Tobacco, oral cancer, and treatment of dependence.

Tobacco dependence is recognised as a life-threatening disorder with serious oral health consequences which responds to treatment in the form of behavioural support and medication. While cigarette smoking is the most hazardous and prevalent form of tobacco use in the west, consideration also needs to be given to other forms such as bidi smoking in India, reverse smoking by several rural populations and use of snuff and chewing tobacco. The evidence that the use of tobacco is the major risk factor for oral cancer and potentially malignant lesions of the mouth is clear.

Preganglionic parasympathectomy decreases salivary SIgA secretion rates from the rat submandibular gland.

Immunoglobulin A (IgA) is transported into saliva by salivary cells expressing the polymeric immunoglobulin receptor (pIgR). In rat salivary glands, autonomic nerves stimulate this process. To examine how nerves affect pIgR-mediated IgA secretion, the chorda-lingual nerve was sectioned.

Secretion of IgA by rat parotid and submandibular cells in response to autonomimetic stimulation in vitro.

The major antibody in saliva is IgA, which is actively transported by pIgR expressed by parenchymal cells within the salivary glands. The rate of IgA secretion into saliva is regulated by the autonomic nerves supplying the glands in vivo. This study examined the mechanism of increased IgA secretion into saliva with autonomimetic stimulation.

An analysis of risk factors for oral cancer in young people: a case-control study.

The incidence of oral cancer amongst young adults is increasing in many European and high incidence countries. The aim of this study was to evaluate the major risk factors for oral cancer in young adults using a case-control design. A sample of 116 patients aged 45 years and younger, diagnosed with squamous cell carcinoma of the oral cavity between 1990 and 1997 from the south east of England were included.

Secondary chondrocyte-derived Ihh stimulates proliferation of periosteal cells during chick development.

The development of the skull is characterised by its dependence upon epigenetic influences. One of the most important of these is secondary chondrogenesis, which occurs following ossification within certain membrane bone periostea, as a result of biomechanical articulation. We have studied the genesis, character and function of the secondary chondrocytes of the quadratojugal of the chick between embryonic days 11 and 14.

Gingival bleeding on probing increases after quitting smoking.

Background: Gingival inflammation associated with plaque accumulation is delayed or impaired in smokers. Anecdotal evidence suggests that smokers who quit experience an increase in gingival bleeding.

Method: A group of 27 subjects on a Quit-smoking programme were examined for changes in gingival health over a 4-6-week period.

Salivary secretion of immunoglobulin A by submandibular glands in response to autonomimetic infusions in anaesthetised rats.

Salivary secretion of immunoglobulin A (lgA) by submandibular glands is increased by stimuli from autonomic nerves. Since it is unclear which specific autonomic receptors transduce such stimuli, we have infused autonomimetics intravenously and compared secretion of fluid, IgA and stored proteins (peroxidase and total protein) with secretory responses during electrical stimulation of the parasympathetic nerve supply in anaesthetized rats. The greatest secretion of IgA was evoked by the alpha-adrenoceptor agonist phenylephrine and this was reduced by the beta-adrenoceptor blocking drug propranolol.

Occlusal adjustment for treating and preventing temporomandibular joint disorders.

Background: There has been a long history of using occlusal adjustment in the management of temporomandibular disorders (TMD). It is not clear if occlusal adjustment is effective in treating TMD.

Objectives: To assess the effectiveness of occlusal adjustment for treating TMD in adults and preventing TMD.

Constitutive secretion of immunoglobulin A and other proteins into lumina of unstimulated submandibular glands in anaesthetised rats.

Salivary fluid secretion is dependent upon reflex stimuli mediated by autonomic nerves. In order to determine if immunoglobulin A (IgA) and salivary proteins are secreted in the absence of nerve stimulation, small volumes (< 2 microl) of saliva were consecutively collected from the submandibular duct of anaesthetised rats following rest pauses in order to sample the protein contents of the ductal system. Within the first 5 microl of such saliva collected by parasympathetic nerve stimulation, IgA and other salivary proteins reached peak concentrations that were over 20-fold greater than levels in parasympathetically stimulated saliva subsequently collected during a 5 min period of stimulation.

Squamous cell carcinoma of the oral cavity in patients aged 45 years and under: a descriptive analysis of 116 cases diagnosed in the South East of England from 1990 to 1997.

Background: there is, currently, much anecdotal and some epidemiological evidence for a rise in oral cancer rates amongst younger individuals, many of whom have had no exposure to traditional risk factors such as tobacco and heavy alcohol use, or at least not the exposure over decades usually associated with this disease. The probity of this assertion and the presence or absence of traditional risk factors needs further evidence.

Objectives: this paper describes the demography and the exposure to potential risk factors amongst a cohort aged 45 years and younger, diagnosed with squamous cell carcinoma of the oral cavity between 1990 and 1997 from the South East of England.

Wnt regulation of chondrocyte differentiation.

The Wnt family of growth factors are important regulators of several developmental processes including skeletogenesis. To further investigate the role of Wnts we analysed their expression in the developing chick limb and performed functional analyses in vivo and in vitro. We found that Wnt5b and Wnt11 are restricted within the prehypertrophic chondrocytes of the cartilage elements, Wnt5a is found in the joints and perichondrium, while Wnt4 is expressed in the developing joints and, in some bones, a subset of the hypertrophic chondrocytes.

