Effect of experimental mouthrinses containing the combination of NaF and TiF4 on enamel erosive wear in vitro

Toothpaste containing TiF4 and chitosan against erosive tooth wear in situ

OBJECTIVE

This study compared the protective effect of an experimental TiF4/Chitosan toothpaste with a commercial toothpaste on the prevention of erosive tooth wear (ETW) in situ.

METHODS

Fifteen subjects took part in this crossover and double-blind study, in which they wore a palatal appliance containing 4 bovine enamel and 4 dentin in 3 phases (5 days each). Half of the samples were subjected to erosive challenges (90 s in 0.1 % citric acid, pH 2.5, 4 times/day), and the other half to erosive plus abrasive challenges (15 s plus 45 s of contact, 2 times/day). The phases corresponded to the application of the different toothpastes: 1) TiF4 (1400 ppm F-) plus Chitosan, 2) Elmex®, Erosion Protection (1400 ppm F-, Chitosan), and 3) Placebo (negative control). Tooth wear was measured using contact profilometry (μm) and submitted to two-way RM ANOVA/Tukey test (p < 0.05).

RESULTS

No significant differences were detected between the experimental and commercial toothpastes, regardless of the challenge on both tissues. Both significantly reduce ETW compared to negative control (p < 0.0006). Tooth wear was increased by brushing only on eroded enamel (p < 0.01), but not on dentin (p = 0.6085). TiF4/Chitosan [erosion 2.98 ± 1.12 μm vs. erosion and abrasion 3.12 ± 1.33 μm] and Elmex® toothpastes [erosion 2.35 ± 0.93 μm vs. erosion and abrasion 2.98 ± 1.0 μm] minimized the impact of brushing compared to placebo on enamel [erosion 4.62 ± 1.48 μm vs. erosion and abrasion 5.15 ± 1.50 μm].

CONCLUSIONS

TiF4 plus chitosan toothpastes showed to be effective in minimizing the ETW as the commercial toothpaste is in situ.

CLINICAL RELEVANCE

The experimental toothpaste has similar effect against ETW compared to the commercial toothpaste. Considering the increased ETW prevalence worldwide, this result supports clinical trials and a possible application of this experimental anti-erosive toothpaste in the future.

Effect of an experimental TiF4/NaF solution in preventing tooth erosion

OBJECTIVE

This was a randomized, double-blind, parallel, placebo-controlled in vivo study investigating the protective potential of a titanium tetrafluoride/ sodium fluoride (TiF4/NaF) solution compared to its respective positive and negative controls under an in vivo model, as well as the perception of participants regarding the use of this experimental solution.

METHODS

After the ethics approval and the selection procedures, 33 participants were divided into three treatments: TiF4/NaF solution (500 ppm F, pH 4.4); AmF/NaF/SnCl2-mouthwash (500 ppm F, pH 4.5) and water (pH 7.0) (n = 11). After professional cleaning, the participants rinsed with one of the solutions for one minute and waited two hours for the erosive challenge. The erosive solution (1 % citric acid, pH 2.5) was applied for 10 s on each central incisor (enamel area: 4 mm2) and collected for calcium analysis using III Arsenazo colorimetric method. The Ca2+ release data were compared using Kruskal-Wallis/ Dunn tests (p < 0.05).

RESULTS

Teeth treated with both fluoride solutions released less calcium into the acid (median and interquartile interval: TiF4/NaF - 0.45/0.19 mM and AmF/NaF/SnCl2 - 0.46/0.15 mM Ca2+, p = 0.99) compared to the negative control (1.12/0.42 mM Ca2+, 60 % reduction, p < 0.0006). For both F solutions, only one participant per group reported unpleasant taste. Four participants belonging to AmF/NaF/SnCl2-mouthwash reported burning sensation post-rinse, while only one participant described such feeling after TiF4/NaF rinsing.

CONCLUSION

The experimental TiF4/NaF solution was as effective as the commercial AmF/NaF/SnCl2-mouthwash in protecting enamel against erosive demineralization with a good acceptability by the participants.

