Enamel Remineralisation with a Novel Sodium Fluoride-Infused Bristle Toothbrush

This study aims to investigate whether toothbrushes with fluoride-infused bristles have any (re)mineralisation effects on bovine enamel. Bovine incisors (N = 160) were extracted, and the buccal side of the crown was cut into dimensions of ~5 mm × 5 mm with a low-speed saw. These specimens were randomly allocated into four groups: half (80 teeth) were stored in demineralising solution (DM), and the other half were stored in deionised water (DW) for 96 h. Then, they were brushed with a force of 2.0 ± 0.1 N for five min with a manual toothbrush with either fluoride-infused (TF) or regular (TR) bristles. Microhardness (Vickers), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM) were used to investigate the surfaces of the bovine enamel specimens before and after brushing. Two-way ANOVA was used to analyse the hardness data, and the pairwise comparison method was used to analyse the Ca/P ratio, for each group at α = 0.05. The results show that brushing with either of these toothbrushes increased the Vickers microhardness on DM and DW enamel (p < 0.001), whereas hydroxyapatite was revealed in all groups by XRD. The DM samples showed a significant increase (p < 0.05) in the Ca/P ratios after brushing with TR and TF. Conversely, under DW conditions, these ratios decreased significantly after brushing. In terms of the F atomic%, TF increased significantly. SEM revealed mineral deposition in the DM groups after toothbrushing. To conclude, toothbrushing effectively induces the microhardness of sound and demineralised enamel, while fluoride-infused bristles might be able to retain fluoride on the enamel surface.

Effect of topical applications containing surface pre-reacted glass-ionomer filler on dental hard tissues-A systematic review

OBJECTIVES

The objective of this systematic review was to assess the efficacy of topical applications containing surface pre-reacted glass-ionomer filler on dental hard tissues.

DATA SOURCES

A comprehensive literature search was conducted in PubMed, MEDLINE, Embase, Scopus, ClinicalTrials.gov, Lilacs and Cochrane Central Register of Controlled Trials (until 15.08.2022). Google and Open Grey were used to search for grey literature and handsearching was conducted.

STUDY SELECTION

Clinical and in vitro studies conducted on human adult teeth were considered eligible without date and language restrictions. The electronic database generated 2,488 results. In total, 227 studies were found to be relevant from which 71 duplicates were removed. Title and abstract screening were then conducted, and a total of 33 studies met the inclusion criteria were assessed for full text screening. Two authors concluded that 11 studies satisfied the eligibility criteria. In vitro studies were evaluated using an accepted quality assessment tool for dental studies. Cochrane risk of bias tool was used for quality assessment of clinical randomised studies, whilst ROBINS-I tool was used for non-randomised studies.

RESULTS

Nine in vitro and only two non-randomised clinical trials were reported to meet the eligibility criteria. Results were grouped and analysed separately according to the study design. Different modes of surface pre-reacted glass-ionomer filler delivery were reported in the included studies. Three studies tested the effect of surface pre-reacted glass-ionomer filler containing toothpastes, whilst three studies investigated the effect of polishing pastes with surface pre-reacted glass-ionomer filler, three studies used eluates as surface pre-reacted glass-ionomer filler delivery method and two studies reported the effect of the coatings. The effect of those vehicles was tested on enamel, dentine or oral biofilm. Each study was analysed individually, and heterogeneity was detected among in vitro and clinical studies. Half of the in vitro studies were medium risk, whilst three were low and two studies presented with high risk. In clinical trials, outcome, confounding, selection biases were reported. Meta-analysis was therefore unable to be carried out.

CONCLUSION

Regardless of the mode of delivery and type of studies, all included studies demonstrated the efficacy of surface pre-reacted glass-ionomer filler containing topical applications to inhibit demineralisation of dental hard tissues at a dose dependant manner. Antimicrobial properties towards cariogenic species were also reported.

CLINICAL SIGNIFICANCE

Surface pre-reacted glass-ionomer filler containing topical applications may serve as potential caries preventive and cariostatic tools. The systematic review registered in PROSPERO, International prospective register of systematic reviews, No. CRD42022347130.

Long term remineralizing effect of casein phosphopeptide amorphous calcium phosphate in white spot lesions: A systematic review and meta-analysis

BACKGROUND

White spot lesions (WSLs) appear as white, opaque areas on the teeth and are caused by a demineralization of the enamel.

OBJECTIVE

The purpose of this systematic review and meta-analysis was to determine whether casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) has beneficial effects on WSLs and provides remineralizing benefits that are superior to those of placebo or no treatment.

METHODS

Following a thorough analysis of the literature across major online sources, 103 papers - 54 of which underwent in-depth evaluation - were found. We used inclusion and exclusion criteria to choose research articles that were appropriate for our review.

RESULTS

10 papers met this review's requirements and were subsequently included. As compared to the controls, CPP-ACP demonstrated increased efficacy in treatment of WSLs in terms of remineralisation and other parameters which included microhardness tests and enamel surface roughness. The forest plots present the results of meta-analyses comparing the effect of CPP-ACP versus control/other agents on white spot lesions (WSLs). In terms of odds ratios (OR), CPP-ACP showed a small increase in the odds of WSLs compared to control/other agents. In-vitro studies showed no significant difference in relative risk (RR) between CPP-ACP and control/other agents. Randomized control trials indicated a small increase in the risk of WSLs with CPP-ACP treatment, but the overall effect was not statistically significant.

CONCLUSION

There was evidence to support the use of CPP-ACP over other agents for WSL prevention or treatment, but further research is needed to confirm these findings.

