Dental Unit Water Lines and their Disinfection and Management: A Review

The perceived threat to public health from dental unit water line (DUWL) contamination comes from opportunistic and respiratory pathogens such as Legionella spp, Nontuberculous Mycobacteria (NTM) and pseudomonads. These organisms can grow and multiply in the DUWL biofilm to reach infective concentrations, with the potential for inhalation leading to respiratory infections or direct contamination of surgical wounds. In this paper we discuss current legislation and practical methods for delivering water within the DUWL that meets the standards for safety. Clinical relevance: Understanding the clinical relevance and methods for decontaminating DUWL is essential to create a safe working environment in dentistry.

Candidiasis (oropharyngeal)

INTRODUCTION

Candida is a fungus present in the mouths of up to 60% of healthy people, but overt infection is associated with immunosuppression, diabetes, broad-spectrum antibiotics, and corticosteroid use. In most people, untreated candidiasis persists for months or years unless associated risk factors are treated or eliminated. In neonates, spontaneous cure of oropharyngeal candidiasis usually occurs after 3 to 8 weeks.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions to prevent and treat oropharyngeal candidiasis in: adults undergoing treatments that cause immunosuppression; infants and children; people with dentures; and people with HIV infection? Which antifungal treatments reduce the risk of acquiring resistance to antifungal drugs? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2013 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA), the European Medicines Agency (EMA), and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 47 RCTs or systematic reviews of RCTs that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review, we present information relating to the effectiveness and safety of the following interventions: antifungals (absorbed, partially or topically absorbed, or non-absorbed; for example, imidazole [ketoconazole, clotrimazole, toiconazole, miconazole], polyene [amphotericin B, nystatin], triazole [fluconazole, itraconazole], melaleuca and posaconazole), intermittent or continuous prophylaxis, or treatment, and denture hygiene.

Candidiasis (oropharyngeal)

INTRODUCTION

Candida is a fungus present in the mouths of up to 60% of healthy people, but overt infection is associated with immunosuppression, diabetes, broad-spectrum antibiotics, and corticosteroid use. In most people, untreated candidiasis persists for months or years unless associated risk factors are treated or eliminated. In neonates, spontaneous cure of oropharyngeal candidiasis usually occurs after 3 to 8 weeks.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions to prevent and treat oropharyngeal candidiasis in: adults having treatment causing immunosuppression; infants and children; people with diabetes; people with dentures; and people with HIV infection? Which treatments reduce the risk of acquiring resistance to antifungal drugs? We searched: Medline, Embase, The Cochrane Library, and other important databases up to August 2011 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 51 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: antifungals (absorbed or partially absorbed, and topical absorbed/partially absorbed/non-absorbed: e.g., amphotericin B, clotrimazole, fluconazole, itraconazole, ketoconazole, miconazole, nystatin, posaconazole) used for intermittent or continuous prophylaxis or treatment, and denture hygiene.

Candidiasis (oropharyngeal)

INTRODUCTION

Candida is present in the mouths of up to 60% of healthy people, but overt infection is associated with immunosuppression, diabetes, broad-spectrum antibiotics, and corticosteroid use. In most people, untreated candidiasis persists for months or years unless associated risk factors are treated or eliminated. In neonates, spontaneous cure of oropharyngeal candidiasis usually occurs after 3-8 weeks.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions to prevent and treat oropharyngeal candidiasis in: adults having treatment causing immunosuppression; infants and children; people with diabetes; people with dentures; and people with HIV infection? Which treatments reduce the risk of acquiring resistance to antifungal drugs? We searched: Medline, Embase, The Cochrane Library, and other important databases up to September 2008 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 46 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: antifungals (absorbed or partially absorbed, and topical absorbed/partially absorbed/non-absorbed [e.g. amphotericin B, fluconazole, itraconazole, miconazole, and nystatin]) used for intermittent or continuous prophylaxis or therapy, and denture hygiene.

