Surface Pre-reacted Glass-ionomer Filler Research Articles

Bioactivity of human dental pulp-derived stem cells with boron-controlled S-PRG filler eluate by anion exchange.

Surface pre-reacted glass-ionomer (S-PRG) filler is a bioactive glass filler capable of releasing various ions. A culture medium to which was added an S-PRG filler eluate rich in boron was reported to enhance alkaline phosphatase (ALP) activity in human dental pulp-derived stem cells (hDPSC). To clarify the role of boron eluted from S-PRG fillers, the modified S-PRG filler eluate with different boron concentrations was prepared by using an anion exchange material. Therefore, elemental mapping analysis of anion exchange material, adsorption ratio, hDPSCs proliferation and ALP activity were evaluated. For statistical analysis, Kruskal-Wallis test was used, with statistical significance determined at p<0.05. ALP activity enhancement was not observed in hDPSC cultured in the medium that contained the S-PRG filler eluate from which boron had been removed. The result suggested the possibility that an S-PRG filler eluate with controlled boron release could be useful for the development of novel dental materials.

Influence of surface pre-reacted glass-ionomer (S-PRG) filler eluate on collagen morphology, remineralization, and ultimate tensile strength of demineralized dentin

ObjectiveTo evaluate the effect of ions released from surface pre-reacted glass-ionomer (S-PRG) filler on collagen morphology, remineralization, and ultimate tensile strength (UTS) of demineralized dentin. Materials and methodsBovine incisor root dentins were demineralized with EDTA and divided into three treatment groups: 1) water (control); 2) S-PRG filler eluate; 3) 125 ppm sodium fluoride (NaF). After a 3-min treatment, the specimens were stored in simulated body fluid (SBF) for 3 months. Collagen morphology and remineralization were assessed using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). Additionally, ultimate tensile strength (UTS) was measured. ResultsTEM and SEM demonstrated that S-PRG induced more effective remineralization compared to NaF, while the control group exhibited faint mineral deposition with collagen degradation. S-PRG displayed the most homogenous mineral deposition in collagen fibrils, along with closure of interfibrillar spaces. Extensive mineral precipitation was observed within dentinal tubules in the S-PRG group. In addition, S-PRG filler eluate demonstrated significantly higher phosphate-to-amide ratio and UTS compared to NaF and control groups (p < 0.05). ConclusionsIon released from S-PRG filler positively influenced collagen morphology, remineralization, and ultimate tensile strength of demineralized dentin. Clinical significanceS-PRG filler enhances remineralization and improve the biomechanics of demineralized dentin.

Effect of an In-Office Bleaching Agent with Surface Pre-Reacted Glass-Ionomer Filler on the Enamel Surface: A In-Vitro Study.

In-office bleaching with high concentrations of hydrogen peroxide (H2O2) agents causes undesirable alterations in the enamel. Surface pre-reacted glass-ionomer (S-PRG) filler is a functional material known for its acid-neutralizing and demineralization-inhibition properties. This study evaluates the effect of S-PRG filler incorporation in H2O2-based bleaching on the enamel surface. Bovine enamel surfaces were bleached using a bleaching paste formulated with a liquid (35% H2O2) and a powder containing 5% or 10% S-PRG filler. The surface roughness and the Vickers microhardness of the treated enamel surfaces were evaluated. The enamel surfaces were observed under a scanning electron microscope (SEM) and analyzed using energy dispersive X-ray (EDX) technology. The surfaces were challenged by citric acid and observed by SEM. The specimens bleached with the paste containing the S-PRG filler showed lower enamel surface roughness and higher microhardness values than did those bleached with the plain paste (0% S-PRG filler); meanwhile, there were no significant differences between the 5% or 10% S-PRG filler groups. The S-PRG filler groups showed enamel surface morphologies similar to those of the non-bleached enamel, according to SEM observation, and EDX analysis detected the presence of fluoride and strontium ions. The S-PRG filler groups showed a higher resistance to erosion. The S-PRG filler mitigated the detrimental effects of bleaching agents on the enamel surface and provided resistance to erosion.

