Effects of desensitizing agents on dentinal tubule occlusion

The Synergistic Effect of Ozonated Oil and Desensitising Toothpaste on Dentinal Tubule Occlusion: An In Vitro Study

Introduction Dentin hypersensitivity (DH) is the most common problem encountered by clinicians. It can be managed either by blocking neural activities or by occluding tubules. Ozonated oil facilitates the simple passage of desensitizing agents into dentinal tubules. Aim This study aimed to evaluate the effect of ozonated oil on dentinal tubule occlusion before and after the application of desensitizing toothpaste. Materials and methods The study was carried out in Kalinga Institute of Dental Sciences, KIIT (Deemed to be University), Bhubaneswar, India. The sample size of the study was 80. The first group contained specimens for control. The second group comprised specimens treated with ozonated oil. The third group comprised specimens being treated with a desensitizing agent. The fourth group contained specimens treated with both the desensitizing agent and ozonated oil. The specimens then received an acid challenge. The specimens were observed under a scanning electron microscope (SEM) before any therapy, after the application of the therapeutic agents and after the 37.5% ortho-phosphoric acid challenge. Results Inferential statistics to compare between the groups was calculated using one-way analysis of variance (ANOVA) statistics. Post-hoc Tukey's honestly significant difference (HSD) was performed to compare the groups. The mean scores of the partial tubular occlusion of Group 1, Group 2, Group 3 and Group 4 before the acid challenge were 0.035, 0.691, 0.564 and 0.368, respectively. The maximum score was obtained in the case of Group 2, which was statistically significant. The mean scores for partial tubule occlusion after the acid challenge for Group 1, Group 2, Group 3 and Group 4 were 0.055, 0.531, 0.733 and 0.142, respectively. There was evidence of maximum partial tubule occlusion after the acid treatment in the case of Group 3. The mean scores of Group 1, Group 2, Group 3 and Group 4 before the acid challenge were 0.019, 0.309, 0.442 and 0.609, respectively. The maximum score was obtained in the case of Group 4, implying a greater number of total tubular occlusions before the acid challenge. The mean scores of the total tubular occlusions after the acid challenge for Group 1, Group 2, Group 3 and Group 4 were 0.047, 0.465, 0.272 and 0.890, respectively. There was evidence of maximum tubule occlusion in the case of Group 4, which was statistically significant. Conclusion Overall, the application of a desensitizing toothpaste with ozonated oil holds promise as a potentially more effective treatment approach for DH. Further research and clinical studies may be needed to fully validate its efficacy and safety in dental practice.

Glutaraldehyde-based desensitizer does not influence postoperative sensitivity and clinical performance of posterior restorations: A 24-month randomized clinical trial

OBJECTIVES

To evaluate the influence of a glutaraldehyde-based desensitizer (GL) on postoperative sensitivity (POS) in posterior bulk-fill resin composite restorations using an adhesive applied in the self-etch (SE) and etch-and-rinse (ER) strategies; and to assess the clinical performance of the restorations.

METHODS

Posterior resin composite restorations (n = 228) at least 3 mm deep were inserted in 57 subjects using a split-mouth design. The adhesive was applied with/without prior application of a GL. A resin composite was used for all restorations. Spontaneous POS (risk and intensity), as well as POS caused by stimulation with an air blast and assess the response to horizontal and vertical percussion was assessed using two scales in the baseline and after 7, 14, and 30 days. In addition, some parameters were evaluated using FDI criteria up to 24 months of clinical service.

RESULTS

No significant POS was observed (p > 0.05). A higher absolute risk and intensity of spontaneous POS was observed within 7 days (35.1%), without statistically significant differences among groups. At 24 months 5 restorations were considered clinically unsatisfactory, and 73 restorations showed minor discrepancies in adaptation, with no significant differences between groups (p > 0.05).

SIGNIFICANCE

A GL agent does not influence POS in posterior restorations with bulk-fill resin composite. It may be considered a dispensable clinical step in the restorative protocol.

A novel treatment based on powder jet deposition technique for dentin hypersensitivity: a randomized controlled trial

BACKGROUND

This study aimed to evaluate the efficacy and safety of dentin hypersensitivity (DH) treatment using a newly developed device based on a powder jet deposition (PJD) technique that creates a hydroxyapatite (HAP) layer on the dentin surface, thereby alleviating the hypersensitivity. The effect of the PJD treatment was compared with that of conventional treatment using Teethmate Desensitizer (TMD; calcium-phosphate containing material with TTCP (Ca4(PO4)2O) and DCPA (CaHPO4)), which has been used clinically in Japan with well-confirmed effectiveness.

MATERIALS AND METHODS

A randomized controlled trial was conducted including 35 patients who had symptoms of DH in two or more quadrants. Two test teeth were selected per patient (70 teeth in total) and randomly assigned to PJD or TMD treatment. The efficacy was evaluated using the improvement rate for air and scratch pain according to the scores obtained via visual analog scale 12 weeks after treatment. The safety assessment was performed focusing on gingival index (GI) and spontaneous pain. The t-test was used to analyze the non-inferiority of PJD treatment compared to TMD treatment.

RESULTS

The improvement rate of air pain was 69.0% for PJD and 69.7% for TMD. The improvement rate of scratch pain was 80.8% for PJD and 81.7% for TMD. Non-inferiority with a margin of 10% was not observed for both air and scratch pain. No change was observed in GI from baseline and the improvement rate of spontaneous pain for PJD was higher than that for TMD.

CONCLUSION

Non-inferiority of PJD to TMD treatment was not observed in this study; however, it was not statistically demonstrated, and the results were thus interpreted as inconclusive. PJD did improve the DH symptoms, as did TMD. PJD's therapeutic effect was most likely attributable to the deposition of a HAP layer on the tooth surface, which would alleviate hypersensitivity for at least 12 weeks without causing severe adverse events.

TRIAL REGISTRATION

UMIN-CTR. ID: UMIN000025022. date: 02/12/2016.

Glutaraldehyde-based desensitizers' influence on bonding performances and dentin enzymatic activity of universal adhesives

OBJECTIVES

To evaluate the influence of two glutaraldehyde-based desensitizers (L: GLUMA Desensitizer, Heraeus Kulzer and G: GLUMA Desensitizer PowerGel) prior to the adhesive procedures on microtensile bond strength (µTBS) to dentin and endogenous enzymatic activity.

METHODS

Noncarious human third molars (N = 48) were cut to expose middle coronal dentin. Six experimental groups were formed according to the dentin pre-treatment (L or G) and the universal adhesives (IBU - iBond universal, Kulzer or AU - Adhese Universal, Ivoclar Vivadent) used in the self-etch mode (n = 8): 1) L/IBU; 2) G/IBU; 3) IBU; 4) L/AU; 5) G/AU; 6) AU. Specimens were cut into sticks and stressed until failure after 24 h (T0) or 1 yr of aging (T12). Additional 4 teeth were used for in situ zymography evaluation and data were statistically analyzed (α = 0.05).

