Analysis of dentin wear and biological properties promoted by experimental inoffice desensitizing materials.

BACKGROUND: This study aimed to evaluate dentin wear and biological performance of desensitizing materials. METHODS: Seventy bovine root dentin blocks were sectioned. Half of the surface of each specimen was untreated (control) and the other half was immersed in EDTA and treated with the following desensitizing materials: placebo varnish (PLA), fluoride varnish (FLU), sodium fluoride (NaF) varnish + sodium trimetaphosphate (TMP), universal adhesive (SBU), S-PRG varnish (SPRG), biosilicate (BIOS), and amelotin solution (AMTN). After application, the specimens were submitted to an erosive-abrasive challenge and the wear analyzed by optical profilometer. Serial dilutions of extracts obtained from the culture medium containing discs impregnated with those desensitizers were applied on fibroblasts and odontoblasts-like cells cultures. Cytotoxicity and production of total protein (TP) by colorimetric assays were determined after 24 h. Data were statistically analyzed using Kruskal-Wallis, Dunn's, One-way ANOVA and Tukey tests (p ≤ 0.05). RESULTS: No dentin wear was observed only for SBU. The lowest dentin wear was observed for AMTN and TMP. Cell viability was significantly reduced after treatment with undiluted extracts of PLA, FLU, TMP and SBU in fibroblasts and TMP and SBU in odontoblast-like cells. SPRG, BIOS and AMTN were cytocompatible at all dilutions tested. Considering TP results, no statistical difference was observed among the groups and high levels for TP were observed after TMP and FLU treatments. CONCLUSIONS: Universal adhesive system may protect dentin with opened tubules from wear after challenge. Extracts of adhesive and fluoride varnishes presented cytotoxic mainly on fibroblasts. The enamel protein may be a future alternative to treat dentin with opened tubules because it may cause low wear under erosive-abrasive challenge with low cytotoxic effects.

Film-Forming Polymers for Inhibition of Hydroxyapatite Dissolution: A Screening Study.

The aim of this study was to evaluate the effect of film-forming polymer solutions of different concentrations and pH values, either associated or not with sodium fluoride (F; 225 ppm F-), when applied during the initial stage of salivary pellicle formation, to prevent the dissolution of hydroxyapatite (HA), which was determined by the pH-stat method. Polyacrylic acid (PA), chitosan, sodium linear polyphosphate (LPP), polyvinyl methyl ether/maleic anhydride (PVM/MA), and propylene glycol alginate (PGA) were tested in three concentrations (lower, medium, and higher), two pH values (native or adjusted), and either associated or not with F. Distilled water, F, and stannous ion+fluoride (Sn/F; 225 ppm F- and 800 ppm Sn2+, as SnCl2) solutions were the controls, totalizing 63 groups. HA crystals were pretreated with human saliva for 1 min to allow pellicle formation, then immersed in the experimental solutions (1 min), and exposed to saliva for another 28 min. Subsequently, they were added to a 0.3% citric acid solution (pH = 3.8), connected to a pH-stat system that added aliquots of 28 µL 0.1 N HCl for a total reaction time of 5 min. Data were analyzed with one-way ANOVA and Tukey's tests (α = 0.05). For PA alone, the concentrations of 0.1% (native pH), 0.06%, and 0.08% (both pH adjusted) showed significantly lower HA dissolution than the negative control. PA concentrations of 0.1% and 0.08%, of both pH values, improved the effect of F against HA dissolution to a near-identical value as Sn/F. All solutions containing chitosan and LPP significantly reduced HA dissolution in comparison with the control. For chitosan, the concentration of 0.5% (in both pH values) improved the effect of F. LPP at 0.5% (native pH) and all associations of LPP with F outperformed the effect of F. Some PVM/MA solutions significantly reduced HA dissolution but PVM/MA could not improve the protection of F. PGA was incapable of reducing HA dissolution or improving F effect. It was concluded that chitosan, LPP, and some PA and PVM/MA solutions used alone were capable of reducing HA dissolution. Only PA, chitosan, and LPP were able to enhance fluoride protection, but for PA and chitosan, this was influenced by the polymer concentration.

Longitudinal assessment of dental erosion-abrasion by cross-polarization optical coherence tomography in vitro.