In Vitro Models Used in the Formation of Root Caries Lesions-A Review of the Literature

The management of root caries remains a challenge for clinicians due to its unique anatomical location and structure. There is increasing interest in utilising artificial root caries lesions to develop new strategies for remineralisation. An ideal protocol has not yet been agreed upon. The aim of this review is to provide a structured overview of previously reported in vitro root caries models. The literature was screened and mined for information mainly on substrate selection, model systems utilised, and variables used in the models. Human roots (60%) were the most frequently used substrates, followed by bovine roots (40%). Chemical models (69%) were the most frequently utilised model systems, followed by microbiological models (27%), to form root caries lesions. Acetate buffer solution (80%), pH 5.0 or above (40%), and a demineralisation time of five days (25%) were the common variables used in the chemical systems, while mono-species biofilm was most frequently used (73%) in microbiological models and Streptococcus mutans was the most common bacterial strain utilised in these models (80%). This review highlights the variability amongst the experimental approaches, discusses the advantages and limitations of these approaches, and emphasises that standardisation of experimental conditions along with sustained research will benefit root caries research.

Remineralising potential of Ocimum basilicum varnish and fluoride varnish on initial enamel caries: An in vitro microscopic study

Background

The focus of caries research has switched to early identification and non-invasive treatment of carious lesions.

Aim

This study aimed to evaluate and compare the remineralising potential of Ocimum (O.) basilicum varnish and fluoride varnish on initial enamel caries.

Method

The authenticated O. basilicum seeds were procured from a repository, and the extract was prepared using the Soxhlet method, which was vortexed with Indian Pharmaceutical (IP)-graded chemicals to obtain varnish. Extracted premolar tooth samples were divided into three groups of 33 each after demineralisation with a pH of 4.5 for 48 hours at 37°C. Each group was subjected to remineralisation twice daily with respective agents for 4 minutes for 30 consecutive days. Each sample was ground-sectioned through an enamel window. The lesion depth was measured using a light microscope (Leica™ DM2500) and ImageJ software. The data were evaluated using analysis of variance (ANOVA) and post hoc analysis.

Results

The mean (± SD) pre-treatment lesion depth across the groups ranged from 242.11 ± 26.144 μm to 352.66 ± 34.531 μm. The highest lesion depth recovery rate of 45.938% was recorded for the fluoride varnish group, followed by 36.015% in the O. basilicum varnish group, which was statistically significant by Tukey's post hoc analysis (p < 0.001). The gingival fibroblast cells were viable by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay.

Conclusion

The O. basilicum varnish demonstrated a homogenous layer of mineral deposition. However, the remineralising efficacy was slightly lesser than that of the fluoride varnish. Hence, the novel O. basilicum-based remineralisation agent appears to have potential as a non-invasive alternative to topical fluorides in the therapy of early caries lesions.

The effect of calcium phosphate ion clusters in enhancing enamel conditions versus Duraphat and Icon

This study aimed to evaluate and compare the remineralisation, mechanical, anti-aging, acid resistance and antibacterial properties of calcium phosphate ion clusters (CPICs) materials with those of Duraphat and Icon. The remineralisation and mechanical properties were investigated using scanning electron microscopy, Fourier-transform infrared (FTIR) spectroscopy and nanoindentation. CPICs induced epitaxial crystal growth on the enamel surface, where the regrown enamel-like apatite layers had a similar hardness and elastic modulus to natural enamel (p > 0.05). Acid resistance and anti-aging properties were tested based on ion dissolution and surface roughness. CPICs exhibited similar calcium and phosphate ion dissolution to the control (p > 0.05), and its roughness decreased after thermocycling (p < 0.05), thereby decreasing the risk of enamel surface demineralisation. The minimum inhibitory concentration was 0.1 mg/ml, and the minimum bactericidal concentration ranged from 0.05 to 0.1 mg/ml. Overall, this biomimetic CPICs is a promising alternative to dental demineralisation.

Peptide Designs for Use in Caries Management: A Systematic Review

The objective of this study was to review the design methods that have been used to create peptides for use in caries management. Two independent researchers systematically reviewed many in vitro studies in which peptides were designed for use in caries management. They assessed the risk of bias in the included studies. This review identified 3592 publications, of which 62 were selected. Forty-seven studies reported 57 antimicrobial peptides. Among them, 31 studies (66%, 31/47) used the template-based design method; 9 studies (19%, 9/47) used the conjugation method; and 7 studies (15%, 7/47) used other methods, such as the synthetic combinatorial technology method, the de novo design method and cyclisation. Ten studies reported mineralising peptides. Seven of these (70%, 7/10) used the template-based design method, two (20%, 2/10) used the de novo design method, and one study (10%, 1/10) used the conjugation method. In addition, five studies developed their own peptides with antimicrobial and mineralising properties. These studies used the conjugation method. Our assessment for the risk of bias in the 62 reviewed studies showed that 44 publications (71%, 44/62) had a medium risk and that 3 publications had a low risk (5%, 3/62). The two most common methods for developing peptides for use in caries management that were used in these studies were the template-based design method and the conjugation method.

The Use of Toothpastes Containing Different Formulations of Fluoride and Bioglass on Bleached Enamel

To investigate the application of toothpaste either containing calcium sodium phospho-silicate bioglass (NovaMin) or calcium fluorosilicate bioglass (BioMinF) on the surface mineral composition and morphology of enamel after bleaching procedure. Methods: Thirty extracted noncarious human teeth were allocated into five groups (n = 6). Group 1: Bleaching using 40% hydrogen peroxide (HP) and fluoridated toothpaste containing bioactive glass (1450 ppm fluoride). Group 2: Bleaching using 40%HP and toothpaste containing calcium fluorosilicate bioglass (540 ppm fluoride). Group 3: Bleaching using 40%HP and fluoridated toothpaste (1450 ppm fluoride). Group 4: Bleaching alone using 40%HP. Group 5: Negative control with distilled water alone. The surface morphology was evaluated using Scanning Electron Microscope (SEM) and Scanning Probe Microscope (SPM). The concentration of elements as atomic percentages were determined by X-ray Photoelectron Spectroscopy (XPS) and Energy-Dispersive X-ray Spectroscopy (EDS). Results: This laboratory-based study reported that SPM and SEM detected minor changes on the surfaces of all toothpaste-treated enamel samples (Groups 1-3) after 45 days. Bioactive glass deposits were observed on enamel surfaces in Groups 1 and 2, whilst the bleaching-alone samples (Group 4) had rough enamel surfaces. XPS reported that toothpaste containing calcium fluorosilicate bioglass (Group 2) had a high atomic% of calcium and phosphate, whilst silicon values were high in the toothpaste containing bioactive glass and 1450 ppm fluoride (Group 1) after bleaching procedure when compared to other groups (p < 0.05). In addition, EDS detected the highest %F in Groups 1, 2 and 5. Conclusions: Within the limitations of this laboratory-based study, there was no significant decrease in the Ca%, P% values and surface properties of enamel after the bleaching procedure following the use of different formulations of toothpastes for a period of 45 days. However, the Ca% and P% values were significantly high for the toothpaste containing calcium fluorosilicate bioglass (BioMinF) on the bleached enamel. Clinical relevance: The bleaching process can provide optimum aesthetic outcomes, but the effect of peroxides on hard tissues is still in question. Toothpastes containing different formulations of fluoride and bioactive glass might have the potential to prevent mineral loss on bleached enamel. However, further laboratory-based studies and controlled double-blind randomised clinical trials are required to interpret the effects of toothpastes with different fluoride and bioactive glass formulations on enamel surfaces following bleaching procedures.

