Hypersensitive teeth. Part II: Treatment

Efficacy of a novel dentifrice containing bioactive glass-ceramic for dentinal hypersensitivity: A double-blind randomized controlled trial in Chinese adults

OBJECTIVE

To assess the efficacy and safety of a toothpaste containing 7.5 % HX-BGC in combating dentinal hypersensitivity.

METHODS

A single-center, randomized, double-blind, three-group parallel-controlled design was employed, with Schiff Index and Yeaple Index as measurement indicators. The study evaluated the effectiveness of HX-BGC toothpaste, NovaMin toothpaste, and a negative control toothpaste without desensitizing agents. Eligible subjects underwent baseline examination after a 2-week washout period, and those meeting inclusion criteria and not meeting exclusion criteria entered the study. Participants were randomly assigned to use one of the three toothpastes. Follow-up examinations were conducted immediately after a single use and at 2, 4, and 6 weeks. Intra-group and inter-group comparisons were made for Schiff and Yeaple indices. Safety of the experimental toothpastes was assessed through participant feedbacks and oral soft tissue examinations.

RESULTS

Subjects in the three groups were balanced in terms of age and gender distribution, with no baseline differences in indicators. Immediately after a single application of toothpaste, Yeaple indices increased, and Schiff indices decreased, with no significant differences among the groups. After 2 weeks of continuous use, Yeaple indices increased in all groups, with significant differences observed between the HX-BGC group and the other two groups. Schiff indices decreased in all groups, with the NovaMin group showing significant differences compared to the negative control group. At weeks 4 and 6, both indices in the HX-BGC group and the NovaMin group were significantly better than those in the negative control group, with the HX-BGC group outperforming the NovaMin group in the Yeaple index. No serious adverse reactions related to the study products were observed or reported by any participants.

CLINICAL SIGNIFICANCE

This clinical trial confirmed the efficacy of HX-BGC in anti-dentinal hypersensitivity and supported the clinical application of the dentifrice containing HX-BGC.

CONCLUSION

Compared to the negative control group, both HX-BGC and NovaMin toothpaste groups demonstrated more significant effects in combating dentinal hypersensitivity. No adverse reactions related to the experimental toothpastes were observed.

Study on Occluding Dentinal Tubules with a Nanosilver-Loaded Silica System In Vitro

The effects of most clinical treatments for dentin hypersensitivity are not long-lasting. To overcome the defects, the mesoporous silica nanoparticles and silver nanoparticles entered the field of oral materials. This study aimed to synthesize a novel, low-cytotoxic dentin desensitizer and investigate its occlusion effects on dentinal tubules. The biphasic stratification approach, a chemical reduction method, and the Stöber method were used to synthesize silver nanoparticle-loaded and nonporous silica-encapsulated mesoporous silica (Ag-MSNs@nSiO₂), which was a noncrystalline structure with an average size of approximately 128 nm and a silver content of 3.506%. Atomic absorption spectrometry and the 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide cell viability assay showed that Ag-MSNs@nSiO₂ slowly released silver ions and had nearly no cytotoxicity. An electron microscope was used to observe the blocking effects on the dentinal tubules of sensitive tooth disc models, which were randomly divided into the following four groups: a deionized water group, a 5.9 M silver nitrate solution group, an Ag-MSNs@nSiO₂ group, and a Gluma desensitizer group. There were no significant differences in the relative area of open dentinal tubules between the Ag-MSNs@nSiO₂ group and the Gluma desensitizer group (P > 0.05). Detection of protein structures showed that multilevel structures of bovine serum albumin in dentin tubules were significantly changed by silver ions from Ag-MSNs@nSiO₂. These results suggest that nearly noncytotoxic Ag-MSNs@nSiO₂ was successfully synthesized by a series of methods. Ag-MSNs@nSiO₂ occluded dentin tubules immediately and effectively. Moreover, the blockage effects may be enhanced and maintained by continuous condensation of proteins in dentinal tubules.

Effect of two desensitizing agents on dentin hypersensitivity: A randomized split-mouth clinical trial

Background:

Clinical research is important to evaluate the effect of desensitizing agents.

