In situ remineralization of white-spot enamel lesions by 500 and 1,100 ppm F dentifrices

Remineralization potential of dentifrices with calcium sodium phosphosilicate and functionalized tri-calcium phosphate in the deeper incipient carious lesions: An in vitro study

OBJECTIVES

This study evaluated the remineralization potential of calcium sodium phosphosilicate and functionalized tri-calcium phosphate (f-TCP) dentifrices in deeper incipient carious lesions (ICLs).

MATERIALS AND METHODS

Artificial ICLs were created by placing premolars into demineralizing solutions. Teeth were randomly assigned into four groups: calcium sodium phosphosilicate (Group 1), f-TCP (Group 2), 1450 ppm fluoride (Group 3), and distilled water (Group 4), which were subjected to 10-day pH cycling. Mineral density (MD) was assessed using microcomputed tomography (Micro-CT), while hardness (H) and elastic modulus (EM) were assessed using nanomechanical testing.

RESULTS

MD % gain was higher in Groups 1-3 than in Group 4. In addition, Groups 1 and 2 exhibited significantly higher MD % gain than Group 3. Also, Groups 1-3 showed significantly higher EM and H values than Group 4 in the outer enamel area; yet, Groups 1 and 2 displayed significantly higher EM and H values than Groups 3 and 4 in the inner enamel.

CONCLUSIONS

The MD, EM, and H of ICLs significantly increased with the addition of calcium sodium phosphosilicate or f-TCP to fluoridated dentifrices compared to standard fluoride dentifrices. The added active ingredients remineralized the deeper parts of the ICLs, while remineralization at the lesion surface was similar between tested dentifrices.

Analyzing the anti-caries effect of fluoride varnish containing tricalcium phosphate using PIXE/PIGE

This study evaluated the effect of tricalcium phosphate-containing fluoride varnish on the prevention of root caries using an in-air micro-proton induced X-ray/gamma-ray emission system and microcomputed tomography. Either fluoride varnish (FV) or tricalcium phosphate-containing fluoride varnish (WV) was applied to root dentin, whereas dentin without varnish were considered controls. After immersion in saline, dentin sections were prepared, and concentration of fluoride ion was measured. These specimens were demineralized, and the mineral loss was measured. Caries inhibition in sound and demineralized dentin was observed in both FV and WV groups compared to the control group. Significantly low mineral loss was found especially in the demineralized dentin, which is probably due to the combination effect of calcium and fluoride ions at a concentration range of 100,000 ppm, as supplied by the varnish. The use of calcium-containing fluoride varnish, especially in demineralized dentin, is effective in arresting initial dentin caries.

Evaluation of an Artificial Mouth for Dental Caries Development

This study validated a microbial caries model (artificial mouth) for dental caries development to determine the optimal time to create early caries suitable for evaluation of the efficacy of caries therapeutic agents. In all, 40 human enamel blocks were placed in an artificial mouth at 37 °C and 5% CO2 and were exposed to brain heart infusion broth inoculated with S. mutans in continuous circulation (0.3 mL/min). The culture medium was replaced three times daily. Samples were exposed to 10% sucrose for 3 min, 3 times daily to promote biofilm growth. Five samples were harvested from the chamber after 3, 4, 5, 6, 7, 14, 21, and 28 days. At the end of experiment, samples were assessed visually by ICDAS criteria, while lesion depth (LD) and mineral loss (ML) were measured using polarizing light microscopy and transverse microradiography. Data were analyzed by Pearson correlation, ANOVA, and Tukey comparison test (p < 0.05). Results showed significant and strong positive correlation (p < 0.01) between all variables and biofilm growth time. LD and ML profiles of 7-day lesions seem to be the most suitable for remineralization studies. In conclusion, using the evaluated artificial mouth, early-stage caries suitable for products’ evaluation studies was produced within 7 days of exposure to microbial biofilm.

Evaluation of fluoride varnish treatment of postorthodontic white spot lesions by visual inspection and laser fluorescence-A randomized controlled study

OBJECTIVES

White spot lesions (WSLs), as a side effect of orthodontic therapy, can be treated with fluoride varnish, with the difference in efficiency reported.