Do contaminated dental unit waterlines pose a risk of infection?

OBJECTIVES

To review the evidence that the dental unit waterlines are a source of occupational and healthcare acquired infection in the dental surgery.

DATA

Transmission of infection from contaminated dental unit waterlines (DUWL) is by aerosol droplet inhalation or rarely imbibing or wound contamination in susceptible individuals. Most of the organisms isolated from DUWL are of low pathogenicity. However, data from a small number of studies described infection or colonisation in susceptible hosts with Legionella spp., Pseudomonas spp. and environmental mycobacteria isolated from DUWL. The reported prevalence of legionellae in DUWL varies widely from 0 to 68%. The risk from prolonged occupational exposure to legionellae has been evaluated. Earlier studies measuring surrogate evidence of exposure to legionellae in dental personnel found a significant increase in legionella antibody levels but in recent multicentre studies undertaken in primary dental care legionellae were isolated at very low rate and the corresponding serological titres were not above background levels. Whereas, a case of fatal Legionellosis in a dental surgeon concluded that the DUWL was the likely source of the infection. The dominant species isolated from dental unit waterlines (DUWL) are Gram-negative bacteria, which are a potent source of cell wall endotoxin. A consequence of indoor endotoxin exposure is the triggering or exacerbation of asthma. Data from a single large practice-based cross-sectional study reported a temporal association between occupational exposure to contaminated DUWL with aerobic counts of >200cfu/mL at 37 degrees C and development of asthma in the sub-group of dentists in whom asthma arose following the commencement of dental training.

SOURCES

Medline 1966 to February 2007 was used to identify studies for this paper.

STUDY SELECTION

Design criteria included randomised control trials, cohort, and observational studies in English.

CONCLUSIONS

Although the number of published cases of infection or respiratory symptoms resulting from exposure to water from contaminated DUWL is limited, there is a medico-legal requirement to comply with potable water standards and to conform to public perceptions on water safety.

Utility of two oral health-related quality-of-life measures in patients with xerostomia

OBJECTIVES

The study compared the validity of the short form of the Oral Health Impact Profile (OHIP) and Oral Impacts on Daily Performance (OIDP) as measures of oral health-related quality of life in patients with xerostomia in the UK.

METHODS

A cross-sectional comparison of OHIP14 and OIDP with measures of clinical indicators, xerostomia symptom status, speech function, global oral health ratings and psychological well-being, in 85 patients attending outpatient clinics.

RESULTS

Both OHIP14 and OIDP had excellent internal reliability, and good criterion and construct validity when used in this population of xerostomia patients. In regression analyses, salivary gland condition and xerostomia symptom status significantly predicted oral health-related quality of life (OHRQoL), accounting for 29% and 14% of the variance in OHIP and OIDP scores respectively. In turn, OHRQoL predicted global ratings of oral health (26% of variance) and psychological well-being (depression) scores (15%). Sex, ethnicity and age were associated with clinical presentation and patient-reported symptoms. Clinical presentation, OHRQoL (as measured by the OIDP) and speech function were related to duration of symptoms.

CONCLUSION

Both OHIP14 and OIDP have good psychometric properties and appear useful measures of OHRQoL in xerostomia. Overall, the OHIP14 performed better than did OIDP. For both measures, the additive scoring method may be more relevant for this population that the number of impacts.

Testing relationships between clinical and non-clinical variables in xerostomia: A structural equation model of oral health-related quality of life

OBJECTIVES

The aim of the study was to systematically test Wilson and Cleary's [Wilson IB, Cleary PD. JAMA 1995; 273: 59-65] conceptual model of the direct and mediated pathways between clinical and non-clinical variables in relation to the oral health-related quality of life (OHRQoL) of patients with xerostomia.

METHODS

We collected measures of clinical variables, self-reported symptoms, OHRQoL, global oral health perceptions and subjective well-being from 85 patients attending outpatient clinics.

