Interdental and subgingival microbiota may affect the tongue microbial ecology and oral malodour in health, gingivitis and periodontitis

BACKGROUND AND OBJECTIVE

Oral malodour is often observed in gingivitis and chronic periodontitis patients, and the tongue microbiota is thought to play a major role in malodorous gas production, including volatile sulphur compounds (VSCs) such as hydrogen sulphide (H₂ S) and methanethiol (CH₃ SH). This study aimed to examine the link between the presence of VSCs in mouth air (as a marker of oral malodour) and the oral bacterial ecology in the tongue and periodontal niches of healthy, gingivitis and periodontitis patients.

METHODS

Participants were clinically assessed using plaque index, bleeding on probing (BOP) and periodontal probing depths, and VSC concentrations in their oral cavity measured using a portable gas chromatograph. Tongue scrapings, subgingival and interdental plaque were collected from healthy individuals (n = 22), and those with gingivitis (n = 14) or chronic periodontitis (n = 15). The bacterial 16S rRNA gene region V3-V4 in these samples was sequenced, and the sequences were analysed using the minimum entropy decomposition pipeline.

RESULTS

Elevated VSC concentrations and CH₃ SH:H₂ S were observed in periodontitis compared with health. Significant ecological differences were observed in the tongue microbiota of healthy subjects with high plaque scores compared to low plaque scores, suggesting a possible connection between the microbiota of the tongue and the periodontium and that key dysbiotic changes may be initiated in the clinically healthy individuals who have higher dental plaque accumulation. Greater subgingival bacterial diversity was positively associated with H₂ S in mouth air. Periodontopathic bacteria known to be prolific VSC producers increased in abundance on the tongue associated with increased bleeding on probing (BOP) and total percentage of periodontal pockets >6 mm, supporting the suggestion that the tongue may become a reservoir for periodontopathogens.

CONCLUSION

This study highlights the importance of the periodontal microbiota in malodour and has detected dysbiotic changes in the tongue microbiota in periodontitis.

Novel fluoride rechargeable dental composites containing MgAl and CaAl layered double hydroxide (LDH)

OBJECTIVE

This study aims to incorporate 2:1 MgAl and 2:1 CaAl layered double hydroxides (LDHs) in experimental dental-composites to render them fluoride rechargeable. The effect of LDH on fluoride absorption and release, and their physico-mechanical properties are investigated.

METHODS

2:1 CaAl and 2:1 MgAl LDH-composite discs prepared with 0, 10 and 30wt% LDH were charged with fluoride (48h) and transferred to deionized water (DW)/artificial saliva (AS). Fluoride release/re-release was measured every 24h (ion-selective electrodes) with DW/AS replaced daily, and samples re-charged (5min) with fluoride every 2 days. Five absorption-release cycles were conducted over 10 days. CaAl and MgAl LDH rod-shaped specimens (dry and hydrated; 0, 10 and 30wt%) were studied for flexural strength and modulus. CaAl and MgAl LDH-composite discs (0, 10, 30 and 45wt% LDH) were prepared to study water uptake (over 7 weeks), water desorption (3 weeks), diffusion coefficients, solubility and cation release (ICP-OES).

RESULTS

CaAl LDH and MgAl LDH-composites significantly increased the amount of fluoride released in both media (P<0.05). In AS, the mean release after every recharge was greater for MgAl LDH-composites compared to CaAl LDH-composites (P<0.05). After every recharge, the fluoride release was greater than the previous release cycle (P<0.05) for all LDH-composites. Physico-mechanical properties of the LDH-composites demonstrated similar values to those reported in literature. The solubility and cation release showed a linear increase with LDH loading.

SIGNIFICANCE

LDH-composites repeatedly absorbed/released fluoride and maintained desired physico-mechanical properties. A sustained low-level fluoride release with LDH-composites could lead to a potential breakthrough in preventing early stage carious-lesions.

Layered Double Hydroxide Fluoride Release in Dental Applications: A Systematic Review

This systematic review appraises studies conducted with layered double hydroxides (LDHs) for fluoride release in dentistry. LDH has been used as antacids, water purification in removing excess fluoride in drinking water and drug delivery. It has great potential for controlled fluoride release in dentistry, e.g., varnishes, fissure sealants and muco-adhesive strips, etc. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement was followed with two reviewers performing a literature search using four databases: PubMed, Web of Science, Science Direct and Ovid Medline with no date restrictions. Studies including any LDH for ion/drug release in dentistry were included, while assessing the application of LDH and the value of the methodology, e.g., ion release protocol and the LDH production process. Results: A total of 258 articles were identified and four met the inclusion criteria. Based on two in vitro studies and one clinical study, LDH was previously studied in dental materials, such as dental composites and buccal muco-adhesive strips for fluoride release, with the latter studied in a clinical environment. The fourth study analysed LDH powder alone (without being incorporated into dental materials). It demonstrated fluoride release and the uptake of volatile sulphur compounds (VSC), which may reduce halitosis (malodour). Conclusion: LDHs incorporated in dental materials have been previously evaluated for fluoride release and proven to be clinically safe. LDHs have the potential to sustain a controlled release of fluoride (or other cariostatic ions) in the oral environment to prevent caries. However, further analyses of LDH compositions, and clinical research investigating any other cariostatic effects, are required.

Brief Motivational Interviewing in Dental Practice

Motivational Interviewing has been demonstrated to be effective for a wide range of health behaviors. It is an effective behavior change method, which can be utilized in the dental practice setting. It can be used as a brief intervention to increase motivation to improve patients’ oral hygiene behaviors as well as providing a framework for delivering diet, smoking cessation, oral health changes, and alcohol advice. It involves four processes: engaging, focusing, evoking, and planning, guiding, which supports the patient towards a positive behavior change. Motivational Interviewing is a collaborative, patient-centered approach evoking the patient’s own motivation to change, thereby enhancing the relationship between the clinician and patient and improving patient outcomes. This review will provide an overview on the topic for dental professionals as well as helpful suggestions for supporting a positive behavior change in their dental practices.

Is there a role for community pharmacists in promoting oral health?

AIM

The main aim of the present study was to investigate whether pharmacists recognised that they have a role in the promotion of oral health advice within the community.

METHODS

A cross sectional survey was conducted using a structured questionnaire which was distributed to randomly selected pharmacies (n = 1,500) in the London area.

RESULTS

Six hundred and forty-five pharmacies (43%) responded to the initial invitation and 589 (39%) of pharmacy participants acknowledged that pharmacists should have a role in oral health promotion. Participants from 354 pharmacies (23.6%) subsequently agreed to complete the questionnaire. Of those pharmacies completing the questionnaire, 99.4% of the pharmacy participants recognised that there was a role for pharmacists in oral health promotion. Although 91.5% of the pharmacists reported a fairly high level of knowledge for most of the common oral conditions, they also indicated that they were interested in receiving further training on oral conditions through continuing professional development (CPD) courses. A number of the pharmacies (72.5%) expressed a willingness to incorporate oral health promotion within the NHS pharmacy contract.

CONCLUSION

Pharmacies may be used effectively in oral health promotion by virtue of their frequent contact with members of public. As a result of their established role in promoting and improving the health within the community, it may possible to incorporate oral health within the existing NHS contract.

The assessment and implementation of mouth care in palliative care: a review

Aim: From a review of the literature it is evident that the importance and maintenance of oral health for patients with cancer is recognised as an integral part of basic nursing care and yet from practical observation in the hospital environment together with reviewing the published literature it is clear that there appears to be limited evidence of regular assessment of the mouth or implementation of oral protocols on the ward. Furthermore there is a lack of adequate training in the assessment and implementation of mouth care by nurses during their general nurse training. The aim of the present study was to review existing literature published between 1995 and 1999 to determine whether mouth care was effectively assessed and implemented in the palliative care setting.