In vitro remineralization assessment of enamel subsurface lesions using different percentages of surface reaction-type pre-reacted glass-ionomer containing gum-based material

ObjectiveTo identify the remineralization activity of enamel subsurface lesions using different percentages of surface pre-reacted glass-ionomer (S-PRG) filler containing gum-base material. MethodsGum extracts from gum-base materials containing 0wt%, 5wt%, and 10wt% S-PRG filler were prepared as GE0, GE5, and GE10, respectively. A total of 50 bovine enamel specimens were used, and the polished enamel surface of a 3 × 3 mm2 window area was exposed. The specimens were then subjected to a demineralization solution for seven days to create a subsurface enamel lesion. Remineralization was then conducted for seven days using a protocol whereby the specimens were immersed three times a day in prepared gum extracts (0wt%, 5wt%, and 10wt%) and artificial saliva of pH 7 (Control) for 20 min at 37 °C. Thereafter, remineralization assessment was performed by using Swept Source Optical Coherence Tomography (SS-OCT) and micro-computed tomography (μCT). Surface morphology and elemental analysis were conducted by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). ResultsThe depths of the demineralized lesions in the GE5 and GE10 groups were significantly lower than those of the Control and the GE0 groups. SEM observations of the enamel surface morphology of the GE5 and GE10 groups indicated remineralization with S-PRG filler-related elements present. ConclusionThe GE5 and GE10 S-PRG filler containing gum-base materials showed significantly improved surface remineralization and reduced demineralization of the enamel lesions. EDS analysis suggested that the released ions from the S-PRG filler might be responsible for surface remineralization. Clinical significanceThe S-PRG filler containing gum-base material may have a significant remineralization effect and improve the surface morphology of enamel subsurface lesions.

Salivary fluoride concentrations following toothbrushing with experimental toothpaste containing surface pre-reacted glass-ionomer (S-PRG) filler.

Single-blind 9 case comparative studies were conducted to evaluate salivary fluoride concentrations following toothbrushing using experimental toothpaste containing surface pre-reacted glass-ionomer (S-PRG) fillers. Preliminary tests were conducted in order to determine the volume of usage as well as the concentrations (wt %) of S-PRG filler. Based on the results given these experiments, we compared the salivary fluoride concentrations following toothbrushing with 0.5g of 4 different types of toothpastes: 5 wt % S-PRG filler, 1400ppm F AmF (amine fluoride), 1500ppm F NaF (sodium fluoride), and MFP (monofluorophosphate) containing toothpaste. Of the 12 participants, 7 participated in the preliminary study and 8 in the main study. All participants brushed their teeth using the scrubbing method for 2min. At first, 1.0 and 0.5g of 20 wt % S-PRG filler toothpastes were used to compare, then followed by 0.5g of 0 (control), 1, and 5 wt % S-PRG toothpastes, respectively. The participants spat out once and rinsed with 15mL of distilled water for 5s. Saliva was collected for 3min each at different time intervals of 0 (baseline), 5, 10, 15, 30, 60, 120, and 180min after the rinsing. Fluoride concentrations were determined using a fluoride electrode, and the area under the salivary clearance - time curve (AUC: ppm‧min) of each toothpaste was calculated as the salivary fluoride retention. The main study was then conducted to evaluate the salivary fluoride concentrations as well as the AUC value using 0.5g of 5 wt % S-PRG filler toothpaste, followed by NaF, MFP, and AmF toothpastes. Since there were no statistical differences between using 1.0 and 0.5g of 20 wt % S-PRG toothpastes in salivary fluoride concentrations as well as the AUC value throughout the 180min measurement, the volume was set as 0.5g for the following studies. Concentrations of 5 and 20 wt % S-PRG toothpastes retained 0.09ppm F or more in saliva even after 180min. No statistical differences were seen in the salivary fluoride concentrations at any time intervals as well as the AUC value between 5 and 20 wt % S-PRG toothpastes. Based on these results, the concentration of 5 wt % S-PRG toothpaste was used for the main comparative study. MFP toothpaste resulted in by far the lowest salivary fluoride concentrations (0.06ppm F at 180min) and the AUC value (24.6ppm‧min), whereas 5 wt % S-PRG toothpaste (0.15ppm F at 180min, 92.3ppm‧min) displayed retention on par with AmF toothpaste which appeared to result in higher values (0.17ppm F at 180min, 103ppm‧min), compared to NaF toothpaste (0.12ppm F at 180min, 49.3ppm‧min). The salivary fluoride concentrations following toothbrushing with 0.5g of 5 wt % S-PRG filler containing toothpaste showed retention similar to the best performing 1400ppm F AmF toothpaste even 180min after toothbrushing.