Effectiveness of tobacco counseling in the dental office.

This article describes the results of studies among dental care providers regarding tobacco cessation in the past two decades. In the early period, surveys described what dentists were doing in their own practices. The results suggested that they were not adequately communicating to their patients the importance of quitting.

Ethics and dentistry: 2. Ethics and risk management.

The previous paper explored the meaning of ethics, especially its relationship to dentistry. Here, we examine a practical application for solving ethical problems. Together, the two articles should provide dentists with a core of relevant knowledge about ethics and a ready guide to the daily relevance of ethics.

Ethics and dentistry: I. The meaning of ethics.

This short series of two papers will examine the relationship between ethics and dentistry. The first paper explores the meaning of ethics; the second will provide a catalogue of primary sources for dental practitioners who wish to read further in order to gain a core of knowledge about dental ethics.

Misexpression of noggin leads to septal defects in the outflow tract of the chick heart.

BMP-2 and BMP-4 are known to be involved in the early events which specify the cardiac lineage. Their later patterns of expression in the developing mouse and chick heart, in the myocardium overlying the atrioventricular canal (AV) and outflow tract (OFT) cushions, also suggest that they may play a role in valvoseptal development. In this study, we have used a recombinant retrovirus expressing noggin to inhibit the function of BMP-2/4 in the developing chick heart.

Chewing stimulates secretion of human salivary secretory immunoglobulin A.

Immunoglobulin A (IgA) is the most abundant immunoglobulin in saliva and other mucosal secretions and plays an important role in mucosal immunity. The present study examined whether secretion of IgA, like other salivary proteins, is increased by reflex stimulation. Parotid saliva was collected from subjects into separate vials under resting conditions and during chewing-stimulated secretion over 45 min.

Multiple Stafne bone cavities: a diagnostic dilemma.

Salivary gland inclusions in the mandible are relatively uncommon. If defects occur they are generally unilateral, although bilateral cases have been reported. This article describes an unusual case in which the dental panoramic tomogram revealed three radiolucent areas in the mandible.

The management of occupational exposures to blood and saliva in dental practice.

Accidental injuries when handling sharp or rotating instruments can allow inoculation of a dental team member by the patient's blood or saliva. The risk of transmission of HIV from occupational exposure among dental workers is low and to date no occupational exposure has resulted in HIV transmission. However, hepatitis B and C have a high morbidity and mortality and are more infectious than HIV.

Oral midazolam for adults with learning disabilities.

This paper demonstrates how oral midazolam can be employed as an alternative method of behaviour management to general anaesthesia for the dental treatment of people with learning disabilities. A range of treatments, from scaling to root canal therapy, can be carried out successfully using the sedation technique outlined. The advantages of sedation include reduced morbidity and mortality.

A sedation technique for implant and periodontal surgery.

Objective: Evaluation of a sedation technique which involved titrating intravenous midazolam to an 'ideal' sedation end point, followed by a continuous infusion of propofol. This technique might be a satisfactory alternative to general anaesthesia for implant surgery in anxious patients or when procedures exceed 60-min duration.

Material And Methods: 20 patients were treated on 23 occasions.

Nerve-evoked secretion of immunoglobulin A in relation to other proteins by parotid glands in anaesthetized rat.

Secretion of fluid and proteins by salivary cells is under the control of parasympathetic and sympathetic autonomic nerves. In a recent study we have shown that, in the rat submandibular gland, autonomic nerves can also increase the secretion of IgA, a product of plasma cells secreted into saliva as SIgA (IgA bound to Secretory Component, the cleaved poly-immunoglobulin receptor). The present study aimed to determine if parotid secretion of SIgA is increased by autonomic nerves and to compare SIgA secretion with other parotid proteins stored and secreted by acinar and ductal cells.

Sympathetic decentralization abolishes increased secretion of immunoglobulin A evoked by parasympathetic stimulation of rat submandibular glands.

Salivary secretion of immunoglobulin A (IgA) in response to electrical stimulation of the parasympathetic nerve supply was assessed bilaterally in the submandibular glands of anaesthetized rats 1 week following unilateral pre-ganglionic sympathectomy (decentralization). Nerve-mediated stimulation on the non-denervated side increased IgA secretion several fold above an unstimulated rate of secretion whereas sympathetic decentralization reduced the parasympathetically stimulated secretion of IgA without affecting the basal rate. Glandular levels of IgA were increased following decentralization compared to the control glands.

Oral pH and drinking habit during ingestion of a carbonated drink in a group of adolescents with dental erosion.

Objectives: To investigate the relationship between dental erosion, oral pH and drinking habit in a group of adolescents.

Methods: Oral pH was measured simultaneously at the surface of four teeth in 11 patients, aged 10-16 years, with erosion and in 10 controls subjects without erosion using antimony electrodes. Measurements were made before, during and after drinking 330 ml of a carbonated drink.

Double electrophoretic separation and lectin analyses of the component chains of secretory immunoglobulin A from human saliva.

A new method is presented for the separation of secretory immunoglobulin A (SIgA) from salivary samples. Salivary proteins (from parotid or stimulated whole mouth saliva) were precipitated with methanol to concentrate SIgA from salivary samples whilst removing other salivary proteins. SIgA purified from breast milk and salivary proteins was separated by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under nonreducing conditions.