.