MATERIAL AND METHODS

Patients with buccal WSLs were consecutively included in a randomized controlled double-blind study. At first inspection and at three follow-ups over 6 months, 0.1% fluoride varnish and placebo (water) were applied in the test group (N = 21) and control group (N = 21), respectively. The maximum laser fluorescence value (LFV) of WSLs was recorded using DIAGNOdent. Between the groups, differences in the mean numbers of WSLs and the mean LFV of WSLs per patient at different time points were analyzed with mixed-design analysis of variance. Orthodontic therapy duration (OTD) was included in the model as a covariate.

RESULTS

A decrease in the mean WSLs number and LFV was observed; however, there were no significant differences between study groups at any time point. OTD was in interaction only with LFV. Analysis showed a different pattern of mean LFV changes for patients with OTD of >48 months compared to patients with OTD of ≤24.

CONCLUSION

The changes in numbers of WSLs and LFV over the study period indicated regression of WSLs, but an additional effect of FV was not confirmed.

Ultrasonic measurement of dentin remineralization effects of dentifrices and silver diamine fluoride

OBJECTIVE

This study investigated the dentin remineralization effect of the application of a functionalized tri-calcium phosphate (fTCP) dentifrice and a silver diamine fluoride (SDF) solution.

MATERIAL AND METHODS

The materials used were: a fluoride-containing dentifrice with fTCP (fTCP＋), a fluoride-containing dentifrice without fTCP (fTCP-) and a 38% SDF solution. Following treatment, the dentin slabs were immersed in a 0.1-M lactic acid buffer solution and then placed in artificial saliva. This procedure was repeated three times daily for 28 days. The propagation time of longitudinal ultrasonic velocities (UV) and the Knoop hardness (KH) of the samples were measured. The samples were also observed using scanning electron microscopy.

RESULTS

The SDF and fTCP＋ groups showed higher UV than the fTCP - group regardless of the application method. The F-SDF group at 28 days showed significantly higher UV (4121 ± 102 m/s) than the F-fTCP + group (3731 ± 65 m/s) (p < .05). The F-SDF group at 28 days showed significantly higher KH (47.4 ± 2.2) than the F-fTCP＋ group (43.3 ± 1.0) and the F-fTCP - group (42.9 ± 2.1) (p < .05). Closure of the dentinal tubules and crystal precipitation was detected on the surface of the fTCP＋ group to a greater extent than the fTCP - group.

CONCLUSIONS

The fTCP-containing dentifrice and SDF solution effectively enhanced bovine dentin remineralization.

Remineralization of enamel subsurface lesions using toothpaste containing tricalcium phosphate and fluoride: an in vitro µCT analysis

Background

This study aimed to compare the efficacies of experimental toothpastes containing functionalized tricalcium phosphate (fTCP) with and without fluoride for in vitro enamel remineralization under pH-cycling conditions.

Methods

To create artificial white spot lesions, 36 bovine enamel specimens were immersed in a demineralization solution for 10 days. During pH-cycling for 12 days, the specimens were divided into four groups based on the experimental toothpaste type used: (a) fTCP-free, fluoride-free (fTCP − F −); (b) fTCP-containing, fluoride-free (fTCP + F −); (c) fTCP-free, fluoride-containing (fTCP − F +); and (d) fTCP-containing, fluoride-containing (fTCP + F +). Micro-focus X-ray computed tomography (μCT) scans of all specimens were obtained before demineralization, after demineralization, and after pH-cycling. The mineral density and mineral loss (ΔZ) in the enamel subsurface lesions were measured and the percentage of remineralization (%R) was calculated from ΔZ after demineralization and pH-cycling. One-way ANOVA with Tukey’s test was used for statistical analysis of the %R values. The treated enamel surface was investigated via scanning electron microscopy (SEM).

Results

The fTCP − F − group presented with the lowest amount of mineral gain after pH-cycling. In contrast, the fTCP + F + group showed the highest degree of remineralization within all lesion parts. The %R was highest in the fTCP + F + group (38.2 ± 7.8, all P < 0.01). SEM revealed the presence of small crystals on the enamel rods in the fTCP + F − and fTCP + F + groups.

Conclusions

The experimental toothpaste containing fTCP and fluoride increased remineralization of the artificial enamel subsurface lesions during pH-cycling. Furthermore, fTCP and fluoride appear to act independently on the remineralization of enamel subsurface lesions, although they coexisted in one toothpaste type.

