The Effects of Three Remineralizing Agents on the Microhardness and Chemical Composition of Demineralized Enamel

Dynamics of Dental Enamel Surface Remineralization under the Action of Toothpastes with Substituted Hydroxyapatite and Birch Extract

To address tooth enamel demineralization resulting from factors such as acid erosion, abrasion, and chronic illness treatments, it is important to develop effective daily dental care products promoting enamel preservation and surface remineralization. This study focused on formulating four toothpastes, each containing calcined synthetic hydroxyapatite (HAP) in distinct compositions, each at 4%, along with 1.3% birch extract. Substitution elements were introduced within the HAP structure to enhance enamel remineralization. The efficacy of each toothpaste formulation was evaluated for repairing enamel and for establishing the dynamic of the remineralization. This was performed by using an in vitro assessment of artificially demineralized enamel slices. The structural HAP features explored by XRD and enamel surface quality by AFM revealed notable restorative properties of these toothpastes. Topographic images and the self-assembly of HAP nanoparticles into thin films on enamel surfaces showcased the formulations' effectiveness. Surface roughness was evaluated through statistical analysis using one-way ANOVA followed by post-test Bonferroni's multiple comparison test with a p value < 0.05 significance setting. Remarkably, enamel nanostructure normalization was observed within a short 10-day period of toothpaste treatment. Optimal remineralization for all toothpastes was reached after about 30 days of treatment. These toothpastes containing birch extract also have a dual function of mineralizing enamel while simultaneously promoting enamel health and restoration.

New generation of orthodontic devices and materials with bioactive capacities to improve enamel demineralization

OBJECTIVE

The article reviewed novel orthodontic devices and materials with bioactive capacities in recent years and elaborated on their properties, aiming to provide guidance and reference for future scientific research and clinical applications.

DATA, SOURCES AND STUDY SELECTION

Researches on remineralization, protein repellent, antimicrobial activity and multifunctional novel bioactive orthodontic devices and materials were included. The search of articles was carried out in Web of Science, PubMed, Medline and Scopus.

CONCLUSIONS

The new generation of orthodontic devices and materials with bioactive capacities has broad application prospects. However, most of the current studies are limited to in vitro studies and cannot explore the true effects of various bioactive devices and materials applied in oral environments. More research, especially in vivo researches, is needed to assist in clinical application.

CLINICAL SIGNIFICANCE

Enamel demineralization (ED) is a common complication in orthodontic treatments. Prolonged ED can lead to dental caries, impacting both the aesthetics and health of teeth. It is of great significance to develop antibacterial orthodontic devices and materials that can inhibit bacterial accumulation and prevent ED. However, materials with only preventive effect may fall short of addressing actual needs. Hence, the development of novel bioactive orthodontic materials with remineralizing abilities is imperative. The article reviewed the recent advancements in bioactive orthodontic devices and materials, offering guidance and serving as a reference for future scientific research and clinical applications.

Effect of calcium-coacervate infiltration of artificial enamel caries lesions in de- and remineralizing conditions

OBJECTIVES

Calcium-coacervate emulsions (CC) might be considered as mineral precursors to foster remineralization of carious dental hard tissues. This study analyzed the instant effect of repeated infiltration of artificial caries lesions with a CC emulsion as well as the effects of subsequent exposure of CC-infiltrated lesions to demineralizing and remineralizing environments.

METHODS

Bovine enamel specimens were partly covered with varnish to leave three exposed windows. Artificial enamel caries lesions were created (pH 4.95, 17d). Baseline controls (BL) were obtained by preparing a thin section of each specimen. Specimens were allocated to five groups. In three groups lesions were etched with 37 % phosphoric acid gel, infiltrated with dipotassium hydrogen phosphate and subsequently with a calcium coacervate emulsion, prepared by mixing CaCl2 ⋅ 2H2O with polyacrylic acid sodium salt (PAA-Na). Subsequently, the infiltration effect was either analyzed immediately (Inf.) or after exposition to either de- (Inf.+DS) or remineralizing solution (Inf.+RS) for 10 or 20 days, respectively. In two control groups specimens were exposed to either DS or RS, respectively without prior CC infiltration. Integrated mineral loss [ΔZ(vol%×µm)] was analyzed using transverse microradiography (TMR).