This study tested a novel in vitro dental erosion-abrasion model and the performance of cross-polarization optical coherence tomography (CP-OCT) in longitudinally monitoring the simulated lesions. Thirty human enamel specimens were prepared and randomized to receive three dental erosion-abrasion (EA) protocols: severe (s-EA, lemon juice/pH:2.5/4.25%w/v citric acid), moderate (m-EA, grapefruit juice/pH:3.5/1.03%w/v citric acid) and no-EA (water, control). EA challenge was performed by exposing the specimens to acidic solutions 4x/day and to brushing 2x/day with 1:3 fluoridated toothpaste slurry, for 14 days. Enamel thickness measurements were obtained using CP-OCT at baseline (D0), 7 (D7) and 14 days (D14) and micro-computed tomography (micro-CT) at D14. Enamel surface loss was measured with both CP-OCT and optical profilometry at D0, D7 and D14. Data was analyzed with repeated-measures ANOVA and Pearson's correlation (r) (α = 0.05). CP-OCT enamel thickness decreased over time in the s-EA group (D0 >D7 > D14, p < 0.001) and m-EA group (D0 > D14, p = 0.019) but did not change in the no-EA group (p = 0.30). Overall, CP-OCT and micro-CT results at D14 correlated moderately (r = 0.73). CP-OCT surface loss was highest for s-EA (p <0.001) but did not differ between moderate and no-EA (p = 0.25). Enamel surface loss with profilometry increased with severity (no-EA>m-EA>s-EA, p < 0.001). D14 surface loss was higher than D7 for both methods except for the no-EA group with profilometry. CP-OCT and profilometry had moderate overall correlation (r = 0.70). Our results revealed that the currently proposed in vitro dental erosion-abrasion model is valid and could simulate lesions of different severities over time. CP-OCT was a suitable method for monitoring the EA lesions.

Influence of different ultra-soft toothbrushes on erosive tooth wear.

OBJECTIVE: To investigate the influence of different ultra-soft toothbrushes on the progression of erosive tooth wear (ETW). METHODS: Bovine enamel and dentin specimens (n = 10) were submitted to a 5-day erosive-abrasive cycling model (0.3% citric acid for 5 min, artificial saliva for 60 min, 4x/day). Toothbrushing was carried out 2x/day for 15 s, with the different toothbrushes tested (A- Edel White: flexible handle, tapered bristles; B- Oral-B Gengiva Detox: regular handle, criss-cross tapered bristles; C- Colgate Gengiva Therapy: flexible handle, tapered bristles, high tuft density; d- Oral-B Expert Gengiva Sensi: regular handle, round end bristles, high tuft density; E- Oral-B Indicator Plus: soft brush, round end bristles (control). Surface loss (SL, in µm) was assessed by optical profilometry. The toothbrush characteristics were evaluated by a surgical microscope. Data were statistically analyzed (α=0.05). RESULTS: For enamel, toothbrush C showed the highest SL (means±SD: 9.86 ± 1.28) and it did not differ significantly from A (8.60 ± 0.50), both with flexible handles. The lowest SL was observed for the toothbrush Control E (6.76 ± 0.63), which differed significantly from A and C, but not from the other toothbrushes. For dentin, the highest SL was found for toothbrush D (6.97 ± 1.05) and it did not differ significantly from E (6.23 ± 0.71). The lowest SL was observed for B (4.61 ± 0.71) and C (4.85 + 0.83), without significant differences from A (5.01 ± 1.24). CONCLUSIONS: The ultra-soft toothbrushes had different impacts on the progression of ETW on the dental substrates. On enamel, higher ETW values were observed for the flexible handle toothbrushes, while for dentin, round-end bristles (ultra-soft and soft) caused more ETW. CLINICAL SIGNIFICANCE: Knowledge about the effect of different ultra-soft toothbrushes on ETW can help clinicians to recommend the most suitable types for their patients, bearing in mind that toothbrushes can impact enamel and dentin differently.

Tooth color change promoted by different whitening toothpastes under alternate cycles of staining and brushing.