Combined use of stannous fluoride-containing mouth rinse and toothpaste prevents enamel erosion in vitro

OBJECTIVE

To compare the protective effect of commercial stannous-containing mouth rinses on enamel erosion in a simulated 5-day in vitro cycling model.

MATERIALS AND METHODS

81 human enamel specimens were embedded in resin blocks and divided into nine groups as follows; group 1: stannous fluoride (1000SnF2) toothpaste; groups 2,3, and 4 were the same as group 1 plus Elmex®, PerioMed™, and Meridol®, respectively, group 5: stannous fluoride (1450SnF2) toothpaste, groups 6, 7, and 8 were the same as group 5 plus Elmex®, PerioMed™, and Meridol®, respectively, group 9: negative control. An erosive challenge was induced with a 1 min hydrochloric acid (0.01 M, pH 2.2) treatment 3 times per day. Each cycle included immersing in the toothpaste slurry twice for two minutes and a one-minute rinse. The enamel slabs were immersed in artificial saliva between each erosive cycle and incubated overnight at 37 °C. Surface hardness loss and enamel loss were determined by Knoop surface hardness and non-contact profilometry, respectively. Finally, enamel surfaces were analyzed by scanning electron microscopy and X-ray energy dispersive spectroscopy (SEM/EDS).

RESULTS

All three mouth rinses had similar protective effects against erosion when using adjunct with 1000 SnF2 toothpaste (p > 0.05). With 1450 SnF2 toothpaste, Elmex® presented significantly lower surface hardness loss than Meridol® (p < 0.05). The combined use of Elmex® or PerioMed™ with toothpaste provided significantly better erosion protection than toothpaste alone, either 1000 or 1450 SnF2. In addition, 1000SnF2 toothpaste adjunct with mouth rinse is comparable to 1450 SnF2 toothpaste alone in preventing enamel erosion.

CONCLUSION

All three mouth rinses reduced enamel erosion. The additional use of a high concentration stannous containing mouth rinse with 1450 SnF2 toothpaste increases the protective effect against enamel erosion in vitro.

CLINICAL SIGNIFICANCE

To date, no standard protocol for preventing dental erosion is available. There are three stannous-containing mouth rinses on the market; however, no study compared their efficacy or indicated whether using adjuncts with anti-erosion toothpaste provides additional benefits. This study found that adding stannous mouth rinse to twice-daily toothpaste increases erosion protection.

The protective effect of the experimental TiF4 and chitosan toothpaste on erosive tooth wear in vitro

This study evaluated the protective effect of TiF₄ and chitosan toothpaste on erosive tooth wear (ETW) in vitro. Enamel and dentin samples were randomly assigned to toothpastes (n = 12): (G1) TiF₄ (1400 ppm F⁻), (G2) 0.5% chitosan (75% deacetylation, 500 mPas), (G3) TiF₄ (1400 ppm F⁻) plus 0.5% chitosan (75% deacetylation, 500 mPas), (G4) Placebo, (G5) Erosion Protection (Elmex-GABA, 1400 ppm F⁻). Twelve samples were only eroded. All samples were submitted to erosive pH cycles and G1 to G5 to abrasive challenges using toothpastes’ slurries plus 45 s of treatment, for 7 days. The final profile was overlaid to the baseline one for the ETW calculation (µm). The data were subjected to Kruskal–Wallis/Dunn tests. TiF₄ toothpastes, regardless of the presence of chitosan, were able to significantly reduce ETW compared to placebo, while chitosan alone was similar to placebo for both tissues. The toothpastes containing TiF₄ were even superior to the commercial Elmex toothpaste on enamel, while they were similar on dentin; both were also significantly different from placebo for both tissues. TiF₄ and Elmex toothpastes minimized the impact of brushing on eroded surface. In conclusion, TiF₄ toothpastes, regardless the presence of chitosan, showed to be effective in minimizing ETW in vitro.

Effect of TiF4/NaF and chitosan solutions on biofilm formation and prevention of dentin demineralization

OBJECTIVE

This study evaluated the effect of experimental solutions containing TiF₄/NaF and chitosan on bacterial species of microcosm biofilm and on dentin demineralization.