RESULTS

Dentin pre-treatment, adhesive and aging statistically influenced bond strength and enzymatic activity (P<0.001). AU demonstrated higher bond strength values than IBU (P<0.001). The L resulted in higher bond strength compared to the G and control groups (P<0.001). aging statistically influenced bonding performance, especially when no dentin pre-treatment was performed (P<0.001). In situ zymography revealed that at baseline the control groups exhibited lower interfacial fluorescence compared to the experimental groups, irrespective of the adhesive used (P<0,001). However, after 1 yr of artificial storage, no differences were found among the groups (P>0.05).

CONCLUSIONS

Glutharldeadeyde-based products increased bond strength and determined a stabilization of the adhesive interface over time apparently not related to the MMPs inhibition.

CLINICAL SIGNIFICANCE

The results of this in vitro study suggest that the application of glutaraldehyde-based desensitizers prior to the adhesive procedures when associated with universal adhesives could result in increased bond strength and stabilization of the adhesive interface over time.

Development of a new universal adhesive containing CPNE7-derived peptide and its potential role in reducing postoperative sensitivity

Post-operative sensitivity (POS) is the most common clinical dental complaint after tooth preparation and resin-based composite restoration. In our previous study, copine 7 (CPNE7) and CPNE7-derived peptide (CPNE7-DP) induced in vitro odontoblast differentiation and in vivo dentin formation. Here, we incorporated CPNE7-DP into All-Bond Universal (ABU) adhesive, developing ABU/CPNE7-DP. This study aimed to investigate the possibility of reducing POS using ABU/CPNE7-DP. We first determined the stability of CPNE7-DP under low pH. Furthermore, we evaluated its dentinal tubule penetration, in vitro odontogenic differentiation potential, in vivo tertiary dentin formation and its effects on bonding performance. CPNE7-DP was stable at pH 1.2, even lower than ABU's pH of 3.2. ABU/CPNE7-DP can penetrate dentinal tubules, stimulate odontoblast differentiation in vitro and generate tertiary dentin with tubular structure in vivo without interfering with bonding performance. Therefore, ABU/CPNE7-DP may serve as a novel bioactive adhesive for reducing POS.

The Effect of Dentine Desensitizing Agents on the Retention of Cemented Fixed Dental Prostheses: A Systematic Review

Background and Objectives: The use of desensitizing agents (DA) after tooth preparation to prevent hypersensitivity is well documented in the literature. A fixed dental prosthesis (FDP) should have good retention to be successful. Inadequate retention may result in microleakage, secondary caries, and, eventually, dislodgement of the FDP. The effect of DAs on the retention of FDPs has been widely studied in the literature, but the results are conflicting. Thus, this study aimed to conduct a systematic review to assess the effect of dentine desensitizing agents, used to prevent post-cementation hypersensitivity, on the retention of cemented FDPs. The null hypothesis framed was that there is no effect of dentine desensitizing agents on the retention of cemented FDPs. The focused PICO question was as follows: “Does the application of dentine desensitizing agents (I) affect the retention (O) of cemented fixed dental prosthesis (P) when compared to non-dentine desensitizing groups (C)”? Materials and Methods: Four electronic databases were systematically searched and, on the basis of the predefined inclusion and exclusion criteria, 23 articles were included in this systematic review. A modified CONSORT scale for in vitro studies was used to assess the quality of the selected studies, as all included studies were in vitro studies. Results: Most of the studies compared the effect of more than one type of DA on retention. The results of the selected studies varied due to differences in the composition of tested dentine DAs and types of luting cements. Conclusions: Within the limitations of this study, it can be concluded that the retention values of FDPs cemented using zinc phosphate cement were reduced with most of the DAs, whereas retention values increased when GIC, resin-modified GIC, and resin cements were used with the majority of DAs. These findings are important, as they can guide dentists in selecting the DA before cementing the crowns with the luting agent of their choice, without compromising the retention of the crowns.

Effect of an experimental desensitizing gel on bleaching-induced tooth sensitivity after in-office bleaching—a double-blind, randomized controlled trial

OBJECTIVES

To evaluate the risk and intensity of tooth sensitivity (TS), and the efficacy of in-office bleaching after applying an experimental desensitizing gel composed of 10% calcium gluconate, 0.1% dexamethasone acetate, 10% potassium nitrate, and 5% glutaraldehyde.

MATERIAL AND METHODS

In a split-mouth, double-blind, placebo-controlled study, 50 participants had their upper hemiarches randomized into experimental and placebo groups. Desensitizing and placebo gels were applied for 10 min before in-office bleaching (35% hydrogen peroxide, 1 × 50 min; two bleaching sessions; 1-week interval). TS was recorded immediately after bleaching, 1, 24, and 48 h after each session, with a 0-10 visual analogue scale (VAS) and a five-point numerical rating scale (NRS). The color was recorded in all groups at baseline, 1 week after each session, and 1 month after the end of bleaching using shade guide units (ΔSGUs) and a spectrophotometer (ΔE_ab, ΔE₀₀, and ΔWI_D).

RESULTS

Most participants (96%) felt some discomfort during treatment regardless of the study group. The odds ratio for pain was 0.65 (95% CI 0.1 to 4.1; p = 1.0). The intensity of TS did not differ between groups (p > 0.31), and it was only 0.34 VAS units lower in the experimental group. A significant color change occurred in both groups regardless of the group.

CONCLUSIONS

The desensitizing experimental gel applied before in-office bleaching did not reduce the risk and the intensity of TS and did not affect color change.

CLINICAL RELEVANCE

Although the experimental desensitizing agent with varying mechanisms of action did not jeopardize the color change, it did not reduce the risk or intensity of in-office bleaching.

CLINICAL TRIAL REGISTRATION NUMBER

RBR-7T7D4D.

Efficacy of GLUMA for the Treatment of Dentin Hypersensitivity Compared to Lasers: A Systematic Review

OBJECTIVE

Dentin hypersensitivity (DH) is characterized by a short, sharp pain in response to a thermal or tactile stimulus. The application of desensitizing agents such as GLUMA and laser is a non-invasive and safe approach to decrease sensitivity. The evidence for the efficacy of GLUMA desensitizer compared to laser desensitization in patients with DH was evaluated for 6 months.

DESIGN

In March 2022, an electronic search of PubMed, Scopus, and Web of Science databases was conducted. Articles published in English that compared GLUMA and laser in the treatment of DH with a follow-up of 6 months or more were included. Randomized, non-randomized controlled trials, and clinical trials were included. Risk of bias assessment tools developed by the Cochrane collaboration ROB 2 and ROBINS-I were used to assess the quality of studies. The GRADE assessment method was used to assess the certainty of evidence.

RESULTS

About 36 studies were identified in the search results. After applying the predefined eligibility criteria, eight studies with 205 participants and 894 sites were included in this review. Of the eight studies, four were judged to be at high risk of bias, three had some concerns, and one had a serious risk of bias. The certainty of the evidence was graded as low.

CONCLUSION

Based on limited evidence, GLUMA and laser appear to be equally effective in providing relief from DH. GLUMA showed an immediate effect and provided pain relief. Over the course of a week, laser showed long-term stable results. GLUMA is effective in providing immediate relief.