Method and results: Relevant articles selected from the 1995–1999 period highlighted the lack of published research in this very important aspect of care. Results from these published articles raised concern about the lack of training and education among nurses in the assessment of mouth care as well as the need to rationalise the assessment tools used on the ward or hospice. Furthermore, while it was recognised in palliative care that a multiprofessional approach was beneficial, in practice this did not appear to apply to mouth care with a few notable exceptions.

Conclusion: This review has highlighted a number of inconsistencies in both the knowledge of mouth care and its implementation by nursing staff. The importance of establishing protocols and setting standards of care was also indicated in this review. It is clear that without effective assessment of the mouth, the appropriate implementation of care will not be delivered. The implementation of mouth care should not be anecdotal in nature but based on research (evidence-based) and this in turn will enable nurses to embrace an evidence-based practice (which will benefit their patients) that can be effectively audited.

Abrasive wear of enamel by bioactive glass-based toothpastes

PURPOSE

To determine the abrasivity of a 45S5 bioactive glass based toothpaste on enamel as a function of the particle size and shape of the glass.

METHODS

45S5 glass was synthesized ground and sieved to give various particle sized fractions < 38, 38-63 and 63-110 microns. Two different grinding routes were used: percussion milling and ball milling. The glass powders were formulated into toothpastes and their tooth brush abrasivity measured according to BS EN ISO11609 methodology.

RESULTS

Enamel loss increased with increasing particle size. The percussion milled powder exhibited particles that had sharp edges and the pastes were significantly more abrasive than the pastes made with round ball milled powders. One interesting observation made during the present study was that there was preferential wear of the enamel at the dentin-enamel junction (DEJ), particularly with the coarse particle sized pastes.

Antibiotics in the treatment of periodontal disease: a guide for the general dental practitioner

The objective of the present paper is to discuss the appropriate use of systemic and local adjunctive antibiotics/antimicrobials in the management of periodontal diseases using a number of case studies to illustrate an evidence-based approach to treatment.

Periodontal probing: a review

Periodontal probes are the main instruments that are used to assess the status of the periodontium, either for screening purposes or to evaluate periodontal changes throughout the treatment process. With increased knowledge and understanding of periodontal disease, the probes have evolved from a unidimensional manual shape into a more sophisticated computerised instrument. This is due to the need to increase the accuracy and reproducibility of readings and to improve efficiency (time, effort, money). Each probe has characteristic features that makes it unique and, in some cases, specific and limited to use. The aim of this paper is to present a brief introduction to periodontal disease and the methodology of measuring it, followed by probing limitations. The paper will also discuss the methodology of reducing probing error, examiner calibration and probing reproducibility.

Accuracy and reproducibility of probe forces during simulated periodontal pocket depth measurements

AIM

The aim of the present study was to measure the accuracy and reproducibility of probe forces in simulated assessments of periodontal pocket depth. The study included experienced and inexperienced examiners and used manual and pressure-sensitive probes.

MATERIALS AND METHODS

Sixty-one participants were divided into seven groups and asked to probe selected anterior and posterior sites with three different probes (Williams 14W, Chapple UB-CF-15, and Vivacare TPS probes). The model was positioned on a digital electronic balance to measure force, which was recorded initially and after 15 min. Probe preferences were recorded. Accuracy was measured by comparing to a standardized 25 g force, and reproducibility was calculated for all duplicate measurements.

RESULTS

The Vivacare probe produced the most accurate and most reproducible forces, whereas the Williams probe produced the least accurate and least reproducible forces. Probe forces were lighter at anterior sites compared to posterior sites at baseline. Probe forces were reduced at both sites after 15 min compared to baseline.

CONCLUSIONS

Vivacare TPS periodontal probes are more accurate and reproducible than Chapple and Williams probes. Many clinicians in this study preferred the Chapple probe.

In-vitro accuracy and reproducibility evaluation of probing depth measurements of selected periodontal probes

AIM

The purpose of the present in vitro study was to measure the accuracy and reproducibility of three periodontal probes. To eliminate environment- or examiner-related probing errors, two aluminum blocks with predrilled holes of varying depths were examined by participants who had been trained in probing before the study. This methodology improved the likelihood that any probing errors identified were generated by the probes themselves.

MATERIALS AND METHODS

Three probes, Williams 14 W (Hu-Friedy Mfg. Co., LLC, UK), Chapple UB-CF-15 (Implantium, Shrewsbury, UK), and Vivacare TPS (Ivoclar Vivadent, Enderby, UK), were randomly distributed to 23 participants (9 males and 14 females; mean age: 31.35 years). Participants measured 30 holes in two aluminum blocks, average 20 days, SD = 341.05. For each hole, the mean measured depth was calculated for each participant and compared to the true depth. Intra- and inter-examiner accuracy and reproducibility for each of the duplicate measurements were calculated. Data were analyzed by paired-samples t-test with the SPSS 18 software package (IBM Portsmouth, UK). A p-value <0.05 indicated statistical significance. Tables were constructed from the data.

RESULTS

When used by participants, the Williams 14 W probe was reproducible but not necessarily accurate; Vivacare TPS was neither accurate nor reproducible; and Chapple UBCF-15 was both accurate and reproducible.

CONCLUSION

Depth measurements with the Chapple UB-CF-15 probe were more accurate and reproducible compared to measurements with the Vivacare TPS and Williams 14 W probes. This in vitro model may be useful for intra-examiner calibration or clinician training prior to the clinical evaluation of patients or in longitudinal studies involving periodontal evaluation.

Current diagnosis of dentin hypersensitivity in the dental office: an overview

OBJECTIVES

The aim of this overview is to consider the problems that may be associated with making a diagnosis of dentin hypersensitivity (DHS) and to provide a basis for clinicians to effectively diagnose and manage this troublesome clinical condition.

MATERIALS AND METHODS

A PUBMED literature research was conducted by the author using the following MESH terms: ('diagnosis'[Subheading] OR 'diagnosis'[All Fields] OR 'diagnosis'[MeSH Terms]) AND ('therapy'[Subheading] OR 'therapy'[All Fields] OR 'treatment'[All Fields] OR 'therapeutics'[MeSH Terms] OR 'therapeutics'[All Fields]) AND ('dentin Sensitivity'[MeSH Terms] OR ('dentin'[All Fields] AND 'sensitivity'[All Fields]) OR 'dentin sensitivity'[All Fields]). Variations to the above MeSH terms using terms such as 'cervical', 'dentine' and 'hypersensitivity' as substitutes were also explored, but these searches failed to add any further information.

RESULTS

The literature search provided only limited data on specific papers relating to the clinical diagnosis of DHS by dental professionals. Evidence from these published studies would therefore indicate that clinicians are not routinely examining their patients for DHS or eliminating other possible causes of dental pain (differential diagnosis) prior to subsequent management and may rely on their patients' self-reporting of the problem. Furthermore, the findings of the Canadian Consensus Document (2003) would also suggest that clinicians are not confident of successfully treating DHS.

CONCLUSIONS

It is apparent from reviewing the published literature on the diagnosis of DHS that there are a number of outstanding issues that need to be resolved, for example, (1) is the condition under- or overestimated by dentists, (2) is the condition adequately diagnosed and successfully managed by dentists in daily practice, (3) is the impact of DHS on the quality of life of sufferers adequately diagnosed and treated and (4) is the condition adequately monitored by clinicians in daily practice. These and other questions arising from the workshop forum should be addressed in well-conducted epidemiological and clinical studies in order for clinicians to be confident in both identifying and diagnosing DHS and subsequent management that will either reduce or eliminate the impact of DHS on their patients' quality of life.

CLINICAL RELEVANCE

Clinicians should be made aware not only of the importance of identifying patients with DHS but also of the relevance of a correct diagnosis that may exclude any confounding factors from other oro-facial pain conditions prior to the successful management of the condition.

Multi-component bioactive glasses of varying fluoride content for treating dentin hypersensitivity

OBJECTIVE

Dentin hypersensitivity (DH) is a commonly occurring dental condition, and bioactive glasses (BG) are used in dentifrice formulations for treating DH by forming a surface layer of hydroxycarbonate apatite (HCA) on the tooth, thereby occluding exposed dentinal tubules. Fluoride-containing BG, however, form fluorapatite, which is more stable toward acid attack, and provide a more sustainable option for treating DH.