DESIGN

Microcosm biofilm was produced from human saliva mixed with McBain medium (0.2% sucrose) on bovine dentin for 5 days, under 5% CO₂ and 37 °C. From the 2nd day to 5th day, the treatments were applied (1×60s/day) as following: (1) NaF (500 ppm F^-, positive control); (2) TiF₄ and NaF (TiF₄: 190 ppm Ti⁴⁺ and 300 ppm F^-; NaF: 190 ppm F^-); (3) similar to 2 plus 0.5% chitosan (Ch 500 mPa.s, 75% deacetylation); (4) phosphate buffer solution (negative control); and (5) 0.5% chitosan (Ch 500 mPa.s, 75% deacetylation). CFU counting was performed for total microorganism, total streptococci, total lactobacilli and mutans streptococci. Dentin demineralization was measured by transverse microradiography-TMR. The data were compared using ANOVA/Tukey or Kruskal-Wallis/Dunn tests (p < 0.05).

RESULTS

No differences were found between the treatments with respect to CFU counting (p > 0.05). Dentin treated with TiF₄/NaF plus chitosan solution presented the lowest demineralization compared to the negative control and pure chitosan solution. On the other hand, this experimental solution did not significantly differ from TiF₄/NaF solution, being both able to significantly reduce mineral loss.

CONCLUSION

TiF₄/NaF plus chitosan solution, at suitable pH to be clinically applicable, had no antimicrobial effect, but it was able to reduce dentin caries development under this model.

Effect of TiF4/NaF and chitosan solutions on the development of enamel caries under a microcosm biofilm model

OBJECTIVES

To evaluate the effect of experimental solutions containing TiF₄/NaF and chitosan on bacterial species and on enamel caries prevention.

METHODS

Microcosm biofilm was produced from human saliva mixed with McBain saliva (0.2% sucrose) on bovine enamel for five days, under 5% CO₂ and 37 °C. From the second day until the end, the treatments were applied (1 × 60 s/day): (1) NaF (500 ppm F^-, positive control); (2) TiF₄ and NaF (TiF₄: 190 ppm Ti⁴⁺ and 300 ppm F^-; NaF: 190 ppm F^-); (3) similar to 2 plus 0.5% chitosan (Ch 500 mPas, 75% deacetylation); (4) phosphate buffer solution (negative control); and (5) 0.5% chitosan (Ch 500 mPas, 75% deacetylation). CFU counting was performed for total microorganism, total streptococcus, total lactobacillus and Streptococcus mutans. Enamel demineralization was measured by transverse microradiography-TMR. The data were compared using ANOVA/Tukey or Kruskal-Wallis/Dunn tests (p < .050).

RESULTS

No differences were found between the treatments with respect to CFU counting (ANOVA, p > .050). Enamel treated with TiF₄/NaF plus chitosan solution presented the lowest demineralization compared to the negative control and pure chitosan solution. On the other hand, this experimental solution did not significantly differ from TiF₄/NaF and NaF solutions, being all of them able to significantly reduce mineral loss (50-74%), but only TiF₄/NaF plus chitosan reduced lesion depth (55%) compared to the negative control (p = .001).

CONCLUSION

TiF₄/NaF plus chitosan solution had no antimicrobial effect, but it was able to reduce enamel caries development in 79% compared to control under this model.

CLINICAL SIGNIFICANCE

This study showed that TiF₄/NaF plus chitosan solution had no antimicrobial effect, but it was able to reduce enamel caries development under a microcosm biofilm model.

Effect of chitosan solutions with or without fluoride on the protection against dentin erosion in vitro

