Clinical evaluation of a new treatment for dentinal hypersensitivity

Clinical and Radiographic Assessments of Potassium Nitrate in Polycarboxylate Versus Mineral Trioxide Aggregate as Pulpotomy Biomaterials in Immature Mandibular First Permanent Molars: A Randomized Clinical Trial

INTRODUCTION

The purpose of this study was to compare clinically and radiographically the effects of potassium nitrate in polycarboxylate cement and mineral trioxide aggregate (MTA) as pulpotomy agents in vital immature mandibular first molars.

METHODS

The trial design was a parallel randomized, 1:1 allocation ratio, with both the participants and the data assessor blinded. A total of 50 molars of 48 eligible children aged 6-9 years were studied. The children had mandibular immature first molars with extensive caries that revealed pulp exposure during caries excavation. Patients were randomly allocated equally into 2 groups in which potassium nitrate in polycarboxylate cement (the intervention group) and MTA (the control group) were used as pulpotomy biomaterials. The treated teeth were restored permanently. The primary outcome was clinical/radiographic assessment after 1 week, 6 months, and 12 months. The secondary outcomes were radiometric analysis at 6 and 12 months to determine dimensional changes during maturogenesis. The digital radiographs were imported to image processing software to perform radiometric measurements. Data were tabulated and statistically analyzed with significance set at P ≤ .05.

RESULTS

Only a single tooth failed at the 6-month recall, and another one was lost during recall in each group. Thus, the overall success rate for cases/group who finally attended the 12-month follow-up time point was 92% (23/25) with no statistically significant difference between the 2 groups. At the 12-month recall, successful cases showed root development with an increase in root length and a decrease in apical foramen width. Complete apical closure was observed in 65.2% of the roots in the intervention group and 52.1% in the control group.

CONCLUSIONS

The clinical and radiographic success reported in the present study reveals that potassium nitrate in polycarboxylate cement could be used as a biological and economic alternative to MTA as a pulpotomy agent in vital immature mandibular first molars. Further follow-up for longer periods is recommended.

Bioavailable gluconate chelated stannous fluoride toothpaste meta-analyses: Effects on dentine hypersensitivity and enamel erosion

OBJECTIVES

To compare the effect of bioavailable gluconate-chelated stannous fluoride (SnF₂) toothpaste with control toothpastes for treatment of dentine hypersensitivity (DH) and enamel erosion.

DATA AND SOURCES

A Procter & Gamble Oral Care archive of clinical studies was reviewed from 2000 to 2020. Eligible studies were Randomised Controlled Trials (RCTs) investigating bioavailable gluconate-chelated SnF₂ toothpaste efficacy compared to controls in adult participants measured following tactile (Yeaple force) and/or evaporative stimuli (Schiff score) in-vivo, duration <2 months (DH); or by erosive toothwear (profilometry) from in-situ samples, duration 10-15 days. Two authors independently assessed eligibility and resolved disagreements by discussion. A meta-analysis was undertaken and Risk of Bias (RoB) assessed using the Cochrane collaboration RoB tool for randomized parallel-group and cross-over trials.

RESULTS

Fourteen RCTs (1287 participants) assessed DH relief and Six RCTs (184 participants) enamel erosion protection. For DH SnF₂ toothpastes provided a 57 % (evaporative air) and 142 % (tactile) benefit versus negative controls (sodium fluoride/monofluorophosphate, 8 studies; p < 0.001). Compared to positive controls (potassium nitrate or arginine, 6 studies), a 22 % advantage (p = 0.036) was seen for evaporative air. In erosion studies, SnF₂ toothpastes provided an 83 % benefit versus control toothpastes (arginine or sodium fluoride; p < 0.001) with a change (95 %CI) in average surface profilometry level (μm) of -2.02(-2.85, -1.20).

CONCLUSIONS

The use of these bioavailable SnF₂ toothpastes, as part of a daily oral hygiene regimen, will provide patients with enamel erosion protection, combined with alleviation of DH pain when present, improving quality of life.

Amorphous Calcium Magnesium Phosphate Particles for Treatment of Dentin Hypersensitivity: A Mode of Action Study

Occlusion of exposed dentin tubules may eliminate or reduce dentin hypersensitivity by hindering fluid movements within the tubules. In this study, the mode of action of spherical particles of amorphous calcium magnesium phosphate (180-440 nm in diameter) was studied. A degradation study of the particles in Tris-HCl buffer showed that the particles continuously released Ca²⁺, Mg²⁺, and phosphate, and XRD analysis revealed the formation of hydroxyapatite (HA) after 1 week. The occluding effect and efficacy of the spherical particles as an occluding agent were evaluated in an in vitro study. The ACMP particles were incorporated in a gel intended for at-home use and tested on extracted human molars. Application of the particles followed by incubation in artificial saliva resulted in occlusion of exposed tubules, and examination with SEM showed that the particles could penetrate the tubules down to 100 μm from the dentin surface. Transformation of the particles into nanocrystalline HA-structures (nanoHA) was initiated at the dentin surface within 12 h of application, and tubule penetration of the particles, accompanied by further ion release and diffusion of ions, resulted in deep intratubular occlusion in the majority of the tubules within 3 days from application. NanoHA was tightly adhered to the tubule walls, filling the entire tubule volume after 7 days. The results of this study demonstrate the mode of action of the amorphous calcium magnesium phosphate particles in occluding exposed dentin tubules. Interaction with saliva and transformation of the particles within the tubules inducing further mineralization indicate that the particles may be used as an effective treatment to reduce dentin hypersensitivity.

