Experimental Varnish Research Articles

Anti-erosion effect of an experimental varnish on eroded dentin.

This in vitro study evaluated the effect of an experimental varnish containing 20% nano-hydroxyapatite (nHAP) associated with 5% stannous chloride (SnCl2) against erosive-abrasive wear on bovine dentin. Samples of bovine cervical dentin were pre-eroded (0.3% citric acid, pH 2.6 for 10 minutes) and randomized into 4 groups (n=10): Control group - experimental varnish without active ingredient (CG); experimental varnish containing 20% nHAP (nHG); experimental varnish containing 5% SnCl2 (24.800 ppm Sn2+) (SnG); experimental varnish containing 20% nHAP associated with 5% SnCl2 (18.300 ppm Sn2+) (nHSnG). After applying the materials, the erosive-abrasive challenges were performed for five days. Erosive dentin loss and analysis of the pattern of dentinal obliteration were performed by 3D confocal laser microscopy. A one-way ANOVA/Bonferroni test was performed to analyze the data (α=0.05). The SnG and nHSnG experimental groups presented more effectiveness in preventing erosive wear when compared to the other groups (p<0.05). There was no statistically significant difference between the SnG and nHSnG groups (p = 0.731) in tooth structure dentin loss. Regarding the amount of open dentinal tubules, the highest amount of obstructed dentinal tubules was demonstrated in SnG and nHSnG (p < 0.05) when compared to the others. Between SnG and nHSnG there was no significant difference (p = 0.952) in the amount of closed dentinal tubules in the dentin. Experimental varnishes containing 5% SnCl2 associated or not with 20% nHAP showed to be a promising strategy in preventing erosive-abrasive wear of dentin. In addition, nHSnG was able to obliterate dentinal tubules.

Qualitative and Quantitative Profiling of Enamel Remineralizing Potential of Fluoride Varnishes Incorporating Bioactive Glass, Dicalcium Phosphate Dihydrate, and Modified MTA: A Raman Spectroscopic Study.

To evaluate and compare for remineralization potential of enamel at three different time intervals using commercially available MI Varnish and Duraflor Halo varnish [5% sodium fluoride (NaF) varnish] incorporating bioactive glass, dicalcium phosphate dihydrate (DCPD), and biomimetically modified mineral trioxide aggregate (MTA). For the study, a buccolingual division into equal halves was done for 64 decoronated premolar crowns. Among these 64 crowns, we mounted 32 in acrylic discs to be used for microhardness and induced white spot lesions (WSLs) measuring 5 × 5 mm on the exposed enamel surface. These samples were divided into four groups of 24 each depending upon the varnish used. Varnish application was done, followed by immersion of these samples for 24 hours in artificial saliva, followed by peeling off of varnish. A pH cycling of 28 days was done after the varnish application before assessing the remineralization of the samples. Evaluation of all these samples was done at three different time intervals, baseline, after demineralization, and post remineralization for microhardness on the enamel surface. Raman spectroscopy was utilized for the measurement of phosphate (P) ion release. Sectioning of these samples to a thickness of 100 µm approximately was done to be viewed under a polarized light microscope. Bioactive glass incorporated varnish showed the highest microhardness values, mineral content levels, and least depth of lesion posttreatment. All the experimental varnish showed significant remineralizing potential with the best potency seen with bioactive glass incorporated varnish. The nonfluoride agents can be appropriately used in 2 wt% amount to augment the benefits of fluoride. Hardikar AS, Gaonkar NN, Devendrappa SN, et al. Qualitative and Quantitative Profiling of Enamel Remineralizing Potential of Fluoride Varnishes incorporating Bioactive Glass, Dicalcium Phosphate Dihydrate, and modified MTA: A Raman Spectroscopic Study. Int J Clin Pediatr Dent 2023;16(2):363-370.

Anti-erosive profile of an experimental 5% SnCl₂ varnish containing different concentrations of NaF.

