Advanced non-fluoride approaches to dental enamel remineralization: The next level in enamel repair management

Remineralizing effect of NSF on artificial enamel caries

INTRODUCTION

Nanotechnology offers new approaches and endless opportunities for remineralizing tooth decay without being toxic or causing allergies. This study aimed to determine the effect of nanosilver fluoride (NSF) on the remineralization potential of enamel caries-like lesions compared to 5% sodium fluoride varnish in permanent teeth.

METHODS

Fifteen teeth (molars and premolars) were gathered, cleaned, and polished using a scaler. After sectioning the teeth mesiodistally and removing the roots, the thirty specimens were subjected to a demineralized solution to induce early enamel lesions and then assigned randomly into two equal groups. The test materials were applied, and then all the specimens were subjected to a pH cycling model for 30 days. DIAGNOdent and surface roughness were investigated, and an evaluation of the enamel Ca and P weight% for Ca/P ratio calculation was done using SEM-EDX to analyze the specimens at the end of the study. The data were analyzed using an independent t-test.

RESULTS

The mean values for the DIAGNOdent measurements for NSF and NaF at baseline and after demineralization were not significantly different (p > 0.05). After treatment, NaF varnish showed a significantly higher mean DIAGNOdent measurement (11.8 ± 5.80) than NSF (4.7 ± 1.6). The mean surface roughness of the NaF group (1.64 ± 0.39) was much higher than NSF's mean surface roughness (1.07 ± 0.21). Specimens treated with NSF had statistically significant smoother surfaces (p < 0.001). The NSF group had a higher mean Ca/P ratio (2.9 ± 0.35) than NaF (2.2 ± 0.11). This difference was statistically significant (p = 0.012).

CONCLUSION

The study reveals that nano silver fluoride is a more effective treatment than sodium fluoride varnish in enhancing teeth's clinical characteristics, particularly in terms of mineral content and surface roughness, suggesting it could be an improved strategy to prevent dental caries and maintain enamel integrity.

Amelogenin-inspired peptide, calcium phosphate solution, fluoride and their synergistic effect on enamel biomimetic remineralization: an in vitro pH-cycling model

BACKGROUND

Several methods were introduced for enamel biomimetic remineralization that utilize a biomimetic analogue to interact and absorb bioavailable calcium and phosphate ions and induce crystal nucleation on demineralized enamel. Amelogenin is the most predominant enamel matrix protein that is involved in enamel biomineralization. It plays a major role in developing the enamel's hierarchical microstructure. Therefore, this study was conducted to evaluate the ability of an amelogenin-inspired peptide to promote the remineralization potential of fluoride and a supersaturated calcium phosphate solution in treating artificially induced enamel carious lesions under pH-cycling regimen.

METHODS

Fifty enamel slices were prepared with a window (4*4 mm2 ) on the surface. Five samples were set as control healthy enamel and 45 samples were subjected to demineralization for 3 days. Another 5 samples were set as control demineralized enamel and 40 enamel samples were assigned into 8 experimental groups (n=5) (P/I, P/II, P/III, P/AS, NP/I, NP/II, NP/III and NP/AS) according to peptide treatment (peptide P or non-peptide NP) and remineralizing solution used (I; calcium phosphate solution, II; calcium phosphate fluoride solution, III; fluoride solution and AS; artificial saliva). Samples were then subjected to demineralization/remineralization cycles for 9 days. Samples in all experimental groups were evaluated using Raman spectroscopy for mineral content recovery percentage, microhardness and nanoindentation as healthy, demineralized enamel and after pH-cycling. Data were statistically analysed using two-way repeated measures Anova followed by Bonferroni-corrected post hoc test for pairwise multiple comparisons between groups. Statistical significance was set at p= 0.05. Additionally, XRD, FESEM and EDXS were used for crystal orientation, surface morphology and elemental analysis after pH-cycling.