Comparative Efficacy of Novel Biomimetic Remineralising Technologies

Biomimetic technologies for the remineralisation of enamel subsurface lesions (ESLs) have been developed and include: fluorocalcium phosphosilicate bioglass (BG/F); casein phosphopeptide-amorphous calcium phosphate (CPP−ACP) and with fluoride (CPP−ACFP); and self-assembling oligopeptide P11-4 (SAP). The aim of this study was to compare the remineralisation of ESLs in vitro using these technologies. Human enamel slabs with ESLs were cut into two half-slabs; one half-slab was untreated (control), and the other half was treated by exposure to one of the four technologies with artificial saliva (AS) or AS alone for 14 days at 37 °C. The technologies were applied to the ESL surface according to the manufacturer’s instructions. At the completion of each treatment, the treated half-slabs and their paired control half-slabs were embedded, sectioned and the mineral content was determined using transverse microradiography. The change in mineral content (remineralisation) between treatments was statistically analysed using one-way ANOVA. The order from highest to lowest remineralisation was CPP−ACFP (52.6 ± 2.6%) > CPP−ACP (43.0 ± 4.9%) > BG/F (13.2 ± 2.5%) > SAP (5.8 ± 1.6%) > AS (2.1 ± 0.5%). Only CPP−ACFP and CPP−ACP produced remineralisation throughout the body of the lesions. All four biomimetic technologies had some effect on the remineralisation of ESLs; however, CPP−ACFP with calcium, phosphate and fluoride ions stabilised by CPP was superior in the level and pattern of remineralisation obtained.

Caries Management with Non-Metallic Nanomaterials: A Systematic Review

BACKGROUND

Non-metallic nanomaterials do not stain enamel or dentin. Most have better biocompatibility than metallic nanomaterials do for management of dental caries.

OBJECTIVE

The objective of this study is to review the types, properties and potential uses of non-metallic nanomaterials systematically for managing dental caries.

METHODS

Two researchers independently performed a literature search of publications in English using PubMed, Scopus and Web of Science. The keywords used were (nanoparticles OR nanocomposites OR nanomaterials) AND (caries OR tooth decay). They screened the titles and abstracts to identify potentially eligible publications of original research reporting non-metallic nanomaterials for caries management. Then, they retrieved and studied the full text of the identified publications for inclusion in this study.

RESULTS

Out of 2497 resulting publications, this study included 75 of those. The non-metallic nanomaterials used in these publications were categorized as biological organic nanomaterials (n=45), synthetic organic nanomaterials (n=15), carbon-based nanomaterials (n=13) and selenium nanomaterials (n=2). They inhibited bacteria growth and/or promoted remineralization. They could be incorporated in topical agents (29/75, 39%), dental adhesives (11/75, 15%), restorative fillers (4/75, 5%), dental sealant (3/75, 4%), oral drugs (3/75, 4%), toothpastes (2/75, 3%) and functional candies (1/75, 1%). Other publications (22/75, 29%) do not mention specific applications. However, most publications (67/75, 89%) were in vitro studies. Six publications (6/75, 8%) were animal studies, and only two publications (2/75, 3%) were clinical studies.

CONCLUSION

The literature showed non-metallic nanomaterials have antibacterial and/or remineralising properties. The most common type of non-metallic nanomaterials for caries management is organic nanomaterials. Non-metallic nanomaterials can be incorporated into dental sealants, toothpaste, dental adhesives, topical agents and even candies and drugs. However, the majority of the publications are in vitro studies, and only two publications are clinical studies.

Growing Global Research Interest in Antimicrobial Peptides for Caries Management: A Bibliometric Analysis

Objective: Researchers are studying the use of antimicrobial peptides as functional biomaterials to prevent and treat dental caries. This study aims to investigate the global research interest in antimicrobial peptides for caries management. Methods: Two independent investigators systematically searched with keywords ('Caries' OR 'Dental caries') AND ('Antimicrobial peptide' OR 'AMP' OR 'Statherin' OR 'Histatin' OR 'Defensin' OR 'Cathelicidin') on Web of Science, PubMed and Scopus. They removed duplicate publications and screened the titles and abstracts to identify relevant publications. The included publications were summarized and classified as laboratory studies, clinical trials or reviews. The citation count and citation density of the three publication types were compared using a one-way analysis of variance. The publications' bibliometric data were analyzed using the Bibliometrix program. Results: This study included 163 publications with 115 laboratory studies (71%), 29 clinical trials (18%) and 19 reviews (11%). The number of publications per year have increased steadily since 2002. The citation densities (mean ± SD) of laboratory study publications (3.67 ± 2.73) and clinical trial publications (2.63 ± 1.85) were less than that of review articles (5.79 ± 1.27) (p = 0.002). The three publication types had no significant difference in citation count (p = 0.54). Most publications (79%, 129/163) reported the development of a novel antimicrobial peptide. China (52/163, 32%) and the US (29/163, 18%) contributed to 50% (81/163) of the publications. Conclusion: This bibliometric analysis identified an increasing trend in global interest in antimicrobial peptides for caries management since 2002. The main research topic was the development of novel antimicrobial peptides. Most publications were laboratory studies, as were the three publications with the highest citation counts. Laboratory studies had high citation counts, whereas reviews had high citation density.