Dentine sensitivity: past, present and future

OBJECTIVE

This review defines dentine sensitivity (DS), its prevalence, its aetiology, the mechanism(s) responsible for DS, its diagnosis and its treatment. The review then examines the modes of action of various treatments for DS including potassium salts, strontium salts, bioglasses, arginine/calcium carbonate and professional treatments such as adhesives and oxalates. The methods used to evaluate the various treatment modalities are discussed, including laboratory studies and randomised controlled clinical trials.

DATA SOURCES AND STUDY SELECTION

A literature search was conducted using PubMed, Ovid Medline and Cochrane reviews for information on DS and its treatments, as well as laboratory and clinical studies used to evaluate the efficacy of various DS treatments. With regard to efficacy of treatments for DS only reports of clinical studies that were randomised, controlled and blinded were reviewed. The authors offer new insights into the shortcomings of the recent systematic review of the use of oxalates for DS.

CONCLUSION

The authors introduce the concept of a novel desensitising mouthrinse containing 1.4% potassium oxalate: Listerine® Advanced Defence Sensitive mouthrinse. Readers of this supplement issue of the Journal of Dentistry are invited to review the significance of managing the clinical problem of DS. They are also invited to assess data from laboratory and randomised controlled clinical studies in order to understand the advantages offered by regular use of 1.4% potassium oxalate-containing mouthrinse, Listerine Advanced Defence Sensitive, in particular its resistance to daily erosive and/or abrasive challenges.

Chair Side Application of NovaMin for the Treatment of Dentinal Hypersensitivity- A Novel Technique

OBJECTIVE

To evaluate the efficacy of calcium sodium phosphosilicate bioactive glass (NovaMin) as a chair side desensitizing agent.

MATERIALS AND METHODS

The study was conducted on 60 subjects divided into 3 groups of 20 each as follows. Group I (NovaMin application without scaling and root planing), Group II (NovaMin application after scaling and root planing) and Group III (control group). Sensitivity was assessed using air blast and cold water stimulus at baseline, immediately after application, after half an hour and after 8d using Visual Analog Scale (VAS).

RESULTS

Mean VAS (air blast stimulus) for group I was 5.9 at baseline, 3.4 immediately after application, 3.05 after half an hour, and 3.0 after 8 days. In group II VAS score were 6.2, 3.35, 2.9, 2.75 and group III 6.6, 7.0, 7.0, 7.0 respectively. For cold water stimulus in group I VAS score were 5.6, 3.35, 3.15, 3.1, group II VAS score 5.7, 3.35, 3.1, 2.85 and group III 5.8, 6.1, 6.05, 6.05 respectively. VAS scores in between group I and group III and group II and group III were statistically significant (<0.001) immediately after application, after half an hour and after 8days (ANOVA).

CONCLUSION

Chair side application of calcium phosphosilicate bioactive glass can be a therapeutic adjunct to provide immediate relief for the patient with dentinal hypersensitivity.

A comparative evaluation of propolis and 5.0% potassium nitrate as a dentine desensitizer: A clinical study

AIM

The purpose of this clinical study was to evaluate the efficacy of saturated ethanolic solution of Propolis for the treatment of dentin hypersensitivity.

MATERIALS AND METHODS

Ten patients aged 20-40 years with 156 hypersensitive teeth were selected for a 3-month study. Each patient was subjected to treatment with saturated ethanolic solution of Propolis, 5% potassium nitrate and distilled water. The patients were recalled at seventh day, 2 weeks and 4 weeks for the application of the agent and re-evaluation. The final re-evaluation of the patients was done after 3 months from the first application. The responses of the patients to the test temperatures were converted to a ranking and data was statistically analyzed. A statistical analysis was done using ANOVA and Bonferroni test and Tukey HSD test for multicomparison.

RESULTS

The results between the Propolis group and the potassium nitrate group showed no significant difference in the immediate post-treatment period; however, the results were significant at the end of first week and second week. At 4 weeks and 3 months period, a comparison between the groups again showed no significant difference.

CONCLUSION

It was concluded that Propolis was more effective than 5% potassium nitrate in relieving dentinal hypersensitivity and had an immediate and sustained effect.

The efficacy of strontium and potassium toothpastes in treating dentine hypersensitivity: a systematic review

Objectives. The aim of the present paper was to review the published literature in order to identify all relevant studies for inclusion and to determine whether there was any evidence of the efficacy of strontium and potassium toothpastes in the treatment of dentine hypersensitivity (DH). Methods. Following a review of 94 relevant papers both from searching electronic databases (PUBMED) and hand searching of relevant written journals, 13 studies were identified, and 7 papers (1 for strontium-based toothpastes and 6 for potassium-based toothpastes) were finally accepted for inclusion. The main outcome measures were the methodology and assessment used by Investigators in studies designed to evaluate DH. Results. The results of the present paper would indicate that the reported efficacy of both strontium- and potassium-based toothpastes in relieving DH is questionable. Conclusions. The results from the present paper would appear to support the conclusions of previous investigators that there is only minimal evidence for the efficacy of both strontium- and potassium-based toothpastes in relieving symptoms of DH.