This in vitro study evaluated the anti-erosive effect of an experimental varnish containing 5% stannous chloride (SnCl₂) associated with different concentrations of NaF (NaF-free, 2.5% NaF, or 5.2% NaF) on bovine enamel and root dentin. One hundred samples were pre-eroded (0.3% citric acid, pH 2.6, 10 min) and randomized into five groups (n=10 for each substrate): Negative control - milli-Q water; NaF-free - Experimental varnish SnCl₂-free and NaF-free; 2.5 NaF - Experimental varnish 5% SnCl₂ associated with 2.5% NaF; 5.2 NaF: Experimental varnish 5% SnCl₂ associated with 5.2% NaF and positive control - Commercial varnish containing 5% NaF (Duraphat). After the varnishes were applied, the erosive and abrasive challenges were carried out for five days. Loss of tooth structure (TSL) was determined by optical profilometry, and the loss of calcium (ΔCa2+) using atomic absorption spectroscopy. Dentin analysis was also performed by SEM. A one-way ANOVA/Bonferroni test was performed to analyze the data (α=0.05). The experimental 2.5 NaF and 5.2 NaF groups showed greater effectiveness in preventing TSL when compared to the other groups (p <0.05), regardless of the substrate. In addition, these groups showed lower loss in Ca2+ content when compared to the other groups (p <0.05), for enamel and dentin. Dentin showed greater TSL and ΔCa2+ loss when compared to enamel in all treatments (p <0.05). The 5.2% and 2.5% NaF-containing experimental varnishes showed promising results in both, the prevention of TSL and the loss of Ca2+, regardless of the substrate studied.

P4 - Prevention of Alveolar Bone Loss of Colocasia Esculenta Varnish

Periodontitis is the primary cause of tooth loss in adults. Colocasia esculenta extract (CE) was known to have antimicrobial, anti-inflammatory, and anti-osteoclastogenic effects. We fabricated experimental varnish mixed with CE that can be adhered to teeth in the long term. This study aimed to evaluate the prevention effect of the alveolar bone loss of CE varnish using the rat ligature-induced periodontitis model The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CE against Porphyromonas gingivalis were evaluated. Cytotoxicity of CE was determined with a CCK-8 kit for L929 cells. An experimental varnish was fabricated, and 15 wt% CE was mixed with the varnish. Sprague Dawley rats (8-week-old, male) were divided into four groups; Negative control (NC), Positive control (PC), Varnish group(V), and Varnish with CE group(VCE). Periodontitis was induced by ligature of 4/0 silk to the maxillary second molar. In the NC group, the ligation was immediately removed. Then, the varnish was applied around the ligated teeth. After 14 days, the rats were sacrificed, and alveolar bone loss was evaluated using micro-CT. Inflammatory cytokines of the gingiva were analyzed by real-time qPCR. The MIC of CE was 31.3 ?g/mL, and the MBC was 62.5 ?g/mL. CE showed no cytotoxicity at 500 ?g/mL or less. The VCE group showed significantly lower alveolar bone loss than the PC group (p<0.05), but no significant difference from the V group (p>0.05). MMP-9 and IL-6 were significantly lower CEV varnish group than in the V group (p < 0.05). CE was effective in inhibiting P. gingivalis and did not show any cytotoxicity at the antibacterial concentrations. VCE prevented alveolar bone loss in the rat and reduced the expression of inflammatory cytokines. Varnish with CE is regarded to be applied to teeth for the prevention of periodontitis.