The aim of this study was to assess the protective effect of experimental solutions containing chitosan at different viscosities with or without fluoride (TiF₄ /NaF) on dentin loss in vitro. Bovine dentin samples (n = 15) were prepared and allocated to one of the following treatments: (i) 0.5% chitosan (500 mPas); (ii) 0.5% chitosan (2,000 mPas); (iii) 0.042% NaF and 0.049% TiF₄ ; (iv) as (iii) with addition of 0.5% chitosan (500 mPas); (v) as (iii) with addition of 0.5% chitosan (2,000 mPas); (vi) commercial solution with SnCl₂ /AmF/NaF (positive control); or (vii) deionized water (negative control). The samples were submitted to pH cycling for 7 d (0.1% citric acid, 4 × 90 s d^-1 ). The treatment was applied once a day for 30 s. The dentin loss was quantified using a contact profilometer. Three samples per group were evaluated using scanning electron microscopy. The dentin loss (μm) was submitted to anova and Tukey's test for differences between treatments. Among the treatments tested, only chitosan 500 mPas was able to statistically significantly reduce the dentin loss compared to the negative control, being similar to the positive control. TiF₄ /NaF, whether with or without chitosan, had no protective effect. Chitosan 500 mPas and SnCl₂ /AmF/NaF solutions have comparable protective effect against dentin erosion in vitro.

Impact of a simplified in situ protocol on enamel loss after erosive challenge

This study investigated the effect of the period of use and location of intraoral appliances on enamel surface loss. This randomized, single blind in situ study was conducted in 2 crossover phases based on the period of use, in which maxillary and mandibular appliances were simultaneously worn. Bovine enamel blocks (n = 120) were randomly divided among the studied groups by surface hardness. In each phase, fifteen volunteers used one maxillary appliance and two mandibular appliances for 5 days. Erosive challenge was performed 4X/day by immersion in 0.01 M HCL for 2 minutes. In the continuous phase, the intraoral appliances were worn for 20 hours. In the intermittent phase the appliances were worn for 8 hours and 30 minutes. Enamel loss was determined profilometrically. The discomfort of use of the appliances were evaluated in a questionnaire. Data were analyzed by two-way ANOVA/Tukey’s test and chi-square test (p<0.05). The maxillary appliance promoted higher enamel loss compared to the mandibular one (p<0.001). Intermittent use of appliances resulted in similar enamel loss to the continuous one (p = 0.686). All volunteers preferred to use the maxillary appliance in an intermittent regimen. The intermittent use of maxillary appliance is a simplified reliable protocol appropriated for in situ erosion studies in enamel.

Cytotoxicity of novel fluoride solutions and their influence on mineral loss from enamel exposed to a Streptococcus mutans biofilm

OBJECTIVE

This study evaluated the cytotoxicity, antimicrobial activity and in vitro influence of new fluoridated nanocomplexes on dental demineralization.

DESIGN

The nanocomplexes hydroxypropyl-β-cyclodextrin with 1% titanium tetrafluoride (TiF₄) and γ-cyclodextrin with TiF₄ were compared to a positive control (TiF₄), a blank control (without treatment) and negative controls (hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, deionized water), following 12- and 72-hour complexation periods. The cytotoxicity was assessed using the neutral red dye uptake assay at T1-15 min, T2-30 min and T3-24 h. A minimum bactericidal concentration (MBC) against Streptococcus mutans (ATCC 25175) was performed. Enamel blocks were exposed to an S. mutans biofilm, and the percentage of surface microhardness loss was obtained. Biocompatibility and microhardness data were analysed using ANOVA/Tukey tests (p < 0.05).

RESULTS

At T1, the cell viability results of the nanocomplexes were similar to that of the blank control. At T2 and T3, the 72 h nanocomplexes demonstrated cell viability results similar to that of the blank, while the 12 h solutions showed results different from that of the blank (p < 0.05). All fluoridated nanocompounds inhibited S. mutans (MBC = 0.25%), while the MBC of TiF₄ alone was 0.13%. All fluoridated compounds presented a percentage of surface microhardness loss lower than that of deionized water (p < 0.05).

CONCLUSIONS

The new fluoridated nanocomplexes did not induce critical cytotoxic effects during the experimental periods, whilst they did show bactericidal potential against S. mutans and inhibited enamel mineral loss.