RESULTS

Structural equation modelling indicated support for the dominant direct pathways between the main levels of the model; more severe clinical signs predicted worse patient reported symptoms; worse symptom perception was associated with a lower functional status as measured by OHRQoL; and lower OHRQoL predicted worse global oral health perceptions. There was no relationship between the final two levels of the model; global oral health perceptions and subjective well-being. Subjective well-being was associated instead with earlier non-adjacent levels; biological variables, symptoms and functional status. These pathways were both direct (salivary flow-well-being, functioning-well-being) and indirect (clinical signs-well being, symptom status-well-being). There were also indirect pathways; most notably, the impact of clinical variables on OHRQoL was mediated by patient reported symptom status.

CONCLUSIONS

The results support Wilson and Cleary's conceptual model of patient outcomes as applied to a chronic oral health condition and highlight the complexity of (inter)relationships between key clinical and non-clinical variables. Further conceptual development of the model is discussed, particularly the role of individual difference factors, and theoretical and methodological issues in OHRQoL research are highlighted.

Evaluation of the potential risk of occupational asthma in dentists exposed to contaminated dental unit waterlines

INTRODUCTION

Most of the organisms isolated from dental unit waterlines (DUWL) are Gram-negative bacteria, which contain cell wall endotoxin. A consequence of endotoxin exposure is the exacerbation of asthma.

OBJECTIVES

This study examined the prevalence and onset of asthma among dentists and determined whether or not these were associated with the microbiological quality of DUWL in their practices.

METHODS

266 randomly selected dentists (100 from rural Northern Ireland, 166 from London) completed a health questionnaire, which included questions on prevalence and time of onset of asthma. Water samples taken from the dental handpieces and surgery washbasin cold taps in all the practices were analysed using standard techniques. The questionnaire data were evaluated using both single and multivariable logistic regression. The variables considered were: smoking; surgery location; time treating patients per week; DUWL counts of Pseudomonas aeruginosa, total Pseudomonas spp., fungi, Mycobacterium spp., total aerobic colony counts (ACC) at 22 degrees C and 37 degrees C.

RESULTS

There was no significant association between any of the variables tested in dentists and a history of asthma. A subgroup analysis was performed on dentists (n=33) who reported developing asthma since they started dental training. The final multivariable model indicated that passive smoking (OR 0.08, 95% CI 0.01-0.87, P=0.038) and total aerobic counts of >200 cfu/ml at 37 degrees C (OR 6.72, 95% CI 1.15-39.24, P=0.034) were significant variables for developing asthma since starting training as a dentist. ACC were significantly higher in London (P<0.0001) and London dentists were more likely to have developed asthma since they started training than their Northern Ireland counterparts (OR 4.4, 95% CI 1.09-17.72, P=0.033).

CONCLUSIONS

This study suggests that the temporal onset of asthma may be associated with occupational exposure to contaminated DUWL among dentists in London and Northern Ireland.

Randomized-controlled trial: effect of a reservoir biteguard on quality of life in xerostomia

BACKGROUND

To assess the effect of a reservoir biteguard for artificial saliva on the oral health-related quality of life of patients with xerostomia.

METHODS

Double-blind randomized placebo-controlled trial among 86 adults with xerostomia. Study group received the trial biteguard. Control group received a conventional biteguard. Outcomes were number of impacts and total scores as recorded by oral impacts on daily performances (OIDP).

RESULTS

At 1-month follow up 84 people remained in the trial. The median number of impacts in the study and control groups was 3 and 4 respectively. The median total score was 6 and 12 respectively. In ANCOVA receipt of the reservoir biteguard reduced the number of impacts recorded by OIDP but there was no difference in the total score.

CONCLUSIONS

Reservoir biteguards improved the quality of life of people with xerostomia by reducing the number of impacts on daily life.