Aims:

This randomized clinical trial evaluated the immediate and 1 week desensitizing effect of two desensitizing agents Uno Topical Gel and Profluorid.

Materials and Methods:

Thirtyfive patients with teeth presenting with dentin hypersensitivity were included in this clinical trial. Each quadrant in a patient was randomly assigned to one of two groups: Uno Topical Gel or Profluorid Varnish. A VAS score was used to assess tooth sensitivity at baseline, immediately after application of desensitizer and after 1 week. Additionally, 30 dentin discs were prepared, divided into Group 1(Control Group), Group 2 (Profluorid Varnish) and Group 3 (Uno Topical Gel) and examined using scanning electron microscopy (SEM) after 1hour and 24 hours to evaluate tubule occlusion.

Statistical Analysis:

Clinical data were analysed using Friedman's test and Mann – Whitney U test. SEM data was analysed using Student's 2-sample t-test.

Results:

Uno group was significantly better to evaporative stimuli immediately (P=0.01) after application. After 1 week, Uno group was significantly better to tactile (P=0.000) and evaporative (P=0.000) stimuli than Profluorid. SEM images showed that 1 hour after application, Uno and Profluorid demonstrated more than 90% and 80% dentin tubule occlusion respectively. At 24 hours, Uno and Profluorid demonstrated more than 50% and 60% dentin tubule occlusion respectively.

Conclusions:

Uno Topical Gel was significantly better than Profluorid in reducing pain of dentin hypersensitivity due to tactile and evaporative stimuli after 1 week.

Comparison of efficacy of three different desensitizing agents for in-office relief of dentin hypersensitivity: A 4 weeks clinical study

Aim:

To evaluate the effectiveness of three different pastes containing 5% NovaMin, 8% arginine, and 15% hydroxyapatite nanoparticles (n-HA) respectively in the treatment of dentin hypersensitivity (DH).

Materials and Methods:

A 4 weeks study was conducted on 45 adult patients with cervical abrasions leading to hypersensitivity of two or more teeth anterior to molars. Patients were divided into three toothpaste groups. Group I: 5% NovaMin, Group II: 8% arginine, Group III: 15% n-HA. Sensitivity was assessed at baseline, immediately after application and after 1-week and 4 weeks. Tactile stimuli response using a visual analog scale and standard cold air blast using Schiff cold air sensitivity scale were used to compare the efficacies of toothpastes after a single application.

Statistical Analysis:

Two-way analysis of variance and post-hoc Tukey test were used and P ≤ 0.05 was considered statistically significant.

Results:

Visual analog scale analysis: Group III and Group II showed statistically significant reduction in DH at all-time intervals when compared with Group I. In SCA analysis there is no statistically significant difference between Group II and Group III immediately after application.

Conclusion:

Toothpaste containing 15% n-HA was found to be most effective in reduction of DH after a single application up to a period of 4 weeks followed by 8% arginine and 5% NovaMin toothpastes.

Effect of propolis gel on the in vitro reduction of dentin permeability

Objective

The aim of this study was to evaluate the capacity of potassium oxalate, fluoride gel and two kinds of propolis gel to reduce the hydraulic conductance of dentin, in vitro.

Material and Methods

The methodology used for the measurement of hydraulic conductance of dentin in the present study was based on a model proposed in literature. Thirty-six 1-mm-thick dentin discs, obtained from extracted human third molars were divided into 4 groups (n=9). The groups corresponded to the following experimental materials: GI-10% propolis gel, pH 4.1; GII-30% propolis gel; GIII-3% potassium oxalate gel, pH 4,1; and GIV-1.23% fluoride gel, pH 4.1, applied to the dentin under the following surface conditions: after 37% phosphoric acid and before 6% citric acid application. The occluding capacity of the dentin tubules was evaluated using scanning electron microscopy (SEM) at ×500, ×1,000 and ×2,000 magnifications. Data were analyzed statistically by two-way ANOVA and Tukey's test at 5% significance level.

Results

Groups I, II, III, IV did not differ significantly from the others in any conditions by reducing in hydraulic conductance. The active agents reduced dentin permeability; however they produced the smallest reduction in hydraulic conductance when compared to the presence of smear layer (P<0.05). The effectiveness in reducing dentin permeability did not differ significantly from 10% or 30% propolis gels. SEM micrographs revealed that dentin tubules were partially occluded after treatment with propolis.

