Effect of adhesive components in experimental fluoride varnish on fluoride release within 30 days in vitro study.

We aimed to determine whether adhesive components could increase the release time of effective fluoride concentration from an experimental fluoride varnish applied to bovine teeth. An experimental fluoride varnish containing 5% sodium fluoride (EX1) was prepared and combined with 35% hydroxyethyl methacrylate (HEMA) (EX2), 5% glutaraldehyde (EX3), or 35% HEMA/5% glutaraldehyde mixture (EX4). Two commercially available fluoride varnishes were used for comparison. Each group was applied to bovine incisors, and the fluoride release and pH were monitored for 30 days. Cell viability analysis, scanning electron microscopy, and energy-dispersive spectroscopy were performed. EX4 released the highest and most effective concentration of fluoride for the longest period and reached neutral pH at the earliest; the release was maintained for up to 30 days without cytotoxicity. In conclusion, EX4 is considered to be the most effective varnish to prevent dental caries.

Fluoride release potential of arginine-incorporated fluoride varnishes.

The study aimed to examine the fluoride (F) release potential of arginine (Arg)-incorporated F varnishes. Four commercially available F varnishes were included in the study: Duraphat® (5% NaF), Flúor Protector® (0.9% SiH2F2), Fluor Protector S® (NH4F), and Fluorimax™ (2.5% NaF). L-arginine (2% w/v.) was incorporated in these varnishes to estimate F release at 1 h, 4 h, 6 h, 24 h, 3 days, and 7 days using an F-ion selective electrode. The media pH of eluded varnishes was estimated and primary inorganic F extraction was performed. The main effects pH, F release, and computed integrated mean/cumulative F release for experimental groups were significantly higher than the controls (p<0.01). The primary extracted F concentrations for the Arg-containing groups were significantly lower than the control groups (p<0.001) demonstrating a chemical interplay with Arg incorporation. To conclude, irrespective of the inorganic F content, incorporating Arg in F-containing varnishes increases their F release potential.

Effects of bovine milk osteopontin on in vitro enamel remineralization as a topical application prior to immersion in remineralizing solutions with/without fluoride.

The aim of the present study was to investigate the effects of bovine milk osteopontin (OPN) on enamel remineralization as a topical application prior to immersion in remineralizing solutions with/without fluoride. Bovine enamel blocks were demineralized then were divided into the following 3 groups: OPN (2.7 and 5.4 µM) solutions and deionized water (control). Each group was divided into 2 groups (remineralizing solution with or without 1 ppm of fluoride (F)). The specimens were analyzed by micro-CT and scanning electron microscope (SEM). The percentage of remineralization was higher in remineralization solution with than without F (p<0.05). The present results suggest that bovine milk OPN inhibits remineralization in solution without F, but 5.4 µM bovine milk OPN does not inhibit remineralization of the demineralized body using solution containing F by interrupting mineral deposition on the enamel surface.

Fluoride and silver ion concentrations and pH in silver diamine fluoride solutions from Argentina.

The aim of this study was to measure the fluoride (F) and silver (Ag) ion concentration and the pH, over time, of 2 solutions of 38% silver diamine fluoride (SDF) produced in Argentina. The brand Fluorsilver® was established as Group 1 (G1) (Densell), and the brand FAgamin® (Tedequim) as Group 2 (G2), each with two different lots. The following were determined at time 0 (t0) and 30 days after opening (t30): a) fluoride concentration (w/v) by visible spectrophotometry b) Ag content (w/v) by atomic absorption spectrophotometry c) pH. Results: The data in the freshly opened bottles were for G1 lot1/lot2: a) 0.96/1, b) 8.3/7.8, c).11.5/11.3; G2 lot1/lot2: a) 11.5/9.9, b) 39/39, c) 7/6,9; and after 30 days, G1 lot1/lot2: a) 0.85/0.81, b) 7.2/8.2, c) 11.3/11.6; G2 lot1/lot2: a) 9.35/8.43, b) 38/38, c) 7.6/7.6. Conclusion In relation to the expected values (5.0-5.9% fluoride and 24.4-28.8% silver), the average concentration of fluoride and silver ions was lower for G1, but higher for G2. The pH was alkaline for G1 and neutral for G2. Over the 30 days, the content of fluoride and silver tended to decrease.

