Pre-reacted Glass Research Articles

Bioactive Self-Polymerizing Resin with Surface Pre-Reacted Glass Ionomer Fillers for Suppressed Enamel Demineralization.

The treatment of damaged enamel surfaces involves modification of the enamel surface with artificial materials or the development of a pseudo-enamel, with research focusing on bioactive and biomimetic materials. In this study, a bioactive auto-polymerizing resin (APR) was developed by adding surface-pre-reacted glass ionomer (S-PRG) fillers of different quantities to APR. Its bioactive effects were evaluated via pH neutralization, ion release, and inhibition of enamel demineralization studies. The pH and fluoride ion release were measured using ion-specific electrodes, revealing that the APR disk with the S-PRG filler immediately neutralized the lactic acid solution (pH 4.0) through ion release. Inductively coupled plasma atomic emission spectrometry revealed that the Sr ion release peaked on the first day, with the other ions following the order F > B > Si > Al > Na, exhibiting a weekly decrease in the same order. Scanning electron microscopy was used to examine the enamel block morphology of the disks after 7 d of incubation, revealing enamel demineralization in disks without the S-PRG filler, whereas no demineralization occurred in disks with the S-PRG filler. APR containing the S-PRG filler demonstrated acid buffering suppressed enamel demineralization and bioactive properties.

Inhibitory Effects of Surface Pre-Reacted Glass Ionomer Filler Eluate on Streptococcus mutans in the Presence of Sucrose.

The surface pre-reacted glass ionomer (S-PRG) filler is a type of bioactive functional glass that releases six different ions. This study examined the effects of the S-PRG filler eluate on Streptococcus mutans in the presence of sucrose. In a solution containing S. mutans, the concentrations of BO33-, Al3+, Sr2+, and F- were significantly higher in the presence of the S-PRG filler eluate than in its absence (p < 0.001). The concentrations of these ions further increased in the presence of sucrose. Additionally, the S-PRG filler eluate significantly reduced glucan formation by S. mutans (p < 0.001) and significantly increased the pH of the bacterial suspension (p < 0.001). Bioinformatic analyses revealed that the S-PRG filler eluate downregulated genes involved in purine biosynthesis (purC, purF, purL, purM, and purN) and upregulated genes involved in osmotic pressure (opuAa and opuAb). At a low pH (5.0), the S-PRG filler eluate completely inhibited the growth of S. mutans in the presence of sucrose and significantly increased the osmotic pressure of the bacterial suspension compared with the control (p < 0.001). These findings suggest that ions released from the S-PRG filler induce gene expression changes and exert an inhibitory effect on S. mutans in the presence of sucrose.

Analysis of color stability and degree of conversion of different types of resin composites.

Resin composites containing surface pre-reacted glass (S-PRG) have been introduced to reduce demineralization and improve remineralization of the tooth structure. However, water diffusion within the material is necessary for its action, which can impair its overall physicomechanical properties over time, including color stability. This study aimed to evaluate the color stability and related degree of conversion (DC) of four resin composites. Discs (6 x 4 mm, n = 5/group) of microhybrid (MH), nanofilled (NF), nanohybrid (NH), and S-PRG-based nanohybrid (S-PRG-NH) composites with two opacities (A2/A2E and A2O/A2D) were prepared. Color (CIELab and CIEDE2000) was evaluated with a spectrophotometer after aging in grape juice (2 x 10 min/10mL/7days). The DC was analyzed by using Fourier transform infrared spectroscopy before and after light-curing. Data were statistically analyzed by using two-way analysis of variance and post-hoc least significant difference tests (p<0.05). In the color stability analysis, the interaction between filler type and opacity was significant (CIELab, p = 0.0015; CIEDE2000, p = 0.0026). NH presented the highest color stability, which did not differ from that of MH. The greatest color alteration was observed for S-PRG-NH. S-PRG fillers also influenced DC (p < 0.05). The nanohybrid resin composite presented favorable overall performance, which is likely related to its more stable organic content. Notwithstanding the benefits of using S-PRG-based nanohybrid resins, mostly in aesthetic procedures, professionals should consider the susceptibility of such resins to color alteration, probably due to the water-based bioactive mechanism of action.

