Development and psychometric validation of the gum health experience questionnaire.

AIM: To develop and validate a new health-related quality of life measure to capture a wide range of gum-related impacts. MATERIALS AND METHODS: The measure was developed using a multi-stage approach and a theoretical model. Development involved semi-structured interviews, pilot testing, cross-sectional analysis among a general population (n = 152) to assess psychometric properties and test-retest reliability among a subsample (n = 27). RESULTS: Psychometric analysis supports the validity and reliability of the measure's impact scale. The measure has excellent internal reliability (nearly all item-total correlations above .4; Cronbach's alpha between .84 and .91 for subscales), with test-retest reliability also performing well (Intra-class correlation coefficient [ICC] of .91-.97 for subscales). Good content validity (indicated by large standard deviations for item and total scores) and construct validity (correlations of .54-.73 with global gum health rating for subscales, all p < .05) were also observed. Qualitative and quantitative data indicate that people with gum health-related symptoms experience different degrees of discomfort and impacts caused by their condition. CONCLUSIONS: The gum health experience questionnaire holds substantial promise as a measure of gum-related quality of life in people across the gum health-disease continuum. Further face validity, refining and reducing the number of items and longitudinal studies to test evaluative properties are required before the measure can be used with confidence.

Gum health and quality of life-subjective experiences from across the gum health-disease continuum in adults.

BACKGROUND: There has been a lack of qualitative work investigating the effects of the wide range of gum-related symptoms, and the perceived everyday impacts associated with these including on quality of life. While periodontal disease has been shown to have significant effects on quality of life, fewer studies have researched the perceived impacts of gingivitis and symptoms from across the entire gum health-disease continuum, despite evidence that these can also negatively affect quality of life. The aim of this study was to investigate perceived everyday impacts and explore the subjective experiences of adults with a variety of symptoms from across the self-reported gum health-disease continuum, and how these may affect quality of life. METHODS: Participants were recruited at a large UK University using purposive sampling, for self-reported symptoms ranging from mild gingivitis to severe periodontal disease. Semi-structured interviews gathered details on symptom history, changes occurring over time and associated beliefs, as well as perceived impacts on everyday life, and links between these experiences and identity. Interviews were analysed using framework analysis based on the Wilson and Cleary health-related quality of life model. RESULTS: Twenty-seven participants were recruited - 15 with symptoms of gingivitis, 12 with more severe periodontal symptoms. Prominent themes included description of symptoms, changes in daily life, social impacts, psychological impacts, identity, and overall impacts and quality of life. Differences were noted in severity, extent and frequency of symptoms and participant experiences, with greater perceived impacts often felt by those with periodontal disease. However, participants from across the gum health-disease continuum often expressed similar experiences and concerns. CONCLUSION: Findings demonstrate the range of experiences from participants with a variety of gum-related symptoms; notably, gingivitis was reported to have a range of perceived impacts on quality of life alongside those reported by periodontal disease sufferers. Future work should look to include symptoms from across the entire gum health-disease continuum when considering quality of life, as well as considering a more patient-centred approach which could be valuable in both clinical and research settings.

Gingivitis efficacy of a 0.454% w/w stannous fluoride dentifrice: a 24-week randomized controlled trial.

