Influence of desensitizing and anti-erosive toothpastes on dentine permeability: An in vitro study

Brazilian undergraduates' and dentists' knowledge on preventing, diagnosing and managing dentin hypersensitivity: A cross-sectional questionnaire study

OBJECTIVES

To analyse the knowledge of dental undergraduates and dentists on the prevention, diagnosis and management of dentin hypersensitivity (DH); to compare their knowledge scores; and to understand the related variables using a regression model.

METHODS

An original online questionnaire investigated the attitudes, self-reported knowledge ('how much they thought they knew') and real knowledge ('how much they really knew') of 132 students and 338 dentists. Data were analysed descriptively, both knowledge scores were compared using Mann-Whitney and Wilcoxon signed-rank tests and data were subjected to two multiple linear regression analyses considering real knowledge scores as the dependent variable (α < 0.05).

RESULTS

The self-reported knowledge on DH was higher than the real knowledge for both students and dentists, but dentists presented the highest scores. Gingival recession and acidic diet were reported as the main predisposing factors for DH by undergraduates and dentists. Students normally managed DH with dietary and hygiene instructions followed by a desensitizing agent application, while dentists managed with occlusal adjustments. The mechanism of glutaraldehyde/HEMA and bioactive fillers on DH is widely unknown by students and dentists. The majority of the questioned individuals cannot differentiate DH from sensitivity of caries or molar-incisor hypomineralization.

CONCLUSION

Both students and dentists overestimate their knowledge of DH, revealing deficiencies in prevention, diagnosis and management. Students' knowledge improves towards the end of the Dentistry course, while younger dentists and PhD holders are more knowledgeable. Institutions should implement ongoing DH education for undergraduates and conduct interventions for experienced professionals, especially older ones.

Effect of the calcium silicate and sodium phosphate remineralizing products on bleached enamel

Context and Aims

This study evaluated the effect of calcium silicate and sodium phosphate (CSSP) dentifrice and serum on the surface of enamel bleached with hydrogen peroxide (H2O2).

Materials and Methods

A total of 160 bovine enamel slabs were bleached with 35% H2O2 and treated with sodium fluoride (NaF) dentifrice-GI, CSSP dentifrice-GII; CSSP dentifrice + CSSP serum-GIII, or NaF dentifrice + NaF gel-GIV. The dentifrices were applied using a brushing machine three times daily for 7 days. After brushing, sodium phosphate gel and CSSP serum were applied. The microhardness (KNH, n = 14), surface roughness (Ra, n = 14), energy dispersive spectroscopy (n = 6), and scanning electron microscopy (n = 6) were assessed at t0 (before bleaching), t1 (after bleaching), and t2 (after postbleaching treatments).

Statistical Analysis Used

The data were subjected to a two-way analysis of variance and Bonferroni's test.

Results

The KNH decreased at t1 (P < 0.001) but recovered at t2 for all treatments, although only GII showed restored baseline values (P = 0.0109). The surface roughness increased at t1 (P < 0.001) and reduced at t2 (P < 0.001) for all groups, with no significant differences among groups. Enamel composition and morphology did not differ after the treatments, except for silicon accumulation in GIII.

Conclusions

Postbleaching treatment with CSSP dentifrice and serum yielded superior remineralizing effects on bleached enamel.

Novel resin-based material containing β-tricalcium phosphate nanoparticles for the reduction of dentin permeability

OBJECTIVES

To synthesize and characterize a novel dentin adhesive containing Beta-Tricalcium Phosphate (β-TCP) nanoparticles and test its ability to reduce dentin permeability (dP).

METHODS

Experimental adhesives were prepared by mixing Bis-GMA, TEGDMA, HEMA (50/25/25 wt.%), photo-initiators, and inhibitors. The following groups were tested: Experimental adhesives without β-TCP (Exp.); with 10 wt.% β-TCP (Exp.10 wt.% β-TCP); with 15 wt.% β-TCP (Exp.15 wt.% β-TCP), Scotchbond Multi-Purpose (SBMP) and Clearfil SE Protect Bond (CFPB). Degree of conversion (DC%, 10 and 20 s); Flexural Strength (FS), Knoop Hardness (KHN), and Cell Viability (OD%) tests were performed. dP was evaluated by hydraulic conductance, using human dentin disks (n=12), at three-time intervals: post-EDTA (T0); post-treatment (T1); and post-erosion/abrasion cycling (T2). Data were statistically analyzed (α=0.05).