Multiple-Ion Releasing Bioactive Surface Pre-Reacted Glass-Ionomer (S-PRG) Filler: Innovative Technology for Dental Treatment and Care

Surface Pre-Reacted Glass-ionomer (S-PRG) filler, which releases strontium (Sr2+), borate (BO33-), fluoride (F-), sodium (Na+), silicate (SiO32-), and aluminum (Al3+) ions at high concentrations, is a unique glass filler that are utilized in dentistry. Because of its multiple-ion releasing characteristics, S-PRG filler exhibits several bioactivities such as tooth strengthening, acid neutralization, promotion of mineralization, inhibition of bacteria and fungi, inhibition of matrix metalloproteinases, and enhancement of cell activity. Therefore, S-PRG filler per se and S-PRG filler-containing materials have the potential to be beneficial for various dental treatments and care. Those include restorative treatment, caries prevention/management, vital pulp therapy, endodontic treatment, prevention/treatment of periodontal disease, prevention of denture stomatitis, and perforation repair/root end filling. This review summarizes bioactive functions exhibited by S-PRG filler and its possible contribution to oral health.

Clinical evaluation of the remineralizing effect of a mouthguard and paste containing S-PRG filler on white spot lesions

White spot lesions (WSLs) are frequently observed on young permanent teeth. The aim of this clinical study was to evaluate the remineralizing effect of paste and a mouthguard containing surface pre-reacted glass-ionomer (S-PRG) filler by observing and measuring lesion area. A total of 14 children (age range, 8–16 years) with WSLs involving 74 teeth attending Asahi University Medical & Dental Center were examined. Color- and size-matching stickers (Cas Match™, Bear Medic) were photographed with involved teeth. Mouthguards made of an S-PRG filler-containing ethylene-vinyl acetate sheet (sample; SHOFU) with S-PRG filler-containing paste (PRG Pro-Care Gel®; SHOFU) (PRG MG-Paste group) or without paste (PRG MG group; control) were applied to WSLs at bedtime. No teeth required restoration due to caries progression during the experimental period. Mean reductions in lesion area at 6 months after treatment in the PRG MG-Paste group and PRG MG group were 1.66 ± 1.84 mm2 and 0.81 ± 1.27 mm2, respectively. Significant differences were observed between groups (p < 0.05). No significant difference in area reduction was seen between kinds of teeth involved, although significant differences in area reduction were observed among individual subjects. These results suggest that combined use of S-PRG filler-containing paste and a mouthguard is effective for remineralization of WSLs observed on numerous teeth.

Effect of Particle Sizes and Contents of Surface Pre-Reacted Glass Ionomer Filler on Mechanical Properties of Auto-Polymerizing Resin.

Herein, the mechanical properties of an auto-polymerizing resin incorporated with a surface pre-reacted glass ionomer (S-PRG) filler were evaluated. For this, S-PRG fillers with particle sizes of 1 μm (S-PRG-1) and 3 μm (S-PRG-3) were mixed at 10, 20, 30, and 40 wt% to prepare experimental resin powders. The powders and a liquid (powder/liquid ratio = 1.0 g/0.5 mL) were kneaded and filled into a silicone mold to obtain rectangular specimens. The flexural strength and modulus (n = 12) were recorded via a three-point bending test. The flexural strengths of S-PRG-1 at 10 wt% (62.14 MPa) and S-PRG-3 at 10 and 20 wt% (68.68 and 62.70 MPa, respectively) were adequate (>60 MPa). The flexural modulus of the S-PRG-3-containing specimen was significantly higher than that of the S-PRG-1-containing specimen. Scanning electron microscopy observations of the specimen fracture surfaces after bending revealed that the S-PRG fillers were tightly embedded and scattered in the resin matrix. The Vickers hardness increased with an increasing filler content and size. The Vickers hardness of S-PRG-3 (14.86-15.48 HV) was higher than that of S-PRG-1 (13.48-14.97 HV). Thus, the particle size and content of the S-PRG filler affect the mechanical properties of the experimental auto-polymerizing resin.

