The erosion and abrasion-inhibiting effect of TiF(4) and NaF varnishes and solutions on enamel in vitro

The role of calcium in the prevention of erosive tooth wear: a systematic review and meta-analysis

OBJECTIVES

The loss of hard dental tissue due to recurrent acid challenges and mechanical stresses without bacterial involvement is known as erosive tooth wear (ETW). Many studies in the literature have concentrated on variables that may affect the ETW process and prevent its occurrence or reduce its advancement. However, to date, no previous systematic review has evaluated the role of calcium in preventing ETW. Therefore, the purpose of the present systematic review was to review and critically appraise the scientific evidence regarding the role of calcium formulations in the prevention of ETW.

METHODS

The review protocol was registered in the PROSPERO international prospective register of systematic reviews (Ref: CRD42021229819). A literature search was conducted in electronic databases to identify in situ randomized controlled trials evaluating the prevention of ETW following the application of calcium formulations. The outcomes studied included mean enamel loss, surface microhardness, surface roughness, mean erosion/softening depth, mineral loss/precipitation and remineralization. Study characteristics and outcomes of included studies were summarized. Cochrane's risk-of-bias tool 2.0 was used to assess the quality of eligible studies, and meta-analysis using a random effects model was performed.

RESULTS

The search retrieved 869 studies of which 21 were considered eligible. Regarding the results of the quality assessment for potential risk of bias in all included studies, overall, 5 studies were considered as being at low risk, another 12 at unclear risk and 4 at high risk of bias. The findings of the studies showed that the addition of calcium in juice drinks led to reduced enamel loss, with blackcurrant juice presenting 2.6 times statistically significant less enamel loss compared to orange juice (p = 0.0001, I2 = 89%). No statistically significant difference in mean surface microhardness of eroded enamel was recorded between chewing gum with or without casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) (p = 0.31, I2 = 71%). Contradictory were the results regarding the effect of milk and CPP-ACP pastes on prevention of ETW.

CONCLUSIONS

Calcium formulations play an important role in ETW prevention, mainly through their addition to acidic drinks.

Effect of silver diamine fluoride/potassium iodide treatment on the prevention of dental erosion in primary teeth: an in vitro study

INTRODUCTION

Dental erosion has a great effect on oral health, when diagnosed it is irreversible, this sets the importance of different preventive measures being investigated against dental erosion.

AIM

This in vitro study aims to evaluate the effectiveness of silver diamine fluoride and Potassium iodide (SDF-KI) in comparison to casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF) varnish, sodium fluoride (NaF) varnish, silver diamine fluoride (SDF) alone and deionized water as a control group in the prevention of dental erosion in primary teeth and assessing its staining effect.

MATERIALS AND METHODS

Forty deciduous teeth enamel specimens were randomly allocated into the five study groups. Tested materials were applied. An erosive challenge was done by immersing the specimens in a citric acid-containing soft drink with pH 2.85, for 5 min, 4 times/day, for 5 days. Changes in surface microhardness, mineral loss, and color change were evaluated besides recording of the surface topography and surface roughness for selected specimens.

RESULTS

The highest decrease in surface microhardness was recorded in the control group (-85.21 ± 10.60%), with a statistically significant difference (p = 0.002). SDF-KI group (-61.49 ± 21.08%) showed no statistically significant difference when compared to CPP-ACPF, NaF, and SDF groups. For calcium and phosphorous loss, control group was statistically significantly higher compared to the treatment groups (p = 0.003) and (p < 0.001) respectively, while there was no statistically significant difference between the tested treatment groups. The highest mean value for color change was recorded in SDF group (26.26 ± 10.31), followed by SDF-KI group (21.22 ± 12.87) with no statistically significant difference between groups.

CONCLUSIONS

SDF-KI is as effective as CPP-ACPF, NaF varnishes and SDF in the prevention of dental erosion in primary teeth, there was no statistically significant difference regarding its staining potential.