El objetivo de este estudio fue medir las concentraciones de iones de fluoruro (F) y plata (Ag) y el pH, de 2 soluciones de diamino fluoruro de plata (SDF) al 38% producidas en Argentina. Se estableció como Grupo 1 (G1) la marca Fluorsilver® (Densell), y FAgamin® (Tedequim) como Grupo 2 (G2), cada uno con dos lotes diferentes. Se determinó: a) la concentración de fluoruro (p/v) por espectrofotometría visible, b) el contenido de Ag (p/v) por espectrofotometría de absorción atómica y c) el pH, y fue medido en un tiempo 0 (t0) y 30 días después de la apertura del frasco (t30). Resultado: En tiempo 0 para G1 lote1/lote2 fue: a) 0,96/1, b) 8,3/7,8 c).11,5/11,3 y G2 lote1/lote2: a) 11,5/9,9, b) 39/39, c) 7/6,9. A los 30 días G1 lote1/lote2: a) 0,85/0,81, b) 7,2/8,2, c) 11,3/11,6 y G2 lote1/lote2: a) 9,35/8,43, b) 38/38, c) 7,6/7,6. La concentración de iones de fluoruro y plata para G1 fue menor en relación a los valores esperados (5,0-5,9% de fluoruro y 24,4- 28.8% plata), sin embargo G2 obtuvo valores más altos. G1 muestra resultados de pH alcalino y G2 neutro. A lo largo de los 30 días, el contenido de fluoruro y plata tiende a disminuir.

Teaching and use of silver diamine fluoride in Pediatric Dentistry: a questionnaire-based cross- sectional analysis of undergraduate Brazilian dental schools / Ensino e uso do diamino fluoreto de prata em Odontopediatria: análise transversal baseada em questionário com cursos de graduação em Odontologia brasileiros

This study investigated the teaching and use of silver diamine fluoride (SDF) in Pediatric Dentistry in undergraduate Brazilian dental schools through a questionnaire-based cross-sectional analysis. Two-hundred and thirty-five questionnaires were e-mailed to directors of Pediatric Dentistry of undergraduate Brazilian dental schools. The details of the teaching and use of SDF in clinical practice were asked. Obtained data were analyzed descriptively and using the chi-square test. A total of 149 complete questionnaires were returned (63.4%). Most of schools taught SDF in lectures (73.8%, p <0.001). The majority use SDF in clinical practice (64.4%, p <0.001), but its use is not frequent (11.4%, p<0.001). All dental schools reported that SDF is applied in primary teeth, and few reported its use for permanent teeth (36.4%, p = 0.01). SDF has been used mainly for cavitated caries in primary teeth of children aged 0 to 3 years (93.7%, p<0.001), with restricted use in posterior teeth (42.7%, p <0.001). Although SDF is teaching and used in clinical practice in Pediatric Dentistry in most Brazilian undergraduate schools, its use is not frequent. Furthermore, SDF is not considered an option for caries lesions in some dental schools (AU).

Este estudo investigou o ensino e a utilização do diamino fluoreto de prata (DFP) em Odontopediatria em cursos de graduação em Odontologia brasileiros por meio de uma análise transversal baseada em questionário. Duzentos e trinta e cinco questionários foram enviados por e- mail a professores responsáveis pela disciplina de Odontopediatria de cursos de Odontologia brasileiros. Os detalhes do ensino e uso de DFP na prática clínica foram solicitados. Os dados obtidos foram analisados descritivamente e por meio do teste do qui-quadrado. Um total de 149 questionários completos foram devolvidos (63,4%). A maioria das escolas ensina sobre o DFP em aulas teóricas (73,8%, p <0,001). A maioria usa o DFP na prática clínica (64,4%, p <0,001), mas seu uso é pouco frequente (11,4%, p <0,001). Todas as escolas de Odontologia relataram que o DFP é aplicado em dentes decíduos, e poucas relataram seu uso em dentes permanentes (36,4%, p = 0,01). O DFP tem sido usado principalmente em lesões de cárie cavitadas em dentes decíduos de crianças de 0 a 3 anos (93,7%, p <0,001), com uso restrito aos dentes posteriores (42,7%, p <0,001). Embora o DFP seja tópico de ensino e utilizado na prática clínica em Odontopediatria na maioria dos cursos de graduação brasileiros, seu uso é pouco frequente. Além disso, o DFP não é considerado uma opção para lesões de cárie em algumas escolas avaliadas (AU).