BACKGROUND: Plaque-induced gingivitis can be prevented and treated with regular effective oral hygiene, principally via mechanical cleaning with regular toothbrushing. To complement the mechanical plaque removal, antimicrobial ingredients can be incorporated into dentifrices to inhibit the growth of plaque. This study aimed to evaluate and compare gingivitis and the proportion of subjects moving between gingivitis severity (< 10, > 10 < 30, > 30% bleeding sites), and plaque reduction, following twice daily use of an experimental non-aqueous 0.454% weight/weight (w/w) stannous fluoride (SnF2) dentifrice, compared to a negative control dentifrice over 12 and 24 weeks. METHOD: This was a single-center, examiner-blinded, randomized, stratified, two-treatment arm, parallel group, 24-week clinical study in healthy adult volunteers with moderate gingivitis. At baseline, after abstaining from toothbrushing overnight, subjects underwent MGI (modified gingival index), BI (bleeding index) and PI (plaque index) assessments. Eligible subjects, who met the inclusion/exclusion criteria, were stratified based on gender and baseline mean MGI score (Low ≤2.00 /High > 2.00) and randomized to treatment. Following randomization, subjects underwent a thorough dental prophylaxis and flossing. After 12 and 24 weeks of twice daily brushing with their allocated treatment, subjects returned to the site (with overnight plaque, having abstained from oral hygiene procedures for 8 h prior to visit) for MGI, BI and PI assessments. Treatment effect was evaluated by comparing the MGI, BI and PI scores. RESULTS: One hundred and twenty-nine subjects were screened; 98 subjects were randomized and 90 subjects completed the study. Statistically significant differences between treatments, in favour of the 0.454% stannous fluoride dentifrice were observed, compared to the negative control dentifrice, for all outcome measures (MGI, BI, bleeding sites and PI at weeks 12 and 24 p < 0.0001). At 24 weeks, 71% of subjects in the 0.453% SnF2 treatment group demonstrated < 10% of bleeding sites. CONCLUSION: A dentifrice containing 0.454% w/w SnF2 was shown to be superior to a standard dentifrice in controlling gingivitis and supra-gingival plaque, over a 24-week period. Over two thirds of subjects in the 0.454% SnF2 treatment group demonstrated a level of bleeding sites potentially representative of "clinical periodontal health" (< 10%) following a dental prophylaxis and 24 weeks of product use. TRIAL REGISTRATION: This study was retrospectively registered at ClinicalTrials.gov, on 11th Oct. 2019 (NCT04123665).

Randomised study of the effects of fluoride and time on in situ remineralisation of acid-softened enamel.

OBJECTIVES: This single-centre, randomised, crossover study used a short-term in situ dental erosion remineralisation model to explore the remineralisation of acid-softened enamel in the 4-h period immediately following brushing with an anti-erosion, dentin hypersensitivity test dentifrice containing 1150 ppm fluoride (as sodium fluoride [NaF]) or a placebo dentifrice with no fluoride. MATERIALS AND METHODS: Fifty participants wearing a palatal appliance holding surface-softened bovine enamel specimens brushed their natural teeth with their assigned dentifrice. Specimens were removed at 5-, 10-, 15-, 30-, 60-, 120- and 240-min post brushing. Enamel remineralisation effect was evaluated at each timepoint by percent surface microhardness recovery (%SMHR) and enamel fluoride uptake (EFU). After a second in vitro erosive challenge, the percent relative erosion resistance (%RER) was calculated. RESULTS: Statistically significant differences in %SMHR were observed for the test dentifrice compared with the placebo dentifrice from the 60-min timepoint onwards (all p < 0.02; mean difference of 8.66 [95% CI 3.46, 13.87] at 60 min). At each specimen removal time, %RER and EFU were statistically significantly higher for the test dentifrice compared with the placebo dentifrice (p < 0.0001 for all). No treatment-related or serious adverse events were reported. CONCLUSIONS: The NaF-containing anti-erosion, dentin hypersensitivity dentifrice improved remineralisation of acid-softened enamel starting at 60 min of intra-oral exposure. It also improved enamel erosion resistance and fluoride uptake as early as 5 min after exposure to fluoridated dentifrice slurry. CLINICAL RELEVANCE: Brushing with a NaF-containing dentifrice can rapidly improve remineralisation, enamel erosion resistance and fluoride uptake.

In Situ Study to Confirm the Anticaries Potential of a Sodium Monofluorophosphate Dentifrice Containing Calcium Sodium Phosphosilicate.

