Geriatric dentistry, teaching and future directions.

BACKGROUND: Many nations are facing a demographic shift in the age profile of their population, leading the World Health Organization to a 'Call for Public Health Action' on the oral health of older people. METHODS: A search of the literature relevant to geriatric dentistry teaching was undertaken using MEDLINE, Web of Science, Eric and Psychlit. A search of dental professional school websites in Australia and policy and international practice documents was undertaken. RESULTS: The international literature describes requirements for geriatric dentistry courses and various approaches to teaching, including didactic teaching, practical experiences and external placements. Challenges are identified in the area of geriatric dental education. Educational institutions (with others) have an obligation to lead change, yet there appears to be little formal recognition in Australian dental curricula of the need to develop quality education and research programmes in geriatric dentistry. CONCLUSIONS: Internationally, the inclusion of geriatrics within dental curricula has been the subject of consideration since the 1970s. The current evidence indicates that geriatrics/gerodontology is not a significant component of dental curricula. Given the projected age distribution in many countries, the need for implementation of dental curriculum content in the area of geriatrics/gerodontology is evident.

Quantitative assessment of brain microvascular and tissue oxygenation during cardiac arrest and resuscitation in pigs.

Cardiac arrest is associated with a very high rate of mortality, in part due to inadequate tissue perfusion during attempts at resuscitation. Parameters such as mean arterial pressure and end-tidal carbon dioxide may not accurately reflect adequacy of tissue perfusion during cardiac resuscitation. We hypothesised that quantitative measurements of tissue oxygen tension would more accurately reflect adequacy of tissue perfusion during experimental cardiac arrest. Using oxygen-dependent quenching of phosphorescence, we made measurements of oxygen in the microcirculation and in the interstitial space of the brain and muscle in a porcine model of ventricular fibrillation and cardiopulmonary resuscitation. Measurements were performed at baseline, during untreated ventricular fibrillation, during resuscitation and after return of spontaneous circulation. After achieving stable baseline brain tissue oxygen tension, as measured using an Oxyphor G4-based phosphorescent microsensor, ventricular fibrillation resulted in an immediate reduction in all measured parameters. During cardiopulmonary resuscitation, brain oxygen tension remained unchanged. After the return of spontaneous circulation, all measured parameters including brain oxygen tension recovered to baseline levels. Muscle tissue oxygen tension followed a similar trend as the brain, but with slower response times. We conclude that measurements of brain tissue oxygen tension, which more accurately reflect adequacy of tissue perfusion during cardiac arrest and resuscitation, may contribute to the development of new strategies to optimise perfusion during cardiac resuscitation and improve patient outcomes after cardiac arrest.

Human papillomavirus and oral disease - emerging evidence: a review.

Human papillomavirus (HPV) infections have received considerable attention in recent years. Of the 120 or so known types of the virus, some cause a variety of benign wart-like lesions of the skin and genital and oral mucosae, whilst others are aetiologically associated with cervical and anogenital cancers. Recent epidemiologic evidence suggests that HPV may also be an independent risk factor for oropharyngeal cancer. In this context it has been suggested that HPV virus may modulate the process of carcinogenesis in some tobacco and alcohol induced oropharyngeal cancers and act as the primary oncogenic agent for inducing carcinogenesis among non-smokers. Dental practitioners have a major role in detecting all lesions of the oral mucosa caused, or possibly caused, by HPV. This paper briefly reviews the current state of knowledge of molecular and clinical aspects of HPV infections of the oral mucosa.

Early regional response of apoptotic activity in newborn piglet brain following hypoxia and ischemia.

