Caries-like Lesions Research Articles

Effect of Er:YAG and Fluoride Varnishes for Preventing Primary Enamel Demineralisation.

To measure the demineralisation changes on human deciduous enamel produced by pH cycling after preventive treatment with Er:YAG laser irradiation, fluoride varnish application and a combination of the two. Sixty extracted human anterior primary teeth were assigned to six groups (n = 10). Group C: untreated; group L: Er:YAG laser; group TCP-NaF: Clinpro White (5% sodium fluoride and modified tricalcium phosphate); group CPP-ACP-NaF: MI varnish (5% sodium fluoride with casein phosphopeptide-amorphous and calcium phosphate); group L+TCP-NaF: Er:YAG + 5% sodium fluoride + modified tricalcium phosphate; group L+ CPP-ACP-NaF: Er:YAG + 5% sodium fluoride with casein phosphopeptide-amorphous and calcium phosphate. The samples were subjected to a 10-day pH-cycling regimen to create caries-like lesions, with 8 h in demineralising solution and 16 h in remineralising solution at 37°C. Enamel demineralisation was evaluated by laser fluorescence (DIAGNOdent) before and after pH cycling. The Mann-Whitney U-test and Wilcoxon tests were performed with statistical significance set at p ≤ 0.05. The Wilcoxon test revealed statistically significant differences at baseline and after pH cycling in groups C (p = 0.02), L (p = 0.034) and L+TCP-NaF (p = 0.025) and the lowest percentage of healthy tooth substance compared to the other groups. The results suggest that the treatment protocols employed in groups TCP-NaF, CPP-ACP-NaF, and L+ CPP-ACP-NaF had similar effects in terms of preventing demineralisation, as reflected in a higher percentage of healthy dental structure maintained. Hence, these treatments are recommended for clinical use as an effective preventive measure.

Antimicrobial effect of herbal extract of Acacia arabica with triphala on the biofilm forming cariogenic microorganisms

BackgroundDental caries is a biofilm-related infectious disease with a multifactorial etiology, over five billion inhabitants have affected worldwide due to this disease. ObjectiveAntimicrobial efficacy of a mixed herbal powder extract (MHPE) against cariogenic microorganisms was investigated. Materials and methodsMIC, MBC, kinetics of killing, biofilm disruption and anticaries effect of MHPE were determined. For biofilm disruption, biofilms of Streptococcus mutans, Lactobacillus casei, Actinomyces viscosus and Candida albicans were treated with MHPE for 30 min and attached cells were quantified after staining. For live/dead staining biofilm assay, S. mutans biofilm treated with MHPE for 1min, 5min and 1 h was examined with confocal laser scanning system after live/dead staining. Efficacy was experimented by structural quality using Scanning Electron Microscope (SEM). Anticaries effect was determined by formation of caries-like lesion in continuous flow biofilm model. ResultsMHPE exhibited inhibition zones ranging from 12.5 to 24.0 mm. The highest inhibition zone was recorded at concentration of 50 μg/ml. MIC for S. mutans was between 12.23 and 36.7 μg/ml, while the MBC values ranged from 36.7 to 110.65 μg/ml. Inhibitory concentration of MHPE was three fold higher than CHLX. Significant reduction of cell count (49–95%) was observed with increasing time and higher concentration. Percentage biofilm reduction compare with negative control was 96.9% (A. viscosus), 94% (C. albicans), 99.8% (L. casei) and 91.7% (S. mutans). For MHPE-treated biofilm, live/dead staining demonstrated significant (p < 0.05) higher in deceased red fluorescence areas in all kinetics points from 53.6% (1min) to 85% (1h). SEM confirmed the damage in the outer layers of S. mutans. MHPE has components with effective antibacterial activity against caries-inducing microorganisms. ConclusionThe anti-adherence and anti-biofilm effect as well as the faster killing activity suggests that MHPE formula has effective antibacterial activity and could be a useful source of anti-cariogenic agents in near future.

Biomimetic Mineralizing Agents Recover the Micro Tensile Bond Strength of Demineralized Dentin.