Conclusions

Under the conditions of this study, the application of 10% and 30% propolis gels did not seem to reduce the hydraulic conductance of dentin in vitro, but it showed capacity of partially obliterating the dentin tubules. Propolis is used in the treatment of different oral problems without causing significant great collateral effects, and can be a good option in the treatment of patients with dentin sensitivity.

New techniques for drug delivery to the posterior eye segment

Ocular drug delivery has become an increasingly important field of research especially when treating posterior segment diseases of the eye, such as age-related macular degeneration, diabetic retinopathy, posterior uveitis and retinitis. These diseases are the leading causes of vision loss in developed countries which require repeated long-term administration of therapeutic agents. New drugs for the medication of the posterior ocular segment have emerged, but most drugs are delivered by repeated intravitreal injections associated with ocular complications. Advances in ocular drug delivery system research are expected to provide new tools for the treatment of the posterior segment diseases, providing improved drug penetration, prolonged action, higher efficacy, improved safety and less invasive administration, resulting in higher patient compliance. This review provides an insight into the recent progress and trends in ocular drug delivery systems for treating posterior eye segment diseases, with an emphasis on transscleral iontophoresis.

In vitro and in vivo evaluation of carboplatin delivery to the eye using hydrogel-iontophoresis

PURPOSE

To investigate in vitro and in vivo hydrogel-iontophoresis delivery of carboplatin to the eye.

METHODS

Iontophoresis was applied on agar gels resembling the eye using different current intensities and durations. Transscleral iontophoresis was performed on healthy rabbits, applying 0, 1, and 3 mA current for 10 min.

RESULTS

Similar drug concentrations were obtained in all experimental groups, in in vitro and in vivo studies, regardless of the iontophoretic current applied. A 20-mm penetration depth was found for carboplatin at the agar model. High drug levels were found at the sclera and retina, while lower levels were found at ocular fluids.

CONCLUSION

Carboplatin-iontophoretic application at the above conditions does not have an obvious advantage over passive penetration due to high diffusion properties and insufficient molecular charge. Passive carboplatin diffusion from loaded hydrogels inserted in the lower cul-de-sac should be further investigated as a potential clinical treatment for intraocular retinoblastoma.

Methotrexate delivery to the eye using transscleral hydrogel iontophoresis

PURPOSE

To evaluate methotrexate penetration and distribution profile in ocular structures after short low current transscleral hydrogel iontophoresis.

METHODS

Methotrexate iontophoresis was studied in rabbits using drug-loaded hydrogels mounted on a portable iontophoretic device. Drug distribution profile was evaluated 2, 4, and 8 hours after iontophoretic treatment of 1.6 mA/cm2 for 4 min. Ocular drug levels were also determined two hours after iontophoretic treatment of 5 mA/cm2, compared to mock iontophoresis and intravitreal injection of methotrexate.

RESULTS

Therapeutic drug levels were maintained for at least 8 h at the sclera and retina and for 2 h at the aqueous humor following the iontophoretic treatment. After increasing the current density, a twice-higher concentration was achieved at the vitreous and 8 to 20 time higher concentrations at the retina and sclera.

CONCLUSIONS

A short low current non-invasive iontophoretic treatment using methotrexate-loaded hydrogels has a potential clinical value in treating ocular inflammatory diseases and intraocular lymphoma.

Clinical evaluation of dentin hypersensitivity treatment with the low intensity Gallium-Aluminum-Arsenide laser - AsGaAl

The dentin hypersensitivity is a painful condition rather prevalent in the general population. There are several ways of treatment for such condition, including the low intensity lasers. The proposal of this study was to verify the effectiveness of the Gallium-Aluminum-Arsenide diode laser in the treatment of this painful condition, using a placebo as control. MATERIALS AND METHODS: Thirty-two patients were selected, 22 females and 10 males, with ages ranging from 20 to 52 years old. The 32 patients were randomly distributed into two groups, treated and control; the sample consisted of 68 teeth, 35 in the treated group and 33 in the control group. The treated group was exposed to six laser applications with intervals from 48 to 72 hours, and the control group received, as placebo, applications of a curing light. RESULTS: A significant reduction was observed in the pain condition between the initial phase and after six laser applications; however, such reduction could also be observed for the control group exposed to the placebo. CONCLUSION: Therapy with the low intensity Gallium-Aluminum-Arsenide laser - AsGaAl induces a statistically significant reduction in the painful condition after each application and between the beginning and end of treatment, although there was no statistically significant difference between the treated group (laser) and the control group (placebo) at the end of treatment and after the mediate evaluation results (after 6 weeks), this way impairing the real measurement of laser effectiveness and placebo effect.