Responses of selected neuroregulatory proteins that promote (Caspase 3 and Bax) or inhibit (Bcl-2, high Bcl-2/Bax ratio) apoptotic cell death were measured in the brain of piglets subjected to precisely controlled hypoxic and ischemic insults: 1 h hypoxia (decreasing FiO2 from 21 to 6%) or ischemia (ligation of carotid arteries and hemorrhage), followed by 0, 2 and 4 h recovery with 21% FiO2. Protein expression was measured in cortex, hippocampus and striatum by Western blot. There were no significant differences in expression of Caspase-3 between sham operated, hypoxic and ischemic groups. There were significant regional differences in expression of Bcl-2 and Bax in response to hypoxia and ischemia. The changes in Bcl-2/Bax ratio were similar for hypoxia and ischemia except for striatum at zero time recovery, with ischemia giving lower ratios than hypoxia. The Bcl-2/Bax ratio was also lower for the striatum than for the other regions of the brain, suggesting this region is the more susceptible to apoptotic injury.

Carotid body sensory discharge and glomus cell HIF-1 alpha are regulated by a common oxygen sensor.

The carotid body responds to both acute and more prolonged periods of lowered oxygen pressure. In the acute response, the decrease in oxygen pressure is coupled to increased afferent neural activity while the latter involves, at least in part, increase in the hypoxia inducible transcription factor HIF-1 alpha. In this paper, we summarize evidence that both the acute changes in neural activity and the longer term adaptive changes linked to HIF-1 alpha induction share the same oxygen sensor, mitochondrial cytochrome c oxidase.

Trabecular anisotropy and collagen fibre orientation in the mandibular condyle following experimental functional appliance treatment using sheep.

In order to study the modifying effects of functional appliances on the mechanical environment of the temporomandibular joint (TMJ), we characterised the structure of the mandibular condyle subsequent to an experimental functional appliance intervention. Eight, four-month-old, castrated male Merino sheep, were randomly allocated to experimental and control groups (n = 4 in each group). Forward mandibular displacement was induced with an intraoral appliance. The study period was 15 weeks, during which time fluorochromes were administered to all of the animals. Midsagittal sections of the TMJ were selected for analysis and trabecular anisotropy was estimated using bone histomorphometry. Only the experimental group demonstrated that the trabecular bone in the central condylar region was less anisotropic when compared to the subchondral region. Also, the variation in trabecular anisotropy of the central condylar region was found to be smaller in the experimental group. The collagen fibre orientation was analysed under polarised light as the proportion of the dark or bright fibres observed in regions which existed before, and regions which formed during the experiment, as determined by the fluorochrome labels. In the experimental group, more bright collagen fibres were found in the most superior region of the mandibular condyle when compared with the controls. These results suggested that the experimental functional appliances changed the orientation and pattern of the mechanical forces acting on the mandibular condyle, and possibly increased the magnitude of the lateral functional forces applied to the most superior part of the condyle during such treatments.

The dental implications of bisphosphonates and bone disease.

In 2002/2003 a number of patients presented to the South Australian Oral and Maxillofacial Surgery Unit with unusual non-healing extraction wounds of the jaws. All were middle-aged to elderly, medically compromised and on bisphosphonates for bone pathology. Review of the literature showed similar cases being reported in the North American oral and maxillofacial surgery literature. This paper reviews the role of bisphosphonates in the management of bone disease. There were 2.3 million prescriptions for bisphosphonates in Australia in 2003. This group of drugs is very useful in controlling bone pain and preventing pathologic fractures. However, in a small number of patients on bisphosphonates, intractable, painful, non-healing exposed bone occurs following dental extractions or denture irritation. Affected patients are usually, but not always, over 55 years, medically compromised and on the potent nitrogen containing bisphosphonates pamidronate (Aredia/Pamisol), alendronate (Fosamax) and zolendronate (Zometa) for non-osteoporotic bone disease. Currently, there is no simple, effective treatment and the painful exposed bone may persist for years. The main complications are marked weight loss from difficulty in eating and severe jaw and neck infections. Possible preventive and therapeutic strategies are presented although at this time there is no evidence of their effectiveness. Dentists must ask about bisphosphonate usage for bone disease when recording medical histories and take appropriate actions to avoid the development of this debilitating condition in their patients.