Bacterial adhesion and antibacterial property of coating materials containing theobromine and S-PRG filler.

Theobromine (TB) has been reported to promote tooth remineralization, strengthen tooth substance, and relieve dentin hypersensitivity. This study aimed to evaluate experimental tooth coating materials containing TB and surface pre-reacted glass-ionomer (S-PRG) fillers by examining the effects on bacterial adhesion and antibacterial properties. In addition, the amount of TB eluted from the coating material was measured. There was no significant difference in bacterial adhesion depending on the presence or absence of TB in the coating material, however, a significant decrease in the amount of bacterial adhesion was observed when S-PRG fillers were added to the coating material. The amount of eluted TB did not differ depending on the type of the filler in the coating material. It was suggested that TB could be used to develop a new dental material with the potential ability to inhibit the initiation and progression of dental caries.

Impact of surface pre-reacted glass ionomer filler eluate on lipase gene expression in Candida albicans: An in vitro study.

Although a surface pre-reacted glass ionomer (S-PRG) exerts a suppressive effect on Candida albicans (C. albicans) activity and growth, its influence on the expression of the lipase gene (LIP) family including LIP1-LIP10, an indicator of clinical infection, has not yet been investigated. Therefore, in this study, we evaluated the effect of S-PRG filler eluates on LIP expression in C. albicans using real-time reverse-transcription polymerase chain reaction. Candida albicans was treated with an S-PRG filler diluted at ratios of 1:32 and 1:64 for 24 h at 37°C. The diluted S-PRG filler eluates (1:32) suppressed lipase activity in C. albicans by downregulating LIP5 (0.54±0.25 relative to that of the control) and LIP8 (0.35±0.074) expression after 24 h, which corresponded with decreased lipase activity. At a dilution factor of 1:64, there was no significant difference in LIP expression. Thus, the S-PRG filler eluate has potential to suppress fungal activity by downregulating LIP expression.

Effects of mouthguard and paste containing S-PRG filler on remineralization of artificial subsurface carious lesions

The aim of this in vitro study was to evaluate the remineralization effects of ethylene-vinyl acetate (EVA) sheet (sample; SHOFU) and paste (PRG Pro-Care Gel®; SHOFU) containing surface pre-reacted glass-ionomer (S-PRG) filler. Extracted human premolars were decalcified to create subsurface carious lesions on the buccal side. Decalcified tooth specimens were then covered by EVA sheets with two different S-PRG filler contents either with application of paste (PRG MG-Paste and EVA MG-Paste groups) or without application of paste (PRG MG and EVA MG groups), then immersed in a remineralization solution. Control group teeth were not covered with any mouthguard and did not receive application of paste. Micro-CT (μCT) images of the teeth before and after the remineralization process were obtained to compare mineral gains. The percentage remineralization (%R) of each group was calculated using the mineral density (MD) profile from μCT. The microstructure of the tooth surface was observed under scanning electron microscopy, and constituent elements were examined using an electron probe micro-analyzer. The PRG MG group showed a significantly higher %R than the Control or EVA MG groups. The PRG MG-Paste group showed a significantly higher %R than the PRG MG group. In the PRG MG-Paste group, small precipitations were observed on tooth surface, and silica and aluminum were detected. The combination use of S-PRG filler containing EVA sheet and PRG Pro-Care Gel exhibits a synergetic effect on remineralization of pre-cavitation carious lesions.

Effect of a Toothpaste Containing Surface Pre-Reacted Glass-Ionomer Filler on the Remineralization of Artificial Carious Enamel Lesions in situ