A clinical study of the effect of calcium sodium phosphosilicate on dentin hypersensitivity

Objective: Dentinal hypersensitivity is a commonly encountered problem with varied treatment options for its management. A large number of home use products have been tested and used for the management of dentinal hypersensitivity. This 8 week clinical trial investigates the temporal efficacy of commercially available calcium sodium phosphosilicate containing toothpaste in comparison to a potassium nitrate containing toothpaste. Methods: A total 20 subjects between the ages of 18 to 65 years were screened for a visual analogue score (VAS) for sensitivity of 5 or more by testing with a cold stimulus and randomly divided into test and positive control groups. Baseline sensitivity VAS scores to air evaporative stimulus were recorded for minimum two teeth. The subjects were prescribed respective dentifrices and revaluated for sensitivity scores at 2, 4 and 8 weeks. Results:The study demonstrated reduction in symptoms for all treatment groups from baseline to 2, 4 and 8 weeks. The calcium sodium phosphosilicate group showed a higher degree of effectiveness at reducing hypersensitivity to air evaporative stimulus at 2 weeks, than commercially available potassium nitrate. However, there was no significant difference in scores of subjects using the calcium sodium phosphosilicate toothpaste as compared to potassium nitrate at 4 weeks and 8 weeks. Conclusion: Calcium sodium phosphosilicate showed greater reduction in sensitivity compared to potassium nitrate at an earlier stage which is of high clinical value. However, based on the findings of the present study long term effects of calcium sodium phosphosilicate seem to be less promising than previously claimed.

Key words:Dentinal desensitizing agents, dentinal hypersensitivity, toothpaste, pain measurement.

Occluding Effect of Nd:YAG Laser and Different Dentin Desensitizing Agents on Human Dentinal Tubules In Vitro: A Scanning Electron Microscopy Investigation

Objectives

This in vitro study aimed to microscopically evaluate and compare the occluding effect of the Nd:YAG laser and different dentin desensitizing agents on human dentinal tubules.

Materials and Methods

The Nd:YAG laser (SunLase™ 800) and four commercially available and professionally applied dentin desensitizers (Gluma® desensitizer, Tenure Quick®, Quell™ desensitizer, and VivaSens®) were investigated in this study. Sixty-four extracted intact human molars were used. Each dentin surface was divided by shallow indentation into two halves, one of which was used for treatment and the other of which served as a control. The dentin surfaces were etched to remove any smear plugs and to mimic the open dentinal tubules of sensitive dentin using 0.5 M ethylenediaminetetraacetic acid (pH 7.4) for two minutes (applied with a microbrush) and then rinsed with an air-water syringe for 30 seconds. The laser samples (n=16) were randomly divided into four groups of four samples each. These groups were the step-up technique group, the 14-day group, the one-minute group, and the two-minute group. Forty-eight samples were treated with the four tested desensitizing agents and were randomly divided into four groups (n=12/group). Each group was further subdivided into three subgroups (n=4). Samples of the first subgroup were treated for 14 days, while those of the second subgroup were treated once. Samples of the last subgroup were fractured longitudinally after a single treatment. All of the samples were then examined under a scanning electron microscope.

Results

The Nd:YAG laser–irradiated dentin showed reduction or complete obliteration of the dentinal tubule lumen; thus, the treatment modified the original dentinal structure. The lased dentin surface in the two-minute group showed bubble-like changes in the area of the dentinal tubules' orifices. Statistically, the two-minute group was found to have a significantly higher percentage of partially or fully occluded tubules than did the one-minute group. All of the studied desensitizing agents produced occlusion of the dentinal tubules; however, the appearance of the precipitates, the level of coverage, and the degree of dentinal occlusion varied among the tested products.

Conclusion

Throughout the specified period of this study, occlusion and/or narrowing of the open dentinal tubules have been successfully achieved with both treatment approaches.

Efficacy of Two Different CHX-Containing Desensitizers: A Controlled Double-Blind Study

CHX-containing desensitizers are used for treatment of hypersensitive teeth. This positive effect shows a durability of 3-month.

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.

Patient-applied treatment of dentinal hypersensitivity

This article reviews the evidence regarding the effectiveness of various patient-applied interventions for dentinal hypersensitivity. Self-applied treatments are popular because they are both economical and easy to use. The disadvantages include compliance, difficulty to deliver to specific sites, slow onset of action, and the requirement for continuous use. Conflicting research findings make it difficult for the practitioner to determine which self-applied product to advise patients to use. There are a number of issues that have plagued research in this area, including the lack of standardization of stimulus testing and inadequate sample size. The evidence is insufficient to permit the development of evidence-based guidelines for the treatment of dentinal hypersensitivity.

An audit of dentine hypersensitivity treatments in six general dental practices in Scotland

AIMS

This investigation sought to: (a) determine the agents used by nine dentists to treat dentine hypersensitivity and measure their effectiveness; (b) evaluate the adoptive ease and apparent success of the most effective treatment when used by all nine dentists; and (c) validate a novel categorical ranking score for dentine hypersensitivity.