The use of hydroxyapatite toothpaste to prevent dental caries.

Dissolution of hydroxyapatite from the tooth structure at low pH can lead to the irreversible destruction of enamel and dentin, which if left untreated can result in pain and tooth loss. Hydroxyapatite toothpastes contain hydroxyapatite particles in micro- or nanocrystalline form that have been shown to deposit and restore demineralized enamel surfaces. As such, they are currently being explored as a fluoride-free anti-caries agent. This narrative review article aims to summarize the recent findings of the research investigating the remineralization potential of HAP toothpaste in vitro, in situ and in vivo, as well as some other applications in dentistry.

Fabrication of oral nanovesicle in-situ gel based on Epigallocatechin gallate phospholipid complex: Application in dental anti-caries.

The conventional anti-caries agents exhibit many shortcomings such as poor stability, low efficacy or short residence time in the oral environment, it is urgent to develop efficacy treatments to prevent dental caries. As the most active polyphenols from tea, Epigallocatechin gallate (EGCG) shows remarkable anti-cariogenic bioactivity. However, the poor stability and low bioavailability of EGCG limit its potential application. This study aimed to fabricate nanovesicles in-situ gel based on EGCG phospholipid complex in order to increase its stability and efficacy. The formation of EGCG phospholipid complex was characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The ethanol injection method was used to prepare the EGCG-loaded nanovesicles, an optimal ratio of Poloxamer407 (P407) and Poloxamer188 (P188) as in-situ gel matrix was selected to fabricate oral nanovesicles in-situ gel. EGCG-loaded nanovesicle in-situ gel based on the phospholipid complex had uniform spherical shape without any agglomeration. The discrete nanoparticle with a size (131.44 ± 4.24 nm) and a negative zeta potential value at -30.7 ± 0.5 mV possessed good physical stability and high entrapment efficiency (83.66 ± 3.2%). The formulation exhibited a strong antibacterial activity on S. mutans, which could reduce acid production and tooth surface adhesion. In addition, EGCG formulation could inhibit the formation of glucan and biofilm from S. mutans by suppressing the activity of glycosyltransferase enzymes (GTF). In conclusion, the EGCG-loaded nanovesicle in-situ gel holds great promise as an efficient anti-cariogenic formulation for topical oral delivery.

Advances of Anti-Caries Nanomaterials.

Caries is the most common and extensive oral chronic disease. Due to the lack of anti-caries properties, traditional caries filling materials can easily cause secondary caries and lead to treatment failure. Nanomaterials can interfere with the bacteria metabolism, inhibit the formation of biofilm, reduce demineralization, and promote remineralization, which is expected to be an effective strategy for caries management. The nanotechnology in anti-caries materials, especially nano-adhesive and nano-composite resin, has developed fast in recent years. In this review, the antibacterial nanomaterials, remineralization nanomaterials, and nano-drug delivery systems are reviewed. We are aimed to provide a theoretical basis for the future development of anti-caries nanomaterials.

Farnesal-loaded pH-sensitive polymeric micelles provided effective prevention and treatment on dental caries.

BACKGROUND: Farnesol is a sesquiterpene from propolis and citrus fruit that shows promising anti-bacterial activity for caries treatment and prevention, but its hydrophobicity limits the clinical application. We aimed to develop the novel polymeric micelles (PMs) containing a kind of derivative of farnesol and a ligand of pyrophosphate (PPi) that mediated PMs to adhere tightly with the tooth enamel. RESULTS: Farnesal (Far) was derived from farnesol and successfully linked to PEG via an acid-labile hydrazone bond to form PEG-hyd-Far, which was then conjugated to PPi and loaded into PMs to form the aimed novel drug delivery system, PPi-Far-PMs. The in vitro test about the binding of PPi-Far-PMs to hydroxyapatite showed that PPi-Far-PMs could bind rapidly to hydroxyapatite and quickly release Far under the acidic conditions. Results from the mechanical testing and the micro-computed tomography indicated that PPi-Far-PMs could restore the microarchitecture of teeth with caries. Moreover, PPi-Far-PMs diminished the incidence and severity of smooth and sulcal surface caries in rats that were infected with Streptococcus mutans while being fed with a high-sucrose diet. The anti-caries efficacy of free Far can be improved significantly by PPi-Far-PMs through the effective binding of it with tooth enamel via PPi. CONCLUSIONS: This novel drug-delivery system may be useful for the treatment and prevention of dental caries as well as the targeting therapy of anti-bacterial drugs in the oral disease.