RESULTS

For all groups, exposure time for 20 s presented a higher DC% than for 10 s. For FS, filled adhesives did not differ from unfilled and from CFPB. Experimental adhesives did not differ among them and showed lower KHN than the commercial products. Cell viability did not differ among adhesives, except Exp. 15 wt.%, which showed lower OD% than Exp., Exp. 10% and, CFPB. For dP, only Exp.10 and 15 wt.% β-TCP did not present difference between the times T1 and T2. After cycling, Exp.10 wt.% β-TCP presented lower permeability than Exp. and CFPB.

CONCLUSIONS

The incorporation of 10 wt.% β-TCP nanoparticles into the resin-based dental material did not affect its mechanical properties and biocompatibility, and promoted the greatest reduction in dentin permeability, sustaining this effect under erosive/abrasive challenges.

CLINICAL SIGNIFICANCE

A novel resin-based dental material containing β-TCP nanoparticles was able to reduce dentin permeability, maintaining its efficacy after erosive/abrasive challenges. The synthesized material did not affect dental pulp cell viability and might be promising for other conditions that require dental remineralization, such as tooth wear and dental caries.

Chemical and Ultrastructural Characterization of Dentin Treated with Remineralizing Dentifrices

The aim of this study is to investigate dentin chemical and ultrastructural changes upon exposure to remineralizing dentifrices. Dentin disks were obtained from permanent human molars and treated for 7 days with the dentifrices: (1) C group-control (no dentifrice); (2) S group-Sensodyne Repair & Protect; (3) D group-Dentalclean Daily Regenerating Gel; and (4) DB group-D group + Dentalclean regenerating booster. Afterwards, samples were submitted to an additional 7 days of toothbrushing associated with daily acidic challenge. Samples were imaged and analyzed (days 1, 7, and 14) for Young's modulus by atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). SEM and AFM revealed precipitate deposition on dentin surfaces in groups S, D, and DB, formed as early as day 1. Surface elemental analysis showed a Si increase on all brushed surfaces. Similar surface morphology was maintained after the acidic challenge period. Bright-field TEM/SAED revealed the formation of nanocrystalline hydroxyapatite inside the dentin tubules of groups S, D, and DB after day 7. Group C presented a gradual reduction of Young's modulus from days-1-14, whereas all remaining groups had increased values. All evaluated dentifrices led to successful formation of hydroxyapatite and increased dentin stiffness.

Resin-based materials to control human dentin permeability under erosive conditions in vitro: A hydraulic conductance, confocal microscopy and FTIR study

OBJECTIVES

To characterize the behavior of three different polymeric agents before and after an erosive challenge on dentin permeability, to analyze their degradation in both conditions, and to analyze their degree of conversion (DC).

METHODS

The permeability of human dentin disks (1.0 ± 0.2 mm) was measured with smear layer, after its removal, after treatment (LpTreat) with Gluma Desensitizer, PRG Barrier Coat (PBC) or Icon infiltrant (n = 11/group) and after exposure to citric acid (LpEro) (6%, pH 2.1, 1 min). The specimens were analyzed under a Laser Scanning Confocal Microscope (n = 2/group) and the products' DC were calculated. Data were subjected to 2-way repeated measures ANOVA and post-hoc Bonferroni (permeability analysis), to paired t-test (for specimens treated with Icon) and to t-test (DC analysis) (α < 0.05).

RESULTS

Icon showed the lowest LpTreat and LpEro values, while PBC and Gluma did not differ from each other under these conditions. Icon and PBC showed LpEro similar to a dentin with smear layer. Under the Laser Scanning Confocal Microscope, more deposits were noticeable on dentin after treating with PBC. Gluma presented the deepest penetration in dentin. The DC of PBC was the highest.

SIGNIFICANCE

Icon caused the highest reduction on permeability values, followed by PBC and Gluma. PBC generated more deposits covering dentin and seemed to be more efficient after an erosive challenge. The association of a polymeric resin with inorganic ion-releasing fillers seem to be a great strategy to manage dentin hypersensitivity under erosive conditions.

Effects of immunoglobulin Y-loaded amorphous calcium phosphate on dentinal tubules occlusion and antibacterial activity

Aim: This study aimed to evaluate the effects of immunoglobulin Y (IgY)-loaded amorphous calcium phosphate (ACP) (IgY@ACP) on dentinal tubule occlusion and antibacterial activity.