OBJECTIVES: To compare the effect of whitening toothpastes with different mechanisms of action on discolored teeth subjected to additional staining/or not. METHODS: One hundred twenty tooth specimens were stained for 14 days (staining broth under constant agitation and pH=7) and then allocated into the groups of toothpastes with different whitening ingredients (n=10): 1. Regular - Colgate Total 12 Clean Mint; 2. CLWI - Colgate Luminous White Instant (blue pigment); 3. CLWA - Colgate Luminous White Advanced Expert (hydrogen peroxide); 4. CLWAC - Colgate Luminous White Activated Charcoal (activated charcoal); 5. OB3D - Oral-B 3D WHITE Brilliant Fresh (abrasive); 6. TW - Teeth Whitening (charcoal powder). Specimens were submitted to two experimental models: A. Daily staining-toothbrush cycling: staining solution (5min), toothbrushing (45 strokes) and artificial saliva (3h), 2x/day, for 5 days; B. Only toothbrushing (30.000 brushing strokes). Color change was determined with a spectrophotometer (CIEDE2000 and Whiteness Index for Dentistry - WID) and statistically analyzed (α=0.05). RESULTS: For both models, ΔE00 and Δa did not differ significantly between the whitening toothpastes and the regular. All groups showed a decrease in tooth yellowness (-Δb) and an increase in WID. Group Teeth Whitening exhibited a decrease in luminosity (-ΔL). In model A, Groups did not differ significantly from the Regular in terms of ΔL (p=0.35) and Δb (p=0.74). Groups CLWI and OB3D exhibited a decrease in luminosity. Reduced redness (-Δa) occurred only in Group CLWI. In Model B, Groups OB3D (p=0.021) and CLWA (p=0.001) exhibited higher change in luminosity than in Group Teeth Whitening. All exhibited increased redness (+Δa) and lightness (+ΔL), except the Regular, CLWAC, and Teeth Whitening. Group OB3D had a significantly higher change in Δb than the Regular (p=0.021). CONCLUSIONS: Irrespective of the mechanism of action, all toothpastes reduced tooth yellowness and promoted similar overall color change. Exposure of the teeth to additional staining during the toothbrushing cycles did not influence the effect of the whitening toothpastes. CLINICAL SIGNIFICANCE: Whitening toothpastes should be tested in conditions that more closely simulate their use in a clinical scenario, in which alternate cycles of staining and brushing occur on a daily basis. However, even in such conditions, they were unable to promote a color change that differed from that of a regular toothpaste.

Longitudinal assessment of dental erosion-abrasion by cross-polarization optical coherence tomography in vitro

Abstract: This study tested a novel in vitro dental erosion-abrasion model and the performance of cross-polarization optical coherence tomography (CP-OCT) in longitudinally monitoring the simulated lesions. Thirty human enamel specimens were prepared and randomized to receive three dental erosion-abrasion (EA) protocols: severe (s-EA, lemon juice/pH:2.5/4.25%w/v citric acid), moderate (m-EA, grapefruit juice/pH:3.5/1.03%w/v citric acid) and no-EA (water, control). EA challenge was performed by exposing the specimens to acidic solutions 4x/day and to brushing 2x/day with 1:3 fluoridated toothpaste slurry, for 14 days. Enamel thickness measurements were obtained using CP-OCT at baseline (D0), 7 (D7) and 14 days (D14) and micro-computed tomography (micro-CT) at D14. Enamel surface loss was measured with both CP-OCT and optical profilometry at D0, D7 and D14. Data was analyzed with repeated-measures ANOVA and Pearson's correlation (r) (α = 0.05). CP-OCT enamel thickness decreased over time in the s-EA group (D0 >D7 > D14, p < 0.001) and m-EA group (D0 > D14, p = 0.019) but did not change in the no-EA group (p = 0.30). Overall, CP-OCT and micro-CT results at D14 correlated moderately (r = 0.73). CP-OCT surface loss was highest for s-EA (p <0.001) but did not differ between moderate and no-EA (p = 0.25). Enamel surface loss with profilometry increased with severity (no-EA>m-EA>s-EA, p < 0.001). D14 surface loss was higher than D7 for both methods except for the no-EA group with profilometry. CP-OCT and profilometry had moderate overall correlation (r = 0.70). Our results revealed that the currently proposed in vitro dental erosion-abrasion model is valid and could simulate lesions of different severities over time. CP-OCT was a suitable method for monitoring the EA lesions.

Development of a sodium fluoride and stannous chloride-containing gel for treatment of dental erosion.