Comparative Effects of CPP-ACP and Xylitol F-Varnishes on the Reduction of Tooth Erosion and Its Progression

Abstract Evaluated the effect of CPP-ACP/NaF and xylitol/NaF varnishes in reduce erosion and progression of erosion. Forty enamel blocks were divided into four groups (n=10): G1=CPP-ACP/NaF varnish (MI varnishTM); G2=xylitol/NaF varnish (Profluorid®); G3=NaF varnish (Duraphat®, positive control) and G4=deionized water (MilliQ®, negative control). Samples were immersed in Sprite ZeroTM (pH 2.58, 4x/day, 3 days), in between immersions, the specimens stayed in artificial saliva. After 3 days of erosion, the eroded area was divided in two (half of one received an additional varnish layer while the other half repeated the same 3-day erosion cycle). The 3D, non-contact profilometry technique was used to determinate tooth structure loss (TSL) and surface roughness (SR). Scanning electron microscopy (SEM) and 3D images were utilized to evaluate the topography of the samples. Mann-Whitney, one-way ANOVA and Tukey tests were used (significance level of 0.05%). SEM and 3D images were descriptively evaluated. After 3 or 6 days of erosion, all tested varnishes were better than G4 (p<0.05) for TSL and SR. In addition, G1 had lower values for TSL than G3 (p<0.05) after 3 days of erosion. Under SEM and 3D images observation, all groups presented porosity, irregularities and depressions on the surface enamel after 3 and 6 days of erosion, more pronounced in G4. An application of topical NaF varnishes was effective in reducing TSL and enamel roughness after erosion challenges, being the CCP-ACP/NaF varnish more effective than NaF varnish and water after 3 days of erosion.

The effect of CO2 9.3 μm short-pulsed laser irradiation in enamel erosion reduction with and without fluoride applications-a randomized, controlled in vitro study

The aim of this in vitro study was to evaluate the protective effect of short-pulsed CO₂ 9.3 μm laser irradiation against erosion in human enamel without and combined with TiF₄ and AmF/NaF/SnCl₂ applications, respectively, as well as compared to the protective effect of these fluoride treatments alone. After polishing, ninety enamel samples (3 × 3mm) were used for 9 different treatment groups: 4% TiF₄ gel (pH 1.5, 24,533 ppm F^-); AmF/NaF/SnCl₂ rinse (pH 4.5; 500 ppm F^-, 800 ppm Sn²); CO₂ laser (average power 0.58 W); CO₂ laser (0.58 W) + TiF₄; CO₂ laser (0.58 W) + AmF/NaF/SnCl₂; CO₂ laser (0.69 W); CO₂ laser (0.69 W) + TiF₄; CO₂ laser (0.69 W) + AmF/NaF/SnCl₂; negative control (deionized water). TiF₄ gel was brushed on only once before the first erosive cycling, while samples treated with AmF/NaF/SnCl₂ were daily immersed in 5 ml of the solution before cycling. Laser treatment occurred with a CO₂ laser (wavelength 9.3 μm, pulse repetition rate 100 Hz, pulse duration 14.6 μs/18 μs, average power 0.58 W/0.69 W, fluence 1.9 J/cm²/2.2 J/cm², beam diameter 0.63 mm, irradiation time 10 s, air cooling). TiF₄ was applied only once, while AmF/NaF/SnCl₂ was applied once daily before the erosive challenge. Surface loss (in μm) was measured with optical profilometry immediately after treatment, and after 5 and 10 days of erosive cycling (0.5% citric acid, pH 2.3, 6 × 2 min/day). Additionally, scanning electron microscopy investigations were performed. All application measures resulted in loss of surface height immediately after treatment. After 5 days, significantly reduced surface loss was observed after applying laser irradiation (both power settings) followed by applications of TiF₄ or AmF/NaF/SnCl₂ solution (p < 0.05; 2-way ANOVA and Tukey test) compared to fluoride application alone. After 10 days, compared to after 5 days, a reduced tissue loss was observed in all groups treated with AmF/NaF/SnCl₂ solution. This tissue gain occurred with the AmF/NaF/SnCl₂ application alone and was significantly higher when the application was combined with the laser use (p < 0.05). Short-pulsed CO₂ 9.3 μm laser irradiation followed by additional application of AmF/NaF/SnCl₂ solution significantly reduces the progression of dental enamel erosion in vitro.