This study evaluated the remineralizing effect of a toothpaste containing surface pre-reacted glass-ionomer (S-PRG) filler on demineralized enamel in situ. For this, 180 bovine enamel samples were demineralized by using a microcosm biofilm model for 3 days. Thereafter, the samples were randomly signed to 15 healthy volunteers and to 3 cross-over in situ phases corresponding to the following treatments: (1) toothpaste containing 1,500 ppm F as NaMFP (positive control, Colgate®Cavity Protection), (2) toothpaste containing 5% S-PRG filler (Shofu®), and (3) placebo toothpaste (negative control prepared by Shofu®). Four demineralized enamel blocks were fixed into each palatal appliance per phase. The volunteers wore the appliances for 5 days and were trained to brush their teeth 2 times for 2 min a day, while one drop of the toothpaste’s slurry (1:3) was dripped on each sample for the same period. The surface hardness and TMR analyses were done and analyzed by ANOVA/Tukey and t test (p < 0.05). S-PRG filler and Colgate® toothpastes were equally able to improve 2–2.5× enamel remineralization by the analysis of % surface hardness recovery. However, S-PRG toothpaste was the only one able to significantly improve ΔΔZ (the integrated mineral loss recovery: 1,489 ± 503 %vol.μm) compared to placebo (1,050 ± 467 %vol.μm), while Colgate® did not differ from placebo. No differences were seen between the groups with respect to ΔLD. S-PRG filler and Colgate® toothpastes show similar potential to remineralize the lesion surface. However, S-PRG toothpaste is better to recover mineral loss at the subsurface area.

Surface pre-reacted glass-ionomer eluate protects gingival epithelium from penetration by lipopolysaccharides and peptidoglycans via transcription factor EB pathway.

Surface pre-reacted glass-ionomer (S-PRG) filler, produced by PRG technology for use with various dental materials, is bioactive and known to release ions from a glass-ionomer phase. We previously reported that coxsackievirus and adenovirus receptor (CXADR), a tight junction associated protein, was located in the epithelial barrier of gingival epithelium. In the present study, the tissue protective effects of an S-PRG eluate prepared with S-PRG filler were investigated using a three-dimensional human gingival epithelial tissue model. The results showed that the S-PRG eluate specifically induced CXADR expression at the transcriptional level of messenger RNA as well as the protein level, and also nuclear translocation of transcription factor EB (TFEB) in gingival epithelial cells. Furthermore, shigyakusan, a TFEB inhibitor, canceled induction of the CXADR protein by the S-PRG eluate. Additionally, gingival epithelial permeation by 40-kDa dextran, lipopolysaccharide, and peptidoglycan in the 3D-tissue models was prevented by the eluate, with those effects abrogated by knockdown of CXADR. These findings suggest that S-PRG eluate increases CXADR expression via the TFEB pathway, thus inhibiting penetration of bacterial virulence factors into subepithelial tissues.

A Scanning Electron Microscope Evaluation of the Efficacy of Different Fluoride-releasing Dental Restorative Materials to Prevent Enamel Demineralization: An In Vitro Study

Aim of the present research was to investigate the effectiveness of various fluoride-releasing dental restorative agents in preventing demineralization of enamel. Eighty human mandibular permanent molar teeth constituted the study group. All samples were subjected to storage in thymol, after which they were taken out to prepare alike proximal box in each. Inductions of artificial enamel surface lesions were done by placing the teeth in demineralizing solution for 96 hours. Subsequently, all 80 molars were randomly assigned to any of the four groups (i.e., 20 in every individual group) according to the restoration as group A: giomer (composite resin containing surface pre-reacted glass-ionomer fillers), group B: compomer (polyacid-modified composite resin), group C: resin-modified glass-ionomer cement (RMGIC), group D: fluoride-releasing composite. After this, the pH cycling was performed, and the samples were subjected to examination beneath scanning electron microscope (SEM). Higher mean areas of remineralization were noted when RMGIC (96.34 ± 0.06) was used followed by the compomer (109.52 ± 0.17), giomer (118.39 ± 0.82), and the fluoride-releasing composite group (129.27 ± 0.31) in that order. A statistically significant difference was seen amid the investigational groups that utilized different restorative agents (p <0.001). A pairwise evaluation that was performed revealed that except for the giomer group and the compomer group, a statistically significant difference (p <0.001) was found among the experimental groups. This research infers that the RMGIC-treated samples exhibited significantly superior performance in preventing enamel demineralization in comparison to compomer, giomer as well as fluoride-releasing composites. One among the highly frequently employed anticariogenic materials is fluorides. Owing to this characteristic, they are integrated into numerous restorative substances. Nevertheless, the quantity and speed of fluoride release differ in different agents, which translates to the efficacy of the restorative agent in avoiding demineralization about the restoration.