Application of green tea extracts epigallocatechin-3-gallate in dental materials: Recent progress and perspectives.

Because of excellent biocompatibility, antioxidant activity, and anti-caries ability, epigallocatechin-3-gallate (EGCG) has been widely studied in the treatment of oral diseases, such as periodontal disease, oral cancer, and dental caries. To reach the site of the lesion or achieve sustained release, play the role of anti-caries, anti-inflammatory, or to maintain or improve the physical properties of the modified material，EGCG need to be cross-linked or embedded with dental adhesives, barrier membranes, bone replacement materials, tissue regeneration materials, and antimicrobial anti-caries materials to better prevent or treat oral diseases. This article reviews the applications of EGCG in oral materials, involving various areas of the oral cavity, reveals their excellent potential, and sees shortcomings in these research to promote the better development of EGCG applications in oral materials such as oral repair materials, bone tissue engineering materials and antibacterial and anti-caries materials.

Remineralizing effect of commercial fluoride varnishes on artificial enamel lesions.

The aim of this study was to evaluate soluble and insoluble fluoride concentrations in commercial varnishes, and their remineralization effect on artificial caries enamel lesions using surface and cross-sectional microhardness evaluations. Forty bovine enamel blocks were separated into four groups (n=10): control (no treatment), Enamelast (Ultradent Products), Duraphat (Colgate-Palmolive) and Clinpro White Varnish (3M ESPE). Surface enamel microhardness evaluations were obtained, artificial enamel caries lesions were developed by dynamic pH-cycling, and the varnishes were then applied every 6 days, after which the enamel blocks were submitted to dynamic remineralization by pH cycles. After removal of the varnishes, the enamel surfaces were reassessed for microhardness. The blocks were sectioned longitudinally, and cross-sectional microhardness measurements were performed at different surface depths (up to 300 µm depth). Polarized light microscopy images (PLMI) were made to analyze subsurface caries lesions. The fluoride concentration in whole (soluble and insoluble fluoride) and centrifuged (soluble fluoride) varnishes was determined using an extraction method with acetone. The data were analyzed to evaluate the surface microhardness, making adjustments for generalized linear models. There was a significant decrease in enamel surface microhardness after performing all the treatments (p<0.0001). Enamelast and Duraphat showed significantly higher enamel microhardness values than the control and the Clinpro groups (p = 0.0002). Microhardness loss percentage was significantly lower for Enamelast (p = 0.071; One-way ANOVA). PLMI showed that subsurface caries lesions were not remineralized with the varnish treatments. No significant differences in the in-depth microhardness levels (p = 0.7536; ANOVA) were observed among the treatments. Enamelast presented higher soluble and insoluble fluoride concentrations than the other varnishes (p < 0.0001; Kruskal-Wallis and Dunn tests). Enamelast and Duraphat varnishes promoted enamel surface remineralization, but no varnish remineralized the subsurface lesion body. Although insoluble and soluble fluoride concentration values did not correspond to those declared by the manufacturer, Enamelast presented higher fluoride concentration than the others.

The in vitro remineralizing effect of CPP-ACP and CPP-ACPF after 6 and 12 weeks on initial caries lesion.

OBJECTIVE: The aim of this in vitro study was to determine the effects of remineralization promoting agents containing casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP), or CPP-ACP in combination with fluoride (CPP-ACPF) on artificial white spot lesions (WSLs) after 6 and 12 weeks. METHODOLOGY: White spot lesions were created on 123 sectioned premolars (246 specimens) with a demineralization solution during a 96 hours pH-cycling regime. Two experimental groups were created: a CPP-ACP group (Tooth Mousse™), and a CPP-ACPF group (Mi Paste Plus™). Additionally, two control groups were created, one using only a conventional toothpaste (1450 ppm fluoride) and another one without any working agents. All teeth were also daily brushed with the conventional toothpaste except the second control group. Tooth Mousse™ and Mi Paste Plus™ were applied for 180 seconds every day. The volume of demineralization was measured with transverse microradiography. Six lesion characteristics regarding the lesion depth and mineral content of WSLs were also determined. RESULTS: The application of CPP-ACP and CPP-ACPF had a significant regenerative effect on the WSLs. Compared to Control group 1 and 2 the volume of demineralization after 6 weeks decreased significantly for CPP-ACP (respectively p<0.001 and p<0.001) and CPP-ACPF (respectively p=0.001 and p=0.003). The same trend was observed after 12 weeks. For the CPP-ACPF group, WSL dimensions decreased significantly between 6 and 12 weeks follow-up (p=0.012). The lesion depth reduced significantly after application of CPP-ACP and CPP-ACPF but increased significantly in the Control groups. Mineral content increased for CPP-ACP and CPP-ACPF after an application period of 12 weeks, but this was only significant for CPP-ACP. CONCLUSIONS: Long-term use of CPP-ACP and CPP-ACPF in combination with a conventional tooth paste shows beneficial effects in the recovery of in vitro subsurface caries lesions.