METHODS

A clinical audit methodology was used in the setting of general dental practice. In the initial data-collection round, patients presenting with dentine hypersensitivity were treated using the dentist's favoured regimen. Evaluation of agent effectiveness was made by patient completion of a pre- and post-treatment visual analogue scale (VAS) for the frequency (f) and severity (s) of hypersensitivity. A four-point categorical ranking scale (CRS) was also used to assess the impact of hypersensitivity upon lifestyle (L) (1=No sensitivity/effect on what I eat/drink; 2=Sometimes sensitive, rarely interfering with what I eat/drink; 3=Sometimes sensitive, occasionally interfering with what I eat/drink; 4=Always sensitive, always interfering with what I eat/drink). The most successful treatment was determined and used by all participating dentists. Its effectiveness was then assessed using the same criteria.

RESULTS

Four agents were routinely used to treat hypersensitivity: (Duraphat (D) (Colgate), Duraphat & Sensodyne (DS) (GlaxoSmithKline), Sensodyne (S) (GlaxoSmithKline), Seal & Protect (SP) (De Trey, Dentsply). All produced statistically significant (P<0.001) reductions in VAS (Tukey) and CRS (Kruskal-Wallis) scores, except for DS and S. Of these, the greatest percentage reduction was seen for SP (f=72.01%, s=71.19%, L=45.98%). When SP was applied by all dentists, similar percentage reductions were seen (f=68.74%, s=75.85%, L=38.33%). The CRS, in both data-collection rounds, correlated well with the corresponding VAS scores (Spearman R for f=0.77 (P<0.001) and for s=0.80 (P<0.001).

CONCLUSION

For the dentists in this audit, the use of SP was found to be reliable and predictable. The CRS provided a simple and reliable measure of dentine hypersensitivity. Subject to validation in a larger study, this could be used in a future audit as an alternative to multiple VAS scores.

Potassium containing toothpastes for dentine hypersensitivity

BACKGROUND

Dentine hypersensitivity may be defined as the pain arising from exposed dentine, typically in response to external stimuli, and which cannot be explained by any other form of dental disease. Many treatment regimens have been recommended over the years, and in recent years particular attention has been focused on toothpastes containing various potassium salts.

OBJECTIVES

To compare the effectiveness of potassium containing toothpastes with control toothpastes in reducing dentine hypersensitivity.

SEARCH STRATEGY

The following databases were searched: Cochrane Oral Health Group Trials Register (searched until August 2005); CENTRAL (until August 2005); EMBASE/MEDLINE, PubMed, Web of Science (until September 2005). Bibliographies of clinical studies and reviews identified in the electronic search were checked for studies published outside the electronically searched journals.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in which the effect on dentine hypersensitivity of potassium containing toothpastes was tested against non-potassium containing control toothpastes.

DATA COLLECTION AND ANALYSIS

Two of the review authors independently recorded the results of the included trials using a specially designed form. Sensitivity was assessed by using thermal, tactile, air blast, and subjective methods.

MAIN RESULTS

Six studies were included in the meta-analysis which showed the statistically significant effect of potassium nitrate toothpaste on air blast and tactile sensitivity at the 6 to 8 weeks follow up, e.g. the meta-analysis of air blast sensitivity showed a standardized mean difference in sensitivity score of -1.25 (95% CI: -1.65 to -0.851) in favour of treatment. The subjective assessment failed to show a significant effect at the 6 to 8 week assessment.

AUTHORS' CONCLUSIONS

The evidence generated by this review is based on a small number of individuals. Furthermore, the effect varies with the methods applied for assessing the sensitivity. Thus no clear evidence is available for the support of potassium containing toothpastes for dentine hypersensitivity.

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.

The clinical performance of professionally dispensed bleaching gel with added amorphous calcium phosphate

BACKGROUND

The authors undertook a study to measure how the addition of amorphous calcium phosphate (ACP) to a professionally dispensed 16 percent carbamide peroxide equivalent bleaching gel affects tooth color and dentinal hypersensitivity.

METHODS

The authors assigned two groups to use either the test gel containing ACP or a control gel. Both groups used their respective products for three hours daily for 14 days. At checkpoints during the treatment period, the authors studied tooth color, gingival health and three measures of hypersensitivity. They performed double-blinded clinical measurements on days three, seven, 14 and on the fifth day post-treatment.

RESULTS

The test group demonstrated significantly lower (P < .05) mean thermal sensitivity scores compared with baseline (day 14: 0.21 versus 0.31; fifth posttreatment day: 0.06 versus 0.18). Tactile sensitivity also was substantially lower (P < .05) for test subjects (day 14: 0.26 versus 0.48; fifth posttreatment day: 0.06 versus 0.19). Furthermore, at the conclusion of the study, twice as many subjects were free of thermal sensitivity (test group, 80 percent, compared with control group, 40 percent; P < .001) and there was a similar significant (P < .001) percentage difference for tactile sensitivity. Both groups demonstrated equivalent and significant tooth color enhancement as compared with baseline (control: -7.73 shade change versus test: -8.12; P < .05).

CONCLUSIONS

This study demonstrates that ACP could be added to a 16 percent carbamide peroxide equivalent bleaching gel and result in a significant reduction of clinical measures of dentinal hypersensitivity, both during and after treatment.

CLINICAL IMPLICATIONS

The results of this study offer evidence in support of clinical decisions to treat patients with bleaching gel containing ACP when uncompromised tooth whitening efficacy is desired, yet dentinal hypersensitivity may be a concern.