Biomimetic remineralization is an approach that mimics natural biomineralization, and improves adhesive procedures. The aim of this paper was to investigate the influence of Dentin Caries-like Lesions (DCLL)-Producing Model on microtensile bond strength (μTBS) of etch and rinse adhesive systems and investigate the effect of remineralizing agents such as Sodium Fluoride (NaF), MI Paste™ (MP) and Curodont™ Repair (CR) on caries-affected dentin (n = 6). Nine groups were established: (1) Sound dentin; (2) Demineralized dentin/Chemical DCLL: (3) Demineralized dentin/Biological DCLL; (4) Chemical/DCLL + NaF; (5) Chemical/DCLL + MP; (6) Chemical/DCLL + CR; (7) Biological/DCLL + NaF; (8) Biological/DCLL + MP; (9) Biological/DCLL + CR. Then all dentin blocks were subjected to a bonding procedure with Adper™ Single Bond 2 adhesive system/Filtek Z350XT 4 mm high block, following this they were immersed in deionized water/24 h and then sectioned with ≅1 mm2 beams. The μTBS test was conducted at 1 mm/min/500 N loading. Failure sites were evaluated by SEM (scanning electron microscopy (150×). μTBS data were submitted to factorial ANOVA and Tukey’s test (p < 0.05). The highest values were found when demineralized dentin was treated with MP and CR, regardless caries lesion depth (p < 0.05). There was a predominance of adhesive/mixed in the present study. It was concluded that the use of the artificial dentin caries production models produces differences in the μTBS. Additionally MP and CR remineralizing agents could enhance adhesive procedures even at different models of caries lesion.

Bleaching of simulated stained-remineralized caries lesions in vitro.

Non-invasive esthetic treatment options for stained arrested caries lesions have not been explored. This study aimed to develop laboratory models to create stained-remineralized caries-like lesions (s-RCLs) and to test the efficacy of bleaching on their esthetic treatment. One hundred twelve enamel/dentin specimens were prepared from human molars, embedded, and had their color measured spectrophotometrically at baseline and after demineralization. They were randomly divided into four groups (n = 14) based on the staining/remineralization protocols for a total of 5days: G1, no staining/no remineralization; G2, no staining/remineralization in artificial saliva (AS); G3, non-metallic staining/remineralization with sodium fluoride/AS; and G4, metallic staining/remineralization with silver diamine fluoride/AS. The lesion mineral loss (ΔZ) and depth (L) were measured using transverse microradiography along with color change (ΔE). Specimens were bleached and color was re-evaluated. Data were analyzed using ANOVA models followed by Fisher's PLSD tests (α = 0.05). s-RCLs in G4 were significantly (p < 0.001) darker than G3, G2, and G1 regardless of substrate type and condition. s-RCLs in G2, G3, and G4 showed significantly lower ΔZ and L than G1 (all p < 0.001), confirming occurrence of remineralization. G4 exhibited significantly lower ΔZ and L compared to G2 (p < 0.001). Bleaching was more effective in non-metallic than in metallic stained lesions regardless of substrate type (p < 0.001). The proposed models created distinct s-RCLs. Non-metallic s-RCLs were lighter and more responsive to bleaching compared to metallic s-RCLs. The developed experimental models allow the further investigation of the efficacy and safety of different clinical strategies for the esthetic management of s-RCLs.

Effects of Laser and Fluoride on the Prevention of Enamel Demineralization: An In Vitro Study.