The effect of infection-control barriers on the light intensity of light-cure units and depth of cure of composite

AIM

Dental curing lights are vulnerable to contamination with oral fluids during routine intra-oral use. This controlled study aimed to evaluate whether or not disposable transparent barriers placed over the light-guide tip would affect light output intensity or the subsequent depth of cure of a composite restoration.

METHODS

The impact on light intensity emitted from high-, medium- and low-output light-cure units in the presence of two commercially available disposable infection-control barriers was evaluated against a no-barrier control. Power density measurements from the three intensity light-cure units were recorded with a radiometer, then converted to a digital image using an intra-oral camera and values determined using a commercial computer program. For each curing unit, the measurements were repeated on ten separate occasions with each barrier and the control. Depth of cure was evaluated using a scrape test in a natural tooth model.

RESULTS

At each level of light output, the two disposable barriers produced a significant reduction in the mean power density readings compared to the no-barrier control (P<0.005). The cure sleeve inhibited light output to a greater extent than either the cling film or the control (P<0.005). Only composite restorations light-activated by the high level unit demonstrated a small but significant decrease in the depth of cure compared to the control (P<0.05).

CONCLUSION

Placing disposable barriers over the light-guide tip reduced the light intensity from all three curing lights. There was no impact on depth of cure except for the high-output light, where a small decrease in cure depth was noted but this was not considered clinically significant. Disposable barriers can be recommended for use with light-cure lights.

A 3-year longitudinal, controlled clinical study of a gallium-based restorative material

AIM

The aim of this three-year longitudinal controlled study was to compare the clinical performance of Galloy versus a high copper, mercury based Dispersalloy filling material.

METHODS

Moderate to large class I and class II cavities or replacement restorations were selected and 25 Galloy restorations and 25 Dispersalloy controls were placed in 14 adult patients by a single operator. Restorations were photographed and a silicone impression recorded at baseline, 6 months, 1 year, 2 years and 3 years.

RESULTS

At 3 years all 22 Dispersalloy restorations but only 4 Galloy restorations were still in situ. Three Dispersalloy restorations were lost to follow-up. Tooth fracture was observed in 15 (60%) of the Galloy restorations by the end of the 3 years, compared to one (4%) Dispersalloy restoration, which failed due to tooth fracture. A further six Galloy restorations had to be removed due to complaints of persistent pain. Four teeth restored with Galloy required endodontic treatment but none of the Dispersalloy restored teeth required endodontics. Of the four Galloy restorations remaining in situ, three were relatively small restorations and the fourth a moderate sized restoration required a marginal repair.

CONCLUSION

The clinical performance of Galloy restorations was so grossly inferior to the Dispersalloy controls that Galloy cannot be recommended for clinical use in moderate to large or multi-surface cavities.

Prevalence of legionella waterline contamination and Legionella pneumophila antibodies in general dental practitioners in London and rural Northern Ireland

OBJECTIVES

To determine the prevalence of legionellae in dental unit waterlines (DUWL) in general dental practices in London and rural Northern Ireland and whether the organism occurs at a high enough frequency and magnitude in DUWL to represent a threat to dentists' health.

MATERIALS AND METHOD

Two hundred and sixty six (166 London, 100 Northern Ireland) randomly selected dental surgeries were recruited. Standardised 250 ml water samples were taken from the DUWL and 1 litre samples from the surgery cold water tap to measure the prevalence of legionellae. The dentists provided a blood sample for legionella serology.

RESULTS

The prevalence of legionellae was very low (0.37%). Legionellae were not isolated from DUWL or surgery basin taps in Northern Ireland. Legionella spp were isolated from the DUWL and surgery basin of one practice in London and from the cold water supply of a further three practices. The prevalence of Legionella pneumophila antibodies was less than that seen in a comparable group of London blood donors.

CONCLUSION

The risk to dentists' health from potential exposure to legionellae in this cohort of dentists was very low and this was confirmed by the very low seroprevalence and antibody titres to legionella detected in the dentists.