This study synthesized and tested experimental gels containing fluoride (F-) and stannous (Sn2+) ions for the control of dental erosion. Enamel and dentin polished specimens were eroded (1% citric acid solution, 10 min) and randomly allocated into 5 groups (n=10): Placebo - Hydroxypropyl Methylcellulose (HMC) gel; F+Sn+HMC - 7,500 ppm F- / 15,000 ppm Sn2+; F+HMC - 7,500 ppm F-; Commercial acidulated phosphate fluoride gel (12,300 ppm F-); and Control - no treatment. After treatment (applied for 60 s), specimens underwent an erosion-remineralization cycling (5 min in 0.3% citric acid solution, 60 min in artificial saliva, 4×/day, 20 days). Surface loss (SL, in µm) was determined after the 5th, 10th and 20th days of cycling (α=0.05). For enamel, after 5 and 10 days, F+Sn+HMC presented the lowest SL, which did not differ from the commercial gel. After 20 days, no differences were found between commercial, F+HMC, and F+Sn+HMC groups. Placebo did not differ from the control at any time points, and both groups presented the highest SL when compared to the other groups. For dentin, on the 5th day, F+Sn+HMC, F+HMC and commercial did not differ significantly, showing lower SL than the control and the placebo. On the 10th day, F+Sn+HMC and commercial presented the lowest SL compared to control and placebo. After 20 days, only the commercial gel showed lower SL than the control and placebo. Thus, the experimental F+Sn+HMC gel was able to control the progression of tooth erosion.

Este estudo desenvolveu e testou géis experimentais contendo íons fluoreto (F-) e estanho (Sn2+) para o controle da erosão dentária. Os espécimes polidos, de esmalte e dentina, foram previamente erodidos (solução de ácido cítrico a 1%, 10 min) e alocados aleatoriamente em 5 grupos (n = 10): Placebo - gel de hidroxipropilmetilcelulose (HMC); F + Sn + HMC - 7.500 ppm F- / 15.000 ppm Sn2+; F + HMC - 7.500 ppm F-; Gel de flúor fosfato acidulado comercial (12.300 ppm F-); e Controle - sem tratamento. Após o tratamento (aplicado por 60 s), os espécimes foram submetidos a uma ciclagem de erosão-remineralização (5 min em solução de ácido cítrico a 0,3%, 60 min em saliva artificial, 4 × / dia, 20 dias). A perda de superfície (SL, em µm) foi determinada após o 5º, 10º e 20º dias de ciclagem (α = 0,05). Para o esmalte, após 5 e 10 dias, o F + Sn + HMC apresentou a menor PS, não diferindo do gel comercial. Após 20 dias, não foram encontradas diferenças entre os grupos comercial, F + HMC e F + Sn + HMC. O placebo não diferiu do controle em nenhum momento, e ambos os grupos apresentaram a maior PS, comparado aos demais grupos. Para dentina, no 5º dia , F + Sn + HMC, F + HMC e comercial não diferiram significativamente, apresentando menor PS que o grupo controle e placebo. No 10º dia, F+Sn+HMC e comercial apresentaram a menor PS comparado ao grupo controle e placebo. No 20º dia, apenas o gel comercial apresentou PS menor que o controle e o placebo. Assim, o gel experimental F + Sn + HMC foi capaz de controlar a progressão da erosão dentária.

Development of a sodium fluoride and stannous chloride-containing gel for treatment of dental erosion

Resumo Este estudo desenvolveu e testou géis experimentais contendo íons fluoreto (F-) e estanho (Sn2+) para o controle da erosão dentária. Os espécimes polidos, de esmalte e dentina, foram previamente erodidos (solução de ácido cítrico a 1%, 10 min) e alocados aleatoriamente em 5 grupos (n = 10): Placebo - gel de hidroxipropilmetilcelulose (HMC); F + Sn + HMC - 7.500 ppm F- / 15.000 ppm Sn2+; F + HMC - 7.500 ppm F-; Gel de flúor fosfato acidulado comercial (12.300 ppm F-); e Controle - sem tratamento. Após o tratamento (aplicado por 60 s), os espécimes foram submetidos a uma ciclagem de erosão-remineralização (5 min em solução de ácido cítrico a 0,3%, 60 min em saliva artificial, 4 × / dia, 20 dias). A perda de superfície (SL, em µm) foi determinada após o 5º, 10º e 20º dias de ciclagem (α = 0,05). Para o esmalte, após 5 e 10 dias, o F + Sn + HMC apresentou a menor PS, não diferindo do gel comercial. Após 20 dias, não foram encontradas diferenças entre os grupos comercial, F + HMC e F + Sn + HMC. O placebo não diferiu do controle em nenhum momento, e ambos os grupos apresentaram a maior PS, comparado aos demais grupos. Para dentina, no 5º dia , F + Sn + HMC, F + HMC e comercial não diferiram significativamente, apresentando menor PS que o grupo controle e placebo. No 10º dia, F+Sn+HMC e comercial apresentaram a menor PS comparado ao grupo controle e placebo. No 20º dia, apenas o gel comercial apresentou PS menor que o controle e o placebo. Assim, o gel experimental F + Sn + HMC foi capaz de controlar a progressão da erosão dentária.