OBJECTIVES: A randomized, investigator-blind, five-treatment, crossover, non-inferiority study was conducted to investigate the effect of the addition of calcium sodium phosphosilicate (CSPS), an agent known to relieve dentin hypersensitivity, to a sodium monofluorophosphate (SMFP)-containing dentifrice on the enamel remineralization potential of fluoride (F), as assessed by percentage surface microhardness recovery (%SMHR) and enamel fluoride uptake (EFU) using a standard in situ caries model. METHODS: Seventy-seven subjects wearing bilateral mandibular partial dentures holding partially demineralized bovine enamel specimens 24 hours/day brushed their teeth with their assigned randomized dentifrice containing either 1500 or 0 ppm F with 5% CSPS or 1500, 500, or 0 ppm F with 0% CSPS twice daily for 21 days. The success criterion was to observe a difference in % SMHR between dentifrices containing 1500 ppm F of six units or less in the upper bound of the two-sided 95% confidence interval (CI). RESULTS: Following 21 days of treatment, the upper bound CI of the %SMHR difference between the dentifrices containing 1500 ppm F was 1.66, thus within the non-inferiority limit. No statistically significant differences for %SMHR (p = 0.2601) and EFU (p = 0.2984) were noted between these two dentifrices. CONCLUSIONS: The present in situ caries study provides evidence demonstrating that the addition of the calcium-containing compound CSPS to a 1500 ppm F dentifrice does not interfere with the ability of fluoride to remineralize surface-softened enamel; i.e., CSPS neither impairs nor improves the potential cariostatic value of SMFP dentifrice.

A novel method to quantify dentine tubule occlusion applied to in situ model samples.

OBJECTIVES: To develop an innovative computerised routine, in conjunction with a minimally destructive imaging technique, to quantify dentine tubule occlusion. METHODS: Polished human dentine samples (n = 480) were brushed during a 4-day in situ study with two occlusion-based dentifrices, a sodium fluoride control dentifrice (1,450 ppm) or water. Samples were imaged with tandem scanning microscopy (TSM) and conventional scanning electron microscopy (SEM). The level of dentine patency was then assessed using a visual ordinal scale ('standard') or quantitatively using a specially designed computational routine. RESULTS: The occlusion-based dentifrice resulted in significantly less patent dentine than controls for the 'standard' (p = 0.01) assessment, but not for computer analyses (p = 0.10). The correlation of the number of individual patent tubules counted visually and by the computational routine in calibrations and in the in situ study was ≥ 0.8. CONCLUSIONS: This study identified a new computer-based routine, capable of objectively quantifying the patency of dentine imaged by SEM and TSM.

Multidisciplinary management of malignant ovarian germ cell tumours.

OBJECTIVES: Malignant ovarian germ cell tumours (MOGCT) are rare cancers of young women. Limited prospective trials exist from which evidence-based management can be developed. This review summarizes the available literature concerning MOGT in order to provide the clinician with information relevant to their multidisciplinary management. METHODS: MEDLINE was searched between 1966 and 2010 for all publications in English where the studied population included women diagnosed with malignant ovarian germ cell tumours. RESULTS: The majority of patients can be cured with fertility-preserving surgery with or without combination chemotherapy. Long term survival approaches 100% in early stage disease and is approximately 75% in advanced stage disease. Most studies suggest that the treatment has little, if any, effect on future fertility and limited data suggest that there is no adverse effect on the future quality of life. CONCLUSION: MOGCTs are rare tumours of young women the majority of which can be successfully treated with fertility-preserving surgery with or without chemotherapy with preservation of reproductive function. Minimisation of chemotherapy in good prognostic groups and improved treatment in resistant and relapsed MOGCT are important goals for the future. Further studies are needed to quantify the late adverse effects of treatment in long term survivors.

How does exposure to nitrogen dioxide compare between on-road and off-road cycle routes?

This study demonstrates a simple method to estimate the extent to which the exposure of cyclists to NO(2) is reduced by using off-road cycle routes rather than on-road cycle routes. Diffusion tubes were used to measure monthly NO(2) concentrations on three paired sets of on- and off-road cycle journeys in and around the City of York in August and September 2008. These measurements were combined with estimates of journey times to calculate time-weighted average concentration and exposure on each route. The average concentration of NO(2) was significantly reduced by a mean of 37.5% when off-road routes were used in place of on-road routes and, despite the longer journey times for off-road routes, exposure was also significantly reduced by a mean of 25.5%. The method described in this study could be adopted more widely to provide a cost effective and simple means of assessing the benefits of alternative cycle routes that are provided by Local Authorities.