METHODS

Melt-derived multi-component BG (SiO(2)-P(2)O(5)-CaO-CaF(2)-SrO-SrF(2)-ZnO-Na(2)O-K(2)O) with increasing CaF(2)+SrF(2) content (0-32.7 mol%) were prepared. Apatite formation, occlusion of dentinal tubules in dentin discs and ion release in Tris buffer were characterized in vitro over up to 7 days using X-ray diffraction, infrared spectroscopy, scanning electron microscopy and inductively coupled plasma emission spectroscopy.

RESULTS

The fluoride-containing bioactive glasses formed apatite from as early as 6h, while the fluoride-free control did not form apatite within 7 days. The glasses successfully occluded dentinal tubules by formation of apatite crystals and released ions such as fluoride, strontium and potassium.

SIGNIFICANCE

Fluoride significantly improved apatite formation of the BG, allowing for treatment of DH by occlusion of dentinal tubules. The BG also released therapeutically active ions, such as strontium and fluoride for caries prevention, zinc for bactericidal properties and potassium, which is used as a desensitizing agent in dentifrices.

Managing dentin hypersensitivity

BACKGROUND

The objective of this review is to inform practitioners about dentin hypersensitivity (DH) and its management. This clinical information is described in the context of the underlying biology.

TYPES OF STUDIES REVIEWED

The authors used MEDLINE to find relevant English-language literature published in the period 1999 to 2005. They used combinations of the search terms "dentin*," "tooth," "teeth," "hypersensit*," "desensiti*" and "desensitiz*." They read abstracts and then full articles to identify studies describing etiology, prevalence, clinical features, controlled clinical trials of treatments and relevant laboratory research on mechanisms of action.

RESULTS

The prevalence of DH varies widely, depending on the mode of investigation. Potassium-containing toothpastes are the most widely used at-home treatments. Most in-office treatments employ some form of "barrier," either a topical solution or gel or an adhesive restorative material. The reported efficacy of these treatments varies, with some having no better efficacy than the control treatments. Possible reasons for this variability are discussed. A flowchart summarizes the various treatment strategies.

CLINICAL IMPLICATIONS

DH is diagnosed after elimination of other possible causes of the pain. Desensitizing treatment should be delivered systematically, beginning with prevention and at-home treatments. The latter may be supplemented with in-office modalities.

In vitro quantification of changes in human dentine tubule parameters using SEM and digital analysis

Dentine hypersensitivity is recognized as a pain arising from fluid movement within dentine tubules that are open to the oral environment. Blocking the tubules is considered to be the principal aim of treatment, and the accurate assessment of tubule occlusion is the primary goal of many in vitro studies. This assessment usually comprises either measuring tubule permeability or scanning electron microscope examination of the dentine surface. Several scanning microscopy studies have claimed to quantify tubule occlusion, but are descriptive, qualitative or semi-quantitative evaluations. The present study was undertaken to assess the use of digital image analysis in quantifying the effectiveness of a selected desensitizing agent from micrographs of control and treated dentine surfaces. Using a dentine disc model, an accurate methodology was sought to investigate the occluding potential of Butler Protect (J.O. Butler, Chicago, IL, USA). Subjective examination of the images indicated there was little difference after a single application, but considerable effect after 20 applications. Quantitative digital analysis of a test image, demonstrated reproducibility between two examiners when used in fully- and semi-automated mode. After a single application of Butler Protect, multilevel statistical modelling demonstrated decreases in tubule area and maximum, minimum and mean diameter measurements (P < 0.001), whereas single level analysis showed increases in area and maximum and mean diameters. Multiple application of Butler Protect demonstrated even greater decreases in all parameters (P < 0.001). This quantitative methodology was reproducible between examiners and, when combined with good controls and multilevel statistical modelling, was able to discriminate a single application of desensitizing agent.

Effect of desensitizing agents on the hydraulic conductance of human dentin subjected to different surface pre-treatments-an in vitro study

OBJECTIVES

The aim of this study was to evaluate the variation of fluid filtration across dentin treated with different formulations of potassium oxalate gels and one gel of acidified sodium fluorophosphate, under five different pre-conditioned dentin surfaces.

METHODS

The methodology used for the measurement of hydraulic conductance of dentin in the present study was based on the model suggested by Pashley, Stewart and Galloway [Arch Oral Biol 29 (1984)379]. Two hundred dentin discs 1 mm in thickness, obtained from human extracted third molars, were divided into 20 groups of ten specimens each. The groups corresponded to the following experimental materials: 3% potassium oxalate gel-pH 4; 6% potassium oxalate gel-pH 4; 3% potassium oxalate gel-pH 2.5 and 1.23% fluoride gel (APF gel)-pH 3.6-3.9, applied to dentin under the following surface conditions: air-dried, blot-dried, wet, EDTA air-dried; EDTA blot-dried. General MANOVA and post-hoc Duncan tests were performed on the data.

RESULTS

Regardless of surface pre-treatment the 3% potassium oxalate gel-pH 2.5 produced the greatest reduction in dentinal filtration (p<0.05) even after citric acid challenge. In general, air-drying the dentin was the best surface pre-treatment (p<0.05). The interaction between the material and surface pre-treatment showed values of hydraulic conductance similar for most of the combinations, but the 3% potassium oxalate gel-pH 2.5 under wet conditions produced the largest reduction in hydraulic conductance. The APF gel produced the smallest reduction in hydraulic conductance when compared with the other materials, regardless of surface pre-treatment.

SIGNIFICANCE

the potassium oxalate gels studied in this investigation have a great potential for tubule occlusion and, consequently, should be effective treatments of dentinal hypersensitivity, regardless of dentin wetness.

A preliminary investigation into the ultrastructure of dental calculus and associated bacteria

INTRODUCTION

Though dental calculus is generally recognised as comprising mineralised bacteria, areas of non-mineralised bacteria may be present.

AIM

To investigate the ultrastructure of non-decalcified young and mature supragingival calculus and subgingival calculus, and the possible presence of internal viable bacteria.

MATERIALS AND METHODS

Supragingival calculus was harvested from five patients, 9-10 weeks after scaling and root debridement. Five samples of mature supragingival and subgingival calculus were taken from patients presenting with adult periodontitis. Specimens were fixed and embedded for transmission electron microscopy.

RESULTS

The ultrastructure of young and mature supragingival calculus was similar with various large and small crystal types. Non-mineralised channels were observed extending into the calculus, often joining extensive lacunae, both containing intact non-mineralised coccoid and rod-shaped microorganisms. Subgingival calculus possessed more uniform mineralisation without non-mineralised channels and lacunae.

CONCLUSION

Supragingival calculus contains non-mineralised areas which contain bacteria and other debris. The viability of the bacteria, and their identification could not be determined in this preliminary investigation. As viable bacteria within these lacunae may provide a source of re-infection, further work needs to be done to identify the bacteria in the lacunae, and to determine their viability.

Clinical evaluation of ferric oxalate in relieving dentine hypersensitivity

Previous in vitro permeability and scanning electron microscopic (SEM) studies have demonstrated the effectiveness of the oxalate ion in dentine permeability reduction and effective tubule occlusion. The aim of this randomized double-blind, split mouth 4-week clinical study, therefore was to determine whether a 1-min application of ferric oxalate (Sensodyne Sealant) on exposed root dentine was effective in reducing dentine hypersensitivity (DH). Thirteen subjects [8F:5M, mean age 46.2 (s.d. 4.15) years] completed the study. The subjective response was evaluated by tactile, thermal and evaporative methods of assessment. Data were collected at baseline and post-application at +5 min and 4 weeks. Analysis was based on paired t-test (P=0.05) and Wilcoxon-Mann-Whitney tests. No statistically significant differences were noted between ferric oxalate and placebo preparations at +5 min and 4 weeks for any of the test stimuli. There was, however, a clear trend towards immediate reduction (+5 min) in DH reverting back to baseline values at 4 weeks with the exception of the Biomat Thermal Probe mean values, which maintained the reductions in DH compared with placebo. The results of the present study demonstrated that a 1-min application of ferric oxalate is both rapid and effective in reducing DH although its long-term effectiveness still needs to be determined.