Impact of Dentistry Materials on Chemical Remineralisation/Infiltration versus Salivary Remineralisation of Enamel-In Vitro Study

The aim of this study is to evaluate salivary remineralisation versus chemical remineralisation/infiltration of enamel, using different dentistry materials. The enamel changes were studied using confocal laser scanning microscopy (CLSM), and the depth of lesions and demineralisation/remineralisation/infiltration percentage were calculated. Additionally, the macro elemental composition of the teeth was performed using atomic absorption spectroscopy (AAS). Two studies were performed: (i) demineralisation of enamel in 3% citric acid and infiltration treatment with infiltration resin (Icon, DMG), remineralisation with Fluor Protector (Ivoclar Vivadent) and artificial saliva pH 8; and (ii) enamel demineralisation in saliva at pH 3 and remineralisation at salivary pH 8. The results showed that, firstly, for the remineralisation of demineralised enamel samples, Fluor Protector (Ivoclar Vivadent) was very effective for medium demineralised lesions followed by saliva remineralisation. In cases of deep demineralisation lesions where fluoride could not penetrate, low viscosity resin (Icon, DMG, Hamburg) effectively infiltrated to stop the demineralisation process. Secondly, remineralisation in salivary conditions needed supplementary study over a longer period, to analyse the habits, diet and nutrition of patients in detail. Finally, demineralisation/remineralisation processes were found to influence the macro elemental composition of enamel demineralisation, with natural saliva proving to be less aggressive in terms of decreasing Ca and Mg content.

Hydroxyapatite in Oral Care Products-A Review

Calcium phosphate compounds form the inorganic phases of our mineralised tissues such as bone and teeth, playing an important role in hard tissue engineering and regenerative medicine. In dentistry and oral care products, hydroxyapatite (HA) is a stable and biocompatible calcium phosphate with low solubility being used for various applications such as tooth remineralisation, reduction of tooth sensitivity, oral biofilm control, and tooth whitening. Clinical data on these products is limited with varied results; additionally, the effectiveness of these apatite compounds versus fluoride, which has conventionally been used in toothpaste, has not been established. Therefore, this review critically evaluates current research on HA oral care, and discusses the role and mechanism of HA in remineralisation of both enamel and dentine and for suppressing dentine sensitivity. Furthermore, we position HA’s role in biofilm management and highlight the role of HA in dental applications by summarising the recent achievement and providing an overview of commercialised HA dental products. The review also indicates the existing limitations and provides direction for future research and commercialisation of apatite-based oral care products.

The Amelogenin-Derived Peptide TVH-19 Promotes Dentinal Tubule Occlusion and Mineralization

In this study, the amelogenin-derived peptide, TVH-19, which has been confirmed to promote mineralization, was evaluated to derive its potential to induce dentinal tubule occlusion. The binding capability of fluorescein isothiocyanate (FITC)-labeled TVH-19 to the demineralized dentin surface was analyzed by confocal laser scanning microscopy (CLSM). Additionally, the sealing function of the peptide was studied through the remineralization of demineralized dentin in vitro. The adsorption results showed that TVH-19 could bind to the hydroxyapatite and demineralized dentin surfaces, especially to periodontal dentin. Scanning electron microscopy analysis further revealed that TVH-19 created mineral precipitates. The plugging rate in the TVH-19 group was higher than that in the PBS group. Moreover, energy-dispersive X-ray spectroscopy (EDX) results indicated that the calcium/phosphorus (Ca/P) ratio of the new minerals induced by TVH-19 was close to that of the hydroxyapatite. Attenuated total internal reflection-Fourier transform infrared (ATR-FTIR) spectrometry and X-ray diffraction (XRD) results indicated that the hydroxyapatite crystals formed via remineralization elongated the axial growth and closely resembled the natural dentin components. These findings indicate that TVH-19 can effectively promote dentin sealing by binding to the periodontal dentin, promoting mineral deposition, and reducing the space between the dentin tubules.

Development of strontium-doped nano hydroxyapatite dentifrice and compare its remineralising potential with a topical cream containing casein phosphopeptide- amorphous calcium phosphate - An In Vitro study

Aim

To develop and evaluate the efficacy of synthesised strontium-doped nano hydroxyapatite dentifrice and compare its remineralizing potential with a topical cream containing Casein Phospho Peptide - Amorphous Calcium Phosphate, in remineralizing artificial carious lesion on enamel.

Materials and Methods

Enamel specimens of 4 x 4 x 1 mm were prepared from 90 freshly extracted teeth. Specimens were divided into 3 groups of 30 samples each, based on the type of dentifrice applied that is a control group (Group I) and two experimental groups (Groups II, III). Surface topography and the calcium/phosphorous ratio of all sound specimen were evaluated using Scanning electron microscope and Energy Dispersive X-ray Analysis (SEM-EDAX). The samples in group I and each of the experimental groups were subjected to demineralisation and the calcium/phosphorous ratio of the demineralized specimen were analysed. The samples were then subjected to remineralisation using different agents in each group. Samples in the control group (Group I) were brushed with a conventional dentifrice. In the experimental groups, Group II topical cream with Casein Phosphopeptide and Amorphous Calcium phosphate (CPP-ACP) was used and in Group III laboratory synthesized Strontium-doped nanohydroxyapatite paste (Sr-nHAP), respectively for 28 consecutive days. The samples in the both the control and the two experimental groups were again subjected to SEM-EDAX analysis to analyse the calcium phosphorus ratio following remineralisation cycle. Groupwise comparison of the data was done with one way ANOVA followed by Tukeys Post hoc Test.