Risk assessment of dental unit waterline contamination

Biofilms form rapidly on dental unit waterlines. The majority of the organisms in the biofilm are harmless environmental species, but some dental units may harbour opportunistic respiratory pathogens. This paper describes a risk assessment approach to analysing the hazard from biofilm organisms contaminating dental unit waterlines on the respiratory health of both the dental team and patients. The health risk from the respiratory pathogens Legionella spp, Mycobacterium spp and Pseudomonads was found to be low. Nevertheless, in order to satisfy water regulations and comply with health and safety legislation dentists should institute infection-control measures to maintain the dental unit water at the standard of less than 200 colony-forming units per ml of aerobic bacteria.

Management of dental unit water lines

Dental unit water lines harbour considerable amounts of bacteria, derived from the biofilm on their inner surfaces, and the continuous reservoir of bacteria carries the potential to infect patients and dental workers alike. This article reviews the different methods of control and provides recent recommendations for ensuring that water of satisfactory quality is delivered to the patient.

Sialochemical markers of salivary gland involvement with Sjögren's syndrome secondary to rheumatoid arthritis and primary biliary cirrhosis

Sjögren's syndrome is an autoimmune condition affecting the lacrimal and salivary glands and can be associated with rheumatoid arthritis and primary biliary cirrhosis. Parotid salivas collected from patients and normal controls were analysed for lactoferrin, IgA and beta2-microglobulin (measured by ELISA), and cystatin (measured by a enzyme inhibition assay). Output data provided less variable means, whilst expressing results as a proportion of the total protein provided greater specificity as markers for Sjögren's syndrome. Levels of specificity for IgA, lactoferrin and beta2-microglobulin were all high (100, 95 and 100%, respectively). Sensitivity levels of these markers (but not cystatin) tended to be similar for Sjögren's syndrome secondary to primary biliary cirrhosis (IgA, 25%; lactoferrin, 63%; and beta2-microglobulin, 50%), compared to Sjögren's syndrome secondary to connective tissue diseases such as rheumatoid arthritis (IgA, 50%; lactoferrin, 86%; and beta2-microglobulin; 38%).

Lectin binding studies of parotid salivary glycoproteins in Sjögren's syndrome

Human parotid salivas were collected from patients with secondary Sjögren's syndrome and controls without disease or with drug-induced xerostomia. Parotid glycoproteins were separated by gradient sodium dodecyl sulphate gel electrophoresis (SDS-PAGE), electroblotted onto nitrocellulose membrane and probed with biotinylated lectins of characterised sugar specificities. The binding patterns of lectins from Maclura pomifera (MPA) and Arachis hypogaea (PNA) indicated that many parotid glycoproteins have sialylated O-linked glycans and that sialylation is not affected by disease. Binding by lectins from Ricinus communis (RCA-1), Limax flavus (LFA), Lotus tetragonolobus (LTA) and Ulex europaeus (UEA-1) appeared unaltered in secondary Sjögren's syndrome, suggesting no obvious change in N-glycosylation of parotid glycoproteins. Variations in binding patterns of most lectins was attributable to subject-to-subject variations in recognised polymorphic proteins. Dolichos biflorus agglutinin (DBA) consistently showed increased binding to a 75 kDa (Mr) protein in salivas from patients with secondary Sjögren's syndrome. The binding protein was identified as lactoferrin but found not to contain N-acetylgalactosamine, the sugar to which DBA binds. Binding of DBA to lactoferrin was dependent upon its saturation with iron, modified SDS-PAGE under nonreducing conditions resolved iron-free and iron-saturated lactoferrins and demonstrated increased levels of the iron-saturated form in secondary Sjögren's syndrome. Lectin binding studies of purified lactoferrins from saliva, milk, and polymorphonuclear neutrophils suggested that raised levels of lactoferrin in saliva originate from salivary cells and not from inflammatory cells. These results suggest that DBA binding provides greater specificity as an indicator of salivary gland disease than measurement of lactoferrin levels alone.