RESULTS

Infiltration of enamel caries lesions with coacervate solution resulted in only subtle immediate mineral gain even if repeated. When exposed to demineralizing conditions, infiltrated lesions showed significantly less mineral loss compared to untreated controls (p < 0.05; Kruskal Wallis) and exhibited characteristic mineral depositions within the lesion body.

CONCLUSIONS

While immediate mineral gain by infiltration was only modest, the CC-emulsion might be able to prevent demineralization in acidic conditions.

CLINICAL SIGNIFICANCE

Calcium coacervates might act protective against further demineralization when infiltrated into enamel caries lesions.

Evaluation of ER;CR:YSGG Laser and Remineralization Agents on Mineral Density and Ion Levels of Primary and Permanent Enamel

Objective: The aim of this study is to evaluate the efficacy of two different fluoride varnishes used alone or in combination with laser treatment on permanent and primary tooth enamel. Methods: Ninety-six primary and 96 permanent molar samples were divided into six groups. The levels of calcium, phosphorus, fluoride, and silver ions of each sample were analyzed using energy-dispersive X-ray spectroscopy (EDS). Six different treatments were applied to 12 different groups (n = 15) as control (g1/G1), fluoride varnish (g2/G2), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-fluoride varnish (g3/G3), laser (g4/G4), laser+fluoride varnish (g5/G5), and laser+CPP-ACP-fluoride varnish (g6/G6). After the procedures, ion levels were reanalyzed with EDS. The teeth were subjected to the artificial caries-forming procedure and ion levels were again evaluated by EDS. One sample from each group was prepared separately for the focused ion beam-scanning electron microscope measurement; initial and final images were recorded. The obtained data were statistically analyzed with the SPSS 23.0 program. Results: Compared with the initial measurement, phosphorus percentages increased in most of the groups in the last measurement. Calcium percentages of primary teeth increased in the last measurement, except for the g1 group, but in permanent teeth, there was an increase only in the G6 group. There was a statistically significant difference between g1/G1 and g6/G6 groups in the last measurement of phosphorus and calcium percentages. Conclusions: The combined use of laser with CPP-ACP-fluoride varnish enhanced remineralization in the primary and permanent teeth. However, in permanent teeth, the use of laser alone was not as effective as in primary teeth. Therefore, combined usage with CPP-ACP-fluoride varnish can enhance its efficacy. This in vitro study was approved by the local ethics committee of Hacettepe University (Project No.: GO 20/441).

Theobromine versus casein phospho-peptides/Amorphous calcium phosphate with fluoride as remineralizing agents: effect on resin-dentine bond strength, microhardness, and morphology of dentine

BACKGROUND

This study aimed to assess the impact of theobromine and casein phospho-peptides/amorphous calcium phosphate with fluoride (CPP-ACPF) on the resin-dentine bond strength, microhardness, and dentine morphology.

METHODS

A total of 18 sound human molars for micro-tensile bond strength (µTBS), 20 sound human premolars for microhardness, and 30 premolars for Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) were used. Based on the pre-treatment used, teeth were split into six groups; sound dentine, demineralized dentine, and demineralized dentine treated with theobromine (Sigma Aldrich) and MI paste plus (GC International, USA) for two-time intervals; 5 min and 1 month. The bonded teeth were sectioned to produce 1 mm² resin-dentine sticks which were evaluated for µTBS using a universal testing device (Instron 3365, USA). The dentine microhardness was tested by using the Vickers microhardness tester (Nexus 4000 TM, Netherlands). The pre-treated dentine surface was examined using SEM/EDX (Neoscope JCM-6000 plus Joel benchtop SEM, Japan). µTBS results were analysed with two-way ANOVA. Microhardness and EDX results were analysed with two-way mixed model ANOVA. The significance level was set at (p ≤ 0.05).

RESULTS

While both remineralizing materials at the two-time intervals demonstrated µTBS comparable to sound dentine (46.38 ± 12.18), the demineralized group demonstrated statistically the lowest µTBS (p < 0.001). Whether used for 5 min or 1 month, theobromine significantly increased the microhardness (50.18 ± 3.43) and (54.12 ± 2.66) respectively (p < 0.001), whereas MI paste only increased the hardness (51.12 ± 1.45) after 1 month (p < 0.001).