Sequential development of multiple supernumerary teeth in the mandibular premolar region -- a radiographic case report.

This report presents a case of multiple supernumerary teeth developing in the mandibular premolar region in an Asian female patient. A series of radiographs taken over a 10-year period, demonstrate the sequential development of these teeth during the patient's early and middle teenage years. The importance of regular radiographic review and appropriate management for such cases is discussed.

A retrospective analysis of oral hairy leukoplakia in South Australia.

BACKGROUND: The features of oral hairy leukoplakia (OHL) have been widely reported in the literature. However, no studies have described this lesion in the Australian setting. This study retrospectively examines, with respect to specific clinical factors, the prevalence of OHL in a South Australian HIV-infected population. METHODS: Clinical data were collected from the records of 197 HIV-infected patients who had attended the Adelaide Dental Hospital between January 1986 and February 1995. Data were analysed using the chi-square test. RESULTS: The prevalence of OHL in South Australian HIV-infected patients was 45.2 per cent. The study found the presence of OHL was not related to CD4+ T-lymphocyte count or AIDS-defining illness nor did the length of time a patient had been infected with HIV relate to the presence of OHL. An association was observed between a reduced prevalence of OHL in patients who were taking antiviral medication. CONCLUSION: The prevalence of OHL in South Australia is comparable with results of other studies. This study supports the notion that OHL is not an indicator of immunosuppression in South Australian HIV-infected patients. Further longitudinal studies are required to ascertain the relationship of OHL to HIV disease progression.

In vitro effects of photodynamic therapy on Aspergillus fumigatus.

Photodynamic therapy is a technique for killing cells with visible light after pretreatment with a photosensitizing agent. We demonstrated significant in vitro fungicidal activity against Aspergillus fumigatus of the photosensitizer Green 2W, activated with 630 nm light. This effect was both inoculum- and light dose-dependent. At a Green 2W concentration of 31.5 mg/L, there was complete killing of 2.7 x 10(1) cfu/mL with a light dose of 110 J/cm(2) and up to 2.7 x 10(6) cfu/mL with a light dose of 385 J/cm(2).

Lip cancer in South Australia, 1977-1996.

Lip cancer (140 ICD-9, C00 ICD-10) is a form of oral cancer occurring at the junction between the oral cavity and the skin. Lip cancer has a distinctive global epidemiology that is notably different from cancer occurring at other intraoral sites. This study reviews and analyses the epidemiological data for lip cancer from the South Australian Central Cancer Registry between 1977 and 1996. During this 20-year period, 2716 cases of lip cancer (2095 male, 621 female) and 35 deaths from this disease (23 males, 12 females) were reported. The average age of diagnosis was 58.3 years in males and 66.0 years in females. Very high age-standardised incidence rates (over 15.0 per 100000 per annum in males and 4.0 per 100000 per annum in females) were found, giving the South Australian population amongst the highest incidence of lip cancer in the world. Also of considerable concern was the finding that, contrary to global trends, these rates showed a significant increase over the 20-year period in both sexes. Possible reasons for these findings are discussed.

Dynamic changes in cerebral blood flow, O2 tension, and calculated cerebral metabolic rate of O2 during functional activation using oxygen phosphorescence quenching.

Changes in cerebral blood flow (CBF) using laser-Doppler and microvascular O2 oxygen tension using oxygen-dependent phosphorescence quenching in the rat somatosensory cortex were obtained during electrical forepaw stimulation. The signal-averaged CBF response resulting from electrical forepaw stimulation consisted of an initial peak (t = 3.1 +/- 0.8 seconds after onset of stimulation), followed by a plateau phase that was maintained throughout the length of the stimulus. In contrast, microvascular O2 tension changes were delayed, reached a plateau level (t = 23.5 +/- 1.7 seconds after the onset of stimulation) that remained for the length of the stimulus and for several seconds after stimulus termination, and then returned to baseline. Using Fick's equation and these dynamic measurements, changes in the calculated cerebral metabolic rate of oxygen (CMRO2) during functional stimulation were determined. The calculated CMRO2 response initially was comparable with the CBF, but with protracted stimulation, CMRO2 changes were approximately one-third that of CBF changes. These results suggest that a complex relation exists, with comparable changes in CBF and CMRO2 initially occurring after stimulation but excessive changes in CBF compared with CMRO2 arising with protracted stimulation.