Oral health behaviour and the prevalence of oral manifestations of HIV infection in a group of HIV positive adults

The objectives of this study were to assess the prevalence of oral manifestations of HIV infection, the periodontal health status and the oral health behaviour of a group of 51 HIV infected adults. The design was a cross-sectional descriptive study which took place in a community dental clinic in south London dedicated to treatment of this group of patients. Data were collected through a self-administrated questionnaire, interview and clinical examination and results showed that 76.5 per cent had one or more oral manifestations of HIV infection. Intra-oral herpes, papilloma and non-Hodgkin's lymphoma were not identified. A very positive attitude towards oral hygiene was identified. Plaque levels were low. All individuals studied had some evidence of bleeding gums.

Microbial contamination of dental unit waterlines: the scientific argument

The quality of dental unit water is of considerable importance since patients and dental staff are regularly exposed to water and aerosols generated from the dental unit. The unique feature of dental chair water lines is the capacity for rapid development of a biofilm on the dental water supply lines combined with the generation of potentially contaminated aerosols. The biofilm, which is derived from bacteria in the incoming water and is intrinsically resistant to most biocides, then becomes the primary reservoir for continued contamination of the system. Dental water may become heavily contaminated with opportunistic respiratory pathogens such as Legionella and Mycobacterium spp. The significance of such exposure to patients and the dental team is discussed. There is at the present time, no evidence of a widespread public health problem from exposure to dental unit water. Nevertheless, the goal of infection control is to minimise the risk from exposure to potential pathogens and to create a safe working environment in which to treat patients. This paper evaluates the range of currently available infection control methods and prevention strategies which are designed to reduce the impact of the biofilm on dental water contamination, and are suitable for use in general practice. Bacterial load in dental unit water can be kept at or below recommended guidelines for drinking water (less than 200 colony forming units/ml) using a combination of readily available measures and strict adherence to maintenance protocols. Sterile water should be employed for all surgical treatments.

Controversies in the aetiology of temporomandibular disorders. Part 1. Temporomandibular disorders: all in the mind?

The aetiology of temporomandibular disorders (TMDs) is now considered to be multifactorial but the relative importance of individual aetiological factors is still controversial. Psychosocial factors play an important role in the aetiology of TMDs, in adaptation to pain and eventual recovery. TMD patients exhibit a variety of psychological and behavioural characteristics including increased somatization, stress, anxiety and depression. Subcategorisation of TMD patients into joint-related and muscle-related groups reveals psychological differences. Myogenic patients have increased severity of pain and suffer enhanced psychological distress. Within this group of patients are a minority of refractory cases who show marked overlap with those suffering from chronic pain syndrome; such patients benefit from psychiatric assessment and treatment. However, no common TMD personality profile has emerged from the psychometric test research. Recent knowledge of the molecular pathways induced by stress and the evaluation of stress-response substances may, in the future, provide diagnostically valuable biochemical markers of disease susceptibility. The role of psychological factors in the development of TMDs in the general population is critically examined.

The environmental risk factors associated with medical and dental equipment in the transmission of Burkholderia (Pseudomonas) cepacia in cystic fibrosis patients

Transmission of Burkholderia (Pseudomonas) cepacia by close contact with colonized patients is well documented, and minimizing social contact between cystic fibrosis (CF) patients by segregation and cohorting of B. cepacia colonized patients has achieved some success in controlling the nosocomial and community spread of this organism. However, direct and indirect environmental transmission still occurs. There is evidence for transmission of B. cepacia to CF patients via pulmonary test equipment, nebulizers and other respiratory equipment used both in CF centres and for homecare, but little or no evidence of spread through aerosols, dental equipment, hands, contaminated disinfectants and water supplies. Infection control procedures for reducing the transmission of B. cepacia are discussed.