Introduction: Investigations have demonstrated that fluoride is an essential element in preventive dentistry. However, there are still controversies about the preventive effects of various kinds of laser. The aim of this study was to examine the effect of diode laser irradiation (810 nm) with or without fluoride therapy in the prevention of deciduous enamel demineralization. Methods: Sixty deciduous molar crowns were randomly assigned to 6 groups: C: received no treatment; F: fluoride varnish application; 2L: 2 times diode laser irradiation; 4L: 4 times diode laser irradiation; F2L: 2 times laser irradiation over fluoride varnish; F4L: 4 times laser irradiation over fluoride varnish. Teeth in all groups were subjected to a pH-cycling process to produce artificial caries-like lesions. Results: The analysis of variance (ANOVA) of microhardness values indicated a significant great effect for laser, fluoride, and the interaction of laser- fluoride on reducing the final microhardness value (P<0.001). However, the 2L group was an exception. Despite the 4L group, it did not show a significant prevention of enamel microhardness loss (P=0.125). These 2 groups exhibited different effects in the absence of fluoride (P 2L-4L=0.05) while in the presence of the fluoride varnish, no statistically significant difference was observed between them (P F2L-F4L=0.257). Moreover, no statistically significant difference was observed between the laser-fluoride combination group and the fluoride group (P F2L-F=0.133, P F4L-F=0.926). Conclusion: Our results suggest that fluoride varnish, diode laser, and their combination decrease the loss of the enamel microhardness value and potentially prevent deciduous enamel demineralization. However, the combination of laser and fluoride was not more effective than fluoride.

Comparison of remineralization by fluoride varnishes with and without casein phosphopeptide amorphous calcium phosphate in primary teeth

Objective: To compare MI (5% NaF with 2% CPP-ACP) and Prevident (5% NaF) varnishes in remineralizing caries-like lesions in primary teeth regarding calcium and phosphate enamel content and lesion depth.Material and methods: Caries-like lesions were created in 48 primary teeth which were divided into 2 halves; one left untreated (control) and the other half treated with MI or Prevident varnishes. Calcium and phosphate content was assessed using energy dispersive X-ray spectrometer and reduction in lesion depth was assessed using polarized light microscopy. Demineralization and remineralization values in each group were compared using paired t test and percentage change between groups was compared using t test and Mann Whitney U test.Results: A greater percentage increase of calcium was observed in MI than Prevident specimens (median = 8.97 and 2.67, p < .0001), with greater calcium phosphate ratio percentage increase (median = 28.96 and 7.40) and phosphate percentage reduction (median = 15.5 and 4.51). The mean (SD) percentages reduction in lesion depth in the MI varnish was significantly greater than in Prevident varnish (44.41 (7.12) and 22.73 (9.35), p < .0001).Conclusions: MI varnish had better remineralization effect in primary teeth than Prevident varnish in terms of higher mineral content and shallower lesion depth.

The combined enamel remineralization potential of arginine and fluoride toothpaste

Objective(s)This study examined the remineralization potential of arginine (Arg) in NaF toothpaste. MethodsFifty enamel specimens allocated to five groups (n = 10) were subjected to artificial caries formation. A 10-day pH-cycling was performed to treat specimens as per group – [1]: 2% Arg – NaF, [2]: 4% Arg – NaF, [3]: 8% Arg – NaF, [4]: NaF and [5]: deionized water. The test solutions were subjected to pH measurement, fluoride estimation, Na-Cl element analysis using ICP-EOS and FTIR analyses. Mineral density of the specimens were assessed using micro-CT; while Ca/P ratio and surface fluorine concentration were determined using energy dispersive x-ray spectroscopy (EDS) and enamel fluoride uptake (EFU) by acid-etch method. ResultspH, fluoride concentration and Na-Cl ratio exhibited significant difference amongst groups (p < 0.001). FTIR analysis showed presence of free amino acids in 2% and 4% Arg-NaF group. The mean mineral gain (0.40 ± 0.07 g/cm3) and percent remineralization (27.91 ± 4.66%) of 2% Arg-NaF group were significantly higher than the other 4 groups (p < 0.001). Conversely, the median Ca/P ratio for 2% Arg-NaF (1.60) was significantly higher than deionized water (1.53) (p = 0.029). The mean surface fluorine concentration of specimens treated with 2% Arg-NaF (1.51 ± 0.14%) was significantly higher than treatment with NaF (1.02 ± 0.28%) (p < 0.001). The EFU of 2% Arg-NaF group (6.84 ± 1.59 μg/cm2) was significantly higher than NaF group (5.22 ± 1.88 μg/cm2) (p < 0.001). ConclusionIncorporation of 2% arginine in NaF toothpaste significantly increased the remineralization of enamel caries-like lesion when compared to NaF toothpaste; while 4% and 8% arginine in NaF toothpastes were ineffective in improving enamel remineralization. Clinical SignificanceIn high-risk patients, daily use of 2% arginine in NaF toothpaste might provide a synergistic anti-caries effect given the proven prebiotic benefits of arginine in caries prevention and the demonstrated remineralization effect in the present study.