The effect of a new toothpaste containing potassium nitrate and triclosan on gingival health, plaque formation and dentine hypersensitivity

OBJECTIVES

The purpose of this study was to investigate the effect of a new toothpaste containing an antiplaque and antiinflammatory agent (0.3% triclosan), a desensitizing agent (5% potassium nitrate) and an anticaries agent (0.76% sodium monofluorophosphate (SMFP)) on gingival health, plaque formation and dentine hypersensitivity in a 12-week home study. The efficacy of the test toothpaste was compared with that of a control toothpaste containing 5% potassium nitrate and 0.76% SMFP and a benchmark product containing only 0.76% SMFP.

MATERIAL AND METHODS

One hundred and two healthy volunteers, who had a minimum of 20 natural permanent teeth with no probing depth >4 mm and at least one sensitive tooth, participated in this study. Following enrollment, the subjects received a dental prophylaxis and instruction in brushing technique. After a 4-week pre-experimental phase, baseline gingival bleeding index (GBI), plaque index (PI) and visual analogue scales (VASs) indicating dentine hypersensitivity levels responding to tactile and air stimuli were assessed. The subjects were then randomly given one of the three toothpastes; test, control, or benchmark toothpaste, and a soft-filamented toothbrush for home use. The GBI, PI and VASs were re-examined at weeks 4 and 12.

RESULTS

Overall, the GBI scores were significantly reduced compared with baseline in all groups (p<0.01). However, there was no significant difference in GBI score among the three comparison groups. The PI score decreased in the test group and benchmark group from baseline to the end of study, whereas there was no significant change in the control group. Post hoc comparison indicated that the PI score was not statistically different between the three groups. There was a significant difference between the three treatment groups for sensitivity. For both the tactile and air stimuli, the reductions in VAS sensitivity scores for the test group and the control group were significantly greater compared with the benchmark group. Although the sensitivity score for air stimulus decreased more rapidly from baseline to week 4 in the test group, there was no overall difference between the test group and the control group.

CONCLUSIONS

This study demonstrated that the new toothpaste was effective in reducing dentine hypersensitivity. More studies are needed to further determine the potential interaction between triclosan and potassium nitrate in dentifrices.

Effect of a 3% Potassium Oxalate Topical Application on Dentinal Hypersensitivity After Subgingival Scaling and Root Planing

BACKGROUND

The present study aimed to verify the effect of a single application of 3% potassium oxalate gel compared to a placebo gel immediately after subgingival scaling and root planing (SRP) on dentinal hypersensitivity (DH).

METHODS

Fifteen patients undergoing periodontal treatment volunteered for this randomized controlled clinical trial. They presented with periodontitis on homologous contralateral canines and premolars, with complaints of dentinal hypersensitivity before periodontal therapy. Immediately after SRP under local anesthesia, the test and placebo agents were randomly applied on the cemento-enamel junction. Evaluation of DH reduction after treatment was self-reported, with assessment made by the patient's indication of how painful each treated. tooth was on a visual analog scale (VAS) at baseline, and 7, 14, and 21 days post-treatment. The results were analyzed by DH percent reduction for each observational moment in relation to baseline, for test and control teeth separately. Mean percent reductions for each group were compared by paired sample t test, with an alpha level of 0.05.

RESULTS

On day 7, percent reduction for the test and control groups was 29.4% and 13.4%, respectively. On day 14 it was 64.6% and 20.5%, and on day 21 it was 81% and 34.7%, respectively. Significant differences between treatments were observed at 14 and 21 days.

CONCLUSION

It may be concluded that subgingival scaling and root planing followed by a single application of a 3% potassium oxalate gel resulted in a significantly higher reduction of dentinal hypersensitivity at 14 and 21 days, when compared to the placebo.

Lasers in endodontics

With the rapid development of laser technology, new lasers with a wide range of characteristics are now available and being used in various fields of dentistry. In the past two decades, much experience and knowledge has been gained. This article provides an overview of the current and possible future clinical applications of lasers in endodontics, including their use in alleviating dentinal hypersensitivity, modification of the dentin structure, pulp diagnosis, pulp capping and pulpotomy, cleaning and shaping of the root canal system, and endodontic surgery. Endodontic procedures for which conventional treatments cannot provide comparable results or are less effective are emphasized.

Evaluation of the efficacy of two potassium nitrate bioadhesive gels (5% and 10%) in the treatment of dentine hypersensitivity. A randomised clinical trial

AIM

A randomised clinical trial was designed to compare the immediate efficacy (48-96 h) of two treatments with bioadhesive gels with different concentrations of potassium nitrate (NK 5% versus NK 10%) on dentine hypersensitivity (DH). We evaluated DH by means of the use of the evaporative stimulus (ES), as the main outcome, using a placebo control group as reference.

PATIENTS AND METHODS

Forty-five consecutive patients who, after stimulation with a blast of air, had at least one tooth with DH > or = 2 according to the verbal ratings scale (VRS) scale were selected. They were randomly treated with a bioadhesive gel with 5% NK, 10% NK or a placebo gel without NK. The DH was evaluated at baseline, days 2, 4, 7 and 14 by an examiner blind to the procedure. The response to the ES with a blast of air, to the tactile stimulation with a probe and the subjective evaluation of the patient measured on the VRS scale were recorded. Statistical analysis was made using the Kruskal-Wallis test.