Abstract: This study synthesized and tested experimental gels containing fluoride (F-) and stannous (Sn2+) ions for the control of dental erosion. Enamel and dentin polished specimens were eroded (1% citric acid solution, 10 min) and randomly allocated into 5 groups (n=10): Placebo - Hydroxypropyl Methylcellulose (HMC) gel; F+Sn+HMC - 7,500 ppm F- / 15,000 ppm Sn2+; F+HMC - 7,500 ppm F-; Commercial acidulated phosphate fluoride gel (12,300 ppm F-); and Control - no treatment. After treatment (applied for 60 s), specimens underwent an erosion-remineralization cycling (5 min in 0.3% citric acid solution, 60 min in artificial saliva, 4×/day, 20 days). Surface loss (SL, in µm) was determined after the 5th, 10th and 20th days of cycling (α=0.05). For enamel, after 5 and 10 days, F+Sn+HMC presented the lowest SL, which did not differ from the commercial gel. After 20 days, no differences were found between commercial, F+HMC, and F+Sn+HMC groups. Placebo did not differ from the control at any time points, and both groups presented the highest SL when compared to the other groups. For dentin, on the 5th day, F+Sn+HMC, F+HMC and commercial did not differ significantly, showing lower SL than the control and the placebo. On the 10th day, F+Sn+HMC and commercial presented the lowest SL compared to control and placebo. After 20 days, only the commercial gel showed lower SL than the control and placebo. Thus, the experimental F+Sn+HMC gel was able to control the progression of tooth erosion.

In-vitro evaluation of the anti-cariogenic effect of a hybrid coating associated with encapsulated sodium fluoride and stannous chloride in nanoclays on enamel.

OBJECTIVE: The aim of this study is to test, in vitro, the anti-cariogenic effect of experimental hybrid coatings, with nano clays of halloysite or bentonite, loaded with sodium fluoride or with a combination of sodium fluoride and stannous chloride, respectively. METHODOLOGY: The varnish Fluor Protector (1,000 ppm of F-) was used as positive control and no treatment was the negative control. Enamel specimens (5 mm × 5 mm) were obtained from bovine teeth. The specimens (n=10) had their surfaces divided into two halves (5 mm × 2.5 mm each), in which one half received one of the treatments (Hybrid; Hybrid + NaF; Hybrid + NaF + SnCl2; Hybrid + NaF Loaded; Hybrid + NaF + SnCl2 Loaded). The specimens were submitted to a cariogenic challenge using a biofilm model (S. mutans UA159, for 5 days). Enamel surfaces both under and adjacent to the treated area were analyzed for mineral loss and lesion depth, by transverse microradiography. The pH of the medium was measured twice a day, and the fluoride release was analyzed. Additional specimens were submitted to confocal analysis. RESULTS: Data were statistically analyzed by two-way ANOVA followed by Tukey test (α=0.05). None of hybrid groups were able to reduce the lesion depth; the Hybrid + NaF group, however, was able to reduce mineral loss differing from the negative control (p=0.008). The groups showed no significant difference in the pH measurement and fluoride release. Confocal analysis confirmed that for all groups the biofilm growth was similar. CONCLUSION: None of the hybrid groups reduced lesion depth, but the Hybrid + NaF group was able to promote protection against mineral loss.

Impact of desensitizing/whitening toothpastes on tooth color change after abrasion and erosion-abrasion.

OBJECTIVE: To evaluate the impact of desensitizing toothpastes (D), their whitening versions (DW) and whitening toothpastes (W) on tooth color change. METHODS: Tooth specimens were allocated into 11 groups (n = 10): 1. Artificial saliva (control); 2. Sensodyne Repair & Protect (SRP-D); 3. Sensodyne Repair & Protect Whitening (SRP-DW); 4. Colgate Sensitive Pro-Relief (CSPR-D); 5. Colgate Sensitive Pro-Relief Real White (CSPR-DW); 6. Colgate Total 12 (CT12); 7. Colgate Total 12 Whitening (CT12-W); 8. Sensodyne True White (ST-W); 9. Curaprox Black Is White (CB-W); 10.Oral-B 3D White Perfection (OB3D-W) and 11. Erosion-only. They were submitted to two models: A. abrasion; B. erosion/abrasion. Color change (ΔE00 ), ΔL, Δa, and Δb were determined with a spectrophotometer. Data were statistically evaluated (α = 0.05). RESULTS: For both models, ∆E00 of D did not differ significantly from DW. An overall decrease in luminosity (-∆L) and increase (+∆b) in yellowness of the tooth occurred. In abrasion, all groups reduced redness (-∆a) and only SRP-DW differed from control (p = 0.016), but for ∆E00 , ∆L and ∆b, all toothpastes did not differ from the control. In erosion/abrasion, CB-W showed significantly lower ∆E00 and ∆b than the control (∆E00 : p = 0.026; ∆b: p = 0.005) and SRP-D (∆E00 : p = 0.028; ∆b: p = 0.025). Only SRP-DW, CSPR-DW, ST-W, CB-W, and erosion-only had increased redness (+∆a), but none differed from control. CONCLUSIONS: The toothpastes did neither promote whitening nor avoid the yellowish aspect of the tooth after abrasion and erosion-abrasion, regardless of their claim. CLINICAL SIGNIFICANCE: Desensitizing and/or whitening toothpastes induced similar changes on tooth color, without promoting whitening effect or reduction in its yellowish aspect.