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.

Dentin hypersensitivity. Occlusion of dentinal tubules by brushing with and without an abrasive dentifrice

Daily toothbrushing with and without an abrasive dentifrice was performed on the ground surfaces of human cervical dentin attached to resin plates, which had been exposed to the oral cavities of 4 subjects for 8 weeks. Brushing with a dentifrice containing calcium hydrogen phosphate as an abrasive caused most of the dentinal tubules to open. The patency of dentinal tubules is thought to induce dentin hypersensitivity. Brushing without a dentifrice, on the other hand, resulted in occlusion of the dentinal tubules with organic pellicle-containing minerals. Furthermore, abrasion did not occur; however, no bacterial plaque or dental calculus were retained. The occluded tubules which were distributed over the entire dentin surfaces will likely prevent hypersensitivity. Such organic-mineral materials occluding the tubules can be derived from saliva and embedded by the brushing. We suggest that use of a non-abrasive dentifrice will prevent or reduce dentin hypersensitivity in the cervical regions.

Bond strength of resin to dentin treated with calcium phosphate desensitizer

In a previous study we proposed a new method utilizing immediate precipitation of calcium phosphate (CaP) in situ for treatment of dentin hypersensitivity. Sequential application of 5% disodium phosphate followed by 10% calcium chloride on patent dentin surface resulted in instant occlusion of dentin tubules and immediate relief from the hypersensitivity. To guarantee long-lasting effectiveness of the CaP treatment, resin coverage of the treated dentin surface will be the next practical approach. However, the CaP covering the surface may possibly affect bonding of resins. This study determined the effect of the CaP treatment on tensile bond strength of adhesive resins to dentin. Independent of the type of resin used, a bond strength of 4-5 MPa was obtained; cohesive failure occurred within the resin-CaP hybridized composite layer rather than at the dentin surface. The CaP treatment produced a significant increase in the bond strength of one resin.

An evaluation of smear layer with various desensitizing agents after tooth preparation

According to hydrodynamics, any agent blocking the dentinal tubules reduces the flow of fluids and diminishes hypersensitivity. The properties of the desensitizing agents that sponsor tubular occlusion and the barrier efficiency resulting from the interaction of the smear layer with test materials were examined with the scanning electron microscope and energy-dispersive x-ray microanalysis. Selected dentinal desensitizing was accomplished with burnishing procedures, cavity varnish, calcium hydroxide, and topical fluoride. Subjective evaluations were also recorded clinically after tooth preparation. This investigation indicated that the smear layer did not protect against zinc phosphate cement, and that cavity varnish prevented the formation of the smear plugs. The smear layer and plugs were basically composed of calcium and phosphorus, the major ingredients of dentin.

Managing dentin hypersensitivity: what treatment to recommend to patients

Dentin hypersensitivity affects nearly 40 million Americans at one time or another. The authors outline its causes and describe treatment agents and procedures.

Sensitivity restored of Class V abrasion/erosion lesions

The effectiveness of restorative treatment in reducing sensitivity associated with the Class V erosion/abrasion lesion was evaluated and the efficacy of three tooth-colored restorative materials in reducing sensitivity was compared. The 108 lesions were restored with either glass ionomer restorative material, composite resin with a dentin bonding agent, or composite resin with a dentin bonding agent and a glass ionomer liner. Composite resin with glass-ionomer liner restorations significantly reduced sensitivity to air and hot and cold water. Glass ionomer restorations and restorations with composite resin and a dentin bonding agent significantly reduced sensitivity but were also associated with increased sensitivity to air and cold respectively in 20% to 30% of the lesions restored when evaluated at 6 months.