Methodology: IgY@ACP was synthesized based on a biomimetic mineralization strategy. The structure was examined by transmission electron microscopy and Fourier transform infrared spectroscopy. The IgY release property was assessed in vitro. The cell biocompatibility of IgY@ACP was evaluated by CCK-8. The dentin disks were prepared using healthy human molars, and their dentinal tubules were exposed to EDTA. Subsequently, they were randomly selected and treated with or without IgY@ACP for 7 days. The tubule occlusion morphologies and newly formed layers were observed by scanning electron microscopy (SEM) and x-ray diffraction, respectively. To evaluate the acid resistance and abrasion resistance of IgY@ACP, dentin disks that were treated for 1 day were immersed in acid solution or subjected to a toothbrush. The antibacterial effects against Streptococcus mutans (S. mutans) were evaluated by colony-forming unit (CFU) counting, adhesion property assessment, and crystal violet and live/dead bacterial staining. Finally, the occlusion effect was evaluated in rat incisors in vivo. One-way analysis of variance (ANOVA) was performed for statistical analysis. The level of significance was set at 0.05.

Results: IgY@ACP presented an amorphous phase with a nanosize (60–80 nm) and sustained release of protein within 48 h. The CCK-8 results showed that IgY@ACP had good biocompatibility. After treatment with IgY@ACP for 1 day, the majority of dentinal tubules were occluded by a 0.3-μm-thick mineralized layer. Seven days later, all dentinal tubules were occluded by mineralization with a thickness of 1.4 μm and a depth of 16 μm. The newly mineralized layer showed hydroxyapatite-like diffraction peaks. In addition, IgY@ACP had good acid and abrasion resistance. After treatment with IgY@ACP, the CFU counting and adhesion rate of S. mutans were significantly reduced, the crystal violet staining was lighter, and the S. mutans staining revealed more dead cells. Most importantly, IgY@ACP had a certain occluding property in rat incisors in vivo.

Conclusion: IgY@ACP can effectively occlude dentinal tubules with acid-resistant stability and has prominent anti-S. mutans effects, rendering it a potentially suitable desensitization material in the clinic.

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.

Topical Agents for Nonrestorative Management of Dental Erosion: A Narrative Review

A nonrestorative approach to the management of dental erosion is the foremost option: controlling dental erosion. The objectives of this study are to provide an overview and to summarise the effects and properties of topical anti-erosive agents as a nonrestorative treatment of dental erosion. A literature search was conducted on five databases of peer-reviewed literature—Cochrane Library, EMBASE, PubMed, Scopus and Web of Science—to recruit articles published between 1 January 2000 and 31 December 2021. The literature search identified 812 studies; 95 studies were included. Topical anti-erosive agents can be broadly categorised as fluorides, calcium phosphate-based agents, organic compounds and other anti-erosive agents. In the presence of saliva, fluorides promote the formation of fluorapatite on teeth through remineralisation. Calcium phosphate-based agents supply the necessary minerals that are lost due to the acid challenge of erosion. Some organic compounds and other anti-erosive agents prevent or control dental erosion by forming a protective layer on the tooth surface, by modifying salivary pellicle or by inhibiting the proteolytic activity of dentine collagenases. Topical anti-erosive agents are promising in managing dental erosion. However, current evidence shows inconsistent or limited results for supporting the use of these agents in clinical settings.

Effect Of Calcium Silicate, Sodium Phosphate, and Fluoride on Dentinal Tubule Occlusion and Permeability in Comparison to Desensitizing Toothpaste: An In Vitro Study

This study compared the ability of a calcium silicate-, sodium phosphate-, and fluoride-based (CSSPF) toothpaste (TP) in promoting dentinal tubule occlusion and reducing dentin permeability with that of other commercially available antisensitivity TPs. Seventy-eight dentin discs (1.0±0.1 mm thick) were prepared from the midcoronal area and were treated with 37% phosphoric acid for 2 minutes; then they were randomly divided into six groups according to treatments: No treatment [positive control (PC)], entirely covered with nail varnish [negative control (NC)], hydroxyapatite (HAP)-containing TP [Desensin Repair (DES)], NovaMin-based [Sensodyne Repair & Protect (SEN)], CSSPF-based TP [Regenerate Advanced (REG)], sodium monofluorophosphate, potassium citrate, zinc citrate TP [Signal Sensitive Expert (SIG)]. Dentin permeability was tested by the dye percolation method (DP%). Scanning electron microscope (SEM) micromorphological and energy dispersive X-ray elemental analysis (EDX) of the dentin surfaces were done following each treatment. Results were analyzed using one-way analysis of variance (ANOVA) followed by Tukey post hoc test at a 95% confidence level (α=0.05). All the tested groups showed higher DP% than NC and lower percolation than the PC (p<0.05). REG and SIG were statistically comparable, and showed significantly lower DP% (p<0.05) than SEN and DES. None of the TPs tested was able to obliterate the lumen of the dentinal tubules (DT) completely. REG exhibited the highest weight percentage of calcium deposition, followed by SEN. Compared to the tested desensitizing TPs, CSSPF-based TPs demonstrated equal or less dentin permeability and better DT occlusion.