Novel anti-biofouling light-curable fluoride varnish containing 2-methacryloyloxyethyl phosphorylcholine to prevent enamel demineralization.

We evaluated the efficacy of light-curable fluoride varnish (LCFV) that contains 2-methacryloyloxyethyl phosphorylcholine (MPC) in terms of anti-biofouling properties and prevention of tooth enamel demineralization. MPC was mixed with and incorporated into LCFV at 0 (control), 1.5, 3.0, 5.0, 10.0, 20.0, and 40.0 weight percentage (wt%). Addition of high wt% of MPC resulted in increased film thickness and decreased the degree of conversion, indicating loss of the advantageous properties of LCFV. Addition of 1.5, 3, or 5 wt% MPC significantly reduced the amount of bovine serum albumin adsorbed from a solution and proteins adsorbed from brain heart infusion medium compared to the control (P < 0.001). A similar pattern was observed for bacterial adhesion: significantly less Streptococcus mutans cells adhered on the surface of LCFV with 1.5, 3, or 5 wt% MPC (P < 0.001) than on the control, and similar results were obtained for Actinomyces naeslundii and Streptococcus sanguinis adherence to LCFV with 3 wt% MPC. Finally, bacterial adhesion, surface microhardness loss, and the depth of demineralization were substantially lower on bovine tooth enamel surface coated with LCFV containing 3 wt% of MPC than in the control treatment (0 wt% MPC). Therefore, this novel LCFV containing a low concentration of MPC (e.g., 3 wt%) would be effective in anti-biofouling while maintaining the important advantageous features of light-curable fluoride in preventing demineralization.

Effect of a resin-modified glass-ionomer with calcium on enamel demineralization inhibition: an in vitro study.

We assessed the effect of a new coating material based on resin-modified glass-ionomer with calcium (Ca) in inhibiting the demineralization of underlying and adjacent areas surrounding caries-like lesions in enamel. The measures used were surface hardness (SH) and cross-sectional hardness (CSH). Thirty-six bovine enamel specimens (3 × 6 × 2 mm) were randomly allocated into three groups (n = 12): No treatment (NT); resin-modified glass-ionomer with Ca (Clinpro XT Varnish, 3M ESPE) (CL), and fluoride varnish (Duraphat, Colgate) (DU). The specimens were subjected to alternated immersions in demineralizing (6 h) and remineralizing solutions (18 h) for 7 days. SH measurements were conducted at standard distances of 150, 300, and 450 µm from the treatment area. CSH evaluated the mean hardness profile over the depth of the enamel surface and at standard distances from the materials. The energy-dispersive X-ray spectroscopy analysis was conducted to evaluate the demineralization bands created on the sublayer by % of calcium (Ca), phosphorus (P), and fluoride (F). Ca/P weight ratio was also calculated. Based on SH and CSH measurements, there was no difference between groups at the distances 150 µm (p = 0.882), 300 µm (p = 0.995), and 450 µm (p = 0.998). Up to 50 µm depth (at 150 µm from the treatment area), CL showed better performance than DU ( p< 0.05). NT presented higher loss of Ca and P than CL and DU (p < 0.05). There was no significant difference in the % of F ion among the three groups. The new coating material was similar to F varnish in attenuating enamel demineralization.

Fluoride Binding to Dental Biofilm Bacteria: Synergistic Effect with Calcium Questioned.