Effect of borate, fluoride and strontium ions on biomimetic nucleation of calcium phosphate studied using solid-state nuclear magnetic resonance and X-ray diffraction

ObjectivesApatite minerals can have various anions and cations in their crystal structure in addition to phosphate ion (PO₄³⁻) and calcium ion (Ca2+). The aim of this study is to investigate effects of the borate, fluoride and strontium ions on biomimetic nucleation of calcium phosphate. MethodsNano-crystalline hydroxyapatite (H-Ap) was obtained from a supersaturated buffered solution containing 4.12 mM HPO42- and 5.88 mM Ca2+ (H-Ap). Four additives were used in solid solution methods: (i) 0.588 mM F- (F-Ap), (ii) 5.88 mM Sr2+ (Sr-Ap), (iii) 4.12 mM BO33- (BO3-Ap), and (iv) a surface pre-reacted glass ionomer (S-PRG) filler eluate that contained 0.17 mM Sr2+, 0.588 mM F-, 11.1 mM BO33-- (SPRG-Ap). Apatite crystallization was investigated using a solid-state magic-angle spinning NMR spectroscopy and X-ray diffraction (XRD) with the Rietveld analysis. ResultsA 2D 1H–31P heteronuclear-correlation NMR showed F- ion incorporation in the apatite structure of the F-Ap and SPRG-Ap. The peaks on the 31P axis of the F-Ap, Sr-Ap, and BO3-Ap were different from that of the H-Ap, and the full width at half maximum increased in the following order: H-Ap∼F-Ap∼BO3-Ap< SPRG-Ap< Sr-Ap, suggesting the incorporation of the F-, Sr2+ and BO33-. The incorporation of F and BO3 was further confirmed by 19F and 11B NMR. The XRD revealed that Sr2+ was preferentially incorporated into the CaII site. SignificanceThe F-, Sr2+ and BO33-ions might be involved in modifying the crystallization of apatite precipitation, producing a variety of apatite. S-PRG filler that release these ions may have an effect on remineralization, i.e., the reformation of apatite lost due to caries.

In vitro analysis of durability of S-PRG filler-containing composite crowns for primary molar restoration.

To evaluate the reliability, maximum principal stress, shear stress, and crack initiation of a computer-aided design/computer-aided manufacturing (CAD/CAM) resin composite (RC) incorporating surface pre-reacted glass (S-PRG) filler for primary molar teeth. Mandibular primary molar crowns fabricated by experimental (EB) or commercially available CAD/CAM RCs (HC) were prepared and cemented to a resinous abutment tooth using an adhesive resin cement (Cem) or a conventional glass-ionomer cement (CX). These specimens were subjected to a single compressive test (n=5/each) and the step-stress accelerated life testing (SSALT) (n=12/each). Data was evaluated using Weibull analyses and reliability was calculated. Afterwards, the maximum principal stress and crack initiation point of each crown was analyzed by finite element analysis. To evaluate bonding of EB and HC to dentin, microtensile bond strength (μTBS) testing was conducted using primary molar teeth (n=10/each). There was no significant difference between the fracture loads of EB and HC for either cement (p>0.05). The fracture loads of EB-CX and HC-CX were significantly lower than EB-Cem and HC-Cem (p<0.05). The reliability at 600N for EB-Cem was greater than that for EB-CX, HC-Cem, and HC-CX. The maximum principal stress concentrated on EB was lower than that on HC. The shear stress concentrated in the cement layer for EB-CX was higher than that for HC-CX. There was no significant difference among the μTBSs of EB-Cem, EB-CX, HC-Cem, and HC-CX (p>0.05). The crowns fabricated with the experimental CAD/CAM RC incorporating S-PRG filler yielded greater fracture loads and reliability than the crowns manufactured with commercially available CAD/CAM RC regardless of the luting materials. These findings suggest that the experimental CAD/CAM RC crown may be clinically useful for the restoration of primary molars.

Antibacterial Activity of a Bioactive Tooth-Coating Material Containing Surface Pre-Reacted Glass in a Complex Multispecies Subgingival Biofilm.

Bioactive materials were developed with the ability to release fluoride and provide some antimicrobial potential, to be widely used in dentistry today. However, few scientific studies have evaluated the antimicrobial activity of bioactive surface pre-reacted glass (S-PRG) coatings (PRG Barrier Coat, Shofu, Kyoto, Japan) on periodontopathogenic biofilms. This study evaluated the antibacterial activity of S-PRG fillers on the microbial profile of multispecies subgingival biofilms. A Calgary Biofilm Device (CBD) was used to grow a 33-species biofilm related to periodontitis for 7 days. The S-PRG coating was applied on CBD pins from the test group and photo-activated (PRG Barrier Coat, Shofu), while the control group received no coating. Seven days after treatment, the total bacterial counts, metabolic activity, and microbial profile of the biofilms were observed using a colorimetric assay and DNA-DNA hybridization. Statistical analyses were applied; namely, the Mann-Whitney, Kruskal-Wallis, and Dunn's post hoc tests. The bacterial activity of the test group was reduced by 25.7% compared with that of the control group. A statistically significant reduction was observed for the counts of 15 species: A. naeslundii, A. odontolyticus, V. parvula, C. ochracea, C. sputigena, E. corrodens, C. gracilis, F. nucleatum polymorphum, F. nucleatum vincentii, F. periodonticum, P. intermedia, P. gingivalis, G. morbillorum, S. anginosus, and S. noxia (p ≤ 0.05). The bioactive coating containing S-PRG modified the composition of the subgingival biofilm in vitro, thereby decreasing colonization by pathogens.