Trial registration: This is not a human subject research.

Comparative efficacy of a hydroxyapatite and a fluoride toothpaste for prevention and remineralization of dental caries in children

Objective

This in situ study compared the effectiveness of two toothpastes containing hydroxyapatite or 500 ppm fluoride in promoting remineralization and inhibiting caries development.

Materials and methods

Two enamel blocks (human primary teeth), one sound and one with artificially-produced caries lesion, were exposed to toothpaste containing either 10% hydroxyapatite or 500 ppm F⁻ (amine fluoride) via intra-oral appliance worn by 30 adults in two-arm double blind randomized crossover study lasting 14 days per arm (ClinicalTrials.gov: NCT03681340). Baseline and post-test mineral loss and lesion depth (LD) were quantified using microradiography. One-sided t-test of one group mean was used for intragroup comparison (baseline vs. post-test), while two-sided t-test of two independent means was used to compare the two toothpaste groups.

Results

Pairwise comparison (baseline vs. test) indicated significant (p < 0.0001) remineralization and LD reduction by either toothpaste; however, when compared against each other, there was no statistically significant difference in remineralization or LD reduction between the two toothpastes. No demineralization could be observed in sound enamel blocks exposed to either toothpaste. While F⁻ induced lesion surface lamination, HAP produced a more homogenous lesion remineralization.

Conclusions

10% hydroxyapatite achieved comparable efficacy with 500 ppm F⁻ in remineralizing initial caries and preventing demineralization. Thus the HAP toothpaste is confirmed to be equal to the fluoride toothpaste in this study.

Current treatment modalities of orthodontically induced white spot lesions and their outcome - a literature review

Introduction

White spot lesion is a demineralization of the enamel that appears as a white spot on the surfaces of the tooth. The cause of this spot is determined by the activity of the bacterial plaque and it represents the initial stage of a carious lesion. This lesion is a common side effect for patients with fixed orthodontic appliances mainly because of the brackets' position that favors the accumulation of plaque that ultimately leads to the formation of the white spot.

Methods

We conducted a search on a single database, PubMed. "Orthodontic", "white spot lesions", "enamel demineralization treatment" and "remineralization" were the search terms used. We found 324 articles, but we took in consideration only the ones from the last 10 years, which resulted in 223 articles.

Results

The first step after research was article selection: first by scrutinizing the title and secondly by reviewing the abstracts or full texts. The exclusion criteria were: meta-analysis, reviews, original articles regarding prevention of white spot lesions and their prevalence or incidence. We included the articles that seemed relevant for the treatment of white spot lesions, made either on extracted teeth either on orthodontic patients. We found 75 articles to be eligible for this research and we eliminated 5 because of the lack of an abstract or full text and a further 22 were rejected because they did not fit the aforementioned criteria.

Conclusion

Although some traditional methods for the treatment of white spot lesions seem to have undesirable results, nowadays with new technologies and thorough investigations in nanotechnology, the eradication of the lesion appears to be short term.

Carious lesion remineralizing potential of fluoride- and calcium-containing toothpastes: A laboratory study

BACKGROUND

The authors conducted a laboratory study to determine the carious lesion remineralization and fluoridation potential of fluoride (F)- and calcium-containing toothpastes.

METHODS

The authors created early carious lesions in bovine enamel specimens and assigned them to 7 treatment groups on the basis of their surface Vickers microhardness: Clinpro Tooth Crème (Clinpro) (3M ESPE), CTx4 Gel 1100 (CTx4) (Oral Biotech), Enamelon Fluoride Toothpaste (Enamelon) (Premier Dental), MI Paste ONE (MI-One) (GC America), Crest Cavity Protection Toothpaste (Crest) (Procter & Gamble), and 2 F-dose controls (low F, high F). The authors pH cycled the specimens for 10 days by using an established model, determined changes in surface microhardness, calculated percentage of surface microhardness recovery (%SMHr; primary outcome variable), and measured enamel F uptake (EFU). The authors used a 1-way analysis of variance for data analysis.