Sensitivity Treatments for Teeth with Molar Incisor Hypomineralization: Protocol for a Randomized Controlled Trial.

BackgroundThe sensitivity of teeth with molar incisor hypomineralization (MIH) can affect children’s quality of life and is a challenging problem for dentists. Remineralizing agents such as sodium fluoride varnish seem to reduce the sensitivity of teeth with MIH, but long-term clinical trials with large samples are still needed for more evidence about its effectiveness as a desensitizing agent before its clinical recommendation.ObjectiveThis randomized clinical trial aims to compare three treatment interventions for teeth with MIH and hypersensitivity.MethodsA total of 60 children aged 6-10 years presenting with at least one first permanent molar with sensitivity and no loss of enamel will be randomly assigned to three groups: the control group (sodium fluoride varnish; Duraphat, Colgate); experimental group I (4% titanium tetrafluoride varnish); and experimental group II (a coating resin containing surface prereacted glass-ionomer filler; PRG Barrier Coat, Shofu). The sodium fluoride varnish and 4% titanium tetrafluoride varnish will be applied once per week for 4 consecutive weeks and the PRG Barrier Coat resin will be applied in the first session and the application will be simulated the following 3 weeks to guarantee the blinding of the study. The primary outcome will be sensitivity level measured at different moments (before each material application, immediately after application or simulation, and 1, 2, 4, and 6 months after the last application/simulation) by one examiner using the Wong-Baker FACES Pain Rating Scale, the Schiff Cold Air Sensitivity Scale, and the FLACC (Face, Legs, Activity, Cry, Consolability) scale. As secondary outcomes, parental satisfaction and child self-reported discomfort after the treatment will be measured with a questionnaire prepared by the researcher. The data will undergo statistical analysis and the significance level will be set at 5%.ResultsThe project was funded in 2018, and enrollment was completed in November 2019. The recruitment of participants is currently underway and the first results are expected to be submitted for publication in 2022.ConclusionsIf found effective in reducing the patient’s sensitivity long term, these agents can be considered as a treatment choice, and the findings will contribute to the development of a treatment protocol for teeth with sensitivity due to MIH.Trial RegistrationBrazilian Registry of Clinical Trials Universal Trial Number U1111-1237-6720; https://tinyurl.com/mr4x82k9International Registered Report Identifier (IRRID)DERR1-10.2196/27843

In vivo Assessment of Tissue Compatibility of Root Canal Sealer Containing Surface Pre-reacted Glass-ionomer Fillers

<i>In vivo</i> Assessment of Tissue Compatibility of Root Canal Sealer Containing Surface Pre-reacted Glass-ionomer Fillers

Physical properties and wear behavior of CAD/CAM resin composite blocks containing S-PRG filler for restoring primary molar teeth

ObjectivesThis study aimed to develop computer-aided design/computer-aided manufacturing (CAD/CAM) resin composite blocks (RCBs) containing surface pre-reacted glass-ionomer (S-PRG) filler for primary molar teeth and evaluate their physical properties and wear resistance. MethodsExperimental CAD/CAM RCBs containing S-PRG filler for primary molar teeth (EB), a commercial CAD/CAM RCB (HC), two resin composites for primary teeth (BKP and BKZ) and one for permanent teeth (BⅡ) were used. Hardness tests, three-point bending tests, fracture toughness tests, and water absorption tests were conducted. Wear tests were conducted for these materials and stainless steel crowns (SSCs). ResultsThe Vickers hardness of EB was lower than that of HC (p < 0.05), and there was no significant difference among BKZ, BKP, and BⅡ (p > 0.05). After 1 week of water immersion, EB and HC showed greater flexural strength than the other materials (p < 0.05). EB showed greater fracture toughness than the other materials (p < 0.05). The water absorption of EB was lower than that of HC, BKZ, and BKP (p < 0.05), and greater than that of BⅡ (p < 0.05). Antagonist wear was significantly smaller in EB than in HC and BⅡ (p < 0.05), and significantly greater than in BKZ (p < 0.05). Antagonist wear could not be measured in SSC because of excessive wear that was out of range of the surface roughness tester. SignificanceThe CAD/CAM RCBs containing S-PRG filler for primary molar teeth developed in this study demonstrated adequate physical properties and wear performance, suggesting that they are suitable for restoration of primary molar teeth and could function in place of SSCs.