Impact of toothbrushing frequency and toothpaste fluoride/abrasivity levels on incipient artificial caries lesion abrasion

ObjectivesTo investigate the interplay among brushing frequency, dentifrice slurry abrasivity, and fluoride content on the surface loss (SL) of incipient enamel caries-like lesions. MethodsLesions were created in 96 bovine enamel specimens (5 × 5 mm) using methylcellulose acid gel. Specimens were randomly allocated to 12 groups (n = 8), resulting from the association of three experimental factors: (1) slurry abrasive level [low: REA = 4/RDA = 69 and high: REA = 7/RDA = 208], (2) fluoride concentration [275 and 1250 ppm F as NaF], and (3) brushing frequency [1, 2 and 3× daily]. Specimens were kept in artificial saliva in between brushings and overnight. SL was determined by optical profilometry after lesion creation, 1, 3, 5, and 7 days. Data was analyzed with repeated measures ANOVA and Tukey’s tests (α = 0.05). ResultsHigh abrasive slurry caused significantly more SL than low with 275 ppm (p < 0.001) but not with 1250 ppm fluoride (p = 0.34). Fluoride at 275 ppm had significantly more SL than 1250 ppm with high abrasive slurry after 7 days (p = 0.008). Brushing 1×/day had significantly less SL than 3×/day after 7 days with high abrasive slurry (p = 0.016), especially in the 275 ppm fluoride groups. ConclusionsHigher fluoride concentration increased protection against the deleterious effect of high abrasive slurry. SL was higher if brushing was performed more than twice daily especially in low fluoride groups. Clinical significanceHighly abrasive toothpaste formulations might cause more surface wear to incipient caries lesions, especially at higher brushing frequencies. Increasing the fluoride content may be beneficial at these circumstances.

Comparing topical fluoride application, laser irradiation and their combined effect on remineralisation of enamel

The aim of the study was to verify whether subablative Er:YAG laser irradiation combined with fluoride application could provide a significantly greater inhibition of enamel demineralization histologically using Polarized light microscopy and to and to compare microhardness of enamel around orthodontic brackets after treatment by either fluoride, laser, or both. Material and methods: eighty freshly extracted premolars were randomly assigned to four groups after bonding: (A) control, (B) irradiated by Er: YAG laser& Voco Bifluoride 10™ varnish, (C) treated by Voco Bifluoride 10™ varnish, (D) irradiated by Er: YAG laser before pH cycle. Caries-like lesions were created by pH-cycling. At the end of the pH cycle, each group was divided into 2 equal sub-groups: first subgroup was prepared for microhardness test and examined under polarized light microscope, second subgroup received a second application of therapeutic agents then entered a second pH cycle for another 14 days then teeth were prepared for measuring surface micro hardness and examination under polarized light microscope. Results: group B showed decrease in percentage of lesion depth compared to control group by more than 70% and there was statistically significant difference between it and the other groups. Group D showed increase in percentage of lesion depth with marked loss of enamel surface compared to control group by 29% after 14 days and 9% after 28 days. Moreover group B showed the highest microhardness values and Group D showed the lowest values. Conclusion: In this in vitro study, laser and fluoride combination enhance the resistance of sound enamel around orthodontic brackets more effectively than Er: YAG laser application alone.

Root Caries Prevention Potential of Chopped CO2 Laser: an In Vitro Study

The objective of this study aimed to assess the caries-preventive potential of various chopped CO2 laser parameters, and to explore the effect of the laser energy density on the caries inhibition activity.Roots of extracted human premolar teeth were irradiated with three various energy densities (25.47, 50.93, and 101.86) J/cm2, by changing the number of pulses, the pulse duration, and the spot diameter. The CO2 laser system emitted laser with 10.6m in wavelength. All roots were subjected to carieslike lesion formation by 3.5 pH lactic acid for 21 days. The roots after that were sectioned into ground cross sections and the lesion depths were measured under a polarizing microscope.Chopped CO2 laser preventive treatments inhibited carieslike lesion progression up to 36%. This effect was improved with decreased total energy density within the limits of the examined laser parameters.