Antimicrobial and cytotoxic capacity of pyroligneous extracts films of Eucalyptus grandis and chitosan for oral applications

Chitosan films containing distilled pyroligneous extracts of Eucalyptus grandis (DPEC), characterized and developed by Brazilian Agricultural Research Corporation—Embrapa Temperate Agriculture (EMBRAPA-CPACT), were evaluated for antimicrobial activity against Candida albicans, Streptococcus mutans, and Lactobacillus acidophilus by direct contact test. Further, their capacity for the prevention of teeth enamel demineralization and cytotoxicity in vitro were also determined. The natural polymers were tested at different concentrations (1500–7500 µg mL−1) and the formulation of an experimental fluoride varnish with antimicrobial activity was evaluated by direct contact test, whereas cytotoxicity was analyzed through the colorimetric MTT assay. Preliminary data showed no statistically significant differences in cytotoxicity to NIH/3T3 cell line when DPEC is compared to the control group. On the other hand, the antimicrobial capacity and demineralization effects were found between the test groups at the different concentrations tested. Chitosan films containing distilled pyroligneous extracts of E. grandis may be an effective control strategy to prevent biofilm formation related to dental caries when applied as a protective varnish. They may inhibit the colonization of oral microorganisms and possibly control dental caries through a decrease in pH and impairment of enamel demineralization.

접착성 성분을 첨가한 실험용 불소바니쉬의 항균 지속성

본 연구는 불소바니쉬에 글루타르알데하이드와 하이드록시에틸 메타크릴산(HEMA)과 같은 접착성 성분을 혼합하였을 때 Streptococcus mutans에 대한 항균의 지속성이 증가되는지를 평가하고자 하였다. 실험용 불소바니쉬(EX1)를 제작 후, EX1군에 HEMA를 혼합(EX2), 글루타르알데하이드를 혼합(EX3), HEMA와 글루타르알데하이드를 혼합(EX4)하여 접착성 성분이 들어간 불소바니쉬를 제작하였다. 직경 6 mm polyethylene terephthalate 필름 디스크에 각 실험군을 5 μL씩 적용하였고, 증류수에 넣은 후 37℃ 진탕배양기에서 각각 1시간, 3시간, 8시간, 12시간, 1일, 5일, 10일동안 보관하여 불소바니쉬가 용출되도록 하였다. 각 시간 별로 필름 디스크를 꺼내어 S. mutans균에 대한 한천배지시험을 실시하여 항균력이 지속되는지 평가하였다. 모든 불소바니쉬는 10일까지 항균 능력을 보였고, EX3군과 EX4군은 8시간에서 10일까지 유의성있게 높은 항균 능력을 보였으며, 10일에서는 EX2군과 유의성 있는 차이가 없었다. Glutaraldehyde와 HEMA 혹은HEMA 첨가 시 불소바니쉬의 항균의 지속성을 증가시킬 수 있다.

Efficacy of S-PRG filler containing varnishes on enamel demineralization prevention

This study evaluated the efficacy of S-PRG vanishes on preventing enamel demineralization. Bovine enamel specimens were obtained, polished and the baseline Knoop microhardness was evaluated. Specimens were stratified into six groups (n = 15), according to the varnish applied: S10—experimental varnish containing 10% of S-PRG fillers, S20—20% of S-PRG fillers, S30—30% of S-PRG fillers; S40—40% of S-PRG fillers; PC (positive control)—5% of NaF; NC (negative control)—no treatment was performed. Half of enamel surfaces were protected to work as a control and varnishes were applied over the unprotected area. A demineralizing pH-cycling was performed, and surface and cross-sectional microhardness were measured. The percentage of microhardness of the treated area was calculated comparing with the untreated area. Statistical analysis was performed by one-way ANOVA and Tukey’s test (p = 5%). All experimental S-PRG varnishes protected against demineralization in relation to no treatment, but S40 was the most effective on the surface. For all depths, S30 and S40 were superior in enamel demineralization prevention than other S-PRG filler concentrations and 5% NaF. It was concluded that S-RPG filler containing varnishes were effective to prevent enamel demineralization. The higher concentrated products were more effective than 5% sodium fluoride on surface demineralization prevention.