RESULTS

Nanocrystals clumped in a directional manner were detected in peptide-treated groups. P/II showed the highest significant mean values in mineral content recovery (63.31%), microhardness (268.81±6.52 VHN), elastic modulus (88.74±2.71 GPa), nanohardness (3.08±0.59 GPa) and the best crystal orientation with I002/I300 (1.87±0.08).

CONCLUSION

Despite pH changes, the tested peptide was capable of remineralizing enamel with ordered crystals. Moreover, the supplementary use of calcium phosphate fluoride solution with peptide granted an enhancement in enamel mechanical properties after remineralization.

Antibiofilm Properties and Demineralization Suppression in Early Enamel Lesions Using Dental Coating Materials

This study aimed to investigate the effects of dental coating materials on Streptococcus mutans biofilm formation. The test materials were PRG Barrier Coat (PRG), BioCoat Ca (BioC), and FluorDental Jelly (FluorJ). Bovine enamel specimens were demineralized to mimic early enamel lesions. The biofilm was developed on a specimen treated with one of the materials by using a modified Robbins device flow-cell system. Scanning electron and fluorescence confocal laser scanning microscopy, viable and total cell counts, and gene expression assessments of the antibiofilm were performed. Ion incorporation was analyzed using a wavelength-dispersive X-ray spectroscopy electron probe microanalyzer. All materials allowed biofilm formation but reduced its volume. FluorJ was the only material that inhibited biofilm accumulation and had a bactericidal effect, revealing 0.66 log CFU in viable cells and 1.23 log copy reduction in total cells compared with the untreated group after 24 h of incubation. The ions released from PRG varied depending on the element. BioC contributed to enamel remineralization by supplying calcium ions while blocking the acid produced from the biofilm. In summary, the dental coating materials physically prevented acid attacks from the biofilm while providing ions to the enamel to improve its mechanical properties.

Advances in Preventive and Therapeutic Approaches for Dental Erosion: A Systematic Review

This review discusses both preventive measures and clinically implemented therapy procedures that have been developed recently for the prevention and treatment of tooth erosion.

METHODS

The databases PubMed, Scopus, and Web of Science were used for a thorough search. Studies on the prevention and treatment of dental erosion that were conducted in English and used in vitro were among the inclusion criteria.

RESULTS

The search turned up 391 papers in total, with 34 of those publications matching the requirements for inclusion. Varnishes, toothpastes, and solutions containing fluoride and other substances were used as preventive measures.

CONCLUSIONS

Dental erosion is a significant issue, and taking preventative steps is crucial to lessening the disease's spread and its effects. Interventions based on fluoride seem to be successful at halting erosion and encouraging remineralization. To effectively address severe tooth erosion, therapeutic methods, including composite restorations, prosthetic crowns, and veneers, are available. Dental erosion causes aesthetic and functional issues that are best addressed with less invasive treatments like direct composite restorations. To improve and broaden the range of available treatments for this common dental issue, additional research and development are required.

Restorative Dental Resin Functionalized with Calcium Methacrylate with a Hydroxyapatite Remineralization Capacity

The ability of dental materials to induce the mineralization of enamel like hydroxyapatite (HA) is of great importance. In this article, a novel kind of dental restorative material characterized by a mineralization ability was fabricated by photopolymerization. Calcium methacrylate (CMA) was introduced into the classical bisphenol A-glycidyl methacrylate (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) dental resin formulation. This functional dental resin (BTCM) was calcium-rich and can be prepared simply by one-step photopolymerization. The influence of CMA on the photopolymerization kinetics, the dental resin's mechanical properties, and its capacity to induce dynamic in situ HA mineralization were examined. Real-time FTIR, compression modulus, scanning electron microscopy, X-ray spectroscopy, MTT assay, and cell attachment test were carried out. The obtained data were analyzed for statistical significance using analysis of variance (ANOVA). Double bond conversion could be completed in less than 300 s, while the compression modulus of BTCM decreased with the increase in CMA content (30 wt%, 40 wt%, and 50 wt%). After being soaked in Ca(NO3)2 and Na2HPO4 solutions alternatively, dense HA crystals were found on the surface of the dental resin which contained CMA. The amount of HA increased with the increase in CMA content. The MTT results indicated that BTCM possesses good biocompatibility, while the cell adhesion and proliferation investigation demonstrated that L929 cells can adhere and proliferate well on the surface of BTM. Thus, our approach provides a straightforward, cost-effective, and environmentally friendly solution that has the potential for immediate clinical use.