Secondary caries formation with a two-species biofilm artificial mouth

ObjectivesThe present study aimed to establish Lactobacillus casei in a completely automated Streptococcus mutans-based artificial mouth model and to investigate secondary caries inhibiting properties of glass ionomer cements / resin composite groups in vitro. MethodsSixty extracted, caries-free human third molars were used for preparation of standardized class-V-cavities. Specimens were restored with a resin-modified (Photac Fil; PF) as well as a conventional glass ionomer cement (Ketac Molar; KM) and one resin composite bonded with and without conduction of etch-and-rinse technique (Prime&Bond NT, Ceram X mono; C+ERT, C). Following an incubation in distilled water for 28d at 37°C, specimens were exposed to 10,000 thermocycles (+5 °C/+55°C). A completely automated S. mutans-based (DSM No.: 20523) artificial mouth model was extended by establishment of L. casei (DSM No.: 20021). During microbiological loading, demineralization (4h/d) was caused by acid production resulting from bacterial glycolysis and artificial saliva was used for remineralization (20h/d). For quantitative margin analysis under am SEM, epoxy replicas were produced from impressions taken after thermocycling and after microbiological loading. Specimens were cut in half perpendicularly to restoration surfaces and demineralization depths at restoration margins and in 500μm distance from margins were evaluated by means of a fluorescence microscope (FITC filter). ResultsAfter microbiological loading, overall demineralization depths in enamel at restoration margin (EM) and in 500μm distance (ED) as well as in cementum/dentin at restoration margin (DM) and in 500μm distance (DD) were measured as follows (μm±SD): PF: EM 42±15, ED 60±17, DM 83±18; DD 127±16; KM: EM 46±22, ED 62±17, DM 104±21, DD 143±28; C+ERT: EM 67±19, ED 61±17, DM 165±31, DD 176±35; C: EM 65±23, ED 64±17, DM 161±27, DD 166±33. For the glass ionomer cements, the overall demineralization depths at restoration margins were significantly lower than in 500μm distance from margins (T-test, p<0.05). Especially at restoration margins in cementum/dentin, the resin composite groups showed significantly larger overall demineralizations than the glass ionomer cements (ANOVA, mod. LSD, p<0.05). Decreases of marginal quality were detected in all groups after microbiological loading (Friedman-test, p<0.05). SignificanceThe refined experimental setup was suitable for production of artificial secondary caries-like lesions. Glass ionomer cements as fluoride-releasing materials may show an inhibition of secondary caries formation to a certain extent.

Remineralizing effect of a fluoridated gel containing sodium hexametaphosphate: An in vitro study

ObjectivesTo evaluate in vitro the effect of neutral pH topical gels with reduced fluoride concentration (F), supplemented or not with sodium hexametaphosphate (HMP) on the remineralization of dental enamel, using a pH-cycling model. Materials and methods Bovine enamel blocks with caries-like lesions were randomly treated with five gels (n = 24/group): without F/HMP (Placebo); 4500 ppm F (4500F), 4500F plus 9% HMP (4500F + HMP); 9000 ppm F (9000F); and 12,300 ppm F (Acid gel). After pH-cycling, the percentage of surface hardness recovery (%SHR), integrated loss of subsurface hardness (ΔKHN), and concentrations of loosely- (CaF2) and firmly-bound (FA) fluoride formed and retained in/on enamel were determined. The results were analyzed by ANOVA followed by the Student-Newman-Keuls test (p < 0.001). ResultsThe 4500F + HMP gel promoted the highest %SHR among all groups; the lowest ΔKHN was achieved by 4500F + HMP and Acid gel, without significant differences between these. The Acid gel group presented the highest CaF2 and FA formed and retained on/in enamel (p < 0.001). ConclusionBased on the present results, the addition of 9% sodium hexametaphosphate to a gel with reduced fluoride concentration (4500F) was able to significantly enhance the remineralization of artificial carious lesions in vitro when compared to 4500F, reaching protective levels similar to an acidic formulation with ∼3-fold higher fluoride concentration.