Electrostatic core shielding in dendritic polyglutamic porphyrins.

Polyglutamic dendritic porphyrins of the general formula H2PophGlu(N)OR (H2Porph = free-base meso-tetra-4-carboxyphenylporphyrin (H2TCPP), Glu=dendrimer layer composed of L-glutamates, N= 1-3: dendrimer generation number, R = terminal group (All, H)) were synthesized and characterized with NMR and MALDI-TOF mass spectroscopy. The free-acid terminated compounds were found to be highly soluble in water, with both their absorption and fluorescence spectra dependent on pH. The value of the porphyrin mono-protonation constant, measured by fluorescence rationing, increased monotonously in the studied series of dendrimers (pK3=6.31. 6.70, and 6.98, for N=1, 2, 3, respectively). For the largest dendrimer, H2PorphGlu(3)OH, pK3 was found shifted by almost two pH units relative to the non-modified H2Porph. The second protonation constant (K4) was much less affected by the dendritic substituents. At pH values less than 3.5 there were noticeable changes in fluorescence intensity and quantum yield even for the highly soluble H2PorphGlu(3)OH. This suggests that interactions between individual dendritic molecules in solution are favored by full protonation of the peripheral glutamic carboxyls. The "dendrimer-protected" porphyrins are convenient fluorescent pH sensors in the biological pH range.

Synovial chondromatosis of the temporomandibular joint.

We report two cases of temporomandibular joint (TMJ) synovial chondromatosis, one of which was in the early stage and treated arthroscopically. The second was more advanced and recurred after removal of the free bodies, and so required condylectomy and synovectomy.

The epidemiology of mouth cancer: a review of global incidence.

Mouth cancer (143-145 ICD-9) is a major health problem in many parts of the world. While its incidence is relatively low in most western countries there are some important exceptions to this trend: on the Indian subcontinent and in other parts of Asia it remains one of the most common forms of cancer. This review article summarises the global incidence of mouth cancer using cancer maps. Data have been compiled from the latest edition of Cancer Incidence in Five Continents and recent studies from various locations around the world. Significant geographic variation is noted in the incidence of mouth cancer, with high rates reported for the Indian subcontinent and parts of Asia (male incidence rates in excess of 10 per 100,000 per annum). It is also noted that as with other forms of oral cancer, the majority of population-based data for mouth cancer comes from the Western world with a paucity of reliable data from the so-called developing countries. Mouth cancer remains a serious health problem in many parts of the world with many regions reporting increasing incidence rates particularly in males. Ongoing research into the aetiologic risk factors associated with this disease must remain a very high priority if the causes of mouth cancer are to be established and disease control protocols introduced widely.

The epidemiology of tongue cancer: a review of global incidence.

The tongue (141 ICD-9) is the most common intraoral site for cancer in most countries, however its global epidemiology shows significant geographic variation. This review paper summarises the global incidence of cancer of the tongue using cancer maps and references to recent studies from various locations. Tongue cancer remains a serious health problem in many countries including India (male incidence rates up to 6.5 per 100,000 per annum) and parts of Europe (male incidence rates in France up to 8.0 per 100,000 per annum). It is noted that as with other forms of oral cancer the majority of population-based data for tongue cancer comes from the Western world with a paucity of reliable data from the so-called developing countries. The tongue remains the most common intraoral site for oral cancer worldwide and in a number of countries it is a serious public health problem with significant morbidity and mortality. While the incidence of tongue cancer appears to be stable or falling in some regions of the world, in other areas it is rising, particularly among younger people.