Results

Both experimental groups (II, III) showed statistically significant remineralisation potential after demineralisation, compared to the control group I. Intergroup comparison showed that the samples in Group III showed the higher remineralisation potential than Group II and was statistically significant.

Conclusion

Both CPP- ACP containing tooth cream as well as Sr doped nHAp showed remineralisation potential. Sr doped nanohydroxyapatite showed better remineralisation than CPP ACP and can be considered for enamel repair in incipient carious lesions.

Emerging nanomaterials for dental treatments

The emergence of nanomaterials for dental treatments is encouraged by the nanotopography of the tooth structure, together with the promising benefits of nanomedicine. The use of nanoparticles in dentistry, also termed as 'nanodentistry', has manifested in applications for remineralisation, antimicrobial activity, local anaesthesia, anti-inflammation, osteoconductivity and stem cell differentiation. Besides the applications on dental tissues, nanoparticles have been used to enhance the mechanical properties of dental composites, improving their bonding and anchorage and reducing friction. The small particle size allows for enhanced permeation into deeper lesions, and reduction in porosities of dental composites for higher mechanical strength. The large surface area to volume ratio allows for enhanced bioactivity such as bonding and integration, and more intense action towards microorganisms. Controlled release of encapsulated bioactive molecules such as drugs and growth factors enables them to be delivered more precisely, with site-targeted delivery for localised treatments. These properties have benefitted across multiple fields within dentistry, including periodontology and endodontics and reengineering of dental prosthetics and braces. This review summarises the current literature on the emerging field of nanomaterials for dental treatments.

Commercial Silver Diamine Fluoride (SDF) Products on Caries Lesion Progression in Primary Enamel: An In Vitro Study

Purpose: Evidence has shown that silver diamine fluoride (SDF) at 30-38% has the potential to control and revert caries lesions. However, SDF can be found at lower concentrations on the market. In this study, we evaluated the effect of different commercially available SDF products on the progression of non-cavitated caries lesion in primary teeth assessed by a pH-cycling model. Materials and Methods: Subsuperficial caries lesions were formed in primary teeth using a demineralising solution for 96 h. Demineralised samples were randomly allocated to the following groups (n = 12/group): (G1) Negative Control, deionised water; (G2) Cariostatic, Inodon; 10%* SDF; (G3) Cariestop, Biodynamics, 12%* SDF; (G4) Cariostal, Iodontec, 16%* SDF; (G5) Cariestop, Biodynamics, 30%* SDF (*concentrations declared in the label). Products were applied according to the manufacturer's recommendation and reapplied after 7 days. Samples were exposed to a pH-cycling model for 14 days. After the cycle was completed, samples were sectioned, analysed by polarised light microscopy, and lesion depth was estimated as indicator of caries lesion progression. Groups were compared by multiple comparisons test (p < 0.05). Results: The negative control group exhibited the greatest lesion depth. All SDF products reduced the caries lesions depth and differed from the negative control. It was a trend observed (G1>G2>G3>G4), but no statistical differences among G3, and G5, and between G4 and G5 were observed for lesion depth. Conclusion: The tested SDF products reduced the depth of non-cavitated carious lesions in primary enamel. Although SDF products with declared concentrations between 12% and 30% (G3, G4, and G5) demonstrated a similar lesion depth in primary enamel, the effect of the concentration remains unclear.

Resin-Based Sealant with Bioactive Glass and Zwitterionic Material for Remineralisation and Multi-Species Biofilm Inhibition

Since pits and fissures are the areas most commonly affected by caries due to their structural irregularity, bioactive resin-based sealant (RBS) may contribute to the prevention of secondary caries. This study aims to investigate the mechanical, physical, ion-release, enamel remineralisation, and antibacterial capabilities of the novel RBS with bioactive glass (BAG) and 2-methacryloyloxyethyl phosphorylcholine (MPC). For the synthesis, 12.5 wt% BAG and 3 wt% MPC were incorporated into RBS. The contact angle, flexural strength, water sorption, solubility, and viscosity were investigated. The release of multiple ions relating to enamel remineralisation was investigated. Further, the attachments of bovine serum albumin, brain heart infusion broth, and Streptococcus mutans on RBS were studied. Finally, the thickness and biomass of a human saliva-derived microsm biofilm model were analysed before aging, with static immersion aging and with thermocycling aging. In comparison to commercial RBS, BAG+MPC increased the wettability, water sorption, solubility, viscosity, and release of multiple ions, while the flexural strength did not significantly differ. Furthermore, RBS with MPC and BAG+MPC significantly reduced protein and bacteria adhesion and suppressed multi-species biofilm attachment regardless of the existence of aging and its type. The novel RBS has great potential to facilitate enamel remineralisation and suppress biofilm adhesion, which could prevent secondary dental caries.

The Effects of Different Anticavity Agents and Er:YAG Laser Usage on Enamel Surface Microhardness

PURPOSE

The purpose of this study was to perform an in vitro evaluation of the protective effects of anticavity agents applied to enamel, by themselves and in combination with Er:YAG.

MATERIALS AND METHODS

In this study 150 extracted third molars were used. Measurements were made using DIAGNOdent, and samples with scores of 0-13 were included in the study. These were divided into 15 groups (n = 20). Use of the agents sodium fluoride (NaF), tricalcium phosphate (Ca3PO4), titanium tetrafluoride (TiF4), Tooth Mousse (CPP-ACP), MI Paste Plus (CPP-ACP), and NovaMin (bioactive glass), individually and then in combination with Er:YAG laser, was assessed based on their effects on microhardness values. After treatment, the groups were exposed to a demineralisation solution. Statistical analyses were conducted using SPSS 20.0 package software.

RESULTS

The highest test result value was observed in the TFL (TiF4/Er:YAG laser) group. Statistically significant differences were determined among all the groups (p <0.05). When the groups in which the agents were applied alone were compared with those involving combined use of Er:YAG laser, combined use provided significantly higher microhardness values, with the exception of the TML group (Tooth Mousse/Er:YAG laser) (p <0.05).