RESULTS

A greater reduction of DH after ES was observed after 48 h of treatment in the NK10% group (35.8%) compared to the NK5% group and placebo group (11.8% and 13.4%, respectively). This difference increased significantly at 96 h (p=0.003). No significant differences were observed for the other variables. These preliminary results may support the usefulness of an NK 10% gel to reduce the DH after stimulation with a blast of air during the first 4 days of its appearance.

Efficacy of a 3% potassium nitrate desensitizing mouthwash in the treatment of dentinal hypersensitivity

BACKGROUND

Potassium nitrate has been used previously in a dentifrice or gel to alleviate dentinal hypersensitivity. The aim of this study was to compare a 3% potassium nitrate/0.2% sodium fluoride mouthwash with a 0.2% sodium fluoride control mouthwash in a 6-week double-blind study.

METHODS

Fifty subjects were evaluated using 2 tactile methods and cold air sensitivity (dental air syringe), along with subjective perception of pain (0 to 10 scale) at baseline and at 2 and 6 weeks.

RESULTS

There was a general decrease in dentinal hypersensitivity levels in both groups over the 6-week study period as demonstrated by all 4 methods of assessment. There was also a statistically significant difference in decrease in sensitivity between the groups.

CONCLUSIONS

This study showed that a 3% potassium nitrate/0.2% sodium fluoride mouthwash appears to have therapeutic potential to alleviate dentinal hypersensitivity.

Potentiometric determination of nitrate in products used for the treatment of dentinal hypersensitivity

In this paper, a rapid, simple and inexpensive potentiometric method for the determination of the potassium nitrate contained in different dentinal desensitizer products is described. The nitrate-selective electrode, using a tetraoctylammonium salt as sensor, was constructed without an internal filling solution. The ionic strength of the sample solutions was fixed by means of a 0.33 mol 1(-1) K2SO4 solution and direct potentiometry was used as the analytical technique of measurement. Precision and accuracy of the method developed were adequate since the mean of the relative standard deviations was 1.2% and the average percentage of spike recoveries was 100.9%. Eleven samples of toothpastes, gels and mouthwashes were analyzed by the proposed potentiometric method and the quality of the results was compared by means of linear regression analysis with those obtained by high-performance liquid chromatography (HPLC), adopted as the reference technique. Satisfactory agreement was observed.

The effects of a potassium citrate, cetylpyridinium chloride, sodium fluoride mouthrinse on dentine hypersensitivity, plaque and gingivitis. A placebo-controlled study

Home-use studies on dentine hypersensitivity have most commonly involved toothpastes and rarely have mouthrinses been employed. Potassium and/or fluoride toothpastes have been shown effective in the treatment of dentine hypersensitivity. The aim of this study was to evaluate the effectiveness of a total formulation, containing potassium citrate, sodium fluoride, cetylpyridinium chloride mouthrinse compared to the base rinse minus actives in the reduction of dentine hypersensitivity. The study was a randomised placebo controlled, double blind parallel design. At a screening visit, 90 adult subjects were recruited who were suffering from dentine hypersensitivity from at least 1 tooth responding to tactile stimulation (45gm pressure) and had at least 2 teeth responding to evaporative stimulation (air blast). During a washout period of 28 days and throughout the 56-day study period, subjects used a soft filament toothbrush and standard fluoride toothpaste. At baseline (day 1), threshold sensitivities to incremental tactile (10 g to 70 g) and evaporative stimuli were determined. Gingival health was assessed by recording bleeding on probing at 25 g pressure at mesiobuccal and lingual sites. Plaque scores from buccal and lingual surfaces of disclosed teeth were also measured. Subjects then used the prescribed rinse, 10 ml for at least 30 s after brushing 2x per day returning on days 28 and 56 for rescoring of sensitivity, gingivitis and plaque. Data from 88 subjects were used with the intent to treat analyses and 83 in the completely evaluable analyses. Groups were well balanced for demographic data and product returns suggested good compliance. Both groups showed highly significant improvements in tooth sensitivity. The pattern was for greater improvement in the test compared to the control group (statistically significant for the plaque score), whereas bleeding scores, already low, showed no change in either group. By definition, the placebo rinse could not have exerted any therapeutic action; the study therefore provides clear direct evidence as to the magnitude (30%-40%) of the little studied, but assumed, placebo response in dentine hypersensitivity trials.

Dentine hypersensitivity and the placebo response. A comparison of the effect of strontium acetate, potassium nitrate and fluoride toothpastes

A considerable number of varied agents are apparently effective in the treatment of dentine hypersensitivity. In particular, the literature supports the efficacy of strontium, potassium and fluoride containing toothpastes. This study was a double-blind, randomised, parallel group comparison of three products, namely strontium- and potassium-based desensitising toothpastes both containing fluoride, and a conventional fluoride toothpaste. A total of 131 subjects entered a 4-week wash-in phase using the conventional fluoride toothpaste, of whom 120 entered a 6-week treatment phase. Sensitive teeth were evaluated at wash-in baseline, treatment baseline and after 2 and 6 weeks use of the treatment pastes. Dentine hypersensitivity was assessed with tactile and cold air stimuli together with an overall subjective assessment. Analysis of the findings was performed using non-parametric statistical methods. Of the original 120 subjects, 112 completed the trial. All 3 toothpaste groups showed reductions in sensitivity over the 6 weeks; however, no significant differences were found between the three products at any given time. Interestingly, there was no significant change in sensitivity between wash-in baseline and treatment baseline for the cold air stimulus with the fluoride-only-based paste. However, for the group using the same fluoride toothpaste, there was significant improvement between wash-in baseline and week 6, and treatment baseline and week 6 for this stimulus, suggesting a substantial placebo effect occurred. There is a need for further investigation of a wash-in period and examination of the placebo effect when evaluating dentine hypersensitivity trials.