The Effect of Biomimetic Remineralization of Calcium Phosphate Ion Clusters-Treated Enamel Surfaces on Bracket Shear Bond Strength

Purpose

To evaluate the remineralization effect of calcium phosphate ion clusters (CPICs) on demineralized enamel surfaces and their effects on bracket shear bond strength.

Patients and Methods

Extracted premolars were prepared in resin blocks. The samples in the form of resin blocks were divided into five experimental groups: control group, demineralized group, and groups of CPIC solution treatment for 30, 60, and 90s. The specimens were examined using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDX), microhardness testing, micro-computed tomography (micro-CT) assessment, shear bond strength (SBS) test, and adhesive remnant index (ARI) score.

Results

The SEM images revealed epitaxial growth of enamel and a decrease in the thickness of the demineralized enamel layer when treated with CPIC solution. The EDX analysis revealed an increase in the Ca/P ratio in the CPIC-treated groups. The microhardness value significantly increased when treated with CPICs; however, it showed a lower value than that of the sound enamel groups. As a result of the micro-CT test, radiolucency decreased gradually as the CPIC treatment time increased. The SBS test and ARI score results showed an improvement in bonding stability after treatment with CPICs.

Conclusion

We demonstrated an enamel biomodification approach using CPIC solution treatment, which is a promising strategy for enamel remineralization. Specifically, remineralization of demineralized enamel improves the orthodontic bracket SBS.

Remineralization Effect of Calcium Glycerophosphate in Fluoride Mouth Rinse on Eroded Human Enamel: An In Vitro Study

Aims and Objectives

The aim of this in vitro study was to evaluate the remineralization effect of calcium glycerophosphate (CaGP) in fluoride mouth rinse on permanent enamel eroded by a soft drink.

Materials and Methods

Forty sound permanent premolars were embedded in self-curing acrylic resin and immersed in Coca-Cola to create erosive lesions. The teeth were divided into four groups (n = 10): Group I artificial saliva; Group II sodium fluoride; Group III sodium fluoride + sodium monofluorophosphate; and Group IV sodium monofluorophosphate + CaGP. The specimens in the assigned groups underwent pH cycling for ten days. The baseline, after erosion, and after remineralization surface microhardness (SMH) values were determined. The data were analyzed by one-way analysis of variance (ANOVA). The mean SMH value between groups and one-way repeated measures ANOVA for the mean SMH value within each group and Bonferroni's for multiple comparisons at a 95% confidence level were determined. The average SMH was used and calculated as the percentage recovery of SMH.

Results

After being eroded by the cola soft drink, the mean SMH values in all groups were significantly decreased. After remineralization, Group I had the lowest %SMHR. The %SMHR of Groups II, III, and IV were significantly higher than Group I (P < 0.001). However, there were no significant differences among Groups II, III, and IV (P > 0.05).

Conclusions

Fluoride mouth rinse with and without CaGP showed similar efficacies in remineralizing eroded permanent enamel.