CONCLUSION

Within the limits of this study, the combined use of remineralisation agents and Er:YAG laser elicited better results than using the agents alone. The most effective remineralisation agent was TiF4/Er:YAG laser, which may be considered an alternative method for protecting the enamel against demineralisation.

Measuring Bacterial Growth Potential of Ultra-Low Nutrient Drinking Water Produced by Reverse Osmosis: Effect of Sample Pre-treatment and Bacterial Inoculum

Measuring bacterial growth potential (BGP) involves sample pre-treatment and inoculation, both of which may introduce contaminants in ultra-low nutrient water (e.g., remineralized RO permeate). Pasteurization pre-treatment may lead to denaturing of nutrients, and membrane filtration may leach/remove nutrients into/from water samples. Inoculating remineralized RO permeate samples with natural bacteria from conventional drinking water leads to undesired nutrient addition, which could be avoided by using the remineralized RO permeate itself as inoculum. Therefore, this study examined the effect of pasteurization and membrane filtration on the BGP of remineralized RO permeate. In addition, the possibility of using bacteria from remineralized RO permeate as inoculum was investigated by evaluating their ability to utilize organic carbon that is readily available (acetate, glucose) or complex (laminarin, gelatin, and natural dissolved organic carbon), as compared with bacteria from conventional drinking water. The results showed that membrane filtration pre-treatment increased (140-320%) the BGP of remineralized RO permeate despite the extensive soaking and flushing of filters (>350 h), whereas no effect was observed on the BGP of conventional drinking water owing to its high nutrient content. Pasteurization pre-treatment had insignificant effects on the BGP of both water types. Remineralized RO permeate bacteria showed limitations in utilizing complex organic carbon compared with bacteria from conventional drinking water. In conclusion, the BGP bioassay for ultra-low nutrient water (e.g., remineralized RO permeate) should consider pasteurization pre-treatment. However, an inoculum comprising bacteria from remineralized RO permeate is not recommended as the bacterial consortium was shown to be limited in terms of the compounds they could utilize for growth.

Prevention and caries risk management in teenage and orthodontic patients

As patients progress from childhood through to teenage years, they progress through periods of high caries risk as they undergo changes in lifestyle and oral microflora. Removable or fixed orthodontic treatment also alters the oral microflora and can dramatically increase caries risk. This paper outlines ways to identify the transition to higher caries risk, and practical ways to lower the risk of hard tissue loss from dental caries during orthodontic treatment across the teenage years, including tooth surface protection, optimised use of mechanical and chemical plaque control, and appropriate delivery of remineralising agents over time.

Rational Design of β-sheet Peptides with Self-Assembly into Nanofibres on Remineralisation of Initial Caries Lesions

OBJECTIVE

To explore the self-assembly and gelation properties of synthetic peptides, and their efficacy on hydroxyapatite (HAP) nucleation and in situ remineralisation of initial caries lesions.

METHODS

Mass spectrometry and reversed-phase high performance liquid chromatography (RPHPLC) were used to confirm the successful synthesis of peptides. Their self-assembly properties and conformation stability were evaluated using circular dichroism (CD) spectroscopy and Fourier-transform infrared spectroscopy (FTIR). Cell Counting Kit-8 (CCK-8; Dojindo, Kumamoto, Japan) was used to evaluate their cytotoxicity. The efficacy of the peptides on HAP nucleation and in situ remineralisation of initial caries lesions was explored using FTIR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction and transverse microradiography analysis.

RESULTS

Two kinds of self-assembly β-sheet peptides named ID4 and ID8, respectively, were successfully synthesised with purities greater than 95%. Both were stable under neutral physiological conditions and had low cytotoxicity. ID4 and ID8 showed calcium responsive self-assembly properties and could self-assemble into nanofibres. Compared with ID4, ID8 resulted in the rapid formation of hydrogel with a lower concentration of calcium, and self-assembled ID8 hydrogel induced the formation of flower-like HAP and significantly promoted the remineralisation of initial enamel caries.

CONCLUSION

ID8 could serve as the template to induce HAP nucleation and promote biomimetic remineralisation of initial caries lesions. These results underpin future research on peptide design, and ID8 may be a promising bioactive component for anti-caries applications.

Comparison of Remineralising Potential of Nano Silver Fluoride, Silver Diamine Fluoride and Sodium Fluoride Varnish on Artificial Caries: An In Vitro Study

PURPOSE

To evaluate the remineralisation effect of an experimental nano silver fluoride (NSF) formulation using an in vitro remineralisation model, compared with silver diamine fluoride (SDF) and sodium fluoride varnish (NaF) in current clinical use.

MATERIALS AND METHODS

45 sound human third molars were sectioned in buccolingual and mesiodistal direction and 180 enamel specimens were divided into four groups (NSF; SDF; NaF; Control). Early caries-like lesions were artificially created. Remineralisation agents were applied with a microbrush for 2 min in NSF and SDF group; NaF varnish were applied in a thin layer and then all specimens were stored in a moist environment at 37°C for 24 h. Each group was subjected to a pH cycling model for 7 days. The Vickers microhardness values (VHN) of specimens were compared before treatment, after demineralisation and after remineralisation. In addition, scanning electron microscope (SEM) images were investigated to compare morphological changes on the surfaces. Kruskal-Wallis and Mann-Whitney U tests were used for statistical analysis to compare the groups at p < 0.05.

RESULTS

All remineralisation agents were found to be statistically significant for the rehardening of the demineralised enamel specimens (p < 0.001). There was a statistically significant difference between the all groups after remineralisation (p < 0.001). The VHN values for postdemineralisation were determined as, respectively, NaF (229.96) > SDF (222.96) > NSF (191.36) > Control (175.80). SEM images have also supported the microhardness values.

CONCLUSIONS

NSF was not found to be effective as sodium fluoride varnish and SDF on artificial enamel caries lesions. Additional investigation is needed to recommend it as an alternative agent to routine fluoride treatments.

Effect of nonfluoridated remineralizing agents on initial enamel carious lesions: A systematic review

Background

Although fluoride enables remineralization, presence of calcium and phosphate ions is necessary to promote the process. So, various nonfluoridated remineralizing agents have been emerging to treat the noncavitated carious lesions.