Artificial intelligence in radiation oncology: A review of its current status and potential application for the radiotherapy workforce.

OBJECTIVE: Radiation oncology is a continually evolving speciality. With the development of new imaging modalities and advanced imaging processing techniques, there is an increasing amount of data available to practitioners. In this narrative review, Artificial Intelligence (AI) is used as a reference to machine learning, and its potential, along with current problems in the field of radiation oncology, are considered from a technical position. KEY FINDINGS: AI has the potential to harness the availability of data for improving patient outcomes, reducing toxicity, and easing clinical burdens. However, problems including the requirement of complexity of data, undefined core outcomes and limited generalisability are apparent. CONCLUSION: This original review highlights considerations for the radiotherapy workforce, particularly therapeutic radiographers, as there will be an increasing requirement for their familiarity with AI due to their unique position as the interface between imaging technology and patients. IMPLICATIONS FOR PRACTICE: Collaboration between AI experts and the radiotherapy workforce are required to overcome current issues before clinical adoption. The development of educational resources and standardised reporting of AI studies may help facilitate this.

Assessment of brominated flame retardants in a small mixed waste electronic and electrical equipment (WEEE) plastic recycling stream in the UK.

Identifying the presence of brominated flame retardants (BFRs) within individual polymer types prior to extrusion has given us a unique perspective on which polymers may be problematic in meeting European Union (EU) low persistent organic pollutant (POP) content limits (LPCLs) and the potential for mixed engineering plastics (MEP) to be used as a viable recycled product. Our findings suggest that careful management of the polymer types within the feed chips prior to extrusion could deliver extruded polymer pellets that meet the EU LPCL values for POP-BFRs (i.e. <1000 mg/kg). Within this study, three fractions of extruded polymer pellets ("light", "medium", and "heavy" MEP) were created using density separation. Each fraction was characterised for 28 legacy and novel BFRs with brominated diphenyl ether-209 (BDE-209) (68-37,000 mg/kg) and tetrabromobisphenol-A (TBBP-A) (17-120,000 mg/kg) both predominant and ubiquitous. Portable X-ray fluorescence (XRF) was utilised to measure Br in 120 individual MEP chips of various polymer types. Those chips that XRF flagged as having high Br concentrations (>2500 mg/kg) were subjected to further evaluation for BFR content via mass spectrometry analysis and the results compared with the XRF Br data. This revealed that in 22% of the 120 chips studied, XRF incorrectly identified the LPCL to be exceeded. Our data also identifies the presence of the novel BFRs decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE) in plastics derived from waste electronic and electrical equipment (WEEE). While the "light-MEP" samples contained POP-BFR concentrations below LPCLs, the "medium-MEP" and "heavy-MEP" fractions exceeded such limits. Management of the polymer chips by colour sorting resulted in significant reductions in concentrations of all BFRs in the clear polymers such that LPCL limits were not exceeded; however, concentration reductions in white polymers were insufficient to meet LPCLs.

Dynamic nucleotide mutation gradients and control region usage in squamate reptile mitochondrial genomes.