나노 크기 수산화인회석과 삼인산칼슘을 첨가한 실험용 불소바니쉬의 재광화 효과

이 실험의 목적은 불소바니쉬 단독과, 불소바니쉬에 나노 크기의 수산화인회석과 나노크기의 삼인산칼슘을 첨가한 후, 탈회/재광화 사이클링 하에서 재광화 정도를 비커스 경도로 평가하는 것이다. 불화나트륨 5 wt%를 함유한 로진제재의 실험용 불소바니쉬를 제작하였다(EX). 실험용 불소바니쉬에 나노 수산화인회석(HA+EX)과 나노 삼인산칼슘(TC+EX)을 각각 10 wt%씩 넣어 제작하였다. 기성품인Casein phosphopeptide-amorphous calcium phosphate (CP: Tooth mousse, GC, Japan)는 비교를 위해 사용되었다. 대조군은 아무런 처리도 하지 않았다. 우치 전치부를 아크릴릭 레진에 포매한 후 우식유발 용액에 72시간 노출시킨 후, EX, HA+EX, TC+EX, CP를 시편에 도포하였다. 탈회/재광화 사이클은 각각1시간/23시간으로 구성되었고, 20일까지 반복하였다. 재광화 정도를 평가하기 위해 시험 전과 각 처치 후 비커스 경도를 측정하였다. 각 군의 재료들을 도포한 지 24시간 후 CP군이 가장 높은 경도값을 보였고(p0.05), 다른 군들은 통계적으로 유의한 차이가 없었다(p0.05). 탈회/재광화 사이클링 10일 후, TC+EX군이 가장 높은 경도값을 보였지만(p0.05) HA+EX군과는 차이가 없었다(p0.05). 탈회/재광화 사이클링 20일 후, TC+EX군은 가장 높은 경도값을 보였고, HA+EX군과 EX군이 그 다음으로 높았다(p0.05). 결론적으로10 wt%의 나노 삼인산칼슘이 첨가된 실험용 불소바니쉬 군이 탈회/재광화 사이클하에서 법랑질을 가장 효과적으로 재광화시켰다.

항균물질과 혼합한 실험용 불소바니쉬의 Streptococcus mutans 에 대한 항균의 지속성

항균물질과 혼합한 실험용 불소바니쉬의 Streptococcus mutans 에 대한 항균의 지속성

Effect of fluoride varnishes on the surface hardness of bovine teeth under demineralization/remineralization cycling

We investigated whether fluoride varnishes recover the hardness of bovine teeth under 20 days of demineralization/remineralization cycling. The fluoride varnish groups (two commercial fluoride varnishes [V-varnish (Vericom, Korea) and CavityShield (3M ESPE, USA)] and an experimental fluoride varnish including 5 wt.% NaF were compared with a control group without fluoride varnish. Vickers hardness was measured at baseline, 3 days after immersion in caries-inducing solution, 24 hours after application of a fluoride varnish, and after 10 and 20 days of demineralization/remineralization cycling. Afterward, tooth surfaces were observed by scanning electron microscope. After fluoride varnish application and the cycling 10 and 20 days, the experimental varnish group showed the highest hardness, while the CavityShield and the control groups demonstrated the lowest hardness. The experimental varnish group recovered the hardness of the baseline at 24 hours after application of the varnish, while it was recovered after 20 days of the cycling in case of the V-varnish. However, the CavityShield and the control groups did not recover the hardness even after 20 days of the cycling. The experimental fluoride varnish with fast recovery in the hardness of the baseline can be used as an effective fluoride varnish to resist demineralization and to facilitate remineralization.

Effect of TiF4 varnish on microbiological changes and caries prevention: in situ and in vivo models.