In-vitro evaluation of the anti-cariogenic effect of a hybrid coating associated with encapsulated sodium fluoride and stannous chloride in nanoclays on enamel

Abstract Objective The aim of this study is to test, in vitro, the anti-cariogenic effect of experimental hybrid coatings, with nano clays of halloysite or bentonite, loaded with sodium fluoride or with a combination of sodium fluoride and stannous chloride, respectively. Methodology The varnish Fluor Protector (1,000 ppm of F-) was used as positive control and no treatment was the negative control. Enamel specimens (5 mm × 5 mm) were obtained from bovine teeth. The specimens (n=10) had their surfaces divided into two halves (5 mm × 2.5 mm each), in which one half received one of the treatments (Hybrid; Hybrid + NaF; Hybrid + NaF + SnCl2; Hybrid + NaF Loaded; Hybrid + NaF + SnCl2 Loaded). The specimens were submitted to a cariogenic challenge using a biofilm model (S. mutans UA159, for 5 days). Enamel surfaces both under and adjacent to the treated area were analyzed for mineral loss and lesion depth, by transverse microradiography. The pH of the medium was measured twice a day, and the fluoride release was analyzed. Additional specimens were submitted to confocal analysis. Results Data were statistically analyzed by two-way ANOVA followed by Tukey test (α=0.05). None of hybrid groups were able to reduce the lesion depth; the Hybrid + NaF group, however, was able to reduce mineral loss differing from the negative control (p=0.008). The groups showed no significant difference in the pH measurement and fluoride release. Confocal analysis confirmed that for all groups the biofilm growth was similar. Conclusion None of the hybrid groups reduced lesion depth, but the Hybrid + NaF group was able to promote protection against mineral loss.

Erosive tooth wear inhibition by hybrid coatings with encapsulated fluoride and stannous ions.

This study aimed to formulate a hybrid coating material (HC) and to modify this HC with fluoride (NaF) and stannous (SnCl2) ions, directly or encapsulated in nano containers, testing the effects of these materials against dental erosion and erosion-abrasion. Enamel and dentin specimens were treated with the HCs, and then tested in erosion or erosion-abrasion cycling models of 5 days (n = 10 for each substrate, for each model). Deionized water was the negative control, and a fluoride varnish, the positive control. Surface loss (SL, in µm) was evaluated with an optical profilometer, and data were statistically analyzed (α = 0.05). For enamel, in erosion, the positive control and HC without additives showed significantly lower SL than the negative control (p = 0.003 and p = 0.001). In erosion-abrasion, none of the groups differed from the negative control (p > 0.05). For dentin, in erosion, the positive control, HC without additives, HC with non-encapsulated F, and HC with encapsulated F + Sn showed lower SL than the negative control (p < 0.05). In erosion-abrasion, none of the groups differed significantly from the negative control (p < 0.05). HC without additives showed a promising potential for protecting the teeth against dental erosion (with upward trend for improved protection on dentin), but not against erosion-abrasion. The presence of additives did not improve the protective effect of the HC, on both substrates.

The Addition of Propylene Glycol Alginate to a Fluoride Solution to Control Enamel Wear: An in situ Study.