Mechanism of Action of TiF4 on Dental Enamel Surface: SEM/EDX, KOH-Soluble F, and X-Ray Diffraction Analysis

This in vitro study aimed to evaluate the action of TiF4 on sound and carious bovine and human enamel. Sound (S) and pre-demineralised (DE) bovine and human (primary and permanent) enamel samples were treated with TiF4 (pH 1.0) or NaF varnishes (pH 5.0), containing 0.95, 1.95, or 2.45% F for 12 h. The enamel surfaces were analysed using SEM-EDX (scanning electron microscopy/energy-dispersive X-ray spectroscopy) (n = 10, 5 S and 5 DE) and KOH-soluble fluoride was quantified (n = 20, 10 S and 10 DE). Hydroxyapatite powder produced by precipitation method was treated with the corresponding fluoride solutions for 1 min (n = 2). The formed compounds were detected using X-ray diffraction (XRD). All TiF4 varnishes produced a coating layer rich in Ti and F on all types of enamel surface, with micro-cracks in its extension. TiF4 (1.95 and 2.45% F) provided higher fluoride deposition than NaF, especially for bovine enamel (p < 0.0001). It also induced a higher fluoride deposition on DE samples compared to S samples (p < 0.0001), except for primary enamel. The Ti content was higher for bovine and human primary enamel than human permanent enamel, with some differences between S and DE. The XRD analysis showed that TiF4 induced the formation of new compounds such as CaF2, TiO2, and Ti(HPO4)2·H2O. In conclusion, TiF4 (>0.95% F) interacts better, when compared to NaF, with bovine and human primary enamel than with human permanent enamel. TiF4 provoked higher F deposition compared to NaF. Carious enamel showed higher F uptake than sound enamel by TiF4 application, while Ti uptake was dependent on the enamel condition and origin.

The Impact of the Demineralized Organic Matrix on the Effect of TiF4 Varnish on the Progression of Dentin Erosive Loss

This in vitro study compared the effect of TiF4 varnish with that of NaF varnish, applied on pre-eroded bovine dentin samples, with respect to the progression of erosive loss, in the presence or absence of the demineralized organic matrix (DOM). One hundred and sixty bovine dentin samples were pre-eroded (0.1% citric acid, pH 2.5, 30 min). Half of the samples were subjected to the DOM removal (collagenase solution, 5 days). Samples with and without the DOM were treated according to the groups (n = 20 with DOM and 20 without DOM/group): TiF4 varnish (2.45% F), NaF varnish (2.45% F), placebo varnish (without fluoride) and control (no treatment). Thereafter, the treated samples were submitted to erosive challenges 4 × 90 s/day (0.1% citric acid, pH 2.5) during 7 days. Between the challenges, the samples were immersed in artificial saliva. The dentin erosive loss was measured using contact profilometry (µm, n = 15). Five dentin samples per group were prepared for energy-dispersive X-ray spectroscopy analysis. Data were compared using 2-way ANOVA/Bonferroni test (p < 0.05). Both fluoride varnishes were effective in reducing the erosive loss progression regardless of the dentin condition when compared to placebo varnish and control groups. Despite the fact that the TiF4 varnish was more effective than the NaF varnish for both dentin conditions (p < 0.001), its effect was significantly reduced in the absence of DOM (p < 0.05). It can be concluded that the TiF4 varnish is the best treatment in reducing the progression of dentin erosive loss (100%) in vitro, but its protective effect is more pronounced in the presence of DOM.

Comparison of antimicrobial effects of titanium tetrafluoride, chlorhexidine, xylitol and sodium fluoride on streptococcus mutans: An in-vitro study

Introduction

No studies have yet documented the bactericidal effects of TiF4, and its role in the treatment of dental caries, and no definite protocol has been introduced to regulate its use. The aim of this study was to determine the antimicrobial/bactericidal effects of TiF4 on Streptococcus Mutans (S. Mutans) and to compare it with chlorhexidine (Chx), sodium fluoride (NaF) and xylitol.

Methods

This study was conducted at the Shiraz University of Medical Sciences microbiology laboratory during March 2015 to September 2015. In this in-vitro study, first a bacterial suspension was prepared and adjusted to a 0.5 McFarland standard (equivalent to 1×10⁸ CFU/ml). The minimal inhibitory concentration (MIC) and minimal bactericidal concentrations (MBC) of TiF4, Chx, NaF and xylitol were assessed using broth microdilution assay and disk diffusion methods. In order to neutralize the acidic nature of TiF4, we used a sodium hydroxide preparation to obtain a pH of 7.2 and repeated all of the previous tests with the neutralized TiF4 solution. We reported the final results as percentages where appropriate.

