Caroline L. Pankhurst

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

ObjectivesThe 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.MethodsWe collected measures of clinical variables, self-reported symptoms, OHRQoL, global oral health perceptions and subjective well-being from 85 patients attending outpatient clinics.ResultsStructural 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.ConclusionsThe 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 hand-pieces 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°C and 37°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°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.

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.

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

Human parotid salivas were collected from patients with secondary Sjögrens 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 Sjögrens 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 Sjögrens 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 Sjögrens 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.

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.

An ultrastructural study of adherence to buccal epithelial cells of Simonsiella sp.

Simonsiella, an unusual aerobic Gram‐negative multicellular, filamentous bacterium present in the oral flora, possesses a marked dorsal‐ventral differentiation. The morphology and ultrastructure of the structural appendages on the ventral surface were examined. Two types of fibrils could be distinguished; in vitro adherence of Simonsiella to buccal epithelial cells was by means of the short fibrils.