Prevention of Enamel Caries by Low Power Dye Assisted He-Ne Laser: an In Vitro Study

The objective of this study aimed to assess the carieslike lesion preventive potential of low power dye assisted He-Ne laser.Enamel of extracted human premolar teeth were painted with methylene blue dye and irradiated with 5 mW of He-Ne laser, which emitted laser with 632.8 nm in wavelength. Another group were irradiated without dye application, and the third group was served as control (without laser irradiation). All samples were subjected to carieslike lesion formation by 3.5 pH lactic acid for 21 days. The crowns after that were sectioned into ground cross sections and the lesion depths were measured under a polarizing microscope.According to this study, successful carieslike lesion inhibition could be achieved to 29% extent, by using low power dye assisted He-Ne laser irradiation.

The Effect of Laser Irradiation on the Thickness of the Caries Surface Zone

The objective of this study aimed to assess the relation between various CW CO2 laser parameters and the thickness of the surface zone in the created carieslike lesion.A total of twenty four extracted human premolar teeth were irradiated with three various power densities (63.66, 31.83, and 15.9) W/cm2. The CO2 laser system emitted laser with 10.6m in wavelength. All samples were subjected to 3.5 pH lactic acid for 21 days to form carieslike lesion. The crowns after that were sectioned into ground cross sections and the surface zone thicknesses were measured under a polarizing microscope.Continuous wave (CW) CO2 laser had a noticeable effect on the prominence of the surface zone. The mean of the surface zone thicknesses found to be directly related to the power density of CW CO2 laser.

Effect of Siwak Extract on the Microhardness and Microscopic Feature of Initial Caries-Like Lesion of Permanent Teeth, Compared to Fluoridated Agents

Siwak is a chewing stick used to clean the teeth and message the gum. Theirroutine use was shown to be associated with the reduction in severity of dental caries.This study aimed to test the effect of water Siwak extract on the microhardness andmicroscopic features of artificially initiated carious lesion of the outer enamel surface,in comparison to stannous fluoride and sodium fluoride. Upper first premolars wereextracted and subjected to pH cycling procedure. Teeth immerged individually in 20ml of selected agents for four minutes then rinsed by de ionized water. Agentsinvolved were 5% and 10% water Siwak extract, 8% stannous fluoride and 0.05%sodium fluoride. Samples were subjected to Vickers microhardness test andmicroscopic examination before and after the pH cycling and following insertion inthe agents. Water Siwak extract, stannous fluoride and sodium fluoride were found toincrease the microhardness values of de mineralized enamel surfaces, this werestatistically highly significant for Siwak extract and stannous fluoride (P&lt; 0.01) andsignificant for sodium fluoride. However none of the mentioned agents was able toincrease the micro hardness to approximate the original values of the sound enamel.Under polarized light results revealed that water Siwak extracts and stannous fluorideproduce the best remineralization surface zone. Water Siwak extracts is very effectivein remineralization of initial carious lesion.

Sodium Trimetaphosphate as a Novel Strategy for Matrix Metalloproteinase Inhibition and Dentin Remineralization

The effect of sodium trimetaphosphate (STMP) as an antiproteolytic and remineralizing agent on demineralized dentin was evaluated in vitro. The inhibitory potential of STMP at 0.5, 1.5, 3.5, and 5% against recombinant matrix metalloproteinases (MMPs) MMPs-2 and -9 was assessed by zymography. To investigate its remineralization potential, 40 bovine root specimens were obtained and subjected to a demineralization protocol to produce caries-like dentin lesions. After that, dentin surfaces were divided into 3 areas: (1) mineralized (no treatment); (2) demineralized; and (3) demineralized/treated with STMP and submitted to a pH-cycling associated or not with STMP (1.5, 3.5, or 5% STMP, 10 min of treatment). After that, superficial hardness (SH) and cross-sectional hardness (CSH) were determined. Polarized light microscopy (PLM) was used to qualitatively evaluate mineralization within the caries-like lesions. The zymographic analysis showed that STMP solution is a potent inhibitor of the gelatinolytic activity of MMPs-2 and -9 depending on the dose, since the lowest concentration (0.5%) partially inhibited the enzyme activity, while the higher concentrations completely inhibited enzyme activity. Regarding remineralization effect, only 1.5% STMP solution enhanced both the SH and CSH. PLM showed that the area treated with 1.5% STMP presented similar birefringence as mineralized sound dentin. In conclusion, 1.5% STMP solution is effective as an antiproteolytic agent against MMPs and promotes dentin remineralization.

