Real-time confocal imaging, during active air abrasion -- substrate cutting.

Air abrasion cutting, using particulates accelerated in a controlled compressed gas stream, is currently being re-evaluated as a precision tissue removal technique for dental cavity preparation. The minimal vibrations and heat generated during cutting commend the technique for use in the shaping of fragile or brittle materials that are vulnerable to vibrations and thermal stresses. Traditional air abrasion studies have relied solely upon post-procedure imaging, and cutting process details have been inferred from the nature of the residual surface.

Altered protein expression of Streptococcus oralis cultured at low pH revealed by two-dimensional gel electrophoresis.

Streptococcus oralis is the predominant aciduric nonmutans streptococcus isolated from the human dentition, but the role of this organism in the initiation and progression of dental caries has yet to be established. To identify proteins that are differentially expressed by S. oralis growing under conditions of low pH, soluble cellular proteins extracted from bacteria grown in batch culture at pH 5.

Effect of curing with a plasma light on the properties of polymerizable dental restorative materials.

Specimens of light-curable dental restoratives have been prepared using either a conventional dental curing lamp (for 20 or 30 s) or a plasma light (for 1 or 2 s). The specimens were then stored in water until their mass equilibrated, then dried to constant mass. Most specimens lost material in this process but the losses in all specimens cured with the plasma light were significantly greater than those cured with the conventional lights (P < 0.

The ethnicity of dental practitioners in the United Kingdom.

Objective: To describe the proportion of dental practitioners, currently practising in the UK, who are from different ethnic groups.

Method: Analysis of data from the British Dental Association Omnibus Survey 2000. The sample comprised 970 qualified dentists in all fields of practice.

The contribution of imaging and digitised data to mandibular reconstruction and implant stabilised occlusal rehabilitation: a case report.

Different methods are recommended for the surgical reconstruction of the resected mandible. The advantages for implant stabilised prostheses in restoring the occlusion are recognised but few papers provide adequate data to identify the successful outcome of treatment. The literature is reviewed and the advantages of imaging together with the use of digitised data is highlighted by a case requiring rehabilitation with enhanced planning methods.

Oral health in children undergoing liver transplantation.

Aims: To determine the prevalence of dental caries in children undergoing liver transplantation and to compare the plaque, gingivitis, and gingival overgrowth indices and oral mucosal lesions in children before and after liver transplantation.

Patients And Methods: Patients undergoing liver transplantation at King's College Hospital were examined before transplantation, at 3 and 106 days post-transplantation. Healthy children from the Greenwich Health District, south-east London, were matched to the liver transplant patients by age, gender, socio-economic factors and the presence or absence of active dental caries.

A comparison of two nickel-titanium instrumentation techniques in teeth using microcomputed tomography.

Aim: The aim of the study was to compare the shaping of root canals by two nickel-titanium instrumentation techniques using microcomputed tomography (MCT).

Methodology: Ten mandibular first molar teeth (30 canals) that had intact crowns and fully formed roots were scanned using MCT. Fifteen canals were instrumented using NiTiFlex hand files (Maillefer) using balanced force.

Detection of bacterial virulence genes associated with infective endocarditis in infected root canals.

Aim: The aim of this study was to examine whether bacteria associated with root canals possess genes that might predispose to bacterial colonization of the endocardium.

Methodology: Oligonucleotides were designed from DNA sequences encoding the functional binding regions of streptococcal fibronectin-binding protein (FnBP) and staphylococcal fibrinogen-binding protein (FgBP). The specificity and cross-reactivity of the oligonucleotide primers were investigated; streptococcal primers were tested for recognition of FnBP genes in other strains of streptococci, and the staphylococcal primers for detection of FgBP from other staphylococci.

Dental caries-protective agents in milk and milk products: investigations in vitro.

Objectives: To characterise and identify the anti-dental caries components that exist in milk and milk products.

Methods: Standard enamel or hydroxyapatite demineralisation tests were devised to simulate the action of acid on tooth mineral, and they were used to show which constituents of milk possessed a potential protective action against acid attack.

Results: Milk and milk products were fractionated and tested, revealing that minerals, including calcium and phosphorus, played a part in this protective process.

Mannosidase production by viridans group streptococci.

The production of mannosidase activity by all currently recognized species of human viridans group streptococci was determined using an assay in which bacterial growth was dependent on the degradation of the high-mannose-type glycans of RNase B and subsequent utilization of released mannose. RNase B is an excellent substrate for the demonstration of mannosidase activity since it is a glycoprotein with a single glycosylation site which is occupied by high-mannose-type glycoforms containing five to nine mannose residues. Mannosidase activity was produced only by some members of the mitis group (Streptococcus mitis, Streptococcus oralis, Streptococcus gordonii, Streptococcus cristatus, Streptococcus infantis, Streptococcus parasanguinis, and Streptococcus pneumoniae) and Streptococcus intermedius of the anginosus group.

The occlusal management of maxillary anterior single-unit implant-supported restorations.

This paper, with the aid of clinical examples, highlights some of the common occlusal problems that can be associated with maxillary anterior single-unit implant-supported restorations. The authors stress the importance of thorough pre-operative planning to identify any likely occlusal problems. This allows patients to be fully informed of the impact of any necessary clinical compromise and of the need for and nature of modifications to the natural dentition.

Adverse reaction to dental local anaesthetic injection--'allergy' is not the cause.

Objective: To investigate patients considered to have experienced allergic reactions to local anaesthetics administered for dental treatment.

Setting: Dental facility within a general hospital.

Procedure: Skin and intra-oral challenge tests.