Inhibitory effect of a gel paste containing surface pre-reacted glass-ionomer (S-PRG) filler on the cariogenicity of Streptococcus mutans

Surface pre-reacted glass-ionomer (S-PRG) filler is a bioactive functional glass that releases six different ions. Although several dental materials containing S-PRG filler have been developed, few self-care products containing S-PRG filler have been reported. We investigated the inhibitory effects of PRG gel paste containing S-PRG filler on Streptococcus mutans, a major pathogen of dental caries. PRG gel paste inhibited bacterial growth of S. mutans in a concentration-dependent manner, and all S. mutans were killed in the presence of ≥ 1% PRG gel paste. Additionally, it was difficult for S. mutans to synthesize insoluble glucan from sucrose in the presence of 0.1% PRG gel paste. A biofilm formation model was prepared in which slices of bovine enamel were infected with S. mutans after treatment with or without PRG gel paste. Biofilm formation was inhibited significantly more on the enamel treated with PRG gel paste than on enamel without PRG gel paste (P < 0.001). The inhibitory effects on bacterial growth and biofilm formation were more prominent with PRG gel paste than with S-PRG-free gel paste, suggesting that PRG gel paste may be effective as a self-care product to prevent dental caries induced by S. mutans.

Effects of multi-components released from S-PRG filler on the activities of human dental pulp-derived stem cells.

Numerous studies have shown that the sustained release of ions from dental restorative materials have acid buffering capacity, prevents tooth enamel demineralization, and inhibits bacterial adhesion. Herein, the release behavior and bioresponsiveness of ions released from surface pre-reacted glass-ionomer (S-PRG) fillers were investigated in different types of media based on human dental pulp-derived stem cell (hDPSC) responses. The hDPSCs were cultured for 1-7 days in S-PRG eluates diluted with varying amounts of cell culture media. S-PRG released several types of ions, such as F-, Sr2+, Na+, Al3+, BO33-, and SiO32-. The balance of eluted ions differed depending on the dilution and solvent, which in turn affected the cytotoxicity, cell morphology, cell proliferation, and alkane phosphatase activity of hDPSCs, among other properties. The results suggest that tailored S-PRG filler eluates could be designed and prepared for application in dental practice.

Pulp tissue reaction to a self-adhesive, resin-based direct pulp capping material containing surface pre-reacted glass-ionomer filler

ObjectiveThis study aimed to evaluate the effect of direct pulp capping using an experimental self-adhesive resin for direct pulp capping (SRD) containing silica and surface pre-reacted glass-ionomer (S-PRG) filler on pulpal healing and to monitor the dentin bridge formation in rat pulp 2–4 weeks after operation. MethodsFive types of SRDs (SRD-0: S-PRG fillers 0 wt%; SRD-1: S-PRG fillers 9.1 wt%; SRD-2: S-PRG fillers 18.4 wt%; SRD-3: S-PRG fillers 27.8 wt%; and SRD-6: S-PRG fillers 57.4 wt%) were prepared, and mineral trioxide aggregate (MTA) was used as control (n = 8). Direct pulp capping was performed on rats that were sacrificed for further evaluation 2 or 4 weeks after the operation. The pulp tissue disorganization (PTD), inflammatory cell infiltration (ICI), and reparative dentin formation were histopathologically evaluated; the data were statistically analyzed using the Kruskal–Wallis and the Mann–Whitney U tests. ResultsThe histopathological evaluation of SRD-1-treated test animals 2 weeks post-operation revealed inferior PTD and ICI when compared with that of MTA. Even 4 weeks after the operation in SRD-1- and SRD-2-treated rats, the PTD and ICI were inferior when compared with those of MTA. The dental specimens of SRD-0 and MTA showed orthodentin formation, whereas SRD-treated test animals showed osteodentin formation at a position slightly deeper than the site of the pulpal exposure. SignificanceThe reparative dentin formed by SRD-0 and MTA was genuine, whereas that formed by SRD-3 and SRD-6 was ossified and ectopic. SRD may have the potential to be utilized clinically as a direct pulp capping material.