Caries-Preventive Effect of NaF, NaF plus TCP, NaF plus CPP-ACP, and SDF Varnishes on Sound Dentin and Artificial Dentin Caries in vitro

The aim of this study was to compare the caries-preventive effect of different fluoride varnishes on sound dentin as well as on artificial dentin caries-like lesions. Bovine dentin specimens (n = 220) with one sound surface (ST) and one artificial caries lesion (DT) were prepared and randomly allocated to 11 groups. The interventions before pH cycling were as follows: application of a varnish containing NaF (22,600 ppm F^-; Duraphat [NaF₀/NaF₁]), NaF plus tricalcium phosphate (22,600 ppm F^-; Clinpro White Varnish Mint [TCP₀/TCP₁]), NaF plus casein phosphopeptide-stabilized amorphous calcium phosphate complexes (CPP-ACP; 22,600 ppm F^-; MI Varnish [CPP₀/CPP₁]), or silver diamine fluoride (SDF; 35,400 ppm F^-; Cariestop 30% [SDF₀/SDF₁]) and no intervention (N_NB/N₀/N₁). During pH cycling (14 days, 6 × 120 min demineralization/day) half of the specimens in each group were brushed (10 s; 2 times/day) with either fluoride-free (“0”; e.g., TCP₀) or 1,100 ppm F^- (“1”; e.g., TCP₁) dentifrice slurry. In another subgroup, the specimens were pH cycled but not brushed (N_NB). Differences in integrated mineral loss (ΔΔZ), lesion depth (ΔLD), and colorimetric values (ΔΔE) were calculated between the values after initial demineralization and those after pH cycling, using transversal microradiography and photographic images. After pH cycling, no discoloration could be observed. Furthermore, N_NB, N₀, and N₁ showed significantly increased ΔZ_DT/LD_DT and ΔZ_ST/LD_ST values, indicating further demineralization. In contrast, CPP₀, CPP₁, SDF₀, and SDF₁ showed significantly decreased ΔZ_DT/LD_DT values, indicating remineralization (p ≤ 0.004; paired t test). CPP₀, CPP₁, SDF₀, and SDF₁ showed significantly higher changes in ΔΔZ_DT/ΔLD_DT and ΔΔZ_ST/ΔLD_ST than N_NB, N₀, and N₁ (p < 0.001; Bonferroni post hoc test). In conclusion, under the conditions chosen, all fluoride varnishes prevented further demineralization. However, only NaF plus CPP-ACP and SDF could remineralize artificial dentin caries-like lesions under net-demineralizing conditions, thereby indicating that NaF plus CPP-ACP and SDF may be helpful to high-caries-risk patients.

Comparison between Fluoride and Nano-hydroxyapatite in Remineralizing Initial Enamel Lesion: An in vitro Study