The aim of this study was to evaluate the protective effect of propylene glycol alginate (PGA) associated with sodium fluoride (NaF) against enamel erosion and erosion-abrasion. A 4-phase, split-mouth, double-blind, crossover in situ trial was conducted with the following solutions: F + PGA (225 ppm F- + 0.1% PGA), F (225 ppm F-), F + Sn (225 ppm F- + SnCl2, 800 ppm Sn2+), and negative control (distilled water). In each phase, 12 subjects wore removable mandibular appliances containing 4 enamel specimens, which were submitted either to erosion or to erosion-abrasion challenges for 5 days. Acquired salivary pellicle was formed in situ for 2 h. Erosion-abrasion consisted of acid challenge (1% citric acid solution, pH 2.3, 5 min, 4×/day), exposure to saliva in situ (2 h, 4×/day), brushing (5 s, total 2 min exposure to the slurry), and treatment with the solutions (2 min, 2×/day). For erosion, the same procedures were performed, without brushing. At the end, surface loss (SL; in µm) was evaluated by means of optical profilometry. KOH-soluble fluoride was quantified for erosion-only groups using extra specimens. For both challenges, the SL values found for F + PGA did not differ significantly from those of F and the negative control, and the SL value shown for F + Sn was significantly the lowest. Erosion-abrasion promoted significantly higher SL values than erosion. KOH-soluble fluoride analysis showed that F + Sn had a higher fluoride concentration in comparison with the negative control and F, while F + PGA did not differ from any of the other groups. In conclusion, PGA was not able to improve the protective effect of NaF against erosive enamel wear.

Role of desensitizing/whitening dentifrices in enamel wear.

OBJECTIVES: To analyze the impact of desensitizing (D) and/or whitening (W) dentifrices on erosion and erosion-abrasion. METHODS: Enamel specimens were allocated into 10 groups (n = 20): 1. Artificial saliva (control); 2. Sensodyne Repair&Protect (SRP-D); 3. Sensodyne Repair&Protect Whitening (SRP-W); 4. Colgate Sensitive Pro-Relief (CSPR-D); 5. Colgate Sensitive Pro-Relief Real White (CSPRR-W); 6. Colgate Total 12 (CT); 7. Colgate Total 12 Professional Whitening (CTP-W); 8. Sensodyne True White (ST-W); 9. Curaprox Black is White (CB-W); 10. Oral-B 3D White Perfection (OB3D-W). For abrasion (n = 10), 30,000 brushing strokes were performed and surface roughness (SR) was evaluated. Erosion-abrasion (n = 10) consisted of 1 % citric acid (2 min), artificial saliva (60 min); 6×/day; 5 days. Toothbrushing was carried out 2×/day (45 strokes). Surface loss (SL) was determined with an optical profilometer. Data were statistically analyzed (α = 0.05). RESULTS: Relative to SR, only OB3D-W had a significantly rougher surface than the control (p = 0.014). SRP-D, CSPR-D and ST-W showed no difference from the baseline. High SL was observed for ST-W, OB3D-W and CTP-W, without significant differences from the control. CT showed the lowest SL, not differing from SRP-D and SRP-W. There was a weak negative correlation between SL and concentration of free fluoride in the slurries, SL and SR, and SL and pH, all p > 0.05. CONCLUSIONS: Only one dentifrice increased surface roughness of enamel to a higher degree than brushing with saliva. Brushing with the test dentifrices did not cause higher enamel erosive wear than brushing with saliva. CLINICAL SIGNIFICANCE: This study enhances our knowledge on the effect of desensitizing and whitening dentifrices, indicating that they do not worsen enamel loss due to abrasion and they might be a safe option for individuals with erosive tooth wear.

Using fluoride mouthrinses before or after toothbrushing: effect on erosive tooth wear.

OBJECTIVES: 1. To evaluate the use of fluoridated mouthrinses before or after toothbrushing on erosive tooth wear. 2. To compare the anti-erosive effect of the combination toothpaste and mouthrinse containing fluoride, with or without stannous chloride. DESIGN: Enamel and dentin specimens were randomly distributed into groups (n = 10 of each substrate/group): B-brushing, B + R-brushing + rinsing, and R + B-rinsing + brushing. The treatments were performed using a fluoride toothpaste (BF: 1400 ppm fluoride, as amino fluoride-AmF) combined or not with a fluoride mouthrinse (RF: 250 ppm fluoride, as AmF and sodium fluoride-NaF) or fluoride and stannous toothpaste (BF+Sn: 1400 ppm fluoride, as AmF and NaF, 3500 ppm stannous, as stannous chloride-SnCl2 and 0.5% chitosan) combined or not with fluoride and stannous mouthrinse (RF+Sn: 500 ppm fluoride, as AmF and NaF, 800 ppm stannous, as SnCl2). As control, brushing was performed with artificial saliva (BC). Specimens were submitted to a 5-day erosive-abrasive cycling model. Treatments were performed twice daily. Surface loss (SL) was determined by optical profilometry. Data were analyzed by ANOVA and Games-Howell tests (α = 0.05). RESULTS: For enamel, RF+BF and RF+Sn+BF+Sn presented significantly lower SL than the control, with RF+BF being significantly lower than RF+Sn+BF+Sn. For dentin, BC had the lowest SL, not differing from BF+Sn+RF+Sn, RF+Sn+BF+Sn and BF. Groups RF+BF and BF+RF showed highest SL, not differing from BF+Sn and BF+Sn. CONCLUSIONS: For enamel, the use of a mouthrinse before brushing was able to reduce erosive wear for both fluoride and stannous products. For dentin, the use of stannous-containing products, irrespective of the order of application, presented superior effects.