The aim of this study was to evaluate microbiological changes, oral soft tissue toxicity, and caries-preventive effect of an experimental titanium tetrafluoride (TiF4) varnish compared with a commercially available fluoride varnish (NaF), using in situ and in vivo models. The treatment groups were the following: TiF4 varnish (experimental varnish), Duraphat® (fluoride positive control), placebo varnish (no fluoride), and no treatment (negative control). The varnishes were applied once over the enamel surface using a microbrush. For the in vivo study, 48 Wistar rats were infected with Streptococcus sobrinus 6715, received a treatment, and were submitted to a cariogenic challenge. After 4weeks, S. sobrinus, oral soft tissue toxicity, presence, and severity of caries were evaluated. For the in situ study, 12 volunteers took part in this randomized crossover, double-blind study performed in four phases of 14days each. They used intraoral appliances containing four enamel specimens that received the varnish according treatment group. After 24h, the varnish was removed and plaque accumulation was allowed. A 20% sucrose solution was dripped over the enamel blocks (10×/day for 5min each). Total streptococci, S. mutans, Lactobacillus, Candida spp. counts, and presence of white spot lesions were evaluated. Lesion depth was also quantified by micro-CT. For the in vivo study, the fluoride (F-varnishes) showed a statistically significant reduction in the percentage of S. sobrinus compared to the negative control (p < 0.05). Toxicological analysis revealed no abnormalities in oral tissues of rats from all groups, and both F-varnishes reduced the number and severity of caries lesions, without significant differences (p < 0.05). No statistical differences in microbiological counts were seen for the in situ experiment (p > 0.05). However, the specimens treated with TiF4 exhibited lower percentage of white spot lesions and the lesion depth was significantly reduced by F-varnishes (p < 0.05). F-varnishes showed reduction in the percentage of S. sobrinus in vivo, no oral soft tissue toxicity, and a caries-preventive effect in vivo and in situ. NaF varnish is largely used due its capacity to form CaF2-like layer on enamel. Therefore, development of studies focused on other fluoride compounds such as a TiF4 varnish, which may have greater efficacy than NaF against tooth demineralization, is important.

Effects of a new chlorhexidine varnish on Streptococcus mutans biofilm formation in vitro.

Abstract Background Local sustained-release drug delivery systems increase the substantivity of drugs in the oral environment and subsequently enhance their therapeutic effects. This study sought to compare the effects of two commercially available varnishes and one experimental chlorhexidine (CHX) varnish on formation of Streptococcus mutans biofilm. The solubility rates of the varnishes were evaluated as well. Methods Standard acrylic discs were fabricated and divided into groups based on the varnish applied to the disc surfaces, namely, V-varnish, Pascal, and experimental CHX varnish. The effects of the varnishes on S. mutans biofilm were assessed after 48 h. Bacterial growth on the discs was evaluated by colony count and scanning electron microscopy (SEM). Solubility was assessed by immersing the samples in phosphate buffered saline and recording their weight changes at different times. The data were analyzed using one-way ANOVA. Results In the Pascal and experimental varnish groups, the total number of bacteria did not differ from that in the negative control group. The SEM findings confirmed the aforementioned results. Solubility varied significantly among the materials. V-varnish was detached from the surfaces after 2 days. No significant weight change was noted in the experimental varnish group at 14 days, while Pascal varnish showed gradual weight loss from the 5th day to the 10th day and had a plateau thereafter. Conclusions Biofilm formation was inhibited by the Pascal and experimental varnishes but not by the V-varnish. The highest acceptable rate of solubility was observed in the Pascal samples.

In situ effect of titanium tetrafluoride varnish on enamel demineralization.

The effect of a 4% titanium tetrafluoride (TiF 4 ) varnish on enamel demineralization was evaluated. Twelve volunteers participated in this double-blind, randomized crossover study. Six enamel specimens were positioned in intraoral appliances throughout four treatment stages: 4% TiF 4 varnish (experimental varnish), 5% sodium fluoride (NaF) varnish (Duraphat ® ), placebo varnish, and negative control (deionized water). After 24 h, the varnishes were removed and plaques were allowed to accumulate. A 20% sucrose solution was dripped onto enamel blocks (10x/day). Enamel alterations were analyzed by surface microhardness (SMH), percentage of surface loss (%SML), cross-sectional microhardness (CSMH), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry (EDS). Student's paired t-test was used for SMH analysis and repeated-measures analysis of variance (ANOVA) for %SML and CSMH (∆Z) analyses (p-value=0.05). The TiF 4 varnish group had lower %SML than the placebo and control groups (p=0.044 and p=0.003, respectively), thus showing its capacity to inhibit surface demineralization. TiF 4 and NaF varnishes demonstrated a protective effect against mineral loss on the enamel subsurface. Both were statistically different from the control group when CSMH was analyzed (p=0.000). A titanium dioxide film was observed on enamel surfaces of the TiF 4 group SEM images. EDS confirmed the presence of titanium in all TiF 4 samples. The 4% TiF 4 varnish is a promising compound capable of reacting with enamel to protect it against surface and subsurface demineralization.