Polysaccharide-protein microparticles based-scaffolds to recover soft tissue loss in mild periodontitis

Periodontal regeneration is extremely limited and unpredictable due to structural complications, as it requires the simultaneous restoration of different tissues, including cementum, gingiva, bone, and periodontal ligament. In this work, spray-dried microparticles based on green materials (polysaccharides - gums - and a protein - silk fibroin) are proposed to be implanted in the periodontal pocket as 3D scaffolds during non-surgical treatments, to prevent the progression of periodontal disease and to promote the healing in mild periodontitis. Arabic or xanthan gum have been associated to silk fibroin, extracted from Bombyx mori cocoons, and loaded with lysozyme due to its antibacterial properties. The microparticles were prepared by spray-drying and cross-linked by water vapor annealing, inducing the amorphous to semi-crystalline transition of the protein component. The microparticles were characterized in terms of their chemico-physical features (SEM, size distribution, structural characterization - FTIR and SAXS, hydration and degradation properties) and preclinical properties (lysozyme release, antibacterial properties, mucoadhesion, in vitro cells adhesion and proliferation and in vivo safety on a murine incisional wound model). The encouraging preclinical results highlighted that these three-dimensional (3D) microparticles could provide a biocompatible platform able to prevent periodontitis progression and to promote the healing of soft tissues in mild periodontitis.

Development of a novel, entirely herbal-based mouthwash effective against common oral bacteria and SARS-CoV-2

BACKGROUND

Parallel to the growth of the oral healthcare market, there is a constantly increasing demand for natural products as well. Many customers prefer products that contain fewer toxic agents, therefore providing an environmentally friendly solution with the benefit of smaller risk to the user. Medieval and early modern medicinal knowledge might be useful when looking for natural, herbal-based components to develop modern products. Along with these considerations we created, tested, and compared an entirely natural mouthwash, named Herba Dei.

METHODS

The manufacturing procedure was standardized, and the created tincture was evaluated by GC/MS analysis for active compounds, experimentally tested in cell-based cytotoxicity, salivary protein integrity, cell-free antioxidant activity, anti-bacterial and anti-viral assays, and compared with three market-leading mouthwashes.

RESULTS

Our tincture did not show significant damage in the cytotoxicity assays to keratinocyte and Vero E6 cells and did not disrupt the low molecular weight salivary proteins. Its radical scavenging capacity surpassed that of two tested, partly natural, and synthetic mouthwashes, while its antibacterial activity was comparable to the tested products, or higher in the bacterial aerobic respiratory assay. The active compounds responsible for the effects include naturally occurring phenylpropanoids, terpenes, and terpenoids. Our mouthwash proved to be effective in vitro in lowering the copy number of SARS-CoV-2 in circumstances mimicking the salivary environment.

CONCLUSIONS

The developed product might be a useful tool to impede the transmission and spread of SARS-CoV-2 in interpersonal contact and aerosol-generating conditions. Our mouthwash can help reduce the oral bacterial flora and has an antioxidant activity that facilitates wound healing and prevents adverse effects of smoke in the oral cavity.

Synchrotron X-ray Studies of the Structural and Functional Hierarchies in Mineralised Human Dental Enamel: A State-of-the-Art Review

Hard dental tissues possess a complex hierarchical structure that is particularly evident in enamel, the most mineralised substance in the human body. Its complex and interlinked organisation at the Ångstrom (crystal lattice), nano-, micro-, and macro-scales is the result of evolutionary optimisation for mechanical and functional performance: hardness and stiffness, fracture toughness, thermal, and chemical resistance. Understanding the physical-chemical-structural relationships at each scale requires the application of appropriately sensitive and resolving probes. Synchrotron X-ray techniques offer the possibility to progress significantly beyond the capabilities of conventional laboratory instruments, i.e., X-ray diffractometers, and electron and atomic force microscopes. The last few decades have witnessed the accumulation of results obtained from X-ray scattering (diffraction), spectroscopy (including polarisation analysis), and imaging (including ptychography and tomography). The current article presents a multi-disciplinary review of nearly 40 years of discoveries and advancements, primarily pertaining to the study of enamel and its demineralisation (caries), but also linked to the investigations of other mineralised tissues such as dentine, bone, etc. The modelling approaches informed by these observations are also overviewed. The strategic aim of the present review was to identify and evaluate prospective avenues for analysing dental tissues and developing treatments and prophylaxis for improved dental health.