An in vitro study on the influence of viscosity and frequency of application of fluoride/tin solutions on the progression of erosion of bovine enamel.

OBJECTIVE: To evaluate the influence of the viscosity and frequency of application of solutions containing fluoride (F) and stannous chloride (SnCl2) on enamel erosion prevention. DESIGN: Bovine enamel specimens were randomly distributed into 12 groups (n = 10), according to the following study factors: solution (C: deionized water; F: 500 ppm F-; F + Sn: 500 ppm F- + 800 ppm Sn2+); viscosity (low and high); and frequency of application (once and twice a day). Specimens were submitted to an erosive cycling model, consisting of 5 min immersion in 0.3% citric acid, followed by 60 min exposure to a mineral solution. This procedure was repeated 4×/day, for 5 days. Treatment with the experimental solutions was performed for 2 min, 1×/day or 2×/day. Enamel surface loss (SL) was determined by optical profilometry. Data were analyzed by 3-way ANOVA and Tukey tests (α = 0.05). RESULTS: There were significant differences between the levels of the factor solution (p < .001), viscosity (p < .001) and in the interaction between solution and viscosity (p = .01). Regarding solution, the mean SL ±â€¯standard deviation for the groups was F + Sn (4.90 ±â€¯1.12) < F (7.89 ±â€¯1.19) < C (14.20 ±â€¯1.69). High viscosity solutions demonstrated less SL than low viscosity; however, only when applied once a day (p < .001). Applying the solutions twice a day yielded lower SL than once a day, but only for the low viscosity solutions (p = .003). CONCLUSIONS: Under the conditions of this short-term in vitro experiment, it could be concluded that increasing the viscosity of the oral rinse solutions reduced enamel loss by erosion; however, this effect was small and only observed when the solutions were applied once a day.

Effect of sodium fluoride and stannous chloride associated with Nd:YAG laser irradiation on the progression of enamel erosion.

This study evaluated the progression of enamel erosion after treatment with gels containing sodium fluoride (NaF; 9047 ppm F) and stannous chloride (SnCl2; 3000 ppm Sn), associated or not with Nd:YAG laser irradiation. Sixty enamel specimens were prepared from bovine incisors and protected by a tape, leaving an exposed surface area of 4 × 1 mm. The specimens were immersed in 1 % citric acid (pH = 2.3) for 10 min to create an initial erosion lesion. After, they were randomly divided into six groups: (C) control: gel without active ingredient; (F): NaF gel; (F + Sn): NaF + SnCl2 gel; (laser): Nd:YAG laser irradiation (0.5 W; 50 mJ; ∼41.66 J/cm(2); 10 Hz; 40 s); (F + laser): NaF gel + Nd:YAG; (F + Sn + laser): NaF + SnCl2 gel + Nd:YAG. All gels had pH = 4.5 and were applied for 1 min. Laser irradiation was performed after gel application. The specimens were then submitted to a 5-day erosion-remineralization cycling model using 1 % citric acid (pH = 2.3), six times per day. Enamel surface loss (SL) was analyzed by optical profilometry in the end of the cycling (in µm). Data were analyzed by one-way ANOVA and Holm-Sidak tests (alpha = 0.05). The control and the laser groups presented the highest enamel loss (means ± SD = 53.52 ± 3.65 and 53.30 ± 2.73, respectively), followed by F + Sn (44.76 ± 2.83). The groups F (36.76 ± 2.28), F + laser (36.25 ± 3.59), and F + Sn + laser (39.83 ± 4.62) showed the lowest enamel loss, with no significant difference among them (p > 0.05). In conclusion, NaF by itself or associated with SnCl2 and Nd:YAG laser was able to reduce enamel erosion progression. Nd:YAG laser alone did not show a protective effect.