TiF4 varnish protects the retention of brackets to enamel after in vitro mild erosive challenge

The effect of fluoride agents on the retention of orthodontic brackets to enamel under erosive challenge is little investigated. The aim of this study was to evaluate the effect of titanium tetrafluoride (TiF4) and sodium fluoride (NaF) agents on the shear bond strength of brackets to enamel and on the enamel microhardness around brackets under erosive challenge. Brackets were bonded to bovine incisors. Five groups were formed according to fluoride application (n=10): TiF4 varnish, TiF4 solution, NaF varnish, NaF solution and control (without application). The specimens were submitted to erosive challenge (90 s cola drink/2h artificial saliva, 4x per day for 7 days). Solutions were applied before each erosive cycle and varnishes were applied once. Vickers Microhardness (VHN) was obtained before and after all cycles of erosion and the percentage of microhardness loss was calculated. Shear bond strength, adhesive remnant index and polarized light microscopy were conducted after erosion. The data were analyzed by ANOVA, Tukey, Kruskal-Wallis and Mann-Whitney U tests (α=0.05). The %VHN had no statistically significant differences among the experimental groups. However, considering the comparisons of all groups with the control group, TiF4 varnish showed the highest protection from enamel demineralization (effect size of 2.94, while the effect size for the other groups was >2.4). The TiF4 varnish group had significantly higher shear bond strength compared to other groups. There was no difference among groups for adhesive remnant index. Polarized light microscopy showed higher demineralization depth for the control group. Application of NaF and TiF4 agents during mild erosive challenge minimized the enamel mineral loss around brackets, however only the experimental TiF4 varnish was able to prevent the reduction of shear bond strength of brackets to enamel.

Effect of erosive challenges on deciduous teeth undergoing restorative procedures with different adhesive protocols - an in vitro study

To evaluate the effect of erosive challenges on the tooth- restoration interface of deciduous teeth treated with different adhesive protocols. Deciduous molars were cut mesiodistally, then embedded, abraded and polished (n=80). Samples were randomly divided according to the adhesive system used into: G1 (Adper Single Bond2®, etch-and-rinse), G2 (Universal Single Bond®, self-etching), G3 (OptibondFL®, etch-and-rinse with Fluoride) and G4 (BondForce®, self-etching with Fluoride). After standardized cavity preparation (2 mm diameter x 2 mm depth), adhesive systems were applied and samples were restored (composite resin Z350®). Half of the samples were exposed to erosive/abrasive cycles (n = 10, each adhesive group), and the other half (control group; n = 10) remained immersed in artificial saliva. For microleakage analysis, samples were submersed in methylene blue and analyzed at 40x magnifications. Cross-sectional microhardness (CSMH) was carried out (50 g/5 s) at 25 μm, 50 μm, and 100 μm from the eroded surface and at 25 μm, 75 μm, and 125 μm from the enamel bond interface. Regarding microleakage, 7.5% of the samples showed no dye infiltration, 30% showed dye infiltration only at the enamel interface, and 62.5% showed dye infiltration through the dentin-enamel junction, with no difference between groups (p≥0.05). No significant difference was observed in CSMH at different depths (two-way ANOVA, p≥0.05). We did not observe significant changes in microleakage or CSMH after erosive/abrasive challenges in deciduous teeth treated with different adhesive protocols (etch-and-rinse and self-etching adhesives, with and without fluoride).

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.

Susceptibility of bovine dental enamel with initial erosion lesion to new erosive challenges

This in vitro study evaluated the impact of initial erosion on the susceptibility of enamel to further erosive challenge. Thirty bovine enamel blocks were selected by surface hardness and randomized into two groups (n = 15): GC- group composed by enamel blocks without erosion lesion and GT- group composed by enamel blocks with initial erosion lesion. The baseline profile of each block was determined using the profilometer. The initial erosion was produced by immersing the blocks into HCl 0.01 M, pH 2.3 for 30 seconds, under stirring. The erosive cycling consisted of blocks immersion in hydrochloric acid (0.01 M, pH 2.3) for 2 minutes, followed by immersion in artificial saliva for 120 minutes. This procedure was repeated 4 times a day for 5 days, and the blocks were kept in artificial saliva overnight. After erosive cycling, final profile measurement was performed. Profilometry measured the enamel loss by the superposition of initial and final profiles. Data were analyzed by t-test (p<0.05). The result showed no statistically significant difference between groups (GS = 14.60±2.86 and GE = .14.69±2.21 μm). The presence of initial erosion on bovine dental enamel does not enhance its susceptibility to new erosive challenges.

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.