CONCLUSIONS

The pre-treatment of demineralized dentine with theobromine for 5 min or 1 month could enhance its bond strength and microhardness while for MI paste plus, only 1-month application was efficient to ensure remineralization.

Theobromine versus Casein phospho-peptide/Amorphous Calcium Phosphate with Fluoride as remineralizing agents: Effect on resin-dentine bond strength, microhardness, and morphology of dentine.. [DOI: 10.21203/rs.3.rs-2722167/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background: This study aimed to assess the impact of theobromine and casein phospho-peptides/amorphous calcium phosphate with Fluoride (CPP/ACPF) on the resin-dentine bond strength, microhardness, and dentine morphology. Methods: Based on the pre-treatment used, 18 sound human third molars were split into six groups.; sound dentine, demineralized dentine, and demineralized dentine treated with theobromine and MI paste plus for two-time intervals; 5 minutes and 1 month. The bonded teeth were sectioned to produce 1 mm2 resin-dentine sticks which were evaluated for micro-tensile bond strength (µTBS) using a universal testing device. The dentine microhardness was tested by using the Vickers microhardness tester. The pre-treated dentine surface was examined using Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX). µTBS results were analysed with two-way ANOVA. Microhardness and EDX results were analysed with two-way mixed model ANOVA. Results: While both remineralizing materials at the two-time intervals demonstrated µTBS comparable to sound dentine, the demineralized group demonstrated statistically the lowest µTBS. Whether used for 5 minutes or 1 month, theobromine significantly increased the microhardness, whereas MI paste only increased the hardness after 1 month. Conclusions: The pre-treatment of demineralized dentine with theobromine and MI paste plus could enhance its bond strength and microhardness.

Comparative evaluation of prevention of demineralization of artificial enamel caries treated with two fluoride varnishes and 38% SDF in primary teeth: an in vitro study

BACKGROUND

This study aimed to compare the effect of Clinpro™ White varnish containing 5% sodium fluoride (NaF) and functionalized tricalcium phosphate, MI varnish containing 5% NaF and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), and 38% Silver diamine fluoride (SDF) in preventing demineralization of treated white spot lesions (WSLs) in enamel of primary teeth.

METHODS

Forty-eight primary molars with artificial WSLs were allocated into four groups as follows: Group 1: Clinpro white varnish, Group 2: MI varnish, Group 3: SDF, and Group 4: control (no treatment). The three surface treatments were applied for 24 h and then enamel specimens were subjected to pH cycling. Thereafter, the mineral content of specimens was evaluated by Energy Dispersive X-ray Spectrometer and the lesion depth was assessed via Polarized Light Microscope. One-way ANOVA followed by Tukey's post hoc test were used at p ≤ 0.05 to identify significant differences.

RESULTS

Insignificant difference in mineral content was observed among treatment groups. Treatment groups exhibited significantly higher mineral content compared to control except for Fluoride (F). MI varnish showed the highest mean calcium (Ca) ion content (66.57 ± 0.63), and Ca/P (2.19 ± 0.11), followed by Clinpro white varnish, and SDF. MI varnish also displayed the highest phosphate (P) ion content (31.46 ± 0.56), followed by SDF (30.93 ± 1.02), and Clinpro white varnish (30.53 ± 2.19). Fluoride content was highest in SDF (0.93 ± 1.18), followed by MI (0.89 ± 0.34) and Clinpro (0.66 ± 0.68) varnishes. Significant difference in lesion depth was observed among all groups (p < 0.001). The lowest mean lesion depth (µm) was found in MI varnish (226.23 ± 44.25) which was significantly lower than Clinpro white varnish (285.43 ± 44.70), SDF (293.32 ± 46.82), and control (576.69 ± 42.66). Insignificant difference in lesion depth was found between SDF and Clinpro varnish.

CONCLUSIONS

In primary teeth, WSLs treated with MI varnish displayed better resistance to demineralization compared to WSLs treated with Clinpro white varnish and SDF.