Antibacterial activity against Streptococcus mutans and inhibition of bacterial induced enamel demineralization of propolis, miswak, and chitosan nanoparticles based dental varnishes

Using natural products can be a cost-effective approach for caries prevention especially in low income countries where dental caries is highly prevalent and the resources are limited. Specially prepared dental varnishes containing propolis, miswak, and chitosan nanoparticles (CS-NPs) with or without sodium fluoride (NaF) were assessed for antibacterial effect against Streptococcus mutans (S. mutans) using disk diffusion test. In addition, the protective effect of a single pretreatment of primary teeth enamel specimens against in vitro bacterial induced enamel demineralization was assessed for 3days. All natural products containing varnishes inhibited bacterial growth significantly better than 5% NaF varnish, with NaF loaded CS-NPs (CSF-NPs) showing the highest antibacterial effect, though it didn’t significantly differ than those of other varnishes except miswak ethanolic extract (M) varnish. Greater inhibitory effect was noted with varnish containing freeze dried aqueous miswak extract compared to that containing ethanolic miswak extract, possibly due to concentration of antimicrobial substances by freeze drying. Adding natural products to NaF in a dental varnish showed an additive effect especially compared to fluoride containing varnish. 5% NaF varnish showed the best inhibition of demineralization effect. Fluoride containing miswak varnish (MF) and CSF-NPs varnish inhibited demineralization significantly better than all experimental varnishes, especially during the first 2days, though CSF-NPs varnish had a low fluoride concentration, probably due to better availability of fluoride ions and the smaller size of nanoparticles. Incorporating natural products with fluoride into dental varnishes can be an effective approach for caries prevention, especially miswak and propolis when financial resources are limited.

Urinary fluoride excretion after application of fluoride varnish and use of fluoride toothpaste in young children.

The efficacy and safety of combined use of topical fluoride products are essential issues that must be monitored. To assess urinary excretion of fluoride after application of two different dental varnishes containing 2.26% fluoride in 3- to 4-year-old children and to compare the levels with and without parallel use of fluoride toothpaste. Fifteen healthy children were enrolled to a randomized crossover trial that was performed in two parts: Part I with twice-daily tooth brushing with fluoride toothpaste and Part II with twice-daily brushing with a non-fluoride toothpaste. After a 1-week run-in period, 0.1 mL of the two fluoride varnishes (Duraphat and Profluorid Varnish) was topically applied in a randomized order. Baseline and experimental urine was collected during 6-h periods. The fluoride content was determined with an ion-sensitive electrode. There was a statistically significant increase in the 6-h fluoride excretion after application of both experimental varnishes, with and without parallel use of fluoride toothpaste (P < 0.01). When fluoridated toothpaste was used, the mean fluoride excretion was 0.20 mg/6 h after application of Duraphat and 0.29 mg/6 h after application of Profluorid Varnish (P = 0.18). Topical applications of 0.1 mL of fluoride varnish significantly increased the 6-h fluoride excretion. As some individuals displayed excretion levels exceeding the optimal fluoride exposure, a restricted use of fluoride toothpaste in connection with the varnish applications would decrease fluoride exposure.