The enigma of potassium ion in the management of dentine hypersensitivity: is nitric oxide the elusive second messenger?

We report the development of a 'second-messenger' model in an attempt to re-evaluate the role of K+ as a desensitising agent. Despite unequivocal validation of the effectiveness of potassium-based dentifrices in the management of dentine hypersensitivity, the mechanism(s) of action of K+ remains unclear. Although experimental paradigms of the Nernst equation demonstrate a direct inhibitory effect of K+ ion upon nerve conduction, in vivo considerable constraints can be argued to preclude this mechanism of action. Indeed, measurements of solution velocity within individual dentinal tubules obtained by scanning electrochemical microscopy indicate that outward movement of tubular fluid may represent a far greater barrier to the inward diffusion of K+ ions than previously estimated from measurements of hydraulic conductance across bulk dentine. Despite such probable limited penetration of dentine tubules, K+ ions may desensitise deeply-located nerve terminals through activation of a second-messenger transduction pathway that is capable of controlling the gain of K+-evoked effects which remain physically restricted to the more superficial aspects of the tubule. In addition to a direct effect upon transmembrane potential K+ can also indirectly attenuate neural activity through effects upon levels of the endogenously-synthesised free radical, nitric oxide (NO). Stimulation of the release of NO by K+ has been observed using a variety of cell preparations, which include endothelium, smooth muscle, adrenal medulla, hypothalamus and cerebellum. Importantly, a growing number of studies now report that an increase in the production of NO is associated with analgesia through a modulation of nociceptive input and a downregulation of sensitised nociceptors, most likely achieved through an increase in intraneural content of cGMP. The clinical role of a K+-evoked liberation of NO as a principal mechanism in the management of dentine hypersensitivity is supported by recent findings which include: (1) the localisation of NADPH-diaphorase activity and inducible nitric oxide synthase (iNOS) immunoreactivity within odontoblasts, their processes in dentine, and the subodontoblast layer of the pulp; (2) iNOS causes a sustained release of large (nanomolar) amounts of NO; (3) NO is freely diffusible and capable of displaying remarkably potent effector actions at distant target cells; (4) the actions of NO may be enhanced by endogenous carrier molecules such as S-nitrosothiols; (5) the synthesis of NO can be evoked by concentrations of K+ ion far less (i.e. <1 mM) than those required for direct inhibitory effects upon neural activity.

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.

A mathematical model of potassium ion diffusion in dentinal tubules

Desensitizing agents containing potassium ions (K+) are believed to inactivate intradental nerves by raising extracellular [K+]. A mathematical model was used to investigate factors affecting [K+] in dentinal tubules. The most important factors affecting the steady-state tubular [K+] were the tubular fluid-flow velocity, salivary [K+] and the permeability to potassium (k) of the barrier between the tubule and the pulp. Tubular [K+] decreased with increasing outward flow velocity and increasing k. whereas the dimensions of the tubule and odontoblast process had little effect. Following a 1 min simulated application of 500 mmol/1 K+ to the dentine surface, [K+] at the inner end of the tubule increased above steady-state levels for 20-30 min. The maximum [K+] attained at the inner end of the tubule was around 30 mmol/l for an impermeable barrier (k = 0) and flow velocity of 1.4 microns/s, but lower maximum tubular [K+] were achieved when either the outward flow velocity or k was increased. The model suggests that applying potassium-containing preparations to dentine may increase [K+] at the inner ends of dentinal tubules to levels sufficient to inactivate intradental nerves. However, the localized increase in [K+] is transient, and the concentration change will be lessened by conditions that increase the tubular fluid-flow velocity or the permeability of the barrier between the tubule and pulp.

Assessing the efficacy of three dentifrices in the treatment of dentinal hypersensitivity

A multicenter clinical trial conducted by the authors compared the desensitizing efficacy of a new 5 percent potassium nitrate: 0.243 percent sodium fluoride dentifrice along with two clinically proven, commercially available desensitizing dentifrices to a placebo dentifrice. Sensitivity to cold air and tactile stimulation, along with patients' subjective assessments, were evaluated to assess the dentinal desensitizing efficacy of the test dentifrices. Results demonstrated that after four weeks, participants who used the new dentifrice formulation experienced significant decreases in dentinal sensitivity compared to the placebo group for all measured indexes.