Prevention of Enamel Adjacent to Bracket Demineralization Following Carbon Dioxide Laser Radiation and Titanium Tetra Fluoride Solution Treatment: An In Vitro Study

Introduction: The aim of this study was to assess the caries-preventive potential of carbon dioxide (CO₂) laser application in conjunction with the use of titanium tetra fluoride solution on the enamel adjacent to bracket. Methods: Seventy-five freshly extracted bovine incisors were used. In order to attach the brackets, the area of examination was covered with adhesive tape to limit acid etching of the entire enamel surface. Metal orthodontic brackets for upper central were bonded to all the teeth following the manufacturer's instruction. Then all the teeth were painted with 2 layers of acid-resistant nail varnish on all surfaces except the boxes area cervical to the brackets. The teeth were then randomly divided into five groups (n = 15): control group (C); laser group (L); titanium group (T); laser-titanium group (LT) and titanium-laser group (TL). The laser-titanium group was first irradiated with CO₂ laser (same as the L group) then TiF4 solution was applied on the enamel (same as the T group). Samples in the TL group were first treated with TiF4 solution (same as the T group) and then irradiated with CO₂ laser on the surface (same as the L group). Then, the teeth were immersed in pH-cycling solutions. After that, the amount of calcium released into the two solutions (de- and re-mineralization) was measured with an atomic absorption spectroscopy. The data were analyzed by one-way Analysis of var-iance (ANOVA) and Tukey test. Results: Calcium loss in LT, TL and T groups were significantly lower than those in the L and C groups (P < 0.05). Conclusion: The application of Titanium tetra fluoride 4% solution on enamel can inhibit as much as 87% of subsequent caries like lesion progression.

Effect of Fluoride Varnish Containing CPP-ACP on Preventing Enamel Erosion

This study aimed to investigate the effect of a fluoride varnish with added casein phosphopeptide-amorphous calcium phosphate treatment on the prevention of enamel erosion, and it compared the results with those of other fluoride varnishes. Fifty enamel specimens obtained from bovine incisors were randomly divided into five groups (n = 10) based on the type of surface pretreatment used: intact enamel (Group 1); intact enamel+erosive cycles (Group 2); intact enamel+MI varnish+erosive cycles (Group 3); intact enamel+Clinpro White varnish+erosive cycles (Group 4); and intact enamel+Duraphat varnish+erosive cycles (Group 5). The specimens were subjected to erosive cycles for five days. The surface roughness was evaluated using atomic force microscopy. The results were statistically analyzed using one-way ANOVA and Tukey's tests. Group 1 had the smoothest surfaces. After the erosive cycles, the greatest surface roughness values were observed in Group 2, followed by Groups 5, 4, and 3, respectively. Statistically significant differences were observed among all groups (p < 0.05). The application of fluoride varnishes had some positive effects on preventing enamel erosion; however, the most effective agent was fluoride varnish with added casein phosphopeptide-amorphous calcium phosphate.

Enamel lesions: Meta-analysis on effect of prophylactic/therapeutic agents in erosive tissue loss

This study aims to perform a meta-analysis on the effect of prophylactic/therapeutic agents in enamel tissue loss due to erosion. A paper search was done on Medline, PubMed, Embase, and Cochrane Library, and 732 papers were identified. The inclusion criteria were very restrictive in order to be able to compare different protocols and methodologies used on those studies. Sixteen papers were eligible, grouped according to the measurement method of enamel tissue loss, and a meta-analysis was done for each type of fluoride- and casein-based agent applied. Standardized mean differences were pooled across studies. There was a significant difference between all the treatment groups and their respective control groups. The highest standardized mean difference on enamel tissue loss (mean; 95% confidence interval) was obtained by stannous fluoride (4.789 μm; 1.968-7.610; P < 0.001), followed by amine fluoride (2.485 μm; 0.746-4.225; P < 0.010), and titanium tetrafluoride (1.787 μm; 1.106-2.469; P < 0.001); the lowest difference was obtained by casein phosphopeptide-amorphous calcium phosphate (0.869 μm; 0.007-1.731; P < 0.050) and sodium fluoride (0.820 μm; 0.417-1.223; P < 0.001). Stannous fluoride as a fluoride-based prophylactic/therapeutic agent allowed the lowest enamel tissue loss in erosive conditions. Standardization among future study protocols will allow better comparison regarding the prophylactic/therapeutic agent with the best clinical efficacy.

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.

The Special Needs of Preterm Children - An Oral Health Perspective

Preterm births are defined as those before 37 weeks of gestation. With advances in fertility medicine and neonatal medicine, the numbers of preterm children in the community have significantly increased. Developmental delays and complications among preterm children are well recognized. Much less consideration is given to the dental complications of preterm children. Manifestations include palatal deformations, enamel defects, tooth size variations and tooth shape deformities, malocclusions, and increased risks of early childhood caries and tooth wear. This article explores orodental risks and orodental needs of preterm children and suggests preventive and management strategies for optimizing the oral health of special needs children.