Gradients of nucleotide bias and substitution rates occur in vertebrate mitochondrial genomes due to the asymmetric nature of the replication process. The evolution of these gradients has previously been studied in detail in primates, but not in other vertebrate groups. From the primate study, the strengths of these gradients are known to evolve in ways that can substantially alter the substitution process, but it is unclear how rapidly they evolve over evolutionary time or how different they may be in different lineages or groups of vertebrates. Given the importance of mitochondrial genomes in phylogenetics and molecular evolutionary research, a better understanding of how asymmetric mitochondrial substitution gradients evolve would contribute key insights into how this gradient evolution may mislead evolutionary inferences, and how it may also be incorporated into new evolutionary models. Most snake mitochondrial genomes have an additional interesting feature, 2 nearly identical control regions, which vary among different species in the extent that they are used as origins of replication. Given the expanded sampling of complete snake genomes currently available, together with 2 additional snakes sequenced in this study, we reexamined gradient strength and CR usage in alethinophidian snakes as well as several lizards that possess dual CRs. Our results suggest that nucleotide substitution gradients (and corresponding nucleotide bias) and CR usage is highly labile over the approximately 200 m.y. of squamate evolution, and demonstrates greater overall variability than previously shown in primates. The evidence for the existence of such gradients, and their ability to evolve rapidly and converge among unrelated species suggests that gradient dynamics could easily mislead phylogenetic and molecular evolutionary inferences, and argues strongly that these dynamics should be incorporated into phylogenetic models.

Variability of antarctic sea ice: and changes in carbon dioxide.

A definitive long-term decrease in the extent of antarctic sea ice is not detectable from 9 years (1973 to 1981) of year-round satellite observations and limited prior data. Regional interannual variability is large, with sea ice decreasing in some regions while increasing in others. A significant decrease in overall ice extent during the mid-1970's, previously suggested to reflect warming induced by carbon dioxide, has not been maintained. In particular, the extent of ice in the Weddell Sea region has rebounded after a large decrease concurrent with a major oceanographic anomaly, the Weddell polynya. Over the 9 years, the trends are nearly the same in all seasons, but for periods of 3 to 5 years, greater winter ice maxima are associated with lesser summer ice minima. The decrease of the mid-1970's was preceded by an increase in ice extent from 1966 to 1972, further indicating the presence of cyclical components of variation that obscure any long-term trends that might be caused by a warming induced by carbon dioxide.

Development of an in situ methodology for the clinical evaluation of dentine hypersensitivity occlusion ingredients.

OBJECTIVE: The aim of these clinical studies was to evaluate an in situ dentine tubule occlusion model, and to determine the occluding effect from novel occluding agents on patent dentine tubules compared to a positive control (8% strontium acetate--Sensodyne Mint) and negative control (a non-occluding agent) after four days of brushing treatment. METHODS: These two in situ clinical studies were of single-center, randomized, crossover, single-blind design. Healthy participants wore two lower intra-oral appliances retaining four dentine samples for four treatment days for each period of the study. Samples were power-brushed each day with the test product. Assessment utilized surface topological analysis with a replica-based methodology under scanning electron microscopy (SEM). RESULTS: Both clinical trials demonstrated that the positive control (8% strontium acetate) occluded dentine tubules significantly better (p = 0.0007; p < 0.0009) than the negative controls in the two studies, respectively. The experimental occluding agents demonstrated varying degrees of success for occluding effect compared to the controls. CONCLUSION: The methodology clearly demonstrates that this in situ clinical model can robustly and reproducibly detect the dentine tubular occlusive effects of positive and negative controls in the treatment of dentine hypersensitivity brushed on the dentine surface. Using this methodology, new occlusion agents for the relief of dentine hypersensitivity can be assessed for occlusive effects on dentine.

Growth hormone receptor antagonists: discovery, development, and use in patients with acromegaly.

An understanding of the events that occur during GH receptor (GHR) signaling has facilitated the development of a GHR antagonist (pegvisomant) for use in humans. This molecule has been designed to compete with native GH for the GHR and to prevent its proper or functional dimerization-a process that is critical for GH signal transduction and IGF-I synthesis and secretion. Clinical trials in patients with acromegaly show GHR blockade to be an exciting new mode of therapy for this condition, and pegvisomant may have a therapeutic role in diseases, such as diabetes and malignancy, in which abnormalities of the GH/IGF-I axis have been observed. This review charts the discovery and development of GHR antagonists and details the experience gained in patients with acromegaly.

Personalising Treatment for High-Grade Serous Ovarian Carcinoma.