Bond Strength Survival of a Novel Calcium Phosphate-Enriched Orthodontic Self-Etching System after Various Ageing Protocols: An In Vitro Study

Objective

This study aimed to evaluate the orthodontic bond strength and enamel-preserving ability of a hydroxyapatite nanoparticles-containingself-etch system following exposure to various ageing methods.

Materials and Methods

Hydroxyapatite nanoparticles (nHAp) were incorporated into an orthodontic self-etch primer (SEP, Transbond™ plus) in three different concentrations (5%, 7%, and 9% wt) and tested versus the plain SEP (control) for shear bond strength (SBS), adhesive remnant index (ARI) scores, and enamel damage in range-finding experiments using premolar teeth. The best-performing formulation was further exposed to the following four artificial ageing methods: initial debonding, 24 h water storage, one-month water storage, and one-month acid challenge. A field-emission scanning electron microscope (FE-SEM) was used to examine the integrity of debonded enamel surfaces and calcium-phosphates (CaPs) reprecipitation.

Results

The best-performing formulation (7% nHAp-SEP) resulted in significantly lower SBS (p < 0.001) than the control SEP following the four artificial ageing methods. Nevertheless, it survived the ageing protocols and yielded clinically acceptable SBS with the advantages of leaving minimal adhesive residue, preserving enamel integrity and smoothness, and inducing CaP reprecipitation as confirmed by FE-SEM images.

Conclusions

A newly developed SEP produced adequate orthodontic bond strengths and left unblemished debonded enamel surfaces with minimal remnant adhesive and remineralisation potential, thereby suggesting simpler and safer bonding/debonding procedures.

Development of a remineralizing calcium phosphate nanoparticle-containing self-etching system for orthodontic bonding

Objectives

This study aimed to incorporate hydroxyapatite nanoparticles (nHA) or amorphous calcium phosphate nanoparticles (nACP) into a self-etch primer (SEP) to develop a simplified orthodontic bonding system with remineralizing and enamel preserving properties.

Materials and Methods

nHA and nACP were incorporated into a commercial SEP (Transbond™ plus) in 7% weight ratio and compared with the plain SEP as a control. Shear bond strengths (SBS), enamel damage, and adhesive remnant index (ARI) scores were evaluated at 24 h and post 5000 thermocycling. Field-emission scanning electron microscope (FESEM) was used to inspect the distribution of the nanoparticles in the experimental SEPs and evaluate the enamel surface integrity both before bracket bonding and post bracket debonding. Phase determination and remineralizing capability of the modified SEP were characterized by X-ray diffraction and Raman spectroscopy, respectively.

Results

The addition of nHA or nACP to the SEP significantly reduced the SBS, ARI, and enamel damage (p < 0.05) as compared to the control SEP; however, only nHA-SEP survived the thermocycling protocol and yielded acceptable SBS (13.38 MPa). Enamel remineralizing ability of the developed nHA-SEP was confirmed by both FESEM images and Raman phosphate map.

Conclusions

Incorporating nHA into SEP resulted in clinically acceptable bond strengths with remineralizing ability.

Clinical relevance

The newly developed nHA-SEP has unprecedented ability to simultaneously etch, prime, and remineralize the enamel in a single step leaving immaculate enamel surface with the potential of saving cost and time at the post-debonding step.