Effects of erosive challenge on the morphology and surface properties of luting cements

Abstract Introduction Few studies investigated the surface properties of luting cements after erosive challenge. Objective To evaluate the surface roughness (Ra), Vickers hardness (VHN) and morphology of 4 luting cements after erosive challenge. Material and method Twenty specimens of each cement were prepared (4×2mm) and divided into experimental (erosive challenge) and control (artificial saliva) groups (n=10): Rely X U200 (U200); Rely X ARC (ARC); Ketac Cem Easy Mix (Ketac) and Zinc phosphate (ZnP). The erosive challenge was performed by four daily erosive cycles (90s) in a cola drink and 2 h in artificial saliva over 7 days. Ra and VHN readings were performed before and after erosion. The percentage of hardness loss (%VHN) was obtained after erosion. The surface morphology was analyzed by scanning electron microscopy (SEM). ANOVA, Tukey and Student-T tests were used (α=0.05). Result After erosion, all luting cements had increase in Ra values and U200 and ZnP groups had the highest %VHN. After saliva immersion, only U200 and ZnP groups had significant increases in Ra values and there were no significant differences among the groups in %VHN. SEM analysis showed that Ketac and ZnP groups had rough and porous surfaces, and U200 group had higher resin matrix degradation than ARC group. Conclusion Erosive challenge with a cola drink affected the surface properties of all luting cements.

Artificial Saliva Formulations versus Human Saliva Pretreatment in Dental Erosion Experiments

The aim of this study was to evaluate the erosion-preventive effect of different artificial saliva formulations and human saliva in vitro compared to human saliva in situ. In the in vitro experiment, bovine enamel and dentin specimens were stored in artificial saliva (4 different formulations, each n = 20), deionized water (n = 20) or human saliva (n = 6 enamel and dentin specimens/volunteer) for 120 min. In the in situ experiment, each of the 6 enamel and dentin specimens was worn intraorally by 10 volunteers for 120 min. The specimens were then eroded (HCl, pH 2.6, 60 s). Half of the specimens were subjected to microhardness analysis (enamel) and the determination of calcium release into the acid (enamel and dentin), while the other half were again placed in the respective medium or worn intraorally, respectively, for 120 min before a second erosion was performed. Knoop microhardness of enamel and the calcium release of enamel and dentin into the acid were again determined. Statistical analysis was conducted by two-way repeated-measures ANOVA or two-way ANOVA (α = 0.05). Enamel microhardness was not significantly different between all test groups after the first and the second erosive challenge, respectively. Enamel calcium loss was significantly lower in situ compared to the in vitro experiment, where there was no significant difference between all test groups. Dentin calcium loss was significantly lower than deionized water only after the first and than all except one artificial saliva after the second erosion. Under the conditions of this experiment, the use of artificial saliva formulations and human saliva in vitro does not reflect the intraoral situation in dental erosion experiments adequately.

Experimental study of iron and multivitamin drops on enamel microhardness of primary tooth

OBJECTIVES

Iron and multivitamin drops are being frequently prescribed in children less than 2 years of age. Due to their low pH levels, these drops may lead to the softening of enamel and accelerate the destructive process. The aim of the present study was to investigate the enamel microhardness of primary teeth after exposing them to iron and multivitamin drops.

MATERIALS AND METHODS

Forty healthy anterior teeth were randomly divided into four groups of 10 samples each. Samples were exposed to two iron drops of Kharazmi (Iran) and Ironorm (UK) and two multivitamin drops of Shahdarou (Iran) and Eurovit (Germany) for 5 min. The surface microhardness was measured before and after exposure and data processing was done using statistical paired t-test and analysis of variance (ANOVA) test. The surface structure of the teeth was examined by scanning electron microscope (SEM).

RESULTS

In all groups, microhardness was decreased, but it was not significant in Eurovit multivitamin group (P = 0.088). The reduction rate in Kharazmi iron group was significant compared to that in other groups (P < 0.005). Hardness reduction percent for Kharazmi iron drop was 28/12 ± 47/43. In SEM analysis, irregular granular appearance was observed in the enamel exposed to Kharazmi iron drop.

CONCLUSION

The results showed that all the studied drugs have the potential to cause erosion; this potential is the most in Kharazmi iron drop and the least in Eurovit multivitamin drops. Therefore, after using these kinds of drops, preventive measures should be used in children.