Dental post-operative sensitivity associated with a gallium-based restorative material.

Introduction: This study forms part of a 2-year longitudinal clinical trial to compare the performance of a gallium-based restorative material (Galloy) with a high copper, mercury based (Dispersalloy) control material.

Method: Following Ethical Committee approval, 25 galloy restorations and 25 Dispersalloy controls were placed in 14 adult patients, by a single operator. The cavities were of moderate size, indicating the use of amalgam as the restorative material.

The rate of change of pH of lactic acid exposed to glass-ionomer dental cements.

The rate of change of pH of aqueous lactic acid at pH 4.2-4.5 (i.

Cowden's syndrome (multiple hamartoma and neoplasia syndrome): diagnostic dilemmas in three cases.

Cowden's syndrome is a multisystem disease inherited as an autosomal dominant trait with incomplete penetrance and variable expression. The disease has typical oral manifestations which often precede more systemic involvement, and the dental professional is therefore well placed to institute a regime of regular checks to ensure early treatment of any neoplasms which may occur. However, since not all of the classical signs are present in all patients, diagnosis may be difficult.

A study on the use of the dentatus AEB face bow and its modification as an ear bow.

This study investigated the siting of the earbow mounting pins on the Dentatus ARL articulator relative to the condylar axis. Further, it showed the repeatability of registrations using the Dentatus AEB face bow and its modification as an earbow. Three face bow and three earbow recordings were made of 35 subjects.

Inhibition of Wnt signaling by exogenous Mfrzb1 protein affects molar tooth size.

Wnt extracellular signaling molecules have essential roles as regulators of cell proliferation, migration, differentiation, and in epithelial-mesenchymal interactions involved in tissue morphogenesis. Frizzled integral membrane proteins have been shown to function as receptors for Wnt signaling molecules. Vertebrates also produce secreted proteins related to Frizzled receptors, Frizzled-related proteins (FRPs), which contain the cysteine-rich domain of Frizzleds and appear to function as Wnt antagonists.

Wnt/Shh interactions regulate ectodermal boundary formation during mammalian tooth development.

Interactions between the Wnt (wingless) and hedgehog signaling pathways were first described as playing a role in establishing boundaries between ectodermal cells in Drosophila segmentation. During the initiation of mammalian tooth development, boundaries that distinguish oral from dental ectoderm must be formed to correctly position the sites of tooth formation. We describe a reciprocal relationship between the expression of Wnt-7b in presumptive oral ectoderm and Shh in presumptive dental ectoderm in mouse embryos that mark boundaries between these cells with different developmental fates.

Multiple maxillary and mandibular exostoses associated with multiple dermatofibromas: a case report.

Exostoses of the maxilla and mandible are nodular protuberances of mature bone that need to be accurately distinguished from other more diagnostically significant lesions, notably exosteal osteomas. Multiple dermatofibromas are rare and may be associated with altered immune function. We report the case of an otherwise healthy 47-year-old woman who was first seen with multiple maxillary and mandibular exostoses associated with multiple dermatofibromas.

The effect of minocycline on the metabolism of androgens by human oral periosteal fibroblasts and its inhibition by finasteride.

The antimicrobial minocycline has matrix-stimulatory effects on connective tissue and bone. The aim here was to study the effect of minocycline on 5alpha reduction of androgen substrates to 5alpha-dihydrotestosterone (DHT) in periosteal fibroblasts and the influence of the antiandrogen finasteride on this conversion. Confluent cultures of periosteal fibroblasts established from oral periosteum isolated from the bone surface were incubated in duplicate in multiwell dishes with two androgen substrates, [(14)C]-testosterone/[(14)C]-4-androstenedione, in the presence or absence of serial concentrations of minocycline or the antiandrogen finasteride or the two in combination for 24 h.

Isolation and characterisation of sialidase from a strain of Streptococcus oralis.

Streptococcus oralis, the most virulent of the viridans streptococci, produces a sialidase and this exo-glycosidase has been implicated in the disease process of a number of pathogens. The sialidase of S. oralis strain AR3 was purified in order to understand the characteristics of this putative virulence determinant.

Measurement of misfit at the implant-prosthesis interface: an experimental method using a coordinate measuring machine.

Measurement of misfit at the implant-prosthesis interface is a difficult procedure. One factor common to all methods that attempt to measure 3-dimensional distortion to the micron level is the difficulty in providing verifiably consistent reference points between individual measurement sets. Consequently, the majority of studies use a relative distortion model in which the coordinate reference system is integral to the framework, thus limiting the value of the data gathered.

Knowledge, attitudes and beliefs of adult South Asians living in London regarding risk factors and signs for oral cancer.

Background: South Asian communities in the UK are thought to be a high-risk group for oral cancer, primarily because of betel-quid (pan) chewing habits. However there has been little research on the communities' perception of oral cancer.

Aim: This investigation was undertaken to assess the knowledge, attitudes and beliefs of South Asian adults (n = 367) regarding the risk factors and signs for oral cancer.

Temporospatial cell interactions regulating mandibular and maxillary arch patterning.

The cellular origin of the instructive information for hard tissue patterning of the jaws has been the subject of a long-standing controversy. Are the cranial neural crest cells prepatterned or does the epithelium pattern a developmentally uncommitted population of ectomesenchymal cells? In order to understand more about how orofacial patterning is controlled we have investigated the temporal signalling interactions and responses between epithelium and mesenchymal cells in the mandibular and maxillary primordia. We show that within the mandibular arch, homeobox genes that are expressed in different proximodistal spatial domains corresponding to presumptive molar and incisor ectomesenchymal cells are induced by signals from the oral epithelium.