Xylitol Fluoride Varnish: In Vitro Effect Analysis on Enamel by Atomic Force Microscopy

(1) Background: Numerous studies have shown the beneficial role of fluoride in the primary prevention of dental caries. The aim of the present study was to put into evidence the change in the enamel structure immediately after the application of a fluoride varnish. (2) Methods: A xylitol−fluoride varnish was evaluated. The enamel specimens (n = 10) were analyzed by atomic force microscopy on enamel surface and treatment with fluoride varnish applied. The dimensional topographic analysis was performed by 2D and 3D analysis software. Statistical analysis was performed using SPSS Version 26.00 (IBM, Armonk, NY, USA). A one-sample statistics test was used to identify significant differences (p < 0.05). (3) Results: Surface roughness (Ra) measurements ranged from Ra = 0.039 μm (±0.048), to Ra = 0.049 μm (±0.031), respectively (p < 0.05), with an increase in the surface roughness passing from the intact enamel to the enamel exposed to fluoride varnish. When comparing Ra values of the nonfluorinated enamel and fluorinated enamel, significant differences (p < 0.05) were found, suggesting that the varnish had a protective effect on the enamel surface. (4) Conclusions: Xylitol−fluoride varnish, even in one single short-time application, is effective in reducing the surface roughness of enamel structure exposed to abrasion, thus increasing resistance to dental caries.

Risk of Dental Caries and Erosive Tooth Wear in 117 Children and Adolescents' Anorexia Nervosa Population-A Case-Control Study

INTRODUCTION

Restrictive type of anorexia nervosa (AN) is still one of the most severe eating disorders worldwide with an uncertain prognosis. Patients affected by AN should be encouraged to undertake psychiatric care and psychotherapy, but whether they should necessarily be included in careful dental care or not may still be questionable. Even though there is a constantly increasing number of AN studies, there are just a few data about the youngest group of AN children and adolescents aged < 18.

METHODOLOGY

This case-control study aimed to compare the dental health and gingival inflammation level in female adolescent inpatients affected by severe AN restrictive subtype vs. controls. Based on clinically confirmed 117 AN cases (hospitalized in years 2016-2020 in public Psychiatric Unit, BMI < 15 kg/m², mean age 14.9 ± 1.8), the dental status has been examined regarding the occurrence of caries lesions using Decay Missing Filling Teeth (DMFT), erosive wear as Basic Erosive Wear Examination (BEWE), gingival condition as Bleeding on Probing (BOP) and plaque deposition as Plaque Control Record (PCR). The results were compared with age-matched 103 female dental patients (BMI 19.8 ± 2.3 kg/m², age 15.0 ± 1.8, p = 0.746) treated in a public University dental clinic.

RESULTS

AN patients were found to present a higher incidence of oral-related complications according to dental status (DMFT 3.8 ± 4.5 vs. 1.9 ± 2.1, p = 0.005), erosive tooth wear (BEWE 18.9 vs. 2.9%, p < 0.001), less efficient in controlling plaque (PCR 43.8 vs. 13.7%, p < 0.001) and gingival inflammation (BOP 20.0 vs. 3.9%, p < 0.001) compared with female adolescents. In the AN group, a significant correlation between BOP, BEWE, and duration of AN disease (p < 0.05), similarly to the number of decayed teeth D, filled teeth F and PCR were detected (p < 0.05).

CONCLUSIONS

Although the obtained results did not reveal any severe oral status, our findings indicated impaired dental and gingival conditions in young anorexics. Considering AN's potential role in oral health, it is essential to monitor dental treatment needs and oral hygiene levels in their present status to prevent forward complications in the future.

Amorphous calcium phosphate, the lack of order is an abundance of possibilities

For almost three decades from its discovery, amorphous calcium phosphate (ACP) was not considered a suitable biomaterial due to its structural instability. Thanks to its unique properties in respect to crystalline calcium phosphate phases, nowadays ACP is used in promising devices for hard tissue regeneration. Here we have highlighted the features of ACP that were harnessed to create excellent biomaterials for dental remineralization, self-setting bone cements, drug delivery, and coatings of prostheses. Its current limitations as well as future perspectives of development were concisely described. Despite more research works are needed, we envisage that the future of ACP is bright.