Comparison of two different forms of varnishes in the treatment of dentine hypersensitivity: A subject-blind clinical study in Lagos State university teaching hospital

Background: Dentine hypersensitivity is a significant clinical problem affecting several age groups within a population. Aim: This subject-blind randomized clinical study was designed to determine the clinical outcomes of two different varnishes in the management of dentine hypersensitivity. Materials and Methods: Self-reporting, consenting patients (n = 56) referred to the restorative unit of the dental center, Lagos State University Teaching Hospital (LASUTH), were examined for dentine hypersensitivity using the air jet and tactile probe methods. Enlisted patients were randomly assigned into Duraphat or Cervitec Plus varnish groups in a split-mouth study design. The teeth were assessed for sensitivity, and this procedure was repeated on week(s) 1, 2, and 4 following the initial visit. The data collected were analyzed using SPSS version 20, and statistical significance was done using the Student's t-test. P ≤ 0.05 was considered statistically significant. Results: The most affected teeth were the first molars (27.8%) followed by the second premolars (17.6%). There was a significant reduction in sensitivity following application of both control and experimental varnishes on day 1 and much further reduction by week 4. At week 4, P value using the tactile method was 0.090 while that of the air jet was 0.101. However, there was no statistically significant difference in the efficacy of the control and experimental varnishes. Conclusion: Duraphat exhibited better efficacy in the reduction of dentinal hypersensitivity, though the difference was not statistically significant. The Duraphat and Cervitec Plus varnishes can be substituted one for the other, though the Duraphat varnish is more readily available in our environment and costs less than Cervitec Plus varnish.

Fluoride varnishes containing calcium glycerophosphate: fluoride uptake and the effect on in vitro enamel erosion.

Calcium glycerophosphate (CaGP) was added to fluoride varnishes to analyze their preventive effect on initial enamel erosion and fluoride uptake: potassium hydroxide (KOH)-soluble and KOH-insoluble fluoride bound to enamel. This study was carried out in two parts. Part 1: 108 enamel samples were randomly distributed into six varnish groups: base varnish (no active ingredients); Duraphat® (2.26%NaF); Duofluorid® (5.63%NaF/CaF2); experimental varnish 1 (1%CaGP/5.63 NaF/CaF2); experimental varnish 2 (5%CaGP/5.63%NaF/CaF2); and no varnish. Cyclic demineralization (90 s; citric acid, pH = 3.6) and remineralization (4 h) was made once a day, for 3 days. Change in surface microhardness (SMH) was measured. Part 2: 60 enamel samples were cut in half and received no varnish (control) or a layer of varnish: Duraphat®, Duofluorid®, experimental varnishes 1 and 2. Then, KOH-soluble and KOH-insoluble fluoride were analyzed using an electrode. After cyclic demineralization, SMH decreased in all samples, but Duraphat® caused less hardness loss. No difference was observed between varnishes containing CaGP and the other varnishes. Similar amounts of KOH-soluble and insoluble fluoride was found in experimental varnish 1 and Duofluorid®, while lower values were found for experimental varnish 2 and Duraphat®. The addition of CaGP to fluoride varnishes did not increase fluoride bound to enamel and did not enhance their protection against initial enamel erosion. We observe that the fluoride varnishes containing CaGP do not promote greater amounts of fluoride bound to enamel and that fluoride bound to enamel may not be closely related to erosion prevention.

The erosion and abrasion‐inhibiting effect of TiF4 and NaF varnishes and solutions on enamel in vitro