The effect of a toothpaste containing 2% zinc citrate and 0.3% Triclosan on bacterial viability and plaque growth in vivo compared to a toothpaste containing 0.3% Triclosan and 2% copolymer

OBJECTIVE

To compare the antimicrobial efficacy and effect on plaque growth of a new silica-based fluoride toothpaste containing 2% zinc citrate/ 0.3% Triclosan with a silica-based fluoride toothpaste containing 0.3% Triclosan/2% copolymer.

METHODS

In Study 1, plaque was collected after one week's use of each toothpaste and assessed for bacterial viability, live/ dead ratio and microbial membrane integrity. In study 2, plaque was measured immediately and 18 hours after a single brushing with the specified toothpastes.

RESULTS

The 2% zinc citrate/0.3% Triclosan formulation significantly reduced the total number of viable aerobic and anaerobic bacteria (p = 0.0223 and p = 0.0443 respectively) compared to the 0.3% Triclosan/2% copolymer formulation. Both toothpastes increased the bacterial membrane permeability significantly. However, the proportion of live bacteria for the 2% zinc citrate/0.3% Triclosan product was significantly reduced (p < 0.05). Study 2 showed significantly less plaque growth 18 hours after using the 2% zinc citrate/0.3% Triclosan toothpaste compared to the 0.3% Triclosan/2% copolymer toothpaste (p < 0.01).

CONCLUSION

Regular use of a fluoride toothpaste containing 2% zinc citrate and 0.3% Triclosan, significantly reduced the viability of plaque bacteria compared to a fluoride toothpaste containing 0.3% Triclosan/ 2% copolymer 12 hours after brushing. In addition, a clinical plaque growth study confirmed that this anti-microbial efficacy leads to a significant reduction in plaque growth.

The effect of oral care feed-back devices on plaque removal and attitudes towards oral care

OBJECTIVES

Two studies were carried out to investigate whether the effect of specific oral care feed-back devices would result in better plaque removal (Study 1) and lead to changes in attitudes and views relating to oral health (Study 2). The objective of the first study was to compare the ability of a toothbrush system consisting of a new toothbrush plus plaque disclosing tablet (SIGNAL Integral) to remove supra-gingival plaque to that of a marketed toothbrush (Oral B Cross Action) following a single unsupervised brushing.

METHODS

Study 1 had a cross-over design and included 21 healthy adult volunteers. Subjects refrained from any form of oral hygiene for 24 hours prior to each test session. Plaque levels (Modified Quigley-Hein Plaque index) were assessed prior to and following each unsupervised brushing. When the new toothbrush was used, subjects self-disclosed their plaque with a disclosing tablet (erythrosine) immediately prior to brushing. At each occasion, brushing time (in sec) was also recorded. Study 2 had a two-cell, parallel design (test and control group) and lasted for five days. Healthy adult volunteers were enrolled. Subjects in the test group (n = 30) were given a fluoride toothpaste and four saliva test strips to use at home. The saliva test strip is designed to change colour in the pH range of 6.5 to 10, allowing the user to verify the effect of brushing. The control group (n = 29) received no saliva test strips. Subjects completed a questionnaire after 4 days of product use.

RESULTS

In Study 1, significantly more plaque was removed (p < 0.05) and brushing time was increased by more than 20% when subjects used the new toothbrush together with the disclosing tablet compared to brushing with the marketed toothbrush. In Study 2, significant increases in motivation relating to oral hygiene were found in the test group who had been using the saliva test strip.

CONCLUSION

The two studies have provided significant evidence that the provision of feed-back devices in an oral care context can lead to improved removal of plaque and increased motivation.

The effects of a novel Bioglass dentifrice on dentine sensitivity: a scanning electron microscopy investigation

Dentine sensitivity (DS) is a common condition which affects 8-35% of the population. Both In-Office and Over-the-Counter products have been used in treatment, usually occluding open dentine tubules on the exposed root surface. Currently there appears to be no ideal material which permanently occludes dentine tubules. Bioactive and biocompatible glasses are known to induce osteogenesis in physiological systems and may offer suitable materials for surface reactivity which could theoretically occlude tubules. A new dentifrice formulation containing a modified Bioglass material replacing part of the abrasive silica component was compared with original 45S6 bioactive glass. Dentine discs were treated with original Bioglass, three coded dentifrices containing 0, 2.5 and 7.5% Bioglass and two further selected dentifrice products. These specimens were prepared for scanning electron microscopy (SEM) and viewed in a Cambridge stereoscan 90B. The results demonstrated that original bioactive glass particles covered the dentine surface and/or occluded dentine tubules, although this original formulation was easily dislodged. Dentifrice with different ratios of added Bioglass was assessed to provide greater surface coverage and tubule occlusion than without Bioglass. It was concluded that the inclusion of bioactive glass particles in a suitably formulated vehicle may be an effective agent for the treatment of dentine sensitivity.

Dentine hypersensitivity in subjects recruited for clinical trials: clinical evaluation, prevalence and intra-oral distribution

Relatively few studies have reported on the frequency, distribution and severity of dentine hypersensitivity (DH) in subjects recruited for clinical trials of desensitizing agents. Potential subjects (n= 48 M, 81 F, mean age 35.1 years) for inclusion into such a study were screened to determine the extent of the problem. 117 subjects (41 M, 76 F) mean age 24.9 years were clinically examined. Evaluation by questionnaire indicated that the prevalence of DH was proportionately higher in the 20-29.9 years (34.9%), and 30-39.9 years groups (33.3%), respectively. Sensitivity to cold was the main presenting symptom. Tactile (probe) and cold air (dental air syringe) stimuli were used to clinically evaluate DH. Of the teeth eligible for evaluation 1561/3136 (49.8%) responded to either one or both of the test stimuli; 274/3136 (8.7%) responded to tactile only stimulation, 779/3136 (24.8%) to thermal only stimulation and 508/3136 (16.2%) to both tactile and thermal stimulation. Of those teeth responding to the stimuli, 477 (30.6%) were premolars, 437 (28%) incisors, 415 (26.8%) molars and 232 (14.9%) canines. The results agree with those of previously reported studies in that DH is most frequently observed on premolars and that proportionately more teeth are sensitive to evaporative than to tactile stimulation. Furthermore it would appear from the results of the study that tactile is less effective than thermal/evaporative stimulation in the evaluation of DH.

Dentists' perceptions of dentine hypersensitivity and knowledge of its treatment

The aim of the present investigation was to determine by questionnaire, UK dentists' perception of Dentine Hypersensitivity (DH) and knowledge of its treatment. A total of 403 questionnaires were sent to a selected group of UK dentists who had either inquired about further postgraduate education or had attended a course at the Eastman Dental Institute/Hospital. A total of 181 of 403 dentists (44.9%) (118M; 36F, 17 no response, mean age 38.2 years [s.d. 8.97]) returned the questionnaire. About 92.8% (n=168) of responding dentists claimed to see patients with DH in their practice. According to the dentists' replies at least one of four of their patients suffered from the complaint. About 71.8% (n=130) of dentists reported that DH was a severe problem in at least 10% of their patients and that pain from DH lasted no more than 4 weeks. Most of responding dentists claimed to be asked about DH by their patients and stated that they offered advice or treatment to their patients. Nearly 87.3% (n=158) of responding dentists provided a wide range of treatment options/advice which included both in-office and over-the-counter (OTC) products. Popular responses included desensitizing pastes/gels, Topical F(-) varnishes and toothpastes/rinses/gels, advice on atraumatic tooth brushing, dentine bonding agents (DBA), glass-ionomer cements (GIC) and other unspecified restorations. Of the various in-office treatments Duraphat was the most cited choice of varnish/primer options. Sensodyne toothpaste was the most popular of the specified OTC products. Most dentists appeared to understand the aetiological features associated with DH and provided a wide range of factors including the effects of incorrect tooth brushing, dietary acids as well as the possible influence on non-dental topics such as stress. Most responding dentists believed that their advice on DH was generally effective although they did highlight that certain aspects on the condition were lacking such as appropriate scientific information including the prevention of DH and its treatment. The results from the present study highlight several discrepancies in the perception and knowledge of the treatment of DH between dentists and their patients. The results from this study are, however, reasonably consistent with those previously reported by Dutch investigators. The results from this study also highlighted a need for guidelines on the aetiology, prevention and treatment of DH for both dentists and their patients. The reported average frequency and duration of discomfort from DH by the responding dentists appeared to be consistent with the available literature.