Ovarian cancer is a heterogeneous group of cancers that differ by cell of origin and genomic features. High-grade serous ovarian cancer (HGSOC) is the commonest histiotype and is characterized by extreme genomic complexity and dysregulation of DNA damage repair pathways, particularly homologous recombination deficiency. New insights from molecular profiling into homologous recombination deficiency now offers the credible possibility of personalizing treatment choices for women with HGSOC using poly(ADP-ribose) polymerase inhibitor (PARP) therapy. Although the presence of tumour infiltrating lymphocytes (TILs) in the microenvironment is associated with improved survival in HGSOC, the role of anti-angiogenic and immune checkpoint inhibitor therapy remains unclear. PARP inhibition combined with immunotherapy is an exciting combination strategy for future therapeutic development for women with advanced HGSOC.

Precision of 655nm Confocal Laser Profilometry for 3D surface texture characterisation of natural human enamel undergoing dietary acid mediated erosive wear.

OBJECTIVES: To assess the precision of optical profilometry for characterising the 3D surface roughness of natural and polished human enamel in order to reliably quantify acid mediated surface roughness changes in human enamel. METHODS: Forty-two enamel samples were prepared from extracted human molars and either polished flat or left unmodified. To investigate precision, the variability of thirty repeated measurements of five areas of one polished and one natural enamel sample was assessed using 655nm Confocal Laser Profilometry. Remaining samples were subjected to forty-five minutes orange juice erosion and microstructural changes were analysed using Sa roughness change (µm) and qualitatively using surface/subsurface confocal microscopy. RESULTS: Enamel surface profilometry from the selected areas revealed maximal precision of 5nm for polished enamel and 23nm for natural enamel. After erosion, the polished enamel revealed a 48% increase in mean (SD) Sa roughness of 0.10 (0.07)µm (P<0.05), whereas in contrast the natural enamel revealed a 45% decrease in mean (SD) roughness of -0.32 (0.42)µm (P<0.05). These data were supported by qualitative confocal images of the surface/subsurface enamel. SIGNIFICANCE: This study demonstrates a method for precise surface texture measurement of natural human enamel. Measurement precision was superior for polished flat enamel in contrast to natural enamel however, natural enamel responds very differently to polished enamel when exposed to erosion challenges. Therefore, thus future studies characterising enamel surface changes following erosion on natural enamel may provide more clinically relevant responses in comparison to polished enamel.

Multigene analyses identify the three earliest lineages of extant flowering plants.

Flowering plants (angiosperms) are by far the largest, most diverse, and most important group of land plants, with over 250,000 species and a dominating presence in most terrestrial ecosystems. Understanding the origin and early diversification of angiosperms has posed a long-standing botanical challenge [1]. Numerous morphological and molecular systematic studies have attempted to reconstruct the early history of this group, including identifying the root of the angiosperm tree. There is considerable disagreement among these studies, with various groups of putatively basal angiosperms from the subclass Magnoliidae having been placed at the root of the angiosperm tree (reviewed in [2-4]). We investigated the early evolution of angiosperms by conducting combined phylogenetic analyses of five genes that represent all three plant genomes from a broad sampling of angiosperms. Amborella, a monotypic, vessel-less dioecious shrub from New Caledonia, was clearly identified as the first branch of angiosperm evolution, followed by the Nymphaeales (water lillies), and then a clade of woody vines comprising Schisandraceae and Austrobaileyaceae. These findings are remarkably congruent with those from several concurrent molecular studies [5-7] and have important implications for whether or not the first angiosperms were woody and contained vessels, for interpreting the evolution of other key characteristics of basal angiosperms, and for understanding the timing and pattern of angiosperm origin and diversification.

Ifosfamide encephalopathy.

Encephalopathy is a potentially fatal toxicity of ifosfamide. Clinical manifestations of encephalopathy range from fatigue and confusion to coma and death. Early identification of this toxicity and prompt cessation of ifosfamide are the essential elements in the management of ifosfamide encephalopathy. Accurate prediction of this toxicity is often difficult. Based on the limited available evidence, methylene blue, an electron acceptor, may have a role in the treatment and the prevention of neurotoxicity. This paper reviews the current understanding of ifosfamide encephalopathy.