Effects of Remineralizing Agents Based on Calcium Phosphate, Sodium Phosphate, or Sodium Fluoride on Eroded Cervical Dentin

OBJECTIVES

To evaluate the effect of remineralizing agents on collagen matrix pattern, precipitate formation, and dentinal tubule obliteration in eroded cervical dentin.

METHODS AND MATERIALS

One hundred bovine cervical dentin specimens were previously eroded (0.6% hydrochloric acid, pH 2.3, 5 minutes) and then randomized into five groups (n=20): G1, control (without treatment); G2, Desensibilize Nano P (FGM); G3, MI Paste Plus (Recaldent); G4, Regenerate (NR-5); and G5, Desensibilize KF 2% (FGM). These treatments were applied in four sessions with 7-day intervals. During this period, the samples were subjected to an erosive challenge with orange juice (pH 3.8, 5 minutes). The specimens were analyzed by polarized light microscopy with picrosirius red staining, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX).

RESULTS

The G3 showed a higher concentration of type I collagen than G2 and G5 (p<0.05). The G3 showed greater formation of surface precipitates than that of G1 and G5 (p<0.05). In addition, G4 and G5 showed a greater number of open dentinal tubules than that of G3 (p<0.05).

CONCLUSIONS

Calcium phosphate-based remineralizing agents have shown to be a promising alternative treatment for preventing deleterious effects on the eroded dentin collagen matrix. In addition, they promoted precipitate formation and dentinal tubule obliteration on the eroded dentin.

Protection of calcium silicate/sodium phosphate/fluoride toothpaste with serum on enamel and dentin erosive wear

Objective

To evaluate the effect of a toothpaste containing calcium silicate/sodium phosphate/fluoride associated or not to the boost serum (BS) against erosive tooth wear (ETW) on enamel and dentin.

Methodology

Bovine enamel and dentin specimens were subjected to an erosion-abrasion cycling model (1% citric acid - pH 3.6 -2 min / artificial saliva – 60 min, 4×/day, 5 days). Toothbrushing was performed for 15 s (2 min exposed to slurry), 2×/day, with the toothpastes (n=10): control without fluoride (Weleda), Arg/Ca/MFP (Colgate Pro-Relief), Si/PO₄/MFP (Regenerate-Unilever), and Si/PO₄/MFP/BS (Si/PO₄/MFP with dual BS – Advanced Enamel Serum-Unilever). The effect of treatments on the eroded tissues was assessed by surface microhardness in the first day, and surface loss (SL) resulting from ETW was evaluated by profilometry (μm) after three and five days. Additional dentin specimens (n=5/group) were subjected to 20,000 brushing cycles to verify the abrasivity of the toothpastes. Data were subjected to ANOVA and correlation tests (5%).

Results

For enamel, no difference in microhardness was observed among the treated groups, and similar SL was obtained after 5 days. For dentin, Si/PO₄/MFP/BS resulted in higher microhardness values, but none of the groups presented significantly lower SL than the control. There was no significant correlation between SL and abrasiveness.

Conclusion

The calcium silicate/sodium phosphate toothpaste and serum increased microhardness of eroded dentin, but they did not significantly reduce enamel and dentin loss compared to the non-fluoride control toothpaste. The abrasiveness of the toothpastes could not predict their effect on ETW.

In situ evaluation of desensitizing toothpastes for protecting against erosive tooth wear and its characterization

OBJECTIVE

This five-phase, single-blind, crossover in situ trial evaluated the effects of desensitizing or anti-erosive toothpastes on dentin erosive wear and tubule occlusion.