A study of the prevalence and distribution of dentine sensitivity in a population of 17-58-year-old serving personnel on an RAF base in the Midlands

Previous studies have reported on dentine sensitivity (DS) prevalence in hospital and general practice populations. Results from these studies indicate that perception and prevalence of DS vary depending on the population. The study aimed to determine any major differences in the perception and prevalence of DS in subjects in a military training establishment. Questionnaires from 228 subjects [188 completed by males, 39 completed by females, with one person not indicating their gender of mean age 24.0 years (s.d. 7.16)] were collected and analysed using the Statistical Package for the Social Sciences (SPSS). Fifty percent of the subjects (n=114) claimed to have DS. Yet approximately 30% of the subjects (29.8%, n=68) perceived the condition as a slight problem and approximately 40% of the subjects (40.8%, n=93) claimed it was an occasional problem and approximately 50% (49.1%, n=112) did not seek treatment. Seventeen subjects (7.5%) used a desensitizing paste during periods of discomfort. No clear pattern emerged with regard to seasonal variation in DS although 5.7% (n=13) subjects considered DS to be more of a problem in winter. Only 7.9% (n=18) reported any previous periodontal surgery, consistent with previous studies (12.6 and 15.5%). Of those who received regular scaling (27.2%, n=62), only 23 (10.1%) reported any discomfort following treatment, which did not last >or=5 days. The results indicate that self-reporting of DS was similar to previous reports, although it is of fundamental importance that such studies should be supplemented with a thorough clinical examination to determine more reliable prevalence data.

The effects of oxalate-containing products on the exposed dentine surface: an SEM investigation

In-office products containing oxalates have been claimed to be clinically effective in reducing dentine sensitivity, although there has been limited supporting clinical data. The rationale for their use appears to be based on their potential to act as occluding and/or nerve desensitizing agents. Four commercially available oxalate-containing products were applied to etched dentine discs and the extent of tubule occlusion was observed by scanning electron microscopy. Tenure Quick (aluminium oxalate), Sensodyne Sealant (ferric oxalate) and MS Coat (oxalic acid) covered the dentine surface and occluded the tubules. However, Butler Protect (potassium oxalate) did not cover the surface to any great extent but provided some occlusion. The presence of oxalates after application to glass slides and dentine discs was examined using thin film X-ray diffraction. From samples on glass, only potassium oxalate could be clearly identified (JCPDS 14-0845). No oxalate was detected on dentine discs in either thin film geometry or standard theta two theta mode. We have demonstrated that professionally applied in-office products containing oxalate are capable of covering the dentine surface and/or occluding the tubules to varying degrees. However, X-ray diffraction analysis was unable to confirm the oxalate profile for all products as described in the available commercial literature.

Utilisation of locally delivered doxycycline in non-surgical treatment of chronic periodontitis. A comparative multi-centre trial of 2 treatment approaches

AIM

In the present 6-month multicentre trial, the outcome of 2 different approaches to non-surgical treatment of chronic periodontitis, both involving the use of a locally delivered controlled-release doxycycline, was evaluated.

MATERIAL AND METHODS

105 adult patients with moderately advanced chronic periodontitis from 3 centres participated in the trial. Each patient had to present with at least 8 periodontal sites in 2 jaw quadrants with a probing pocket depth (PPD) of > or =5 mm and bleeding following pocket probing (BoP), out of which at least 2 sites had to be > or =7 mm and a further 2 sites > or =6 mm. Following a baseline examination, including assessments of plaque, PPD, clinical attachment level (CAL) and BoP, careful instruction in oral hygiene was given. The patients were then randomly assigned to one of two treatment groups: scaling/root planing (SRP) with local analgesia or debridement (supra- and subgingival ultrasonic instrumentation without analgesia). The "SRP" group received a single episode of full-mouth supra-/subgingival scaling and root planing under local analgesia. In addition, at a 3-month recall visit, a full-mouth supra-/subgingival debridement using ultrasonic instrumentation was provided. This was followed by subgingival application of an 8.5% w/w doxycycline polymer at sites with a remaining PPD of > or =5 mm. The patients of the "debridement" group were initially subjected to a 45-minute full-mouth debridement with the use of an ultrasonic instrument and without administration of local analgesia, and followed by application of doxycycline in sites with a PPD of > or =5 mm. At month 3, sites with a remaining PPD of > or =5 mm were subjected to scaling and root planing. Clinical re-examinations were performed at 3 and 6 months.

RESULTS

At 3 months, the proportion of sites showing PPD of < or =4 mm was significantly higher in the "debridement" group than in the "SRP" group (58% versus 50%; p<0.05). The CAL gain at 3 months amounted to 0.8 mm in the "debridement" group and 0.5 mm in the "SRP" group (p=0.064). The proportion of sites demonstrating a clinically significant CAL gain (> or =2 mm) was higher in the "debridement" group than in the "SRP" group (38% versus 30%; p<0.05). At the 6-month examination, no statistically significant differences in PPD or CAL were found between the two treatment groups. BoP was significantly lower for the "debridement" group than for the "SRP" group (p<0.001) both at 3- and 6 months. The mean total treatment time (baseline and 3-month) for the "SRP" patients was 3:11 h, compared to 2:00 h for the patients in the "debridement" group (p<0.001).

CONCLUSION

The results indicate that simplified subgingival instrumentation combined with local application of doxycycline in deep periodontal sites can be considered as a justified approach for non-surgical treatment of chronic periodontitis.

The efficacy of potassium salts as agents for treating dentin hypersensitivity

Formulations containing potassium salts (e.g., chloride, nitrate, citrate, oxalate) are widely used for treating dentin hypersensitivity (DH). The purpose of this review was to evaluate evidence for the clinical efficacy of potassium salts in reducing DH and also to consider the biologic basis for any effects. Literature searches were used to identify reports of clinical trials of potassium-containing preparations. Searches revealed 3 trials of potassium nitrate solutions or gels; 2 trials of mouthwashes containing potassium nitrate or citrate; 6 trials of potassium oxalates; and 16 double-blind randomized trials of toothpastes containing potassium nitrate, chloride, or citrate. The toothpaste studies provided quantitative data on treatment effects. These outcome measures were expressed as percentage reductions in sensitivity to cold air and mechanical stimulation and the patients' subjective reports. Trials of topically applied solutions yielded inconsistent results. Potassium-containing mouthwashes produced significant reductions in sensitivity. All potassium-containing toothpastes produced a significant reduction in sensitivity to tactile and air stimuli, as well as subjectively reported sensitivity. In most studies, the active agent (potassium) was superior to the minus-active control (placebo), but a few of the more recent trials have demonstrated significant placebo effects. It is postulated that potassium ions released from toothpastes diffuse along the dentinal tubules to inactivate intradental nerves. However, this principle has never been confirmed in intact human teeth. The mechanism of the desensitizing effects of potassium-containing toothpastes remains uncertain at present.