Effectiveness and cytotoxicity of two desensitizing agents: a dentin permeability measurement and dentin barrier testing in vitro study

Background

When evaluating the efficacy and safety of various desensitizing products in vitro, their mechanism of action and clinical utility should be considered during test model selection. This study aimed to evaluate the effects of two desensitizers, an in-office use material and an at-home use material, on dentin specimen permeability, and their dentin barrier cytotoxicity with appropriate test models.

Methods

Two materials, GLUMA desensitizer (GLU) containing glutaraldehyde and remineralizing and desensitizing gel (RD) containing sodium fluoride and fumed silica, were selected. Human dentin specimens were divided into three groups (n = 6): in groups 1 and 2, GLU was applied, and in group 3, RD was applied and immersed in artificial saliva (AS) for 24 h. Dentin specimen permeability before and after each treatment/post-treatment was measured using a hydraulic device under a pressure of 20 cm H₂O. The perfusion fluid was deionized water, except in group 2 where 2% bovine serum albumin (BSA) was used. The representative specimens before and after treatment from each group were investigated using scanning electron microscopy. To measure cytotoxicity, test materials were applied to the occlusal surfaces of human dentin disks under which three-dimensional cell scaffolds were placed. After 24-h contact within the test device, cell viability was measured via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays.

Results

GLU significantly reduced the dentin permeability and occluded the dentinal tubules when 2% BSA was used as perfusion fluid. RD significantly reduced dentin permeability and occluded the tubules, but permeability rebounded after AS immersion. GLU significantly decreased cell viability, but RD was non-cytotoxic.

Conclusions

In vitro GLU application induced effective dentinal tubule occlusion only following the introduction of simulated dentinal fluid. RD provided effective tubule occlusion, but its full remineralization potential was not realized after a short period of immersion in AS. GLU may harm the pulp, whereas RD is sufficiently biocompatible.

Deep and compact dentinal tubule occlusion via biomimetic mineralization and mineral overgrowth

Dentinal tubule (DT) occlusion by desensitizing agents has been widely applied to inhibit the transmission of external stimuli that cause dentin hypersensitivity (DH). However, most desensitizing agents merely accomplish porous blocking or the formation of a superficial tubular occlusion layer, resulting in a lack of mechanical and acid resistance and long-term stability. Herein, combining biomimetic mineralization and mineral overgrowth of the dentinal matrix was shown to effectively occlude DTs, resulting in the formation of a compact and deep occluding mineral layer that is strongly bound to the organic matrix on tubule walls. This DT occlusion method could achieve both mechanical resistance and acid resistance, demonstrating the potential of an inexpensive, long-term, and efficient therapy for treating DH.

Postoperative sensitivity in posterior resin composite restorations with prior application of a glutaraldehyde-based desensitizing solution: A randomized clinical trial

OBJECTIVES

To evaluate the effect of a glutaraldehyde-based desensitizer on the postoperative sensitivity (POS) in posterior resin composite restorations up to 12 months using a universal adhesive (Tetric N-Bond Universal) with selective enamel etching (SE) or an etch-and-rinse (ER) strategy.

METHODS

Class I and class II resin composite restorations (n = 220) at least 3 mm deep were inserted in 55 subjects. The universal adhesive was applied using the SE (self-etch strategy on dentin with selective enamel etching) or the ER strategy, with or without prior application of a glutaraldehyde-based desensitizer (Gluma Desensitizer - GL) to form groups SEGL and ERGL. A bulk-fill resin composite (Tetric NCeram Bulk Fill) was used for all restorations. Spontaneous POS was assessed 7 days after the restorative procedure using the Visual Analog Scale (VAS) and the Numeric Rating Scale (NRS). After 7, 14, and 30 days of completing each restoration, the subjects were reassessed to evaluate POS caused by stimulation with an air blast, horizontal and vertical percussion. In addition, marginal discoloration, marginal adaptation, fracture, and recurrence of caries were evaluated using the FDI (World Dental Federation) criteria after 7 days and at 12 months.

RESULTS

No significant spontaneous or stimuli-induced POS was observed when restorations with or without GL were compared (p>0.05). A higher risk of spontaneous POS was observed within 7 days (40.0%; 95% CI 28.1 to 53.1), without statistically significant differences among groups. None of the participants reported POS at 12 months, however five restorations were considered clinically unsatisfactory (p > 0.05).

CONCLUSIONS

The previous application of GL did not significantly reduce spontaneous or stimuli-induced POS in posterior resin composite restorations at any time, regardless of the adhesive strategy used.

CLINICAL SIGNIFICANCE

The use of a glutaraldehyde-based desensitizing agent did not generate lower incidence of postoperative sensitivity in resin composite posterior restorations.

An Eggshell-Based Toothpaste as a Cost-Effective Treatment of Dentin Hypersensitivity

Objectives This study aimed to test the efficacy of two experimentally produced eggshell-based toothpastes on dentinal tubules occlusion.

Materials and Methods Two experimental eggshell toothpastes, based on natural ingredients, with or without titanium dioxide nanoparticles (TNPs) were produced and coded “TNPs eggshell toothpaste [TNPsESTP]” or “eggshell toothpaste [ESTP],” respectively. Mid-coronal dentin discs, from 28 human extracted molar teeth, etched with 37% phosphoric acid for 60 seconds to simulate the hypersensitive dentin, were randomly divided into four groups—G1: no treatment (negative control), G2: ESTP treated, G3: TNPsESTP treated, and G4: Biorepair treated (positive control). All treated discs were brushed for 2 weeks and 1 month using a toothbrush simulator at 40 mm/s. Dentinal tubules occlusion was studied using a cross-polarization optical coherence tomography (CP-OCT) and scanning electron microscopy (SEM).

Statistical Analysis Unpaired t -test was conducted using GraphPad software (San Diego, California, United States). Continuous variables were expressed as means ± standard deviation and p < 0.05 was considered statistically significant.

Results From CP-OCT, a marked increase in surface reflectivity of dentin was observed after brushing with tested toothpastes. ESTP and NPsESTP showed higher or comparable grayscale values than Biorepair indicating increase in surface density of dentin. From SEM, at 2 weeks, ESTP showed comparable number of completely occluded dentinal tubules to Biorepair. TNPsESTP showed significantly lower numbers of CODT than Biorepair. At 1 month, the number of CODT was difficult to count for all treated groups. Both ESTP and TNPsESTP showed significantly higher numbers of partially occluded dentinal tubules than Biorepair.

Conclusion ESTP or TNPsESTP could offer a cost-effective substitute for the treatment of dentin hypersensitivity.

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.

Clinical Efficacy of Different Dentin Desensitizers

CLINICAL RELEVANCE

Teethmate Desensitizer, Clinpro White Varnish, Shield Force Plus, and Gluma could be recommended for treating dentin hypersensitivity in terms of clinical efficacy.