MATERIALS AND METHODS

Some characteristics such as relative dentin abrasivity (RDA), viscosity (V), cytotoxicity, and fluoride and calcium (Ca) availability of the toothpastes were also tested. Samples were positioned on removable intraoral appliances from 15 volunteers (n=4), according to the groups, C-control (0 ppm fluoride), F-sodium monofluorophosphate (MFP), A-MFP and arginine+calcium carbonate, CSP-calcium sodium phosphosilicate, and CS-MFP and calcium silicate+sodium phosphate. Erosion-abrasion cycling was performed (1% citric acid, 2min, 6×/day; toothbrushing, 5s, 2×/day). Surface loss (SL) was evaluated by optical profilometry. Environmental scanning electron microscopy images (ESEM) counted the number of open dentin tubules (ODTs). Data were statistically analyzed (α=0.05).

RESULTS

There were no significant differences in SL among groups (p=0.468). The ODT for CSP, CS, and A groups were significantly lower than the control. CSP and CS presented significantly less ODT than F, but they did not significantly differ from A. F and CS were more abrasive than all the other toothpastes; CSP was more abrasive than A, and C was the least abrasive. CSP presented higher V (p<0.05). All toothpastes presented lower cell viability than the control without toothpaste exposure. F and A presented significantly higher values of F^- (p<0.05). All fluoride toothpastes had similar amount of Ca, differing from the control (p<0.05).

CONCLUSION

Although the toothpastes caused similar degree of erosive wear, CSP and CS were able to occlude the dentin tubules.

CLINICAL RELEVANCE

Desensitizing toothpastes containing calcium, sodium, phosphate, and silicate could be a suitable option for treating dentin hypersensitivity.

Bioactive glass versus Arginine dentifrices on the reduction of dentin permeability and acid tolerance

Objectives

To compare the efficacy of calcium sodium phosphosilicate (CSPS) and arginine dentifrices on dentin permeability and acid tolerance.

Material and Methods

Sixty dentin discs were randomly assigned into 3 groups, then brushed for 1 min with CSPS, arginine, or fluoride (control) dentifrices. To test acid tolerance, each disc was soaked in 6% citric acid for 1 min. Dentin permeability was measured before, following brushing, and acid challenge. Ten discs per group were similarly treated and evaluated for tubule occlusion following a single dentifrice application, while other five discs per group were employed in an acid tolerance assay.

Results

The percentage reduction in dentin permeability was 39.26%, 32.27%, and 21.71% in the arginine, CSPS, and control groups, respectively. The differences in dentin permeability reduction between the arginine and CSPS groups following brushing and acid challenge were not significant (p = 0.398 and p = 0.211, respectively). The arginine dentifrice demonstrated a significant reduction in permeability compared with the control (p = 0.011). In addition, the occlusion exhibited by the arginine and CSPS dentifrices was more resistant to acid challenge compared with that of the control (p < 0.001). From SEM analysis, dentinal tubule occlusion was observed after a single application in all groups. Some open dentinal tubules were detected in the test groups, while almost all of the orifices were open in the fluoride group following acid challenge.

Conclusions

There is no significant difference between arginine and CSPS dentifrices in reducing dentin permeability following a single application and acid challenge. Following acid challenge, the reduced permeability generated by arginine and CSPS was more stable compared with the fluoride dentifrice.

Fluoride dentifrice containing calcium silicate and sodium phosphate salts on dental erosion: In vitro study

OBJECTIVE

To investigate the effect of a commercial dentifrice containing fluoride, calcium silicate, and sodium phosphate and its dual phase gel serum to prevent erosive tooth wear in enamel.

METHODS

Forty-eight enamel specimens were selected by surface hardness and randomly allocated into 4 groups (n = 12) according to the commercial toothpastes: non-fluoridated (NF); 1100 ppm Stannous fluoride (SnF₂); 1450 ppm MFP + calcium silicate + sodium phosphate (CSSP); CSSP + dual-phase gel (CSSP + Serum). Cyclic experiments were repeated 3x / day for five days, including an erosive challenge with 0.05 M citric acid (pH 3.75 for 30 s), treatment with toothpaste slurries (1 min), and remineralization with artificial saliva (pH 7.0 for 60 min). Surface alterations were determined by stylus profilometry (μm) and scanning electron microscopy (SEM). Data were analyzed by ANOVA and Tukey tests (α = 0.05).

RESULTS

SnF₂, CSSP and CSSP + Serum significantly reduce surface wear compared to NF treated group. Besides, there were no significant differences among SnF₂, CSSP and CSSP + Serum. In micrographs of both groups treated with CSSP, the surface demonstrates the presence of a protective layer as a deposition of particles.

CONCLUSIONS

Dentifrice containing calcium silicate and sodium phosphate with or without the dual-phase gel was able to prevent the erosive tooth wear.