Comparison of dentine hypersensitivity in selected occidental and oriental populations

Epidemiological data on dentine hypersensitivity (DH) prevalence are limited. Few studies have compared prevalence between populations. The aim of this investigation, therefore, was to compare the perception and prevalence of DH in two distinct non-periodontal practice populations, one U.K. and one Korean. Completed questionnaires from 557 patients (230 males and 327 females, comprising 115 males and 162 females, mean age 41.7 years (s.d.=14.36), U.K. and 115 males and 165 females, mean age 29.7 years (s.d.=11.86), Korean) were collected. Analysis was by frequency distribution and cross-tabulation (Statistical Package for the Social Sciences (SPSS)). DH prevalence was similar and at levels comparable with those reported previously. Prevalence was higher in the third and fourth decades in both populations. Although there were no differences between U.K. or Korean males and U.K. or Korean females, there was a significant difference between gender reporting of DH, with more females complaining of DH than males (standard normal deviation (SND)=4.3, 95% confidence interval (CI)=0.1134-0.2736). DH appeared to be regarded by patients as not severe in most cases, so treatment was not generally sought. Of those who claimed to have sought treatment, a significant number had received restorative treatment. Of those patients, only 23.3% of U.K. and <or=2% of Korean patients claimed to have used a desensitizing dentifrice. Pain from DH was reported as low grade (slight, occasional) occurring over 5 years in both populations. Cold appeared to be the most reported stimulus in the two populations. Less periodontal surgery had been undertaken in these two populations (12.6% U.K. and 7.1% Korean) compared with those referred to a teaching hospital periodontal department (34.5%). This compared favourably with previous findings in the general dental population (15.5%). Discomfort following hygiene therapy did not appear to last >or=7 days in either population. The results indicated that there were no significant differences between U.K.- and Korean-based populations in their perception of DH, with the exception that more females complained of sensitivity than males in both groups. Overall, DH was not considered a major dental problem by most patients in either of the populations.

Scanning electron microscopy (SEM) investigation of selected desensitizing agents in the dentine disc model

Dentine sensitivity is a painful clinical conditions that can affect up to 35% of the population at any one time. Both professionally available (in-office) or commercially available (over-the-counter) products have been used to treat dentine sensitivity. The aim of the present study was to investigate whether selected in-office desensitizing agents occluded dentine tubules in the dentine disc model. Both surface effects and tubule penetration of the five selected test products were examined by scanning electron microscopy. The results of the present study appeared to demonstrate that all of the applied desensitizing agents produced some occlusion of the tubules although the level of coverage and occlusion varied between the products. Of all the agents tested, ferric oxalate, the active ingredient of Sensodyne Sealant, produced crystal-like structures which occluded a higher proportion of the tubules across the dentine disc surface. ALL-BOND 2 and One-Step (both light-cured primer systems) produced similar crystal-like structures and, although coverage was not uniform across the disc surface, there was some reduction in tubule diameter. These three products, however, appeared to be more effective than either Butler Protect (potassium oxalate) or Oxa-gel (potassium oxalate in a gel) where there was a marked decrease in both the level of coverage and tubule occlusion. Both quantitative and functional studies are required in order to determine the effects of these agents on dentine permeability (fluid flow) as well as clinical studies to determine their effectiveness over time in reducing pain arising from dentine sensitivity.

Perceptions of dentine hypersensitivity in a general practice population

Recent studies have attempted to determine the prevalence of dentine hypersensitivity (DH) in both hospital and general practice. Results indicate that DH prevalence is higher in patients referred for specialist treatment than in general practice. The aim of this study was to determine perception and prevalence of DH in general practice. Completed questionnaires from 277 patients (115 males, 162 females, mean age 41.7 years [SD 14.36]) were collected. Self-reported DH prevalence (52%) was observed between the third and fourth decades, peaking in the third and in good agreement with that previously published (45.2%), and significantly more females complained of DH than males (SND=2.24, 95% CI 0.01734-0.2661). Cold was perceived as the most common cause of DH, in agreement with other studies. Only 12.6% of patients reported periodontal surgery compared to 15.5% previously. Of those who received hygiene therapy (67.9%) only 15.5% reported DH following treatment which mainly did not last >/=5 days. Most patients with DH did not perceive the condition as severe and did not seek treatment (75.1%). Only 23.3% used a desensitizing dentifrice. The results indicated that self-reporting of DH is lower than reported in a dental hospital population and was not perceived as a major dental problem by most patients in a general dental practice population.

The effectiveness of desensitizing agents for the treatment of cervical dentine sensitivity (CDS)--a review

The treatment of dentine sensitivity or cervical dentine sensitivity (CDS) has been in the form of dentifrices, mouth rinses, sealants, and other therapeutic techniques. Claims of efficacy of the "so-called" active ingredients of these desensitizing agents have been made on the basis of the proposed mode of action generally extrapolated from in vitro or animal studies. Evidence from published, well-controlled clinical studies, however, generally has failed to substantiate such claims, although there has been a reported significant reduction in discomfort by subjects participating in these studies. Currently, the most accepted mechanism of intradental nerve activity associated with dentine sensitivity appears to be hydrodynamic in nature, although other mechanisms cannot be eliminated. The concept of tubule occlusion as a method of dentine desensitization is a logical conclusion from the hydrodynamic hypothesis. This paper reviews the present position with regard to the treatment of dentine sensitivity by various desensitizing agents and evaluates their claims of efficacy in the context of available scientific evidence.

Clinical trial designs for testing of products for dentine hypersensitivity--a review

Dentine hypersensitivity (DH) is a perplexing clinical entity. There is no doubt that patients self-report discomfort arising from various stimuli, but the highly subjective nature of the condition makes it extremely difficult to evaluate DH objectively. This is particularly true when evaluating the efficacy of desensitizing agents in the clinical trial setting. This paper attempts to provide an overview on clinical trial management to evaluate both in-office and over-the-counter (OTC) desensitizing agents. The importance of correct clinical trial design (type, allocation, blinding) with emphasis on patient selection, sample size, statistical power, duration, choice of positive/negative controls, treatment outcomes, and data collection, will be discussed.

The Dentin Disc surface: a plausible model for dentin physiology and dentin sensitivity evaluation

Dentin sensitivity (DS) is a painful clinical condition which may affect 8-35% of the population. Various treatment modalities have claimed success in relieving DS, although at present there does not appear to be a universally accepted desensitizing agent. Current opinion based on Brännström's Hydrodynamic Theory would suggest that following exposure of the dentin surface (through attrition, abrasion, or erosion), the presence of open dentinal tubules, patent to the pulp, may be a prerequisite for DS. The concept of tubule occlusion as a method of dentin desensitization, therefore, is a logical conclusion from the hydrodynamic theory. The fact that many of the agents used clinically to desensitize dentin are also effective in reducing dentin permeability tends to support the hydrodynamic theory. This paper reviews the in vitro evaluation of desensitizing agents, the techniques used to characterize their effects on the prepared dentin surface, and the ability of these agents to reduce permeability through tubule occlusion, and presents recent findings from ongoing research based on the Pashley Dentin Disc model. It can be concluded that the use of this model to determine surface characteristics, and reductions in dentin permeability through tubule narrowing or occlusion, provides a useful screening method for evaluating potential desensitizing agents. Interpreting changes observed in vitro is difficult, and extrapolation to the clinical situation must be tempered with caution.

Clinical evaluation of cervical dentine sensitivity in a population of patients referred to a specialist periodontology department: a pilot study

The prevalence of tooth sensitivity [Cervical Dentine Sensitivity (CDS)] in adult populations indicates that 8-35% of subjects reported CDS depending on the population studied and the methodology used. Few studies, however, have reported on the prevalence of CDS in periodontal patients. The aim of the study was to determine the prevalence, severity and distribution of CDS in patients referred for specialist periodontal diagnosis. Fifty-one patients [27 male, 24 female; mean age 48.5 years (standard deviation 11.63)] who gave their informed written consent were clinically evaluated for CDS using recognized methods of assessment, namely Yeaple probe, cold air blast and subjective evaluation. Other clinical variables (e.g. plaque and recession scores) were also recorded at this visit. Regression analysis and correlation coefficients were used to determine the relationship between the clinical variables. The results demonstrated a prevalence of CDS ranging between 72.5 and 98% of patients, with no significant gender difference. Results for the distribution of tooth types showed that molar teeth were mainly affected, followed by left canines and premolars. No correlation was noted between plaque, recession, response to tactile or thermal stimulation. Pain response from tactile and thermal stimulation showed no significant difference between tooth surfaces. Cold stimulation was perceived to be the dominant pain-producing stimulus as had been previously reported. The results of this investigation support those from another study, which found the prevalence of CDS to be higher in periodontal patients than has been reported elsewhere. This finding would suggest that previous periodontal treatment and/or periodontal disease may play a role in the aetiology of CDS.