SUMMARY

Objective: The aim of this study was to evaluate the clinical efficacy of widely used dentindesensitizing agents (DDAs) (Teethmate Desensitizer, Clinpro White Varnish, Shield Force Plus, and Gluma) in the treatment of dentin hypersensitivity (DH) according to different evaluation parameters over a four-week follow-up period.Methods and Materials: This study was a randomized, single-center, controlled, parallel group study involving 144 teeth in 40 subjects. The baseline DH levels of the subjects were determined using different evaluation parameters. Daily life hypersensitivity and evaporative air stimulus hypersensitivity scores were recorded using a visual analog scale (VAS), and tactile hypersensitivity scores were recorded using a Yeaple probe and measured in grams and on the VAS. Subjects who experienced evaporative air stimulus DH (30-80 mm on the VAS) and tactile hypersensitivity (10-50 g with the Yeaple probe) were included in the study. After application of the DDAs, these evaluation parameters were recorded throughout the follow-up period (immediately after application and at one day and two and four weeks post-application).Results: All four DDAs demonstrated clinical dentin-desensitizing effects throughout the follow-up period according to evaporative air hypersensitivity, tactile sensitivity (g-VAS), and daily life hypersensitivity scores (p<0.05). Only Clinpro White Varnish had tactile sensitivity (g) scores that were similar at baseline and the one-day follow-up (p>0.05). A comparison of DH-reducing effects among the DDAs revealed that they yielded different results immediately after application and at the one-day follow-up time point, depending on which evaluation parameter was used. However, all DDAs showed similar DH-reducing effects at the two- and four-week follow-up time points.Conclusions: Teethmate Desensitizer, Clinpro White Varnish, Shield Force Plus, and Gluma DH showed clinical efficacy for four weeks. DDAs may produce inconsistent clinical evaluation scores not only across different evaluation parameters but also between early and later follow-up time points.

Pathogenesis, diagnosis and management of dentin hypersensitivity: an evidence-based overview for dental practitioners

Though dentin hypersensitivity (DHS) is one of the most common complaints from patients in dental clinics, there are no universally accepted guidelines for differential diagnosis as well as selection of reliable treatment modalities for this condition. The neurosensory mechanisms underlying DHS remain unclear, but fluid movements within exposed dentinal tubules, i.e., the hydrodynamic theory, has been a widely accepted explanation for DHS pain. As several dental conditions have symptoms that mimic DHS at different stages of their progression, diagnosis and treatment of DHS are often confusing, especially for inexperienced dental practitioners. In this paper we provide an up-to-date review on risk factors that play a role in the development and chronicity of DHS and summarize the current principles and strategies for differential diagnosis and management of DHS in dental practices. We will outline the etiology, predisposing factors and the underlying putative mechanisms of DHS, and provide principles and indications for its diagnosis and management. Though desensitization remains to be the first choice for DHS for many dental practitioners and most of desensitizing agents reduce the symptoms of DHS by occluding patent dentinal tubules, the long-term outcome of such treatment is uncertain. With improved understanding of the underlying nociceptive mechanisms of DHS, it is expected that promising novel therapies will emerge and provide more effective relief for patients with DHS.

The ability of a potassium oxalate gel strip to occlude human dentine tubules; a Novel in vitro: In situ Study

OBJECTIVES

To determine if an oxalate strip reduced fluid flow in dentine samples and whether this reduction was maintained following a 14 day intra-oral period.

METHODS

Dentine tubule fluid flow was measured by a modified Pashley cell in 40 acid-etched dentine discs 1 mm thick, diameter >10 mm, with an acquired pellicle, pre-equilibrated with Hartmann's solution and conditioned by toothbrushing, pre and post treatment (10 min) with an oxalate (3.14 %) gel strip or no treatment. One control and one test sample were exposed in-situ for 14 days to the oral environment in 20 healthy adult volunteers, and fluid flow re-measured. The appliance containing the two samples was removed for brushing with water after mealtimes when the participant brushed their teeth and for a 2 min daily soak in chlorhexidine.

RESULTS

Fluid flow rate was reduced significantly immediately following treatment with the oxalate strip compared to baseline flow rate by 58 %. Following 14 days in-situ oral environment phase, a significant further reduction in fluid flow compared to baseline was identified in both control and oxalate strip treated samples, both (p < 0.0001), but the reduction was greater in the test samples, 94 % vs 87 %, p < 0.01.

CONCLUSIONS

This novel investigation is the first to show fluid flow measurement using the Pashley model in dentine samples that have been housed in the mouth for 14 days. Treatment with an oxalate strip designed for dentine hypersensitivity alleviation reduced dentine fluid flow more than control providing evidence that the oxalate treatment withstood the oral environment over a prolonged time.

CLINICAL SIGNIFICANCE

This study demonstrated the efficacy and durability of the oxalate precipitate over a 14 day period in achieving and maintaining dentine tubule occlusion when participants had no dietary restrictions. This demonstrates the suitability of the oxalate strip for the treatment of patients suffering from dentine hypersensitivity pain.

Effect of erosive and abrasive stress on sealing ability of different desensitizers: In-vitro study

This in vitro study examined the sealing ability of different desensitizing agents under a chemo-mechanical stress condition. For the study, a total of 144 extracted, caries-free human third molars were used to produce 1 mm-thick dentin discs. The specimens were divided randomly into four groups: Superseal (SS), Gluma (GL), Gluma Self-etch (GS), and Tooth Coat (TC). For each group, the permeability was measured before and after applying the desensitizer, after being exposed to Coca Cola for 5 minutes, and after 3150 strokes of a brushing abrasion. The decrease in permeability after the erosive and abrasive stress was analyzed by ANOVA and Tukey post hoc test. As a result, the dentin permeability decreased significantly for all desensitizers immediately after application (p < 0.05). SS and GS showed a significant difference in permeability reduction observed immediately after application and after acid action with Coca Cola (p < 0.05). After brushing abrasion, the permeability reduction decreased significantly for all desensitizers tested in this study (p < 0.05). TC showed the largest decrease in dentinal permeability compared to that of the other desensitizers and the differences were significant after brushing abrasion (p < 0.05). All tested desensitizers were effective in reducing dentin permeability. The behavioral characteristics under erosive and abrasive stress varied according to the products used. TC exhibited excellent sealing ability among the other desensitizers.

A randomised controlled trial to investigate the efficacy of an oxalate strip for the management of dentine hypersensitivity pain

OBJECTIVES

To compare a 3.14% potassium oxalate strip and 8% arginine calcium carbonate toothpaste for the reduction of dentine hypersensitivity after 2 and 4 weeks.

METHODS

This was an examiner-blind, parallel study in 80 healthy adults with dentine hypersensitivity (Schiff score >2) in >1 tooth. After acclimatisation, participants were randomised to the oxalate desensitising strip with fluoride toothpaste or the arginine desensitising toothpaste control which also contained fluoride. Products were applied under supervision of study staff after measuring baseline sensitivity, thereafter the strip or control toothpaste (fingertip application) was applied after 1 and 2 weeks, and teeth brushed twice-daily with the fluoride (test group) or the fluoridated arginine control toothpaste. Sensitivity was assessed following airblast (Schiff and VAS) and tactile stimuli (Yeaple probe) at baseline, 2 and 4 weeks.

RESULTS

Both groups showed significant reductions from baseline in VAS, Schiff and Yeaple sensitivity scores after 2 and 4 weeks (p < 0.0005). The oxalate group had significantly lower Schiff and higher Yeaple probe scores compared to control after both time points (p < 0.0002 and p < 0.05), but while scores favoured the oxalate group, there were no significant differences in VAS.