RESULTS

Study results showed an F-dose response for both %SMHr (low-F control: mean, 9.8; 95% confidence interval [CI], 5.7 to 13.8); Crest: mean, 26.2; CI, 21.8 to 30.6; high-F control: mean, 33.5; CI, 29.4 to 37.5) and EFU (low-F control: mean, 47; CI, 12 to 83; Crest: mean, 225; CI, 189 to 260; high-F control: mean, 307; CI, 271 to 342; all micrograms of F per cubic centimeter). For %SMHr, Clinpro (mean, 26.5; CI, 22.5 to 30.6) and CTx4 (mean, 27.3; CI, 23.1 to 31.5) were similar to Crest, all being superior to Enamelon (mean, 15.6; CI, 11.6 to 19.7), which was superior to MI-One (mean, 4.3; CI, 0.3 to 8.3). For EFU, there were no differences between Clinpro (mean, 189; CI, 153 to 224), CTx4 (mean, 177; CI, 142 to 213), Enamelon (mean, 196; CI, 161 to 232), and Crest, all being superior to MI-One (mean, 66; CI, 30 to 102).

CONCLUSIONS

This study's results failed to show superior remineralizing efficacy of any of the toothpastes compared with those of a calcium-free F toothpaste, with 2 of the 4 toothpastes being inferior. Clinical testing will be required to establish conclusive evidence.

PRACTICAL IMPLICATIONS

Clinicians should be aware of the remineralizing potential of new anticaries products.

Protocols to Study Dental Caries In Vitro: Microbial Caries Models

Caries lesions result from the interaction between dental biofilm and sugars. Since the biofilm is an important component in the etiology of the disease, biofilm models have been developed to study the cariogenicity of dietary sugars, as well as the anticaries effect of substances. Two of such models, termed as "static" or "continuous flow," are described in details here together with their advantages, limitations, and applications.

Effect of dentifrice containing fTCP, CPP-ACP and fluoride in the prevention of enamel demineralization

OBJECTIVE

To evaluate the effect of different fluoride- and calcium- and/or phosphate-containing products on their ability to prevent enamel demineralization under pH cycling conditions.

MATERIAL AND METHODS

Enamel bovine specimens were assigned to the following groups: G1-MPP (MI Paste Plus, 0.2% NaF, Recaldent™, GC Corporation Tokyo, Japan); G2-FD (Crest™ Cavity Protection, 0.243% NaF, Procter & Gamble, USA); G3-CLP (Clinpro™ 5000, 1.1% NaF, 3M ESPE, USA); and G4-CO (Control without fluoride, Silica-based dentifrice; Daudt Ltda, Brazil). The specimens were soaked in demineralizing solution for 6 h and remineralizing solution for 18 h alternatively for 10 days. The toothpaste was prepared with deionized water in a 1:3 ratio (w/v) for three minutes daily. The solutions were renewed every 48 h. After cycling, enamel changes were analysed by percentage change of SMH (%SMH) and energy-dispersive X-ray spectroscopy (EDS). The %SMH value observed for G3-CLP (2.9 ± 39.2) was higher than that found in G4-CO (-13.0 ± 20.7), G1-MPP (-8.9 ± 20.9) and G2-FD (-3.9 ± 27.1). The %SMH was similar for all treatment groups (one-way ANOVA and Tukey's HSD; p < .05). The pH, Ca²⁺ and P_total in the remineralization solutions were not different among all groups (Kruskal-Wallis; p < .05). At 24 h, the Ca²⁺ concentration in the demineralization solution was significantly lower in G1-MPP. Ca²⁺ concentration increased in all groups after 48 h, except for G3-CLP. The EDX quantitative analysis showed that the atomic % of elements is lower level at G4-CO.

CONCLUSIONS

The Clinpro™ 5000 demonstrated having the most protective effect against demineralization; however, the % SMH was similar for all groups.

The efficiency of child formula dentifrices containing different calcium and phosphate compounds on artificial enamel caries

OBJECTIVES

Fluoride toothpaste has been extensively used to prevent dental caries. However, the risk of fluorosis is concerning, especially in young children. Calcium phosphate has been an effective remineralizing agent and is present in commercial dental products, with no risk of fluorosis to users. This in vitro study aimed to compare the effects of different calcium phosphate compounds and fluoride-containing dentifrices on artificial caries in primary teeth.