YD, Anil S, Senthilkumar K, Seong GH, Sargod SS, Bhat SS, Venkatesan J. Remineralizing Potential of Natural Nano-Hydroxyapatite Obtained from Epinephelus chlorostigma in Artificially Induced Early Enamel Lesion: An In Vitro Study

Dental caries is a common problem in adolescents, leading to permanent loss of teeth or cavitation. Caries is a continuous process wherein demineralization and remineralization occur regularly. Hydroxyapatite (HA) is one of the most biocompatible and bioactive materials, as it closely resembles the mineral composition of teeth. The present study deals with isolating hydroxyapatite from fish bone (Epinephelus chlorostigma) by alkaline hydrolysis and thermal calcination. The isolated nano HA was characterized using FT-IR, XRD, TGA, FE-SEM-EDX, and HR-TEM analysis. The nano HA isolated by alkaline hydrolysis is nontoxic, and the cells are viable. The isolated HA enhances the proliferation of L929 cells. The remineralization potential of the extracted nano HA was evaluated in healthy premolars by DIAGNOdent/laser fluorescence quantification, surface microhardness test, and SEM-EDX analysis. Surface morphological observations in SEM and EDX analyses show that thermally calcined HA and alkali-treated HA can induce mineralization and deposit minerals. Therefore, HA obtained from Epinephelus chlorostigma could be a potential biomaterial for treating early caries.

Remineralization of Artificially Demineralized Human Enamel and Dentin Samples by Zinc-Carbonate Hydroxyapatite Nanocrystals

(1) Background: Decalcified enamel and dentin surfaces can be regenerated with non-fluoride-containing biomimetic systems. This study aimed to investigate the effect of a zinc carbonate-hydroxyapatite-containing dentifrice on artificially demineralized enamel and dentin surfaces. (2) Methods: Human enamel and dentin discs were prepared and subjected to surface demineralization with 30% orthophosphoric acid for 60 s. Subsequently, in the test group (n = 20), the discs were treated three times a day for 3 min with a zinc carbonate-hydroxyapatite-containing toothpaste (biorepair^®). Afterwards, all samples were gently rinsed with PBS (5 s) and stored in artificial saliva until next use. Samples from the control group (n = 20) received no dentifrice-treatment and were stored in artificial saliva, exclusively. After 15 days of daily treatment, specimens were subjected to Raman spectroscopy, energy-dispersive X-ray micro-analysis (EDX), white-light interferometry, and profilometry. (3) Results: Raman spectroscopy and white-light interferometry revealed no significant differences compared to the untreated controls. EDX analysis showed calcium phosphate and silicon dioxide precipitations on treated dentin samples. In addition, treated dentin surfaces showed significant reduced roughness values. (4) Conclusions: Treatment with biorepair^® did not affect enamel surfaces as proposed. Minor mineral precipitation and a reduction in surface roughness were detected among dentin surfaces only.

Comparative assessment of enamel remineralisation on the surface microhardness of demineralized enamel - an in vitro study

Objective

The main objective of the study was to compare two different remineralising materials containing casein phosphopeptide-amorphous calcium phosphate, bioactive glass on enamel surface microhardness.

Materials and Methods

Thirty premolars were used for specimen preparation. Group 1 (the control group) consisted of intact enamel samples, group 2: CPP-ACPF (Tooth Mousse Plus), group 3: bioenamel remineralising gel (Prevest DenPro). All specimens were subjected to demineralisation except the control group, followed by which remineralising agents were applied. A universal hardness tester was used to assess the surface microhardness of all samples. Results were analysed using one-way ANOVA test and comparison was analysed using Scheffe's post hoc least significant difference (LSD) test.

Results

Both remineralising agents used in groups 2 and 3 have shown significant outcome in terms of improving the surface microhardness in comparison with the control group. Group 2 increased the enamel hardness by 8.34 where P = 0.023 whereas group 3 increased the hardness by 5.87, where P = 0.01.

Conclusion

Group 2 has a superior hardness value than group 3; however, no statistically significant results were obtained between both the groups.