A pilot assessment of alternative methods of quantifying dental pain with particular reference to dentine hypersensitivity

OBJECTIVE

The overall aim of this pilot study was to establish the usefulness and comparability of selected verbal and non-verbal methods in the quantification of sensory and affective aspects of dental pain associated with dentine hypersensitivity (DH).

DESIGN

The assessment of dental pain was conducted during an eight week clinical study. Patients were asked to rate their perception of dental pain using selected methods of quantification following tactile (Yeaple Probe-an electronic pressure-sensitive probe) and evaporative (cold air from a dental air syringe) stimulation; together with an overall assessment of perception to daily stimuli (e.g., cold air/water, toothbrushing, sweet and sour foods). The assessment methods used to quantify pain arising from DH were a continuous visual analogue scale (VAS), a 0-10 numerical rating VAS scale (NRS), and a separate intensity verbal descriptor (IVD) and unpleasantness verbal descriptor (UVD) word scales.

SETTING

A specialist department at a postgraduate dental institute and hospital in London, UK.

SUBJECTS

Twenty-five adult patients (8M + 17F) with a mean age of 42.6 years (95 per cent C.I. 38.8 to 46.4 years) attending the department for a clinical study evaluating the efficacy of a desensitising toothpaste agreed to participate.

OUTCOME MEASURES

The study compared a continuous visual analogue scale (VAS), a 0-10 numerical rating visual analogue scale (NRS), and a separate intensity (IVD) and unpleasantness verbal descriptor (UVD) scales to quantify sensory and affective aspects of pain. An unweighted moving average technique was used to construct graphs of the relative frequency of reported severity gradings over a range of 0-10.

RESULTS

The results of the study indicated that cold air appeared to cause greater discomfort to the patient than tactile sensitivity, with the air intensity curve for both IVD and 0-10 VAS peaking at a severity score of 5 while continuous VAS peaked at a score of 3-4. All methods peaked at score 2 for tactile sensitivity. The UVD scale peaked at score 2-3 and again at 6 for air sensitivity, but conformed to the other scales by peaking at score 2 for tactile sensitivity. NRS and IVD scales therefore appeared to provide acceptable alternatives to continuous VAS, but the UVD scale, probably because of the imprecise nature of the words used in the scale, did not.

CONCLUSIONS

This study partially confirms previous conclusions that both verbal and non-verbal techniques quantify sensory and affective aspects of pain. However, the imprecise nature of UVD words provided misleading information in terms of both accuracy and sensitivity (except at very low levels of discomfort), when assessing pain arising from dentine hypersensitivity. In view of the highly subjective data arising from studies of this nature, the use of a moving average technique may be considered a more pragmatic method of analysis.

An investigation of potential desensitizing agents in the dentine disc model: a scanning electron microscopy study

Cervical dentine sensitivity (CDS) may be defined as pain arising from exposed dentine. The prefix cervical indicates the location of the sensitivity and/or its subsequent treatment. Currently the most accepted mechanism of intradental nerve activation associated with dentine sensitivity appears to be hydrodynamic in nature. The concept of tubule occlusion as a method of dentine desensitization is a logical conclusion of the hydrodynamic theory. The authors employed the dentine disc model, qualitative scanning electron microscopy (SEM) and X-ray microanalysis to investigate whether selected desensitizing agents occlude dentinal tubule orifices. Strict control procedures have been used together with various methods of application to apply these agents to human dentine discs. SEM was used to examine the degree of deposit left by the various agents on disc surfaces and X-ray microanalysis was employed to characterize the elemental composition of the deposit. Analysis of selected agents, both prior to and after application on dentine discs was performed for comparative purposes. The degree of retention of the surface deposit upon rotation with saliva supernatant for 6 h was also studied. The results of this study indicated that ferric oxalate, the active ingredient of Sensodyne Sealant, which produced initial crystal-like structures, occluding almost all the tubule orifices was superior to potassium oxalate (Butler Protect). Of the over-the-counter (OTC) desensitizing products tested, both silica- and calcium-based abrasive components were observed both on the surface and within the tubules, indicating a certain degree of therapeutic potential for these two components. These findings suggest that certain desensitizing agents have tubule occluding properties as observed in this in vitro system which, in turn, may indicate a therapeutic potential in vivo.

The dentine disc. A review of its applicability as a model for the in vitro testing of dentine hypersensitivity

The dentine disc has been extensively used as a model for assessing potential desensitizing agents in vitro by scanning electron microscopy (SEM). Although the disc provides a readily available and reproducible test substrate, this paper addresses the problems associated with this model such as the natural variation in the dentine tubules and the resulting differences in surface morphology. At the ultrastructural level the surface of a single etched disc exhibits variations in the size, density, orientation and extent of etching of the cut dentine tubules. In the present study a precise control procedure was designed which allowed greater correlation between test and control surfaces. Two adjacent areas of the same disc were used, one as the test surface, the other the control. Two proprietary desensitizers were examined using this methodology. This study has shown that the dentine disc is a good, reliable model for in vitro screening and testing of potential desensitizing agents, providing such controls are applied.

Comparison of two desensitizing agents for the treatment of cervical dentine sensitivity

Numerous desensitizing agents have been utilized in an effort to alleviate the discomfort associated with cervical dentine sensitivity (CDS). Recently several new tubule-occluding and sealant systems have been marketed for treatment. The aim of this study was to compare two desensitizing agents (ALL-BOND 2 and Butler Protect) in a 3-month clinical study. Ten subjects (6F; 4M mean age 45.1 years (SD 8.81) who had provided voluntary written informed consent participated in a single-blind 3-month clinical study. Subjects were evaluated for tactile (Yeaple probe) and air sensitivity (dental air syringe) together with subjective perception of pain (VAS scores) at 0.5 min, 1, 2 and 3 months. There was an overall trend in reduction of CDS over the study period in all group with no significant differences detected between groups. The results suggested that while subjects reported overall reductions in sensitivity levels, this may not necessarily be substantiated when assessed objectively. Furthermore, there appeared to be a strong placebo effect in this study.

Aetiology, prevalence and clinical features of cervical dentine sensitivity

Cervical dentine sensitivity (CDS) is a painful response to thermal, physical or chemical stimulation of the cervical area of the tooth. The reported prevalence of this clinical condition ranges from 8 to 35% depending on the population studied and methodology used to evaluate CDS. Detailed epidemiology is lacking with regard to possible causal factors. Well conducted studies in larger populations using accepted standardized methodology for both questionnaire and clinical examination are essential if these factors are to be identified and the condition successfully prevented and treated. This paper reviews current literature on the prevalence, aetiology and oral distribution of this troublesome condition.

Prevalence of cervical dentine sensitivity in a population of patients referred to a specialist Periodontology Department

The reported prevalence of cervical dentine sensitivity (CDS) ranges from 8 to 35%. Detailed epidemiology of the condition, particularly with regard to possible causal factors, is lacking. In particular, no published data appear to exist on its prevalence in periodontal patients. The aim of the present study was therefore to determine the prevalence, distribution and severity of CDS in a population of patients referred to a Periodontology Department of a specialist postgraduate hospital. 507 patients (181 M; 326F, mean age 44.2 (SD 10.31) years) attending a periodontal clinic were assessed for CDS by a questionnaire. The results demonstrated a prevalence of CDS of 84% with no significant gender difference. 71.1% of patients perceived cold as the most common cause of discomfort. A higher prevalence of self-reported discomfort was observed between 40 and 49 years. Of the patients with a reported history of periodontal surgery (34.7%), those treated within 6 months prior to assessment appeared to be more at risk to CDS. Of the patients who received hygienist treatment (88.2%), only 10.5% reported discomfort persisting > or = 3 days after treatment. Generally, patients who complained of varying degrees of discomfort over time (84.5%) did not perceive the condition as severe and consequently did not seek treatment. The prevalence of CDS in these referred patients was very high, suggesting that periodontal diseases and/or treatment effects play a rôle in its aetiology.