MATERIALS AND METHODS

Fifty sound primary incisors were coated with nail varnish, leaving two 1 mm² windows on the labial surface before immersion in demineralizing solution for 96 hours to produce artificial enamel lesions. Subsequently, one window from each tooth was coated with nail varnish, and all 50 teeth were divided into five groups (n = 10); group A - deionized water; group B - casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste (Tooth Mousse); group C - 500 ppm F (Colgate Spiderman^®); group D - nonfluoridated toothpaste with triple calcium phosphate (Pureen^®); and group E - tricalcium phosphate (TCP). Polarized light microscopy and Image-Pro^® Plus software were used to evaluate lesions.

RESULTS

After a 7-day pH-cycle, mean lesion depths in groups A, B, C, D, and E had increased by 57.52 ± 10.66%, 33.28 ± 10.16%, 17.04 ± 4.76%, 32.51 ± 8.99%, and 21.76 ± 8.15%, respectively. All data were processed by the Statistical Package for the Social Sciences (version 16.0) software package. Comparison of percentage changes using one-way analysis of variance and Fisher's least squares difference tests at a 95% level of confidence demonstrated that group A was significantly different from the other groups (P < 0.001). Lesions in groups B and D had a significant lesion progression when compared with groups C and E.

CONCLUSIONS

All toothpastes in this study had the potential to delay the demineralization progression of artificial enamel caries in primary teeth. The fluoride 500 ppm and TCP toothpastes were equal in the deceleration of enamel caries progression and better than CPP-ACP paste and TCP toothpaste.

Efficacy of two calcium phosphate pastes on the remineralization of artificial caries: a randomized controlled double-blind in situ study

To test the efficacy of two calcium phosphate pastes compared to that of fluoride toothpaste on remineralizing artificial caries in situ, this study had a double-blind crossover in situ design, involving three experimental phases of 14 days each, with an 8-day washout period between phases. Nine healthy subjects participated in the study. The subjects wore removable palatal appliances mounted with six human enamel slabs with artificial caries lesions, and in each of the experimental phases, used one of the following methods two times/day: group A, brushing with 1.0 g of Colgate Regular Flavor, followed by applying 0.25 g of Tooth Mousse Plus; group B, brushing with 0.25 g of Clinpro Tooth Crème; and group C, brushing with 1.0 g of Colgate Regular Flavor. After 14 days, the enamel slabs (54 slabs/group) were embedded in resin, sectioned and examined with a polarized-light microscope, and the lesion areas were quantified using Image-Pro Plus. All experimental groups showed a significant reduction in lesion area compared to the initial lesion area (paired t-test, P<0.001). The mean reduction in lesion area of Groups A, B and C were (0.029±0.010), (0.030±0.009) and (0.027±0.009) mm², respectively. There were no statistical differences between groups (Kruskal–Wallis test, P>0.05). All three groups remineralized the enamel slab lesions, indicating model sensitivity to fluoride. Given the differences in usage amounts and treated regimens, Clinpro Tooth Crème provided similar benefits to the fluoride toothpaste; however, no additional benefit of Tooth Mousse Plus was observed when used in conjunction with the fluoride toothpaste.

Fluoride plus functionalized β-TCP: a promising combination for robust remineralization

With more than 50 years of clinical success, fluoride serves as the gold standard agent for preventing tooth decay. In particular, the action of fluoride facilitates saliva-driven remineralization of demineralized enamel and alters solubility beneficially. Still, tooth decay remains problematic, and one way to address it may be through the development of new mineralizing agents. Laboratory and clinical studies have demonstrated that the combination of fluoride and functionalized β-tricalcium phosphate (fTCP) produces stronger, more acid-resistant mineral relative to fluoride, native β-TCP, or fTCP alone. In contrast to other calcium-based approaches that seem to rely on high levels of calcium and phosphate to drive remineralization, fTCP is a low-dose system designed to fit within existing topical fluoride preparations. The functionalization of β-TCP with organic and/or inorganic molecules provides a barrier that prevents premature fluoride-calcium interactions and aids in mineralization when applied via common preparations and procedures. While additional clinical studies are warranted, supplementing with fTCP to enhance fluoride-based nucleation activity, with subsequent remineralization driven by dietary and salivary calcium and phosphate, appears to be a promising approach.