Results

The MIC of TiF4, NaF and Chx for S. Mutans were 12.5%, 12.5% and 6.25%, respectively. At a concentration of 12.5% the inhibition zone diameters were 9 mm, 15mm and 14mm for TiF4, NaF and Chx, respectively. The MBC was 25%, 12.5% and 12.5% for TiF4, NaF and Chx, respectively. Xylitol failed to show any bactericidal or growth inhibitory effect in all of its concentrations. When we repeated the tests with an adjusted pH, identical results were obtained.

Conclusion

TiF4 solutions have anti-growth and bactericidal effects on S. Mutans at a concentration of 12.5% which is comparable with chlorhexidine and NaF, indicating the possible use of this solution in dental practice as an anti-cariogenic agent, furthermore the antimicrobial activity is unaffected by pH of the environment.

Frequency of Application of AmF/NaF/SnCl2 Solution and Its Potential in Controlling Human Enamel Erosion Progression: An in situ Study

Although several studies have demonstrated the efficacy of AmF/NaF/SnCl2 solution in inhibiting dental erosion progression, measures for further improvement in its effectiveness are paramount. Thus, this in situ study evaluated whether the protective effect promoted by the AmF/NaF/SnCl2 solution would be enhanced by increasing its frequency of use. The study was conducted with 12 volunteers, a 4-phase (5 days each) randomized, crossover model. Extraoral erosive challenges (0.5% citric acid, pH 2.6, 6 × 2 min/day) and rinsing protocol (1 or 2 × 2 min/day) were performed. Before the in situ phase, human enamel samples were subjected to an in vitro surface softening (1% citric acid, pH 4.0, for 3 min). Four treatment protocols were tested using samples in replicas (n = 12): group G1 - deionized water (negative control); G2 - NaF solution (positive control, 500 ppm F-, pH 4.5); G3 - AmF/NaF/SnCl2 solution (500 ppm F-, 800 ppm Sn2+, pH 4.5) once a day; G4 - AmF/NaF/SnCl2 solution twice a day. Tissue loss and morphological changes were determined by optical profilometry (n = 12) and scanning electron microscopy (n = 3) analysis, respectively. Data were statistically analyzed by ANOVA with subsequent pairwise comparison of treatments. Tissue loss means (±SD in µm) for each treatment protocol and statistical differences were found as follows: G1 4.55 ± 2.75, G2 4.59 ± 2.13, G3 2.64 ± 1.55, and G4 1.34 ± 1.16. Although there was no difference between the 2 AmF/NaF/SnCl2 solution application regimens (once or twice a day), application of the product twice a day was the only treatment that was able to control erosion progression, differing from the control groups.

Effect of a Single Application of TiF4 Varnish versus Daily Use of a Low-Concentrated TiF4/NaF Solution on Tooth Erosion Prevention in vitro

This study investigated the isolated and combined effect of a single application of TiF4 or NaF varnish versus daily use of a solution containing a low concentration of TiF4/NaF against tooth erosion in vitro. A total of 90 bovine enamel and 108 root dentin samples were treated as follows: control (no treatment), solution containing TiF4/NaF (500 ppm F-, pH 4.4), NaF varnish (24,500 ppm F-, pH 5.0), TiF4 varnish (24,500 ppm F-, pH 1.0), TiF4 varnish + solution, and NaF varnish + solution. The erosive challenges were performed 4 × 90s/day (0.1% citric acid, pH 2.5) and, between them, the samples were immersed in artificial saliva. The tooth loss was measured using contact profilometry (after 7 days for dentin and after 7, 10, and 14 days for enamel). All treatments were effective in reducing tooth loss, except NaF varnish for enamel on day 7 (p < 0.0001). TiF4/NaF solution and TiF4 varnish did not differ with respect to enamel loss for 10 days; thereafter, TiF4 varnish lost its protective effect compared to TiF4/NaF solution. The combination of vehicles was more effective in reducing enamel loss than both varnishes on their own but not compared to the solution. For dentin, TiF4 varnish was more effective than NaF varnish, while TiF4/NaF solution and NaF varnish were similar. The combination of vehicles improved the protective effect only when compared to NaF varnish on its own (p < 0.0001). Both types of TiF4 applications, isolated or combined, were effective against tooth erosion, but some differences in their performance were seen between enamel and dentin.