CONCLUSIONS

This study demonstrated application of a 3.14% potassium oxalate strip combined with toothbrushing with paste was more effective in pain management of dentine hypersensitivity than brushing with arginine toothpaste.

CLINICAL SIGNIFICANCE

Treatment of sensitive teeth with the oxalate strip reduced dentine hypersensitivity after 2 and 4 weeks to a significantly greater degree than a positive control sensitivity toothpaste demonstrating that oxalate strips are an effective targeted treatment for dentine hypersensitivity sufferers.

Effect of an experimental desensitizing agent on reduction of bleaching-induced tooth sensitivity: A triple-blind randomized clinical trial

BACKGROUND

In this randomized study, split-mouth, triple-blind clinical trial, the authors evaluated the efficacy of a desensitizing gel that contained 5% potassium nitrate and 5% glutaraldehyde applied before in-office bleaching with 35% hydrogen peroxide (HP).

METHODS

Treatment with the desensitizing or placebo control gels was randomly assigned to one-half of the maxillary teeth of 42 patients in a split-mouth design. The desensitizing gels were applied and maintained in contact with the tooth enamel for 10 minutes, followed by 2 HP bleaching sessions separated by 1 week. The primary outcome variable was pain intensity assessed with a numeric rating scale and a visual analog scale. Color was evaluated by means of a digital spectrophotometer and a value-oriented shade guide.

RESULTS

The difference in risk of developing tooth sensitivity between the desensitizing gel group (31.7%, 95% confidence interval [CI], 19.6 to 46.9) and the control group (70.7%; 95% CI, 55.5 to 82.3%) was statistically significant (P < .0001), as well as the difference in pain intensity in the first 24 hours (P < .001). No statistically significant difference was found in color change between teeth that received the desensitizing gel and those that received the placebo gel.

CONCLUSIONS

Application of desensitizing gel that contained 5% potassium nitrate and 5% glutaraldehyde before HP whitening reduced the risk and severity of dental sensitivity, without altering the effectiveness of whitening.

PRACTICAL IMPLICATIONS

A single application of desensitizing gel that contained 5% potassium nitrate and 5% glutaraldehyde can reduce tooth sensitivity after dental bleaching systems.

Effect of GLUMA desensitizer on the retention of full metal crowns cemented with Rely X U200 self-adhesive cement

PURPOSE

Considering the importance of retention in the success and long-term clinical service of fixed partial dentures (FPDs) as well as the existing controversy regarding the effect of GLUMA desensitizer on the retention of full metal crowns cemented with RelyX U200 self-adhesive cement, this study aimed to assess the effect of GLUMA desensitizer on the retention of full metal crowns cemented using RelyX U200.

MATERIALS AND METHODS

In this experimental study, 20 sound human premolars were prepared; a 0.5 mm chamfer finish line was prepared above the cementoenamel junction. The teeth were randomly assigned to two groups: a desensitizer group (n = 10, treated with GLUMA desensitizer) and a control (n = 10, no surface treatment). Full metal crowns were fabricated of base metal alloy and had a ring. All crowns were cemented with RelyX U200 and subjected to retention test by using a universal testing machine. The data were analyzed using SPSS version 20 and independent t-test.

RESULTS

The mean tensile bond strength was significantly higher in the GLUMA desensitizer group (230.63 ± 63.8 N) compared to the control group (164.45 ± 39.3 N) (P≤.012).

CONCLUSION

GLUMA desensitizer increases the tensile bond strength of RelyX U200 self-adhesive cement to dentin.

Efficacy of Diode Laser and Gluma on Post-Preparation Sensitivity: A Randomized Split-Mouth Clinical Study

OBJECTIVE

This study aimed to compare the efficacy of a 940-nm diode laser and Gluma desensitizer on post-preparation sensitivity of prepared teeth.

MATERIALS AND METHODS

Twenty patients with 76 teeth participated in the study. For each patient, prepared molar or premolar in one quadrant were individually irradiated by laser. In the symmetrical quadrant, Gluma was applied onto the prepared teeth. No treatment was performed in the control group. Temporary crowns were placed after preparation. Pain response to tactile stimulus was assessed at one day, one week, and two weeks using visual analog scale (VAS). Intergroup comparisons were made with Kruskal Wallis test (p < 0.05).

RESULTS

Mean VAS scores of the control group were statistically higher than laser and Gluma groups (p < 0.017). The difference between VAS scores of the laser and Gluma groups was statistically insignificant (p > 0.05).

CONCLUSIONS

A significant reduction in level of sensitivity after both treatments was observed. The reduction of sensitivity with Gluma was not significantly superior to laser. No significant additional reduction occurred in level of sensitivity from the first day to the second week after both treatments.

CLINICAL SIGNIFICANCE

The application of Gluma or a 940-nm diode laser may be considered as effective in reducing sensitivity after tooth preparation without superiority of either method. (J Esthet Restor Dent 28:405-411, 2016).

Effectiveness of a desensitizing agent before in-office tooth bleaching in restored teeth

OBJECTIVES

The aim of this clinical trial was to evaluate the effectiveness and tooth sensitivity associated with bleaching in patients with composite restorations in anterior teeth after the application of a desensitizing agent.

MATERIAL AND METHODS

Bleaching was performed with 35 % hydrogen peroxide gel in 30 patients with composite restorations in anterior teeth, divided according to the prior application of a desensitizing agent (De), or a placebo (Pl), on maxillary superior teeth. Color was recorded at baseline, 1 week after each session and 6 months after treatment. The experience of tooth sensitivity (TS) was recorded on an NRS (0-4) during bleaching and 24 h after each session. Bleaching effectiveness was evaluated by one-way ANOVA and Tukey's tests (α = 0.05). The percentage of TS was evaluated by Fisher's exact test. For each treatment, periods were compared using the Wilcoxon signed-rank test (α = 0.05), and at each period, treatments were compared using Mann-Whitney U test.

RESULTS

Both groups showed similar tooth color enhancement and color stability after 6 months (p < 0.05). No significant difference in prevalence of sensitivity was detected between groups (p < 0.001). Higher TS intensity (median [first/third quartiles]) was observed for Pl (1.5 [1/1.75]) compared with De (0.5 [0/1]) during treatment (p < 0.05).

CONCLUSIONS

The use of a desensitizing gel (5 % potassium nitrate, 2 % sodium fluoride) before tooth bleaching in patients with composite restorations did not reduce the prevalence of tooth sensitivity, but reduced the intensity of TS during bleaching.

CLINICAL RELEVANCE

Although the use of a desensitizing agent before bleaching, in patients with composite resin restorations, did not reduce the prevalence of TS, a reduction of the TS intensity during the protocol was observed without jeopardizing the whitening outcome.

In Vitro Evaluation of Dentin Hydraulic Conductance After 980 nm Diode Laser Irradiation

BACKGROUND

Dentin hypersensitivity treatments are based on the physical obliteration of the dentinal tubules to reduce hydraulic conductance. The aim of the present study is to evaluate the hydraulic conductance of bovine root dentin after irradiation with a 980-nm diode laser, with or without associated fluoride varnish.