Efficacy of a potassium nitrate mouthwash in alleviating cervical dentine sensitivity (CDS)

Potassium nitrate (KNO3) has been used previously in a dentifrice or gel to alleviate cervical dentine sensitivity (CDS). The aim of this study was to compare a 3% KNO3 Silica/NaF mouthwash with a NaF/silica mouthwash in a 6-week multi-centre double-blind study. 47 subjects (12M; 35F, mean age 36.2 (SD 11.46) years) participated in the study. Subjects were evaluated for tactile (Yeaple probe) and air sensitivity (dental air syringe) together with subjective perception of pain (0-10 scale) at 0, 2 and 6 weeks. Results for Yeaple probe (gm wt) (Wilcoxon paired rank test) between 6 weeks and baseline, were highly significant for both groups. Differences between groups at 6 weeks were statistically significant. Subjective Yeaple probe scores (paired t-tests) between 6 weeks and baseline were significant for both groups. There were no significant differences (unpaired t-tests) between groups over 6 weeks for subjective Yeaple probe scores. Subjective air scores (paired t-tests) between 6 weeks and baseline were significant for both groups. There were significant differences (unpaired t-tests) between groups in favour of the 3% KNO3/Silica/NaF group at 6 weeks. The 2 weeks and baseline results for both groups were the same as reported for 6 weeks and baseline. The results demonstrated that a 3% KNO3/Silica/NaF mouthwash compared to a Silica/NaF control significantly reduced CDS when evaluated by tactile and thermal stimuli. A 3% KNO3/silica/NaF mouthwash would, therefore appear to have therapeutic potential to alleviate CDS.

Comparison of 2 desensitizing dentifrices with a commercially available fluoride dentifrice in alleviating cervical dentine sensitivity

Previous studies have demonstrated efficacy of desensitizing dentifrices containing strontium acetate/sodium fluoride (SrAc2F) and potassium chloride/sodium monofluorophosphate (KCl/MFP) in alleviating discomfort arising from cervical dentine sensitivity (CDS). The aim of this investigation, therefore, was to determine efficacy of a SrAc2F dentifrice compared with KCl/MFP and a commercially available fluoride dentifrice containing sodium fluoride/sodium monofluorophosphate (NaMFP). Fifty-six patients participated in a 2-center double-blind, 3-way comparative parallel 6-week clinical study. Patients were evaluated at 0, 2, and 6 weeks for tactile (Yeaple probe), air sensitivity (dental air syringe), and subjective perception of pain (VAS scores). Results for Yeaple probe scores (Wilcoxon tests) between 2 weeks and baseline were highly significant for KCl/MFP, significant for NaMFP and nonsignificant for SrAc2F; scores between 6 weeks and baseline were, however, highly significant for all groups. Subjective Yeaple probe VAS scores (paired t-tests) between 6 weeks and baseline were significant for all groups; significance was demonstrated in the KCl/MFP group between 2 weeks and baseline. Subjective air visual analogue scores (paired t-tests) between 2 weeks and baseline were highly significant for all groups. There were no significant differences between groups at any time point. The results of the study demonstrated that the commercially available fluoride-containing dentifrice was as effective as the 2 desensitizing dentifrices in alleviating CDS over time.

Assessment of pain in cervical dentinal sensitivity studies. A review

Traditionally cervical dentinal sensitivity (CDS) has been evaluated mainly subjectively on the basis of the individual patient's subjective response, e.g., in the form of verbal rating and visual analogue scales and questionnaires. The stimuli used for evaluating this response can be grouped into 4 main categories: mechanical, chemical, electrical and thermal. This review of the literature, however, indicates that there are problems in evaluating patient subjective response to these various test stimuli used in the assessment and treatment of CDS. Opinions also vary as to the reliability of some of these methods of assessment, although recently, efforts have been made to develop controlled reproducible stimuli more suited to the evaluation of CDS. Currently no single method of eliciting and assessing CDS may be considered ideal. Further research is required to evaluate suitable methodology for the quantification of realistic test stimuli under controlled clinical conditions, whereby the subjective response may be objectively measured by the investigator.

The effect of strontium chloride hexahydrate dentifrices on plaque accumulation and gingival inflammation

2 strontium chloride hexahydrate-containing dentifrices (SCH), similar except for their respective abrasive systems, diatomaceous earth or silica-based, were compared for their effects on plaque accumulation and gingival inflammation as part of a 2-month randomised double-blind parallel clinical study. No attempt was made to change the patients' oral hygiene prior to participation in the study. Plaque was assessed using the Silness & Löe index and the gingival condition by the Löe & Silness index GI. There was a slight and non-significant increase in plaque accumulation at 2 weeks from baseline, but relatively negligible change thereafter, the effect being identical in both groups. Similarly, the gingival condition showed a slight index change from baseline, although it tended to be slightly higher in the diatomaceous earth group. The results do not support the conclusions of previous studies which indicated that SCH dentifrices increased plaque accumulation. Neither plaque accumulation nor gingival condition significantly changed from baseline levels during the course of the study.

Clinical efficacy of a low abrasive dentifrice for the relief of cervical dentinal hypersensitivity

2 strontium chloride hexahydrate-containing dentifrices (SCH), similar except for their respective abrasive systems, were compared in a 2-month randomised double-blind parallel clinical study to evaluate their comparative effectiveness in terms of cervical dentinal hypersensitivity. 2 groups of 20 subjects, each with cervical dentinal hypersensitivity, were evaluated for tactile sensitivity by Yeaple probe, air sensitivity using a dental air syringe and subjective perception of pain by means of a visual analogue scale. There was no difference between the dentifrices as regards reduction of cervical dentinal hypersensitivity at each time point. The response to both dentifrices was evident within 4 weeks of use and the degree of improvement increased throughout the 8-week study period. The results support the conclusion that changing the abrasive component of SCH dentifrices did not significantly increase or decrease the (desensitizing) activity of the original product.

Dentifrice abrasivity and cervical dentinal hypersensitivity. Results 12 weeks following cessation of 8 weeks' supervised use

Following an 8-week controlled investigation of 2 strontium chloride hexahydrate dentifrices (SCH) of differing abrasivity, 2 groups of 20 subjects each, with cervical dentinal hypersensitivity, were re-examined at 20 weeks; that is, 12 weeks after the active period. The examination procedures were conducted in the same manner as in the main clinical trial. Sensitivity levels were assessed by 2 instrument methods: tactile (Yeaple probe), and cold air (dental air syringe), and by subjective perception of pain by means of a Visual Analogue Scale. The results from these methods of assessment demonstrated that 12 weeks following the cessation of 8 weeks' controlled use of standard and low abrasive SCH dentifrices, sensitivity levels reversed on slightly in both groups and, overall, sensitivity remained significantly lower than at baseline. The abrasivity of the dentifrice did not affect the desensitivity activity.

Aqueous Diffusion Measurements by the Lamm Scale Method and Their Correlation with Membrane Diffusion Measurements

The diffusion of potassium chloride, sodium chloride, potassium sulphate, and .sucrose in water is investigated by means of a simplified form of the Lamm scale method. The maximum height method of calculation is modified in such a way that the experimental procedure is less laborious than the original method. The diffusion coefficient values are obtained over a range of temperatures and the activation energies for free diffusion calculated. Comparisons are made with the predictions of the Debye-H�ckel-Onsager theory and with the results of membrane diffusion measurements. The defects of the method are discussed and a more refined method is described by which it should be possible to calculate the concentration dependence of the diffusion coefficient and also the influence of solvent counterflow.