The aim of this study was to compare the effectiveness of nano-hydroxyapatite (nano-HAP) paste and fluoride varnish in remineralizing initial enamel lesion in young permanent teeth and their ability to resist secondary caries under dynamic pH cycling quantitatively and qualitatively. Initial caries-like lesions were artificially developed on 45 specimens. Specimens were divided into three groups: (1) Control (without treatment), (2) fluoride varnish (3M ESPE), and (3) nano-HAP paste (Desensibilize Nano P). The nano-HAP paste was applied twice separated by one pH cycle, and the varnish was applied only once followed by 7 days of pH cycling. All specimens were examined using DIAGNOdent® pen (KaVo, Germany), and a representative specimen was randomly selected from each group for qualitative evaluation using scanning electron microscope (SEM) at four stages: Baseline, after lesion formation, immediately after remineralization, and after pH cycling. Data were statistically analyzed with Statistical Package for the Social Sciences (SPSS), version 20. The degree of demineralization was significantly elevated in control group; however, no significant difference was found between fluoride varnish group and nano-HAP paste group (p < 0.001). Nano-HAP paste showed promising long-term protective effect in terms of surface depositions and maintaining a smooth surface compared with fluoride varnish. Based on the findings of this study, nano-HAP paste might be recommended as alternative remineralizing agent with lower fluoride concentration than fluoride varnish that could be beneficial for children, pregnant females, and those who are at high risk of dental fluorosis.

Effect of Two Remineralizing Agents on Initial Caries-like Lesions in Young Permanent Teeth: An in Vitro Study

To compare the effect of nano-hydroxyapatite (9000 ppm F) and casein phosphopeptide-amorphous calcium phosphate fluoride (900 ppm F) pastes on initial enamel carious lesions of young permanent teeth. Sixty extracted young premolars with a standardized window on enamel were immersed in a demineralizing solution for 48 hours to produce subsurface enamel lesions. They were divided into three groups according to remineralizing agents (n = 20) group I: nano-hydroxyapatite paste; group II: casein phosphopeptide-amorphous calcium phosphate fluoride paste; and group III: control (without an agent). The enamel surface microhardness (SMH) was measured at baseline, after the incipient enamel lesion, and after treatment. Additional twenty young premolars were selected and prepared as mentioned above for surface morphology evaluation by scanning electron microscope (SEM). No significant difference was found in mean surface microhardness in teeth treated with nano-hydroxyapatite paste and those treated with casein phosphopeptide-amorphous calcium phosphate fluoride p = 0.26. SEM showed improvement in surface defects of demineralized enamel in the two test groups. Nano-hydroxyapatite and casein phosphopeptide-amorphous calcium phosphate fluoride pastes were effec -tive in rehardening the initial enamel caries lesions in young permanent teeth. The best strategy for caries management is to focus on the methods of improving the reminer-alization process with the aid of the remineralizing agents. The current study compared the remineralizing effect of two remineralizing agents. Within the limitations of the study, both remineralizing agents were effective for remineralization of early caries-like lesions.

In Vitro Evaluation of the Remineralizing Potential and Antimicrobial Activity of a Cariostatic Agent with Silver Nanoparticles.

Cariostatic treatment has been shown to successfully arrest caries. However, it blackens the carious tooth structure. This study evaluated the effects of an experimental cariostatic agent with silver nanoparticles (Ag-Nano) using microhardness (MH) and microbiological tests. The cariostatic agents tested were: Saforide®, Cariestop®, Ancarie® and Ag-Nano. Sixty-six samples from deciduous enamel were submitted to initial (after pH cycling to obtain initial caries-like lesion) and final (after cariostatic application) MH testing and %MH values were calculated. After longitudinal sectioning, internal (I) MH was evaluated. Strains of Streptococcus mutans, Escherichia coli, and Enterococcus faecalis in brain-heart infusion culture were treated with the cariostatic agents. Agar diffusion tests (ADTs) were performed and minimum inhibitory concentrations were determined. The statistical tests used were: Kruskal-Wallis and Dunn (%MD; ADT; MIC) and ANOVA followed by Tukey's test (I-MH) (p<0.05). The %MH of Saforide® was significantly greater than that of Ag-Nano (p<0.05). Internal MH showed progressive improvement in the enamel remineralization for all cariostatic tested. In ADTs showed greater inhibition of S. mutans, E. faecalis, and E. coli by Saforide® than by Ancarie® and Ag-Nano. Ag-Nano was able to inhibit 100% microorganism growth at a lower concentration than required for the other agents. It was concluded that Ag-Nano treatment promoted remineralization of deciduous tooth enamel with initial caries-like lesion and bactericidal activity.