METHODS

Sixty bovine root dentin specimens were divided into six groups (n = 10 in each group): G1, G3, and G5 (0.5 W, 0.7 W, and 1 W diode laser, respectively); G2, G4, and G6 (fluoride varnish application + 0.5 W, 0.7 W, and 1 W diode laser, respectively). The dentin hydraulic conductance was evaluated at four time periods with a fluxmeter: 1) with smear layer, 2) after 37% phosphoric acid etching, 3) after the treatments, and 4) after 6% citric acid challenge. After the dentinal fluid flow measurements, specimens were also evaluated for mineral composition using energy dispersive X-ray spectroscopy (EDS).

RESULTS

Analysis demonstrated a better result with increased irradiation power (P < 0.001), especially if the diode laser irradiation was associated with the application of fluoride varnish (P < 0.001), ensuring a greater reduction in permeability. Considering the groups treated only with laser irradiation, the 1 W group was superior when compared with the 0.5 W and 0.7 W irradiated groups immediately after treatment (P < 0.001). After citric acid testing, all groups showed similar results, except when comparing the 1 W groups with the 0.5 W groups (P = 0.04). EDS results of the irradiated groups showed an increase in the proportion of calcium and phosphorus ions, which demonstrates a superficial composition modification after laser treatments.

CONCLUSION

Laser irradiation of exposed dentin promoted significant reduction in the dentin hydraulic conductance, mainly with higher energy densities and association with fluoride varnish.

The effect of 30% ethanolic extract of Indian propolis on replica of human dentin compared against commercially available desensitizing agent: A methodological SEM study in vitro

Objective:

This study evaluated the ability of 30% ethanolic extract of Indian propolis on dentinal tubule occlusion comparatively against CPP-ACP containing desensitizing agent GC tooth mousse.

Methodology:

The specimens were prepared from 30 freshly extracted sound human third molars stored in 10% formalin (pH 7.0) at a room temperature. From each specimen, a sectioned sample (5 mm length × 5 mm width × 3.5 mm depth) was obtained including the cervical area. Samples were smoothened and wet-polished with 1000- and 1200-grit aluminum oxide abrasive paper and diamond pastes, in order to stimulate the clinical aspect of hypersensitive dentin cervical surfaces. All the specimens were randomly assigned to three groups (n = 10), according to dentin surface treatments. Negative control: Untreated specimens (n = 4) and pretreated with 6% citric acid (n = 6); Test Group: 30% ethanolic extract of Indian propolis (n = 10); Positive Group: GC Tooth Mousse (n =10). All the specimens were prepared for SEM analysis.

Results:

GC tooth mousse promoted tubule occlusion by crystal-like deposits in the lumen of the tubules. While propolis created a thin, smooth layer over dentin surface.

Conclusion:

According to the SEM analysis, both desensitizing agent were able to occlude the dentinal tubules.

The effect of dentin desensitizers and Nd:YAG laser pre-treatment on microtensile bond strength of self-adhesive resin cement to dentin

PURPOSE

The purpose of this study is to evaluate if pre-treatment with desensitizers have a negative effect on microtensile bond strength before cementing a restoration using recently introduced self-adhesive resin cement to dentin.

MATERIALS AND METHODS

Thirty-five human molars' occlusal surfaces were ground to expose dentin; and were randomly grouped as (n=5); 1) Gluma-(Glutaraldehyde/HEMA) 2) Aqua-Prep F-(Fluoride), 3) Bisblock-(Oxalate), 4) Cervitec Plus-(Clorhexidine), 5) Smart protect-(Triclosan), 6) Nd:YAG laser, 7) No treatment (control). After applying the selected agent, RelyX U200 self-adhesive resin cement was used to bond composite resin blocks to dentin. All groups were subjected to thermocycling for 1000 cycles between 5-55℃. Each bonded specimen was sectioned to microbars (6 mm × 1 mm × 1 mm) (n=20). Specimens were submitted to microtensile bond strength test at a crosshead speed of 0.5 mm/min. Kolmogorov-Smirnov, Levene's test, Kruskal-Wallis One-way Analysis of Variance, and Conover's nonparametric statistical analysis were used (P<.05).

RESULTS

Gluma, Smart Protect and Nd:YAG laser treatments showed comparable microtensile bond strengths compared with the control group (P>.05). The microtensile bond strengths of Aqua-Prep F, and Cervitec Plus were similar to each other but significantly lower than the control group (P<.05). Bisblock showed the lowest microtensile bond strength among all groups (P<.001). Most groups showed adhesive failure.

CONCLUSION

Within the limitation of this study, it is not recommended to use Aqua-prep F, Cervitec Plus and Bisblock on dentin when used with a self-adhesive resin cement due to the decrease they cause in bond strength. Beside, pre-treatment of dentin with Gluma, Smart protect, and Nd:YAG laser do not have a negative effect.

Comparative evaluation of NovaMin desensitizer and Gluma desensitizer on dentinal tubule occlusion: a scanning electron microscopic study

Purpose

In this study, the effect of calcium sodium phosphosilicate (NovaMin) desensitizing agent, which is a powder-based system, and hydroxyethyl methacrylate and glutaraldehyde (Gluma desensitizer), which is liquid-based system, on dentinal tubule occlusion was analyzed by scanning electron microscope. The effects of the above two along with one control group were compared to determine the more effective method of sealing the dentinal tubules after initial application.

Methods

Twenty specimens were allocated to each of 3 groups: Control, Gluma desensitizer, and NovaMin. Two additional samples were also prepared and treated with Gluma and NovaMin; these samples were longitudinally fractured. The specimens were prepared from extracted sound human premolars and were stored in 10% formalin at room temperature. The teeth were cleaned of gross debris and then sectioned to provide one to two dentin specimens. The dentin specimens were etched with 6% citric acid for 2 minutes and rinsed in distilled water. Control discs were dried, and the test discs were treated with the desensitizing agents as per the manufacturer's instructions. The discs as well as longitudinal sections were later analyzed under the scanning electron microscope. The proportions of completely occluded, partially occluded, and open tubules within each group were calculated. The ratios of completely and partially occluded tubules to the total tubules for all the groups was determined, and the data was statistically analyzed using nonparametric tests and statistical significance was calculated.

Results

NovaMin showed more completely occluded tubules (0.545±0.051) while Gluma desensitizer showed more partially occluded tubules (0.532±0.075). The differences among all the groups were statistically significant (P≤ 0.05).

Conclusion

Both materials were effective in occluding dentinal tubules but NovaMin appeared more promising in occluding tubules completely after initial application.