Protective effect of experimental mouthrinses containing NaF and TiF4 on dentin erosive loss in vitro

Objective

This in vitro study assessed the anti-erosive effect of experimental mouthrinses containing TiF₄ and NaF on dentin erosive loss.

Material and Methods

Bovine dentin specimens were randomly allocated into the groups (n=15): 1) SnCl₂/NaF/AmF (Erosion Protection^®/GABA, pH 4.5, positive control); 2) experimental solution with 0.0815% TiF₄ (pH 2.5); 3) 0.105% NaF (pH 4.5); 4) 0.042% NaF+0.049% TiF₄ (pH 4.4); 5) 0.063% NaF+0.036% TiF₄ (pH 4.5); 6) no treatment (negative control). Each specimen was cyclically demineralized (Sprite Zero, pH 2.6, 4x90 s/day) and exposed to artificial saliva between the erosive challenges for 7 days. The treatment with the fluoride solutions was done 2x60 s/day, immediately after the first and the last erosive challenges of the day. Dentin erosive loss was measured by profilometry (μm). The data were analyzed using Kruskal Wallis/Dunn tests (p<0.05).

Results

Mouthrinses containing TiF₄ or Sn/F were able to show some protective effect against dentin erosive loss compared to negative control. The best anti-erosive effect was found for experimental solution containing 0.0815% TiF₄ (100% reduction in dentin loss), followed by 0.042% NaF+0.049% TiF⁴ (58.3%), SnCl₂/NaF/AmF (52%) and 0.063% NaF+0.036% TiF₄ (40%). NaF solution (13.3%) did not significantly differ from control.

Conclusion

The daily application of experimental mouthrinse containing TiF₄ and NaF has the ability to reduce dentin erosion, as well as Erosion Protection^® and TiF₄ alone.

Combined Tin-Containing Fluoride Solution and CO2 Laser Treatment Reduces Enamel Erosion in vitro

The aim of this in vitro study was to evaluate the effect of combined CO2 laser and tin-containing fluoride treatment on the formation and progression of enamel erosive lesions. Ninety-six human enamel samples were obtained, stored in thymol solution and, after surface polishing, randomly divided into 6 different surface treatment groups (n = 16 in each group) as follows: no treatment, control (C); one CO2 laser irradiation (L1); two CO2 laser irradiations (L2); daily application of fluoride solution (F); combined daily fluoride solution + one CO2 laser irradiation (L1F), and combined daily fluoride solution + two CO2 laser irradiations (L2F). Laser irradiation was performed at 0.3 J/cm2 (5 µs/226 Hz/10.6 µm) on day 1 (L1) and day 6 (L2). The fluoride solution contained AmF/NaF (500 ppm F), and SnCl2 (800 ppm Sn) at pH 4.5. After surface treatment the samples were submitted to an erosive cycling over 10 days, including immersion in citric acid (2 min/0.05 M/pH = 2.3) 6 times daily and storage in remineralization solution (≥1 h) between erosive attacks. At the end of each cycling day, the enamel surface loss (micrometers) was measured using a 3D laser profilometer. Data were statistically analyzed by means of a 2-level mixed effects model and linear contrasts (α = 0.05). Group F (-3.3 ± 2.0 µm) showed significantly lower enamel surface loss than groups C (-27.22 ± 4.1 µm), L1 (-18.3 ± 4.4 µm) and L2 (-16.3 ± 5.3 µm) but higher than L1F (-1.0 ± 4.4 µm) and L2F (1.4 ± 3.2 µm, p < 0.05). Under the conditions of this in vitro study, the tin-containing fluoride solution caused 88% reduction of enamel surface loss, while its combination with CO2 laser irradiation at 0.3 J/cm2 hampered erosive loss almost completely.