Remineralization Efficacy of Four Remineralizing Agents on Artificial Enamel Lesions: SEM-EDS Investigation

Dental remineralization represents the process of depositing calcium and phosphate ions into crystal voids in demineralized enamel, producing net mineral gain and preventing early enamel lesions progression. The aim of the present study was to qualitatively and quantitatively compare the remineralizing effectiveness of four commercially available agents on enamel artificial lesions using Scanning Electron Microscopy (SEM) combined with Energy Dispersive Spectroscopy (EDS) techniques. Thirty-six extracted third molars were collected and randomly assigned to six groups (n = 6), five of which were suspended in demineralizing solution for 72 h to create enamel artificial lesions, and one serving as control: G1, treated with a mousse of casein phosphopeptide and amorphous calcium−phosphate (CPP-ACP); G2, treated with a gel containing nano-hydroxyapatite; G3, treated with a 5% SF varnish; G4, treated with a toothpaste containing ACP functionalized with fluoride and carbonate-coated with citrate; G5, not-treated artificial enamel lesions; G6, not demineralized and not treated sound enamel. G1−G4 were subjected to pH cycling over a period of seven days. Analyses of the specimens’ enamel surfaces morphology were performed by SEM and EDS. Data were statistically analyzed for multiple group comparison by one-way ANOVA/Tukey’s test (p < 0.05). The results show that the Ca/P ratio of the G5 (2.00 ± 0.07) was statistically different (p < 0.05) from G1 (1.73 ± 0.05), G2 (1.76 ± 0.01), G3 (1.88 ± 0.06) and G6 (1.74 ± 0.04), while there were no differences (p > 0.05) between G1, G2 and G6 and between G4 (2.01 ± 0.06) and G5. We concluded that G1 and G2 showed better surface remineralization than G3 and G4, after 7 days of treatment.

Comparative Evaluation of Influence of Nd:YAG Laser (1064 nm) and 980 nm Diode Laser on Enamel around Orthodontic Brackets: An In Vitro Study

(1) Background: The prevention of demineralizing lesions at the enamel structure level continues to represent a challenge in daily dental practice. When bacteria influence the pH level, this will decrease below the threshold for remineralization and the dissociation of hydroxyapatite will occur with a high percentage of phosphate and calcium loss. These elements continue to be studied by many authors in order to obtain a working protocol that will lead to their stabilization at the level of the enamel structure, thus preventing the demineralization process. The aim of this study is to evaluate and compare the influence of two types of laser wavelengths on the surface morphology and mineral components of the enamel through an examination with scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDX). (2) Methods: Thirty permanent human incisors extracted for periodontal reasons from patients aged 25−40 years old were selected for this study. Metallic brackets (SS Standard 022 Slot, OC Orthodontics, McMinnville, OR, 97128, USA) were bonded onto each tooth. The buccal surface was randomly assigned three sections: Section A—negative control (no treatment), section B—treated with 980 nm Gallium−Aluminum−Arsenide diode laser (a 300 µm optic fiber was used with 0.8 W output power, energy density of 5.33 J/mm2, in continuous mode, for 30 s, oriented perpendicularly to the enamel surface in contact mode) (KaVo GENTLEray 980 Diode Laser, Kaltenbach & Voigt GmbH, Biberach, Germany), and section C—treated with Nd:YAG laser (a 300 µm fiber was carried out at a 1 mm distance from the enamel surface with 0.75 W power, 75 mJ pulse energy, pulse repetition rate of 10 Hz, 5 J/mm2 fluency, average exposure time of 30 s, and water cooling assisted) (LIGHTWALKER AT S, M021-5AF/1 S, Fotona d.o.o, Ljubljana, Slovenia). The elements evaluated in this study were calcium (Ca), phosphate (P), oxygen (O), and carbon (C). A one-way analysis of variance, paired t-tests, and independent t-tests were carried out to evaluate the results using the SPSS 19 IBM Statistical package software for Microsoft. (3) Results: The evaluation of the data indicated that both wavelengths produced an increase in Ca wt% (for diode laser the mean of Ca wt% before irradiation was 21.06, while that after treatment reached 28.24; and for Nd:YAG laser, the mean of Ca wt% before irradiation was 21.31, while that after treatment reached 33.88); as well, the 980 nm diode laser decreased P wt% (from 17.20 before irradiation to 16.92 after irradiation) and the Nd:YAG laser increased P wt% (from 17.46 before irradiation to 18.28 after irradiation). These results showed a statistically significant difference at the p < 0.05 level. (4) Conclusions: It can be concluded that the best improvement of enamel chemical composition was obtained with Nd:YAG irradiation.