OBJECTIVE. Previous in vitro study has shown that TiF(4) varnish might reduce enamel erosion. No data regarding the effect of this experimental varnish on enamel erosion plus abrasion, however, are available so far. Thus, this in vitro study aimed to analyse the effect of TiF(4) compared with NaF varnishes and solutions, to protect against enamel erosion with or without abrasion. METHODS. Enamel specimens were pre-treated with experimental-TiF(4) (2.45% F), experimental-NaF (2.45% F), NaF-Duraphat (2.26% F), and placebo varnishes; NaF (2.26% F) and TiF(4) (2.45% F) solutions. Controls remained untreated. The erosive challenge was performed using a soft drink (pH 2.6) 4 × 90 s/day (ERO) and the toothbrushing abrasion (ERO+ABR) 2 × 10 s/day, for 5 days. Between the challenges, the specimens were exposed to artificial saliva. Enamel loss was measured profilometrically (μm). RESULTS. Kruskal-Wallis/Dunn tests showed that all fluoridated varnishes (TiF(4) -ERO:0.53 ± 0.20, ERO+ABR:0.65 ± 0.19/NaF-ERO:0.94 ± 0.18, ERO+ABR:1.74 ± 0.37/Duraphat-ERO:1.00 ± 0.37, ERO+ABR:1.72 ± 0.58) were able to significantly reduce enamel loss when compared with placebo varnish (ERO:3.45 ± 0.41/ERO+ABR:3.20 ± 0.66) (P < 0.0001). Placebo varnish, control (ERO:2.68 ± 0.53/ERO+ABR:3.01 ± 0.34), and fluoridated (NaF-ERO:2.84 ± 0.09/ERO+ABR:2.40 ± 0.21/TiF(4) -ERO:3.55 ± 0.59/ERO+ABR:4.10 ± 0.38) solutions did not significantly differ from each other. CONCLUSION. Based on the results, it can be concluded that the TiF(4) varnish seems to be a promising treatment to reduce enamel loss under mild erosive and abrasive conditions in vitro.

Preventive effect of an iron varnish on bovine enamel erosion in vitro

Objective The aim of this study was to evaluate, in vitro, the effect of an experimental varnish containing iron on the dissolution of bovine enamel by carbonated beverage. Methods Eighty specimens were randomly allocated to four groups ( n = 20 per group), according to the following treatments: Fe varnish (FeV, 10 mmol/L Fe), F varnish (FV, 2.71% F), placebo varnish (PV) and control (not treated, NT). The varnishes were applied in a thin layer and removed after 6 h. Then, the samples were submitted to six cycles, alternating re- and demineralisation (only 1 day). Demineralisation was performed with the beverage Coca-Cola ® (10 min, 30 mL/block) and remineralisation with artificial saliva for 1 h. In order to determine the amount of enamel dissolved, the wear was analysed by profilometry. Data were analysed by ANOVA and Tukey's test ( p < 0.05). Results The mean wear (±S.E.) was significantly lesser for the FeV (0.451 ± 0.018 μm) when compared to the other treatments. The FV caused significantly less wear (0.554 ± 0.022 μm) when compared to PV (0.991 ± 0.039 μm) and NT (1.014 ± 0.033), which did not significantly differ from each other. Conclusions The results suggest that the iron varnish can interfere with the dissolution of dental enamel in the presence of acidic beverages.

Efficacy of differently concentrated chlorhexidine varnishes in decreasing Mutans streptococci and lactobacilli counts

The objective of the present prospective trial was to compare the efficacy of differently concentrated chlorhexidine varnishes (EC40 ® = 40% chlorhexidine and Cervitec ® = 1% chlorhexidine + 0.1% thymol) on levels of Mutans streptococci ( ms), lactobacilli ( lb) and plaque formation in interproximal plaque and saliva. Twenty-four volunteers with a high level of ms in saliva were randomized into two groups and treated with the experimental varnishes. Varnish applications were performed in accordance with literature. Over a period of 2 weeks Cervitec ® was applied three times and EC40 ® once or twice, depending on ms counts after first application. Four and 12 weeks after final varnish application ms in plaque and saliva were evaluated. Furthermore, lactobacilli ( lb) counts in saliva and the effect on plaque formation were recorded. Both varnishes revealed a reduction of ms in interproximal plaque and saliva after 4 and 12 weeks. The highly concentrated varnish revealed a significantly stronger reduction of ms in plaque and saliva compared with the lowly-concentrated varnish. No effect could be demonstrated on lb counts and plaque formation. The results indicate that the chlorhexidine varnishes tested may reduce ms in both interproximal plaque and saliva. However, the application of the highly concentrated varnish EC40 ® results in a higher decrease of ms in plaque sites and saliva.