It has been suggested that fluoride binding to dental biofilm is enhanced when more bacterial calcium binding sites are available. However, this was only observed at high calcium and fluoride concentrations (i.e., when CaF2 precipitation may have occurred). We assessed fluoride binding to Streptococcus mutans pellets treated with calcium and fluoride at concentrations allowing CaF2 precipitation or not. Increasing calcium concentration resulted in a linear increase (p < 0.01) in fluoride concentration only in the pellets in which CaF2 precipitated. The results suggest that CaF2 precipitation, rather than bacterially bound fluoride, is responsible for the increase in fluoride binding to dental biofilm with the increase in calcium availability.

Fluoride Penetration and Clearance Are Higher in Exopolysaccharide-Containing Bacterial Pellets.

Extracellular polysaccharides (EPS) could increase the penetration of fluoride through dental biofilm, reducing its cariogenicity. We measured the concentration of fluoride in EPS-containing (EPS+) or not-containing (EPS-) Streptococcus mutans bacterial pellets resembling test biofilms, before and up to 60 min after a 0.05% NaF rinse in situ. Fluoride penetration and clearance were higher in EPS+ bacterial pellets. The data suggest that EPS enhances fluoride penetration, but also accelerates fluoride clearance from dental biofilms.

The in vitro remineralizing effect of CPP-ACP and CPP-ACPF after 6 and 12 weeks on initial caries lesion

Abstract Objective: The aim of this in vitro study was to determine the effects of remineralization promoting agents containing casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP), or CPP-ACP in combination with fluoride (CPP-ACPF) on artificial white spot lesions (WSLs) after 6 and 12 weeks. Methodology: White spot lesions were created on 123 sectioned premolars (246 specimens) with a demineralization solution during a 96 hours pH-cycling regime. Two experimental groups were created: a CPP-ACP group (Tooth Mousse™), and a CPP-ACPF group (Mi Paste Plus™). Additionally, two control groups were created, one using only a conventional toothpaste (1450 ppm fluoride) and another one without any working agents. All teeth were also daily brushed with the conventional toothpaste except the second control group. Tooth Mousse™ and Mi Paste Plus™ were applied for 180 seconds every day. The volume of demineralization was measured with transverse microradiography. Six lesion characteristics regarding the lesion depth and mineral content of WSLs were also determined. Results: The application of CPP-ACP and CPP-ACPF had a significant regenerative effect on the WSLs. Compared to Control group 1 and 2 the volume of demineralization after 6 weeks decreased significantly for CPP-ACP (respectively p<0.001 and p<0.001) and CPP-ACPF (respectively p=0.001 and p=0.003). The same trend was observed after 12 weeks. For the CPP-ACPF group, WSL dimensions decreased significantly between 6 and 12 weeks follow-up (p=0.012). The lesion depth reduced significantly after application of CPP-ACP and CPP-ACPF but increased significantly in the Control groups. Mineral content increased for CPP-ACP and CPP-ACPF after an application period of 12 weeks, but this was only significant for CPP-ACP. Conclusions: Long-term use of CPP-ACP and CPP-ACPF in combination with a conventional tooth paste shows beneficial effects in the recovery of in vitro subsurface caries lesions.

Remineralizing effect of commercial fluoride varnishes on artificial enamel lesions

Abstract: The aim of this study was to evaluate soluble and insoluble fluoride concentrations in commercial varnishes, and their remineralization effect on artificial caries enamel lesions using surface and cross-sectional microhardness evaluations. Forty bovine enamel blocks were separated into four groups (n=10): control (no treatment), Enamelast (Ultradent Products), Duraphat (Colgate-Palmolive) and Clinpro White Varnish (3M ESPE). Surface enamel microhardness evaluations were obtained, artificial enamel caries lesions were developed by dynamic pH-cycling, and the varnishes were then applied every 6 days, after which the enamel blocks were submitted to dynamic remineralization by pH cycles. After removal of the varnishes, the enamel surfaces were reassessed for microhardness. The blocks were sectioned longitudinally, and cross-sectional microhardness measurements were performed at different surface depths (up to 300 μm depth). Polarized light microscopy images (PLMI) were made to analyze subsurface caries lesions. The fluoride concentration in whole (soluble and insoluble fluoride) and centrifuged (soluble fluoride) varnishes was determined using an extraction method with acetone. The data were analyzed to evaluate the surface microhardness, making adjustments for generalized linear models. There was a significant decrease in enamel surface microhardness after performing all the treatments (p<0.0001). Enamelast and Duraphat showed significantly higher enamel microhardness values than the control and the Clinpro groups (p = 0.0002). Microhardness loss percentage was significantly lower for Enamelast (p = 0.071; One-way ANOVA). PLMI showed that subsurface caries lesions were not remineralized with the varnish treatments. No significant differences in the in-depth microhardness levels (p = 0.7536; ANOVA) were observed among the treatments. Enamelast presented higher soluble and insoluble fluoride concentrations than the other varnishes (p < 0.0001; Kruskal-Wallis and Dunn tests). Enamelast and Duraphat varnishes promoted enamel surface remineralization, but no varnish remineralized the subsurface lesion body. Although insoluble and soluble fluoride concentration values did not correspond to those declared by the manufacturer, Enamelast presented higher fluoride concentration than the others.