Aim

The aim of this systematic review was to assess the clinical effectiveness of nonfluoridated remineralizing agents on initial enamel carious lesions.

Methods

Seven electronic databases were searched using the key words. In total, 158 human clinical trials were retrieved in the search from January 1950 to October 2016. Seventy-one repeated articles were excluded. Among the 87 articles obtained, 53 articles were eliminated after reading the title and abstracts. After assessing the full text, 28 articles were excluded. Three more studies were included from the cross references of the articles chosen.

Results

All the nine trials included assessed the clinical effectiveness of casein phosphopeptide amorphous calcium phosphate (CPP ACP). They showed a positive effect of CPP ACP on the remineralization of white spot lesions.

Conclusion

The use of CPP ACP resulted in significant reduction of the white spot lesion size measured using visual examination methods. This systematic review indicated a lack of reliable evidence supporting the clinical effectiveness of other commercially available nonfluoridated remineralizing agents.

Effects of Different Remineralisation Agents and Adhesives Around Orthodontic Brackets: Is There a Relationship Between Remineralisation and Shear Bond Strength?

PURPOSE

The aim of this in-vitro study was to evaluate the effects of different remineralisation agents and adhesives on the remineralisation of white spot lesions (WSL) using quantitative light-induced fluorescence (QLF) and the shear bond strength (SBS) of brackets.

MATERIALS AND METHODS

One hundred fifty premolars were bonded with Transbond XT and resin-modified glass-ionomer cement (RMGIC). WSL were created using a demineralization solution and an APF gel, Tooth Mousse (TM) and Duraphat were applied for remineralisation. WSL were evaluated using QLF and SBS of brackets and tested using an Instron testing machine. Paired-samples t-test, independent-samples t-test and one-way ANOVA were used for comparisons of the ∆F, area and SBS. Post-hoc tests were performed using Tukey's test.

RESULTS

In the Transbond group, all remineralisation agents provided remineralisation, with Duraphat producing greater improvement. In terms of lesion area, the positive control and APF gel group values were close to each other, and a statistically significant improvement was observed in the TM and Duraphat groups' areas. In the RMGIC group, with TM application, the ΔF value was statistically significantly higher; area differences between the APF and TM groups were not statistically significant. The Transbond group showed greater SBS than did RMGIC, and in the Transbond group, Duraphat had the highest SBS value.

CONCLUSIONS

In bonding with Transbond, the Duraphat group demonstrated greater improvement than other remineralisation agents. In the RMGIC group, the best remineralisation was obtained by TM. The Transbond XT and Duraphat combination provided the highest SBS values.

Inhibition Effects of Different Toothpastes on Demineralisation of Incipient Enamel Lesions

PURPOSE

To evaluate the inhibitory effects of different toothpastes on demineralisation of incipient enamel lesions using a toothbrush simulator.

MATERIALS AND METHODS

Fifty enamel specimens were prepared from extracted human molars. The specimens were randomly assigned to the following groups (n = 10/group): 1. no treatment (control); 2. toothpaste containing arginine (ProRelief, Colgate;); 3. fluoride toothpaste (Pronamel, Sensodyne GlaxoSmithKlein); 4. tooth mousse containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) (Recaldent, GC); 5. toothpaste (Restore, Dr. Collins) containing bioactive glass (NovaMin, GlaxoSmithKlein). All specimens were exposed to pH cycling. The remineralising agents were applied to the samples with a toothbrush simulator for 2 min twice a day for five days. The weight percentage of mineral changes for the elements calcium (Ca), phosphorus (P), sodium (Na) and silica (Si) were measured by SEM energy-dispersive x-ray spectroscopy (SEM-EDX). SEM revealed properties of treated enamel surfaces. The data were analysed using one-way ANOVA.

RESULTS

Statistically significantly higher levels of Ca and P were found in all groups compared to the control (p < 0.05).

CONCLUSIONS

The toothpastes' efficacy of inhibiting demineralisation depended on the active ingredients in the respective toothpaste. The demineralisation inhibition efficacy of the tested toothpastes depended on the active ingredients in the toothpaste.

Medical Model in Caries Management

The current mode of dental caries management mainly operates through irreversible and symptomatic treatment by means of drilling and filling, while caries prevention is largely overlooked or omitted. Focus should be redirected through a medical model towards elimination of the disease through tackling its causes and risk factors to address current and future caries initiation. Caries is the demineralisation of dental hard tissues by bacterial acids when periodically exposed to fermentable carbohydrates. The medical model of caries management is a philosophy that steers sustainable caries management through controlling bacterial infection, a reduction of risk levels, remineralisation of teeth and long-term follow-up. Its goal is to prevent new and recurrent caries, arrest ongoing caries processes by alteration of the cariogenic environment, and support the healing of remineralisable enamel and dentine. The mechanism involves dietary counselling and plaque control, placement of dental sealants, administration of fluoride agents and chemotherapeutic medications and use of chewing gum. This paradigm shift from a surgical to a medical model aims to pursue the ultimate intention of maintaining a caries-free dentition and is anticipated to promote true oral health-related quality of life. The objective of this paper is to discuss the medical model of caries management.

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

PURPOSE

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

The Effects of Fluoride Treatment Time and Concentration on In Vitro Caries Lesion Demineralisation and Remineralisation

PURPOSE

To investigate the possible interaction between fluoride treatment time and concentration on enamel caries lesion de-/remineralisation.

MATERIALS AND METHODS

The study design followed a three (fluoride concentration: 0, 275, 1250 ppm as sodium fluoride) x four (treatment time: 10, 30, 60, 120 s) factorial design. Caries lesions were created in bovine enamel and the extent of demineralisation determined using Vickers surface microhardness (VHN). Lesions were pH cycled (18 days) with the daily schedule consisting of two fluoride treatments, a 4-h demineralisation period and exposure to artificial saliva at all other times. VHN was determined again after pH cycling and changes to baseline values calculated (∆VHN). Enamel fluoride uptake (EFU) was determined using the microbiopsy technique. Data were analyzed using two-way ANOVA.