Effects of potassium ions on action potential conduction in A- and C-fibers of rat spinal nerves

Potassium ions in dentifrices for treating 'hypersensitive' dentin are believed to act directly on intradental nerves by raising extracellular potassium ion concentration ([K+]o) sufficiently to prevent action potential generation by axonal accommodation. However, the [K+]o necessary to block nerve conduction is not precisely known, nor is it certain that K+ can diffuse from a dentifrice in sufficient amounts to inactivate intradental nerves. To establish more accurately the [K+]o required to block nerve conduction under controlled conditions, we studied the effects of increased [K+]o on the sizes of compound action potentials (CAP) recorded from rat spinal nerves in vitro. [K+]o was increased by the addition of either KCl or KNO3 to Krebs' solutions applied to the central portion of the nerves. CAP attenuation increased in a dose-dependent manner as [K+]o was raised in the 8 to 64 mmol/L range, and complete block was generally produced with solutions containing at least 32 mmol/L K+. CAP attenuation was reversible, and recovery times increased with increasing [K+]o. The effects of KCl and KNO3 solutions were the same for all [K+]o tested. Half-maximal (50%) reduction in the A beta-fiber component of the CAP occurred with 17.4 mmol/L K+, and with 17.8 mmol/L and 19.3 mmol/L K+, respectively, for the A delta- and C-fiber components. Control experiments with glucose and choline chloride confirmed that the conduction block observed with increased [K+]o was not due to increased solution osmolarity or ionic strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical evaluation of a potassium nitrate dentifrice for the treatment of dentinal hypersensitivity

The effectiveness of a 5% potassium nitrate dentifrice as a daily home treatment for dentinal hypersensitivity was evaluated in a double-blind study in 36 Japanese subjects who complained of cold and/or tactile hypersensitivity. The subjects were divided into 2 groups, with 18 being given a 5% potassium nitrate dentifrice (treated group) and the other 18 a vehicle paste (control group). Both groups were instructed to brush their teeth 2 x a day. The hypersensitivity levels of the affected teeth were assessed by 2 stimuli, one tactile and the other cold air, and by the perception of pain. The results of all 3 assessment methods indicated that the potassium nitrate dentifrice significantly decreased the level of hypersensitivity at weeks 4, 8, and 12. In the treated group, a rapid decrease of positive scores for both the cold air stimulus and the subjective symptoms appeared from week 2. Although a significant decrease of the assessment score was also observed in the control group, the reduction rate of the score was much greater in the treated group by all 3 assessment methods at weeks 4, 8, and 12. Complete relief of subjective symptoms throughout the 12 weeks' examination was noted in 67% of the subjects in the treated group, but in only 6% in the control group. These results suggest the usefulness of a 5% potassium nitrate dentifrice in Japanese patients with dentinal hypersensitivity.

Measurement of tooth hypersensitivity and oral factors involved in its development

The various methods of measurement of dentinal hypersensitivity are based upon the types of stimuli used to elicit a pain response in teeth, which include thermal, tactile, evaporative, electrical and osmotic. Pulpal inflammation in its early stages reduce the threshold of pain response to these stimuli but electrical stimulation may make it possible to assess the possible contribution of such inflammation to sensitivity determinations. Although the magnitude of each stimulus is quantifiable, patient response is subjective, which necessarily makes measurements of dentinal sensitivity semisubjective. Various methods of testing dentinal sensitivity are discussed, along with their advantages and disadvantages. The teeth most suited for measurement in clinical studies are the canines and premolars. This is because approx. 80% of the sensitivity lesions are associated with these teeth, which have similar thicknesses of root dentine. Data from several studies involving the same subjects indicate that individual measurements readily return to baseline and that the commonly seen placebo effect is probably due to some as yet unidentified factor in desensitizing formulations. Possible roles of salivary and plaque environmental factors in the development of dentinal sensitivity are discussed, as well as methods for their measurement.

Self-applied treatments in the management of dentine hypersensitivity

A summary of the research on the different self-applied treatments for hypersensitive dentine provides some support for several agents but invalidates others. This is true for toothpastes, mouthwashes and gels. Direct comparison of studies is difficult because the materials and methods used are different. In addition, the size of patient groups, and methods of stimulation and assessment of the evoked pain reaction are different. Therefore our concept of the efficacy of self-applied treatment is not so much based on a homogeneous pool of data, but rather on a collection of individual studies. If we subtract from these data sets those based on obviously older ways of evaluating efficacy, we are left with surprisingly few studies that properly assess the efficacy of compounds suited to self-applied treatment. Therefore, guidelines should be established for testing such compounds, and publication of the data sets should depend on proper use of such designs. Stimuli, design and pain assessment should be standardized. In addition, patient recruitment could be defined better in relation to criteria for inclusion. Another area of concern is the pretreatment history of the hypersensitive teeth, because some teeth will become hypersensitive during the observation period, whilst others, which were hypersensitive, will spontaneously become insensitive. Therefore one should know the rate of spontaneous change in tooth sensitivity levels in each patient, in order not to assign treatment effects to teeth that would have lost their sensitivity anyway.

Potassium nitrate-zinc oxide eugenol temporary cement for provisional crowns to diminish postpreparation tooth pain

Pulpal injury commonly occurs with tooth preparation for complete fixed partial dentures. This can be documented by the substantial incidence of pain after tooth preparation. In this study, a 4% potassium nitrate-zinc oxide eugenol temporary cement was used to secure provisional crowns over recently prepared teeth and it significantly reduced the incidence and severity of pain after tooth preparation and impression taking.

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.