Diagnosis and management of the dry mouth: Part 1

Dry mouth is a relatively common problem, often neglected by patients and dentists alike. This article reviews the symptoms, causes and treatment of xerostomia and provides guidelines for recognizing the condition at an early stage.

Glycoproteins in human parotid saliva assessed by lectin probes after resolution by sodium dodecyl sulphate-polyacrylamide gel electrophoresis

Human parotid salivary glycoproteins separated by gradient sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and electroblotted onto nitrocellulose have been investigated using a battery of biotinylated lectin probes of characterized sugar specificity. Lectin binding, detected on blots using avidin-biotin complex (ABC) and a chemiluminescence generating substrate, was recorded on photographic film and compared with the original fluorescein isothiocyanate (FITC) stained blots or with Coomassie Brilliant Blue R-250-stained gels run in parallel. A number of glycoprotein bands which were undetected by protein stains or the periodic acid Schiff reaction were revealed by lectins. Binding by lectins from Concanavalia ensiformis, Lens culinaris, Limax flavus, Phaseolus vulgaris, Ricinus communis, Triticum vulgaris, Lotus tetragonobulus and Ulex europaeus indicated that sialylated and fucosylated triantennary and bisected, N-linked complex sugar chains were present on many glycoproteins in addition to the major glycosylated proline-rich glycoprotein (GI). Binding with lectins from Arachis hypogaea and Dolichos biflorus indicated that the O-linked sugar chains were confined to the alpha-heavy chain of Ig A. Comparison of lectin binding in samples from five healthy individuals revealed differences in a number of glycoproteins in addition to the previously characterized G1 and CON 1/CON 2 polymorphisms and demonstrated that the H blood group antigen was expressed mainly on G1 in parotid saliva. This study will be used as a basis upon which to study salivary glycoproteins in diseases affecting parotid glands.

Evaluation of contamination of the dentist and dental surgery environment with Burkholderia (Pseudomonas) cepacia during treatment of children with cystic fibrosis

Pulmonary colonization with Burkholderia (Pseudomonas) cepacia in cystic fibrosis (CF) patients has been associated with high morbidity and mortality. The aim of this study was to investigate whether the dentist and the dental surgery environment become contaminated during treatment of CF patients colonized with B. cepacia. Extensive environmental sampling was carried out during aerosol-generating treatment sessions on four CF patients whose sputum was persistently colonized with B. cepacia. Samples of surgery air, and of water from the air-turbine, three-in-one syringe and their supply-lines, were tested before and after an aerosol-generating treatment session with each patient. Settle plates were placed on the bracket table and work-surfaces, and within the portable suction unit's exhaust housing unit during treatment, and swabs were obtained from various items of dental equipment at the end of treatment. Swabs of the buccal mucosa were obtained from each patient before treatment, and from the dentist before and after treatment. B. cepacia was isolated from the swabs of three of the patients, but not from those taken from the dentist or from any of the environmental samples. The results suggest that CF patients colonized with B. cepacia appear to constitute a low risk for environmental contamination and are unlikely to be an important means of transmission between CF patients.

Use of CHROMagar Candida medium for isolation of yeasts from dental samples

A new differential medium, CHROMagar Candida, for the isolation of clinically important yeasts was investigated to determine its usefulness in facilitating the study of oral yeasts. The recovery of yeasts on the medium was not significantly different from the recovery on Sabouraud dextrose agar. The identities of 450 green colonies on CHROMagar Candida, presumptively identified as Candida albicans on the basis of the manufacturer's instructions, were confirmed by testing for beta-N-acetylgalactosaminidase. Candida tropicalis also formed distinctive colonies, and other yeasts including Candida (Torulopsis) glabrata, Candida Parapsilosis, Candida Magnoliae, Candida lusitaniae, Candida Famata, Candida kefir, and Saccharomyces cerevisiae were readily distinguished from C. albicans and C. tropicalis isolates. CHROMagar Candida is a very useful medium, and its use will facilitate the study of yeasts associated with dental diseases.