An exploratory clinical trial to evaluate the efficacy of an experimental dentifrice formulation in the relief of dentine hypersensitivity.

OBJECTIVES: This study aimed to investigate whether addition of an octadecene/maleic anhydride copolymer (O/MA) to a potassium nitrate (KNO3) dentifrice could facilitate delivery of potassium to dentine and enhance its efficacy in dentine hypersensitivity relief. METHODS: This was a randomised, examiner-blind, controlled, parallel group study in 139 healthy subjects with at ≥2 sensitive teeth. Assessment of dentine hypersensitivity to tactile (Yeaple probe) and evaporative (air) stimuli (Schiff Sensitivity Scale, visual analogue scale [VAS]) was carried out at baseline and after 1, 2, 4 and 8 weeks twice daily treatment with an experimental 5% KNO3/3% O/MA dentifrice, a comparator 5% KNO3 dentifrice (active comparator), a 0% KNO3/3% O/MA dentifrice (placebo) and a regular fluoride dentifrice (negative control). This study was not powered to detect statistically significant differences between treatments. RESULTS: Across the treatment period an improvement in sensitivity to evaporative air stimulus was observed for all products and to a tactile stimulus for the potassium-containing treatments, with the greatest reductions for the experimental dentifrice (5% KNO3/3% O/MA). Reductions in sensitivity observed for the potassium-containing dentifrices compared to the placebo and negative control dentifrices were statistically significantly for Schiff sensitivity score and tactile threshold at all time-points and for VAS at Weeks 4 and 8. Trends in the study data also favoured the experimental dentifrice, compared to the active comparator dentifrice, for all clinical measures. Study treatments were generally well tolerated. CONCLUSION: This study provides initial clinical evidence to suggest that addition of a polymer excipient may enhance the anti-sensitivity efficacy of potassium-containing dentifrices. CLINICAL SIGNIFICANCE: Daily use potassium-containing dentifrices are established as efficacious for the relief of dentine hypersensitivity. Inclusion of a polymer excipient in such formulations may facilitate delivery of potassium to the dentine surface and so enhance clinical efficacy. Further clinical studies are required to confirm this hypothesis.

A randomised clinical in situ study to evaluate the effects of novel low abrasivity anti-sensitivity dentifrices on dentine wear.

OBJECTIVES: To compare the abrasive wear on human dentine in an in situ model associated with use of an experimental low abrasivity anti-sensitivity dentifrice containing 1% alumina and 5% sodium tripolyphosphate (STP) with an experimental ultra-low abrasivity non-alumina 5% STP dentifrice, a higher abrasivity daily-use whitening dentifrice, and water as controls. METHODS: This was a single-centre, single-blind, randomised, split-mouth, four-treatment, two-period, crossover in situ study in 29 healthy subjects. Subjects wore bilateral lower buccal appliances, each fitted with four dentine specimens. Study treatments were applied ex vivo (three times daily). Dentine loss was measured by non-contact profilometry after 5, 10 and 15days' treatment. RESULTS: All 29 subjects were included in the efficacy analysis. Significantly less dentine loss was associated with brushing with the low and ultra-low abrasivity dentifrices than with the higher abrasivity dentifrice at all timepoints (p<0.01). Brushing with ultra-low abrasivity dentifrice or water resulted in statistically significantly less dentine loss compared with brushing with the low abrasivity dentifrice at all timepoints (p<0.05). Dentine loss after brushing with ultra-low abrasivity dentifrice was not significantly different from brushing with water. CONCLUSIONS: The degree of dentine loss observed in this in situ model reflected the abrasivity of the study dentifrices. Brushing with low or ultra-low abrasivity STP-containing anti-sensitivity dentifrices resulted in significantly less dentine loss (equating to dentine wear) than with a higher abrasivity daily-use whitening dentifrice.