Effects of dentifrice containing hydroxyapatite on dentinal tubule occlusion and aqueous hexavalent chromium cations sorption: a preliminary study

In order to endow environmental protection features to dentifrice, hydroxyapatite (HA) was added to ordinary dentifrice. The effects on dentinal tubule occlusion and surface mineralization were compared after brushing dentine discs with dentifrice with or without HA. The two types of dentifrice were then added to 100 µg/ml of hexavalent chromium cation (Cr⁶⁺) solution in order to evaluate their capacities of adsorbing Cr⁶⁺ from water. Our results showed that the dentifrice containing HA was significantly better than the ordinary dentifrice in occluding the dentinal tubules with a plugging rate greater than 90%. Moreover, the effect of the HA dentifrice was persistent and energy-dispersive spectrometer (EDS) revealed that the atomic percentages of calcium and phosphorus on the surface of dentine discs increased significantly. Adding HA to ordinary dentifrice significantly enhanced the ability of dentifrice to adsorb Cr⁶⁺ from water with the removal rate up to 52.36%. In addition, the sorption was stable. Our study suggests that HA can be added to ordinary dentifrice to obtain dentifrice that has both relieving dentin hypersensitivity benefits and also helps to control environmental pollution.

Effect of hydroxyapatite film formed by powder jet deposition on dentin permeability

A powder jet deposition (PJD) process can be used to create a thick hydroxyapatite (HA) film on the surface of a human tooth. This study aimed to investigate in vitro the ability of an HA film, applied using PJD, to diminish dentin permeability. Discs of human coronal dentin were cut perpendicular to the tooth axis and the smear layer was removed by EDTA treatment. The HA film was created by accelerating HA particles, calcinated at 1200°C, onto the dentin discs at room temperature and atmospheric pressure. The surfaces and cross-sections of the HA PJD-treated samples were observed using scanning electron microscopy. Their permeability was indirectly recorded with a split-chamber device utilizing a chemiluminescence technique. MS-coat, a commercial dentin-desensitizing agent, was also evaluated for its effect on reducing liquid flow through the dentin. The scanning electron microscopy images showed that the HA particles were successfully deposited onto the dentin and solidly into the dentin tubules. The permeability of dentin after application of the HA films was significantly lower than that following application of MS-coat. This study showed the potential clinical application of PJD techniques in desensitizing dentin hypersensitivity.

Comparison of effect of desensitizing agents on the retention of crowns cemented with luting agents: an in vitro study

PURPOSE

Many dentists use desensitizing agents to prevent hypersensitivity. This study compared and evaluated the effect of two desensitizing agents on the retention of cast crowns when cemented with various luting agents.

MATERIALS AND METHODS

Ninety freshly extracted human molars were prepared with flat occlusal surface, 6 degree taper and approximately 4 mm axial length. The prepared specimens were divided into 3 groups and each group is further divided into 3 subgroups. Desensitizing agents used were GC Tooth Mousse and GLUMA® desensitizer. Cementing agents used were zinc phosphate, glass ionomer and resin modified glass ionomer cement. Individual crowns with loop were made from base metal alloy. Desensitizing agents were applied before cementation of crowns except for control group. Under tensional force the crowns were removed using an automated universal testing machine. Statistical analysis included one-way ANOVA followed by Turkey-Kramer post hoc test at a preset alpha of 0.05.

RESULTS

Resin modified glass ionomer cement exhibited the highest retentive strength and all dentin treatments resulted in significantly different retentive values (In Kg.): GLUMA (49.02 ± 3.32) > Control (48.61 ± 3.54) > Tooth mousse (48.34 ± 2.94). Retentive strength for glass ionomer cement were GLUMA (41.14 ± 2.42) > Tooth mousse (40.32 ± 3.89) > Control (39.09 ± 2.80). For zinc phosphate cement the retentive strength were lowest GLUMA (27.92 ± 3.20) > Control (27.69 ± 3.39) > Tooth mousse (25.27 ± 4.60).

CONCLUSION

The use of GLUMA® desensitizer has no effect on crown retention. GC Tooth Mousse does not affect the retentive ability of glass ionomer and resin modified glass ionomer cement, but it decreases the retentive ability of zinc phosphate cement.

Tubular occlusion of simulated hypersensitive dentin by the combined use of ozone and desensitizing agents

OBJECTIVE

Ozone was suggested for treatment of hypersensitive dentin. The purpose of this study was to investigate the effect of ozone, with or without the use of desensitizing agents, on patency and occlusion of simulated hypersensitive dentin.

MATERIALS AND METHODS

Sixty standardized dentin slabs were randomly divided into six groups: distilled water (Control), ozone treatment, fluoride desensitizer (ALLSolutions, Dentsply), oxalate desensitizer (D/Sense Crystal, Centrix), combined use of ozone/fluoride and combined use of ozone/oxalate. Ozone gas was delivered from OzonyTronX (Mymed). Specimens were evaluated using a scanning electron microscope and digital image analysis before and after treatment.

RESULTS

Statistical analysis using ANOVA and Mann-Whitney U-tests revealed significantly lower percentage of tubular occlusion with ozone treatment than distilled water at p ≤ 0.05. Scanning electron microscope photomicrographs of oxalate desensitizer specimens revealed a thick homogenous precipitate with significantly higher percentage of tubular occlusion than fluoride desensitizer and distilled water. Combined use of ozone/fluoride resulted in a significantly higher percentage of tubular occlusion than fluoride desensitizer alone. However, no significant difference was found between oxalate desensitizer and combined use of ozone/oxalate.

CONCLUSIONS

The use of ozone gas is a viable adjunct to fluoride-containing desensitizers in enhancing tubular occlusion, but is not effective with oxalate desensitizers.

In vitro dentin permeability after application of Gluma® desensitizer as aqueous solution or aqueous fumed silica dispersion

Objectives

To assess and to compare the effects of Gluma® Desensitizer (GDL) with an experimental glutaraldehyde and HEMA containing fumed silica dispersion (GDG) on dentin permeability using a chemiluminous tracer penetration test.

Material and Methods

Twenty disc-shaped dentin specimens were dissected from extracted human third molars. The dentin specimens were mounted in a split chamber device for determination of permeability under liquid pressure using a photochemical method. Ten specimens were randomly selected and allocated to the evaluation groups Gluma® Desensitizer as aqueous solution and glutaraldehyde/HEMA as fumed silica dispersion, respectively. Dentin disc permeability was determined at two pressure levels after removal of smear with EDTA, after albumin soaking, and after application of the desensitizing agents. Two desensitizer-treated and rinsed specimens of each group were examined by scanning electron microscopy (SEM) for surface remnants.

Results

Comparatively large standard deviations of the mean EDTA reference and albumin soaked samples permeability values reflected the differences of the dentin substrates. The mean chemiluminescence values of specimen treated with GDL and GDG, respectively, were significantly reduced after topical application of the desensitizing agents on albumin-soaked dentin. The effects of GDL and GDG on permeability were not significantly different. Treated specimens showed no surface remnants after rinsing.

Conclusions

The experimental desensitizer gel formulation reduced dentin permeability as effectively as the original Gluma® Desensitizer solution.