RESULTS

The concentration x treatment time interaction was significant for ∆VHN (p < 0.0001) and EFU (p = 0.0298). Dose-response relationships were observed for both variables for fluoride concentration and treatment time. ∆VHN: higher fluoride concentration compensated for shorter treatment time (e.g. ∆VHN [mean ± SD] = 85.5 ± 60.6 for 30 s with 1250 ppm fluoride vs ∆VHN = 84.3 ± 26.9 for 120s with 275 ppm fluoride). EFU data were similar but highlighted a greater ability to discern between fluoride concentrations (e.g. EFU = 4364 ± 1166 ppm vs 8538 ± 9531 ppm; above examples). Although ∆VHN and EFU correlated well (r = 0.723; p < 0.001), lesion demonstrated a greater ability to acquire fluoride than to remineralise.

CONCLUSIONS

Behavioural aspects relating to caries can be studied in vitro, although model limitations must be considered. Adequate exposure times to cariostatic concentrations of fluoride are important in maximising caries prevention.

White Spot Lesion Remineralisation Agents in Primary Teeth: A Systematic Review

PURPOSE

To perform a systematic review of articles related to the clinical efficacy of topical fluoride varnishes/gels, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), and other remineralisation agents of white spot lesions (WSL) in primary teeth.

MATERIALS AND METHODS

Electronic and manual searches were conducted through diverse electronic databases. The search was limited to randomised, clinical, controlled trials, and quasi-experimental papers in full-text version. Suitable individual studies were evaluated through a previously reported quality system, their data extracted and carefully analysed.

RESULTS

The search identified 298 citations, and 95 were chosen and reviewed in full text. Nine relevant citations met the eligibility criteria for inclusion in the systematic review. Pair comparisons were made between fluoride varnishes, CPP-ACP, dental lasers, and control interventions.

CONCLUSIONS

Clinicians are encouraged to discuss more high-quality studies in order to provide sufficient evidence and to confirm the clinical utility of remineralisation agents of WSL in primary teeth.

Shear Bond Strength and Remineralisation Effect of a Casein Phosphopeptide-Amorphous Calcium Phosphate-Modified Glass Ionomer Cement on Artificial "Caries-Affected" Dentine

This study investigated the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-modified glass ionomer cement (GIC) on shear bond strength (SBS) and remineralisation of artificial “caries-affected” dentine. Human dentine slices were demineralised and allocated to three groups: group 1, conventional GIC; group 2, CPP-ACP-modified GIC; and group 3, resin-modified GIC. The SBS was measured using a universal testing machine (n = 16 per group). Remaining samples (n = 8 per group) were subjected to pH-cycling for 28 days. After pH-cycling, lesion depth and micro-mechanical properties at the sample-bonding interface were investigated using micro-computed tomography (micro-CT) and nano-indentation, respectively. The SBS for groups 1 to 3 were 4.6 ± 1.5 MPa, 4.2 ± 1.1 MPa, and 5.9 ± 1.9 MPa, respectively (p = 0.007; group 1, group 2 < group 3). Lesion depths determined by micro-CT for groups 1 to 3 were 186 ± 8 µm, 149 ± 14 µm, and 178 ± 8 µm, respectively (p < 0.001; group 2 < group 1, group 3). The mean (±SD, standard deviation) nano-hardness values for groups 1 to 3 were 0.85 ± 0.22 GPa, 1.14 ± 0.21 GPa, and 0.81 ± 0.09 GPa, respectively (p = 0.003; group 1, group 3 < group 2). The mean (±SD) elastic moduli for groups 1 to 3 were 1.70 ± 0.33 GPa, 2.35 ± 0.44 GPa, and 1.59 ± 0.13 GPa, respectively (p < 0.001; group 1, group 3 < group 2). The results suggest that the incorporation of CPP-ACP into GIC does not adversely affect the adhesion to artificial caries-affected dentine. Furthermore, CPP-ACP-modified GIC is superior to conventional GIC in promoting dentine remineralisation.

A randomised clinical study to evaluate experimental children's toothpastes in an in-situ palatal caries model in children aged 11-14 years

OBJECTIVES

To compare three children's sodium fluoride toothpastes to placebo with respect to enamel remineralisation potential, enamel fluoride uptake and net acid resistance using an in situ palatal caries model in children aged 11-14 years following a single brushing.

DESIGN

This was a randomised, single blind (laboratory analyst), single-centre, four-treatment, crossover study with a 7-day washout period between treatments. The treatments were 1,426 ppm fluoride, 1,000 ppm fluoride, 500 ppm fluoride and 0 ppm fluoride (placebo) toothpaste (NaF/silica). A custom made in situ palatal appliance was used by each subject in all treatment periods. At each of the four treatment visits subjects wore the appliance containing four partially demineralised human enamel specimens for 5 minutes and then brushed their teeth using a standardised procedure for 60 seconds under supervision using 1.0 g (±0.1 g) of their assigned toothpaste. After 4 hours the appliance was removed and enamel specimen recovered. This process was repeated until all subjects completed all four study treatment visits. Recovered enamel specimens were analysed for per cent surface microhardness recovery (%SMHR; Knoop) and enamel fluoride uptake (EFU; microdrill biopsy). Subsequently, specimens were demineralised in vitro to determine their % net acid resistance (%NAR; Knoop).

RESULTS

All three fluoride toothpastes demonstrated significantly greater %SMHR, EFU and %NAR compared with 0 ppm F toothpaste. The model demonstrated a dose response over the range 0 to 1,426 ppm fluoride for %SMHR, EFU and %NAR. There was no significant difference between 500 ppm F and 1,000 ppm F for %SMHR and between 1,000 ppm F and 1,426 ppm F for %SMHR, EFU and %NAR.

CONCLUSIONS

The present in situ study demonstrated that the children's fluoride toothpastes tested are capable of delivering cariostatic amounts of fluoride to early caries lesions following a single brushing.