Activity of sucralfate (sucrose octa-sulphate), an anti-ulcer agent, against opportunistic gram-negative bacilli

The in-vitro activity of sucralfate (sucrose octa-sulphate) in suspension was examined against 128 strains of Gram-negative bacilli. Inhibitory activity was demonstrated against all isolates and bactericidal activity was demonstrated for 68. Sucralfate has inhibitory and bactericidal antibacterial activity which may contribute to its in-vivo clinical efficacy.

Prophylactic application of an intra-alveolar socket medicament to reduce postextraction complications in HIV-seropositive patients

A prospective, controlled trial was performed to investigate the effect of a prophylactic socket medicament containing chlortetracycline, aspirin, and local anesthetics, in reducing the incidence of postextraction pain and infection in patients who are HIV-seropositive. Fifty patients were in the study; 25 received the experimental dressing and 25 had no dressing. Patients were asked to complete a questionnaire rating the pain at 24 hours and 48 hours after surgery. Seven days after extraction, socket healing was scored, and sockets with delayed healing sampled for culture. Four of 25 (16%) patients who received the experimental dressing and 8 of 25 (32%) controls experienced pain during the 48 hours after extraction (p = not significant). None of the group who received the experimental dressing and 7 of 25 (28%) in the control group had delayed healing, of these 4 had alveolar osteitis and three had infected sockets (p = 0.0096). We conclude that the experimental agent is useful as a prophylactic agent to reduce delayed healing in HIV-positive patients who undergo exodontia.

The microbiological quality of water in dental chair units

Infection control is an important issue in the dental surgery but the potential hazards associated with contaminated dental water have received relatively little attention in recent years. The complex design of the equipment results in stagnation of water within the dental chair and subsequent amplification of contaminating environmental organisms, including pseudomonads and legionellae, to potentially hazardous levels. Immunocompromised patients may be at particular risk of infection. Very poor water quality with total bacterial counts above 10(4) ml-1 is unpleasant for all patients, and the dental chair supply should be of drinking water quality. In addition to these problems, bacteria and viruses may be aspirated from the oral cavity and contaminate the handpiece. Measures to reduce microbial contamination of dental chairs and equipment include flushing water through the chair's equipment at the beginning of each day; continuous or pulsed water chlorination, or application of biocides other than chlorine; provision of sterile bottled water in the system; and autoclaving handpieces between patients. Future dental chair design must attempt to resolve the problems associated with microbial contamination of the water supply and aerosols generated during dental procedures.

The efficacy of chlorination and filtration in the control and eradication of Legionella from dental chair water systems

The apparent failure of hyperchlorination and continuous dosing with chlorine to eliminate legionellae from a dental teaching hospital water supply prompted a prospective study to evaluate charcoal filters as a means of decontamination. Legionella pneumophila serogroup 10 and L. bozemanii serogroup 2 were isolated from dental units yielding 10(1)-10(3) colony forming units (cfu) ml-1 with total bacterial counts in the range 10(2)-greater than 10(4) cfu ml-1. After chair-side installation of charcoal filters bacterial contamination of the dental unit water was prevented and legionellae were initially not detected, but after 7 days the total count returned to pre-filtration levels of greater than 10(4) cfu ml-1; L. pneumophila serogroup 10 was eliminated but L. bozemanii serogroup 2 persisted. These results suggest that neither chlorination nor charcoal filtration deal adequately with the potential hazard of Legionella spp. in dental water.

Multiple idiopathic external root resorption. A case report

An unusual case of multiple idiopathic external apical root resorption affecting all four quadrants, in a patient with a history of narcotic intravenous drug addiction and liver disease, is reported. The literature relating to a systemic etiology for external root resorption is briefly reviewed.