Effect of a resin-modified glass-ionomer with calcium on enamel demineralization inhibition: an in vitro study

Abstract We assessed the effect of a new coating material based on resin-modified glass-ionomer with calcium (Ca) in inhibiting the demineralization of underlying and adjacent areas surrounding caries-like lesions in enamel. The measures used were surface hardness (SH) and cross-sectional hardness (CSH). Thirty-six bovine enamel specimens (3 × 6 × 2 mm) were randomly allocated into three groups (n = 12): No treatment (NT); resin-modified glass-ionomer with Ca (Clinpro XT Varnish, 3M ESPE) (CL), and fluoride varnish (Duraphat, Colgate) (DU). The specimens were subjected to alternated immersions in demineralizing (6 h) and remineralizing solutions (18 h) for 7 days. SH measurements were conducted at standard distances of 150, 300, and 450 µm from the treatment area. CSH evaluated the mean hardness profile over the depth of the enamel surface and at standard distances from the materials. The energy-dispersive X-ray spectroscopy analysis was conducted to evaluate the demineralization bands created on the sublayer by % of calcium (Ca), phosphorus (P), and fluoride (F). Ca/P weight ratio was also calculated. Based on SH and CSH measurements, there was no difference between groups at the distances 150 µm (p = 0.882), 300 µm (p = 0.995), and 450 µm (p = 0.998). Up to 50 µm depth (at 150 µm from the treatment area), CL showed better performance than DU ( p< 0.05). NT presented higher loss of Ca and P than CL and DU (p < 0.05). There was no significant difference in the % of F ion among the three groups. The new coating material was similar to F varnish in attenuating enamel demineralization.

Effect of fluoride application during radiotherapy on enamel demineralization

Abstract Radiation-related caries are one the most undesired reactions manifested during or after head and neck radiotherapy. Fluoride application is an important strategy to reduce demineralization and enhance remineralizaton. Objective: To evaluate the effect of the topical application of fluoride during irradiation on dental enamel demineralization. Material and Methods: Thirty molars were randomly divided into three groups: Non-irradiated (NI), Irradiated (I), Irradiated with fluoride (IF). Each group was subdivided according to the presence or absence of pH-cycling (n=5). In the irradiated groups, the teeth received 70 Gy. The enamel's chemical composition was measured using Fourier Transform Infrared Spectrometry (organic matrix/mineral ratio - M/M and relative carbonate content - RCC). Vickers microhardness (VHN) and elastic modulus (E) were evaluated at three depths (surface, middle and deep enamel). Scanning electron microscopy (SEM) was used to assess the enamel's morphology. Results: The FTIR analysis (M/M and RCC) showed significant differences for irradiation, pH-cycling and the interaction between factors (p<0.001). Without pH-cycling, IF had the lowest organic matrix/mineral ratio and relative carbonate content. With pH-cycling, the organic matrix/mineral ratio increased and the relative carbonate content decreased, except for IF. VHN was influenced only by pH-cycling (p<0.001), which generated higher VHN values. ANOVA detected significant differences in E for irradiation (p<0.001), pH-cycling (p<0.001) and for the interaction between irradiation and pH-cycling (p<0.001). Increased E was found for group I without pH-cycling. With pH-cycling, groups I and IF were similar, and showed higher values than NI. The SEM images showed no morphological changes without pH-cycling. With pH-cycling, fluoride helped to maintain the outer enamel's morphology. Conclusions: Fluoride reduced mineral loss and maintained the outer morphology of irradiated and cycled enamel. However, it was not as effective in preserving the mechanical properties of enamel. Radiotherapy altered the enamel's elastic modulus and its chemical composition.