Enamel Caries Detection and Diagnosis: An Analysis of Systematic Reviews.

Detection and diagnosis of caries-typically undertaken through a visual-tactile examination, often with supporting radiographic investigations-is commonly regarded as being broadly effective at detecting caries that has progressed into dentine and reached a threshold where restoration is necessary. With earlier detection comes an opportunity to stabilize disease or even remineralize the tooth surface, maximizing retention of tooth tissue and preventing a lifelong cycle of restoration. We undertook a formal comparative analysis of the diagnostic accuracy of different technologies to detect and inform the diagnosis of early caries using published Cochrane systematic reviews. Forming the basis of our comparative analysis were 5 Cochrane diagnostic test accuracy systematic reviews evaluating fluorescence, visual or visual-tactile classification systems, imaging, transillumination and optical coherence tomography, and electrical conductance or impedance technologies. Acceptable reference standards included histology, operative exploration, or enhanced visual assessment (with or without tooth separation) as appropriate. We conducted 2 analyses based on study design: a fully within-study, within-person analysis and a network meta-analysis based on direct and indirect comparisons. Nineteen studies provided data for the fully within-person analysis and 64 studies for the network meta-analysis. Of the 5 technologies evaluated, the greatest pairwise differences were observed in summary sensitivity points for imaging and all other technologies, but summary specificity points were broadly similar. For both analyses, the wide 95% prediction intervals indicated the uncertainty of future diagnostic accuracy across all technologies. The certainty of evidence was low, downgraded for study limitations, inconsistency, and indirectness. Summary estimates of diagnostic accuracy for most technologies indicate that the degree of certitude with which a decision is made regarding the presence or absence of disease may be enhanced with the use of such devices. However, given the broad prediction intervals, it is challenging to predict their accuracy in any future "real world" context.

Feasibility study: assessing the efficacy and social acceptability of using dental hygienist-therapists as front-line clinicians.

Background The oral health of the adult population has been improving in the United Kingdom decade upon decade. Over half of dental service activity in the National Health Service (NHS) is limited to a check-up without any further treatment. This raises a question as to whether check-ups could be provided by dental hygienist-therapists, rather than general dental practitioners. The aim of this study was to assess the feasibility of a definitive trial to evaluate the costs and effects of using dental hygienist-therapists to undertake the check-up.Methods/design Adult NHS patients were randomised into three arms in two dental practices: patients who only saw dental hygienist-therapists for a check-up, those that saw the general dental practitioner and dental hygienist-therapist alternatively and a control, where patients only saw the general dental practitioner for their check-up. The study ran for 15 months. The primary outcome measures of the study were patient recruitment, retention and fidelity. A parallel and embedded qualitative study was undertaken which recorded the views of participating patients to determine the social acceptability of the intervention.Results Sixty patients participated in the study. The initial recruitment rate for the study was 33.7%. This figure increased to over 82.1% when telephone calls or face-to-face recruitment was utilised. The retention rates were 60% for both the dental hygienist-therapist only group and the alternate general dental practitioner and dental hygienist-therapist group, compared to 70% for the general dental practitioner only group. Fifteen patients were interviewed in the qualitative study and supported a team approach to the provision of check-ups in the NHS. Conclusion This study demonstrates the feasibility of a definitive trial to evaluate the costs and effects of using dental-hygienist-therapists to undertake the check-up.

Hemoglobin polymerization in sickle cells studied by circular polarized light scattering.

We have studied intracellular polymerization of hemoglobin S in suspensions of small populations of sickle cells using circular polarized light scattering. We argue that the preferential scattering of right circular polarized light (as expressed by measurements of the S14 Mueller scattering matrix element) directly reflects the amount of polymer inside cells. This technique has made it possible to investigate the effect of oxygen tension, cell density and osmotic stress on intracellular hemoglobin polymerization. Using S14 to determine hemoglobin polymer, we show that the polymer increases with deoxyhemoglobin concentration, that cells containing higher hemoglobin concentrations show significantly more polymer than cells containing less hemoglobin, and that polymerization occurs in sickle-trait cells in hypertonic solutions as the oxygen tension in the suspension is reduced. We also present kinetic measurements of polymerization, including that induced by osmotic shock. Finally, we demonstrate that the total light scattered (S11 Mueller scattering matrix element) that is routinely measured simultaneously with S14 can be used to estimate the percent of reduced (deoxy) Hb in the sample. These experiments demonstrate the potential of this technique to monitor hemoglobin polymerization simultaneously with oxygen dissociation under a wide variety of physiological conditions.

The efficacy of screening for common dental diseases by hygiene-therapists: a diagnostic test accuracy study.