TiF4 and NaF varnishes as anti-erosive agents on enamel and dentin erosion progression in vitro

OBJECTIVE

This study assessed the effect of fluoride varnishes on the progression of tooth erosion in vitro.

MATERIAL AND METHODS

Forty-eight enamel and 60 root dentin samples were previously demineralized (0.1% citric acid, pH 2.5, 30 min), leading to a baseline and erosive wear of 12.9 and 11.4 µm, respectively. The samples were randomly treated (6 h) with a 4% TiF4 varnish (2.45%F-, pH 1.0), a 5.42% NaF varnish (2.45%F-, pH 5.0), a placebo varnish and no varnish (control). The samples were then subjected to erosive pH cycles (4x90 s/day in 0.1% citric acid, intercalated with artificial saliva) for 5 days. The increment of the erosive tooth wear was calculated. In the case of dentin, this final measurement was done with and without the demineralized organic matrix (DOM). Enamel and dentin data were analyzed using ANOVA/Tukey's and Kruskal-Wallis/Dunn tests, respectively (p<0.05).

RESULTS

The TiF4 (mean±s.d: 1.5±1.1 µm) and NaF (2.1±1.7 µm) varnishes significantly reduced enamel wear progression compared to the placebo varnish (3.9±1.1 µm) and control (4.5±0.9 µm). The same differences were found for dentin in the presence and absence of the DOM, respectively: TiF4 (average: 0.97/1.87 µm), NaF (1.03/2.13 µm), placebo varnish (3.53/4.47 µm) and control (3.53/4.36 µm).

CONCLUSION

The TiF4 and NaF varnishes were equally effective in reducing the progression of tooth erosion in vitro.

In situ investigation of the effect of TiF4 and CO2 laser irradiation on the permeability of eroded enamel

OBJECTIVE

Interest in erosion and its role in tooth wear has increased considerably. Due to the limited contribution of patients in modifying their dietary habits, therapeutic resources aiming to reduce the progression of erosion-like lesions have been discussed. This study sought to evaluate the effect of TiF4 and CO2 laser in controlling the permeability of in situ eroded enamel.

DESIGN

Ten volunteers wore an intraoral palatal device containing two enamel slabs, treated with TiF4 gel and TiF4 gel + CO2 or placebo gel and placebo gel + CO2. After the washout period, volunteers were crossed over to the other treatment. During both phases, specimens were submitted to erosive challenges and then evaluated for permeability measured as the percentage of copper ion penetration over the total enamel thickness.

RESULTS

Two-way analysis of variance (ANOVA) revealed that there was a significant interaction between the factors under study (p = 0.0002). Tukey's test showed that TiF4 significantly reduced the enamel permeability of eroded enamel specimens, regardless of whether CO2 laser irradiation was performed.

CONCLUSIONS

It may be concluded that when the placebo gel was applied, CO2 laser was able to reduce enamel permeability; however, when TiF4 was applied, laser irradiation did not imply a reduction in permeability. TiF4 provided a lower permeability of eroded enamel, regardless of whether the CO2 laser was used.

In vitro effect of calcium nanophosphate and high-concentrated fluoride agents on enamel erosion: an AFM study

BACKGROUND

Calcium nanophosphate paste can provide ions to remineralize enamel. There are, however, no data available about the remineralizing effect of this paste on the prevention of enamel erosion, when compared with highly concentrated fluoride agents.

AIM

To analyze the effect of calcium nanophosphate paste, fluoride gel, and varnish to protect against enamel erosion using surface Knoop hardness (KNH) and atomic force microscopy (AFM).

DESIGN

Forty enamel blocks (4 × 4 mm) of third molars were used for 4 groups (n = 10): 1.23% fluoride gel (Fluorgel-DFL(®) ); calcium nanophosphate paste (Desensibilize NanoP-FGM(®) ); fluoride varnish (Duraphat-Colgate(®) ) and control (without agent). The specimens were immersed in cola drink for 5 min and 2 h in artificial saliva, 4× per day for 5 days. The agents were applied before the first erosive cycle. KNH values were obtained before and after the erosive challenge. The surface morphology was evaluated by AFM. anova, Tukey's, and T-Student tests were applied.

RESULTS

After erosion, no significant difference was found for KNH among gel, nanophosphate, and varnish groups; however, they showed higher KNH than control group. Gel and nanophosphate paste showed a protective layer formation on enamel surface by AFM.

CONCLUSIONS

The calcium nanophosphate paste showed similar protection against enamel erosion compared with high-concentrated fluoride agents, even containing lower fluoride concentration.