Evaluation of mineral content of dentin treated with desensitizing agents and neodymium yttrium-aluminium-garnet (Nd:YAG) laser

The aim of this study was to evaluate the mineral content of dentin prepared using three different desensitizing agents and the Nd:YAG laser. The occlusal third of the crowns of 30 molar teeth were cut with a slow-speed diamond saw sectioning machine under water cooling. Dentin slabs from the 30 teeth were randomly divided into five experimental groups, each comprising six slabs. The five groups were treated as follows: group A, no treatment; group B, treatment with oxalate-containing desensitizing agent (BisBlock); group C, treatment with resin-based desensitizing agent (Admira Protect); group D, treatment with glutaraldehyde-containing desensitizing agent (Systemp); and group E, irradiation with the Nd:YAG laser (DEKATM ) at 0.40 W. The levels of Mg, P, Ca, K, and Na in each slab were measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Data were analyzed by one-way analysis of variance and the Tukey HSD test. The effect of desensitizing agents and laser irradiation on the dentin surface were evaluated using a scanning electron microscope. There were no significant differences between the groups (p > 0.05). Group E was showed the lowest Ca/P ratio. SEM showed that the resin-based agent occluded the dentinal tubules, the glutaraldehyde-containing agent increased the Ca/P ratio, and Nd:YAG laser irradiation decreased the Ca/P ratio. The mean percentages by weight of Ca, Mg, K, Na and P were not affected by Nd:YAG laser irradiation or any of the desensitizing agents.

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.

Comparative assessment of the sealing ability of Nd:YAG laser versus a new desensitizing agent in human dentinal tubules: a pilot study

Dentinal hypersensitivity is a painful condition that occurs following periodontal treatment. Many treatment alternatives have been considered for this problem, including treatments with laser and dentinal adhesives. This study compared the sealing ability of Nd:YAG laser versus a new resin in scanning electron microscopy (SEM) micrographs. Ten human premolars were sectioned yielding 30 specimens of each premolar, which were randomly divided into three groups. The laser group was irradiated by Nd:YAG laser (1 W, 10 Hz, 60 s), the resin group was treated with the new Seal & Protect resin according to the manufacturer's instructions, and the third group served as the control group and did not receive any interventions. After preparation and gold coating of the samples, they were photographed by SEM at two magnifications (1500× and 4000×). The number and diameter (μm) of the dentinal tubules were recorded in selected fields, and analysis of variance (ANOVA) and Tukey tests were used to determine significant differences between groups. The ANOVA results revealed significant differences in both the mean number (P < 0.001) and diameter (P < 0.05) among the three groups. Further statistical analysis showed a significant difference between the laser group and the resin group in both outcome measures (P < 0.05). Thus, both Nd:YAG laser and the new resin reduced the number and diameter of open dentinal tubules, a result that also explains the desensitization mechanism of these interventions. We further conclude that application of the new resin is more effective than Nd:YAG laser in minimizing the number and diameter of exposed dentinal tubules.

In vitro and in vivo analyses of the effects of desensitizing agents on dentin permeability and dentinal tubule occlusion

This study was done to assess the influence of the topical application of two different desensitizing agents on dentin permeability and dentinal tubule occlusion. Twenty-one rats provided 84 teeth: 36 for the in vitro and 48 for the in vivo investigation. The following agents were tested: Group 1, 2% potassium nitrate plus 2% sodium fluoride gel; Group 2, 5% sodium fluoride varnish; Group 3, 3% hydroxyethylcellulose gel (control). Cervical cavities were prepared and EDTA was applied to expose the dentinal tubules. After each treatment, Evans blue dye was applied to the teeth. Dentin permeability, scanning electron microscope (SEM) sections, and energy dispersive X-ray (EDX) were analyzed. One-way ANOVA was used to compare the data. There were significant differences (P < 0.05) among groups for dentin permeability, number of tubules/mm(2), tubule area and tubular diameter. Groups 1 and 2 (both in vitro and in vivo) showed open and partially occluded tubules. Group 3 had the most open tubules. EDX revealed similar composition for both experimental conditions. Within the limits of the study, 2% nitrate potassium plus 2% sodium fluoride gel and 5% fluoride varnish decreased the dentin permeability, resulting in partial tubular occlusion.

Influence of fluoride- or triclosan-based desensitizing agents on adhesion of resin cements to dentin

Effect of desensitizers on the bond strength of resin cements to dentin was evaluated. Intact premolars (N = 90) were embedded in polymethyl methacrylate; dentin surfaces were exposed, and they were randomly divided into two main groups of cements (Duolink (D), Variolink II (V); n = 45 per group) and then into three desensitizer subgroups (n = 15 per subgroup). Teeth in controls (C) were treated according to cements' adhesion protocols; the other two groups received either fluoride- [Aqua-Prep F (F)] or triclosan-based [Seal&Protect (T)] desensitizers. Ceramic disks (Empress 2) were adhered; specimens were thermocycled (×5,000 cycles, 5-55 ± 1°C, dwell time 30 s) and subjected to shear bond strength test (MPa ± SD) in a universal testing machine (crosshead speed 1 mm/min). Failure types were classified using scanning electron microscope. For V, application of both desensitizers (29.6 ± 7.8 and 22.8 ± 2.8 for F and T, respectively) did not present significantly different results than that of the VC (21.2 ± 2.3; p > 0.05, one-way ANOVA). In D, F (20.6 ± 2.4) showed significantly higher results (p < 0.05) than those in T (16.1 ± 3.9) and DC group (15.2 ± 2.3). V showed significantly higher results than D (p < 0.05, Bonferroni). F and T did not negatively affect the bond strength results with D and V. Adhesive failures were more frequent with both T (84%) and F (66%) in D; cohesive failures in the cement (88%) were more commonly observed with F in V. Both F and T desensitizers can be safely used prior to final cementation but F in combination with V seems to be more reliable, considering both the bond strength and the failure types.

The effect of dentin desensitizer with different layers on thermal changes on the pulp during fabrication of provisional restoration

PURPOSE

This study investigated the effects of different desensitizers and an adhesive material application on pulpal temperature rise during direct provisional restoration polymerization.

MATERIALS AND METHODS

Two dentin desensitizers (Systemp, Ivoclar; BisBlock, Bisco) and a dentin adhesive (Prime Bond, Dentsply) were applied to the dentin surfaces as single layer or double layer. One autopolymerizing methacrylate (Prevision, Heraeus Kulzer) and one light polymerizing composite (Revotek LC, GC) provisional restoration materials were used in this study. A total of 160 dentin disks were prepared from extracted molars. These dentin disks were placed on an apparatus developed to measure temperature rise. After the desensitizer or dentin adhesive application, provisional materials were polymerized according to the manufacturers' instructions. The temperature increase was measured under the dentin disk with a J-type thermocouple wire that was connected to a data logger. Differences between initial and highest temperature reading were taken, and 10 readings were averaged to determine the mean value in temperature rise. Statistical analysis was performed with three-way analysis of variance followed by Tukey HSD test (alpha = 0.05).

RESULTS

Temperature rise varied according to the provisional restoration material used (composite resin, methacrylate) (p < 0.001), the agent thickness (single, double) (p < 0.001), and the agent (desensitizer, adhesive) (p < 0.001). The composite resin-based provisional material induced higher thermal changes than methacrylate based provisional material (p < 0.01).

CONCLUSION

The thickness of desensitizing agents affected the thermal changes; however, the desensitizers did not affect on the intrapulpal temperature although the type of provisional material used may be effective.