Regularly attending adult patients are increasingly asymptomatic and not in need of treatment when attending for their routine dental examinations. As oral health improves further, using the general dental practitioner to undertake the "checkup" on regular "low-risk" patients represents a substantial and potentially unnecessary cost for state-funded systems. Given recent regulatory changes in the United Kingdom, it is now theoretically possible to delegate a range of tasks to hygiene-therapists. This has the potential to release the general dental practitioner's time and increase the capacity to care. The aim of this study is to compare the diagnostic test accuracy of hygiene-therapists when screening for dental caries and periodontal disease in regularly attending asymptomatic adults who attend for their checkup. A visual screen by hygiene-therapists acted as the index test, and the general dental practitioner acted as the reference standard. Consenting asymptomatic adult patients, who were regularly attending patients at 10 practices across the Northwest of England, entered the study. Both sets of clinicians made an assessment of dental caries and periodontal disease. The primary outcomes measured were the sensitivity and specificity values for dental caries and periodontal disease. In total, 1899 patients were screened. The summary point for sensitivity of dental care professionals when screening for caries and periodontal disease was 0.81 (95% CI, 0.74 to 0.87) and 0.89 (0.86 to 0.92), respectively. The summary point for specificity of dental care professionals when screening for caries and periodontal disease was 0.87 (0.78 to 0.92) and 0.75 (0.66 to 0.82), respectively. The results suggest that hygiene-therapists could be used to screen for dental caries and periodontal disease. This has important ramifications for service design in public-funded health systems.

Comparative accuracy of different members of the dental team in detecting malignant and non-malignant oral lesions.

OBJECTIVES: Role substitution between primary care dentists (PCDs) and dental hygienists and therapists is increasingly being used in a number of different countries. Opponents to this development argue that it is unsafe and frequently cite the potential for missing oral malignancy as an inherent danger. The aim of the present study was to determine the comparative diagnostic test accuracy of different members of the dental team when differentiating between standardised photographs of mouth cancer, potentially malignant disorders and benign oral lesions. METHODS: A total of 192 dental professionals, comprising 96 PCDs, 63 DH-Ts, nine hospital-based dental staff and 24 other dental professionals were sampled purposively. Following orientation, participants were asked to score 90 clinical photographs that depicted cases of oral squamous cell carcinoma, potentially malignant disorders and non-malignant lesions of the oral mucosa. For each photograph participants were asked to determine whether they felt the lesion was representative of carcinoma, a potentially malignant disorder (test positive), or whether the lesion was benign (test negative). They were also asked to record their confidence in their decision on a 0-10 scale. Judgement decisions were compared against the known histopathological diagnosis of each lesion. Sensitivity and specificity were calculated for each participant and clinical group. RESULTS: The diagnostic test accuracy of PCDs and DH-Ts was similar. There was a median sensitivity of 81% Interquartile range (IQR) 19%) for PCDs and 77% (IQR 19%) for DH-T, with specificity of 73% (IQR 16%) and 69% (IQR 17%) respectively. DH-Ts missed fewer frank malignant lesions compared to PCDs. CONCLUSION: The performance of PCDs and DH-Ts when differentiating between mouth cancer, potentially malignant disorders and benign lesions is comparable. DH-Ts should be regarded as being as competent as PCDs as front-line healthcare workers with regard to detection of mouth cancer. However, considerable heterogeneity in detection was found within both clinical groups, suggesting that training remains paramount.

The time dependence of single file diffusion.

The single file diffusion of particles through a narrow pore membrane separating two media is treated as a stochastic birth and death process. A set of differential-difference equations is derived to describe the probability of finding n particles in the pore at any time whose source is the left-hand medium. Explicit time-dependent solutions for an arbitary number of sites are obtained. These can be used to calculate both one-way and net flux as a function of time. Parameters are estimated from steady state permeability data, and the results of some numerical calculations are presented to illustrate the time required to approach a steady state. In many cases, significant time delays can occur.

Amine spin probe permeability in sonicated liposomes.

Permeabilities for an homologous series of amine nitroxide spin probes were measured in liposomes of varying composition by an electron paramagnetic resonance (EPR) method. Results show that the rate-limiting step in permeation is not adsorption/desorption at the aqueous/membrane interface for two probes in phosphatidylcholine/phosphatidic acid liposomes and for one probe in phosphatidylcholine/cholesterol/phosphatidic acid liposomes. Accordingly, we interpret observed selectivity patterns for the entire series of probes in liposomes and red cells in terms of the properties of the bilayer interior. Results are inconsistent with simple applications of either free volume or hydrocarbon sheet models of nonelectrolyte permeation. In the former case, it was found that liposomes do not select against these probes on the basis of molecular volume. In the latter case, probe permeabilities are all much lower than would be predicted for a sheet of bulk hydrocarbon and the polarity of the rate-limiting region is shown to be greater than bulk hydrocarbon. Together with the results of previous studies of spin-labeled solutes in membranes, as well as studies of lipid dynamics in membranes, these latter results suggest that the rate-limiting region in nonelectrolyte permeation is not in the center of the bilayer, but in the relatively ordered acyl chain segments near the glycerol backbone.