Surface pre-reacted glass reinforced dental composite: Performance assessment of physicochemical, static mechanical, dynamic mechanical and wear properties

The purpose of the present study was to introduce S-PRG fillers and vary in the range of (0–15 wt. %) in the dental composites with partial replacement of organic matrix (BISGMA/TEGDMA/CG/EDMAB in 54 wt. %, 45 wt. %, 0.2 wt. % and 0.8 wt. %). The performance of S-PRG fillers was evaluated by testing the S-PRG reinforced dental composite in terms of chemical properties (polymerization shrinkage, degree of conversion), optical (translucency) and mechanical properties (micro-hardness, compression strength, diametral tensile strength and wear properties). It was revealed that the addition of 5 wt. % of S-PRG ceramic fillers increased depth of cure, degree of conversion, polymerization shrinkage and water sorption by 5.12%, 5.6%, 6.5% and 2.96%, respectively. Whereas, on adding 5 wt. % of S-PRG ceramic fillers, Vickers hardness, compressive strength, flexural strength, diametral tensile strength and wear resistance were increased by 25.8%, 11.6%, 15.8%, 25% and 9.6%, respectively. Data were analyzed statistically with one-way ANOVA and post hoc Tukey's HSD test (α &lt; 0.05). This study demonstrates that the biologically beneficial S-PRG ceramic fillers have exhibited excellent performance in terms of physical, chemical, mechanical and wear properties which lay within the limit specified by ISO 4049 standard. Therefore, it can be suggested to replace expensive nanoparticles in the dental composite.

Effects of in vitro erosion on surface texture, microhardness, and color stability of resin composite with S-PRG fillers.

To evaluate the effect of acid erosion on different physical properties of resin composite with S-PRG (surface pre-reacted glass) fillers, by conducting simulations of intrinsic and extrinsic sources. Cylindrical samples (Ø6 vs. 2 mm) of a conventional nanohybrid resin composite (Forma, Ultradent) and of a nanohybrid resin composite with S-PRG filler (Beautifil II, Shofu) were exposed to erosive cycling (5 days), based on (n=12) remineralizing solution (control); 0.3% citric acid (pH=2.6); or 0.01 M hydrochloric acid (pH=2). Roughness (Ra), microhardness (KHN), and color (CIEL*a*b*, CIEDE2000, and Vita scale (SGU)) factors were analyzed at the initial and final time points, and the general color changes (ΔEab, ΔE00, ΔSGU) were calculated. Final images were obtained using scanning electron microscopy (SEM). The data were evaluated by generalized models, Mann-Whitney, Wilcoxon, Kruskal-Wallis, and Dunn tests (α=0.05). Regarding KHN, there was no difference between the groups or the time periods (p = 0.74). As for Ra, there was a significant increase in the Ra of both composites after cycling with hydrochloric acid, but only the resin composite with S-PRG filler showed a change in Ra after cycling with citric acid (p = 0.003). After cycling with citric and hydrochloric acid, the highest Ra values were found for the resin composite with S-PRG filler (p < 0.0001), corroborating the result of images (SEM) indicating loss of filler and porosities in this material. The resin composite with S-PRG filler showed higher ΔEab and ΔE00, in addition to more negative ΔSGU values and lower L* values after exposure to both acids, compared to the control (p < 0.05). The acidic conditions altered the roughness and color stability of the materials tested, pointing out that the resin composite containing S-PRG filler showed greater degradation of its physical properties than the conventional resin composite. Bioactive materials are relevant, considering that their properties interact with dental hard tissues; however, the S-PRG-based resin composite showed greater degradation under acidic conditions than the conventional resin composite.

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.

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.

Antimicrobial efficacy of S-PRG containing toothpastes on S. mutans biofilm development

Objective: to investigate the antimicrobial effects of toothpastes containing bioactive surface pre-reacted glass particles (S-PRG) on S. mutans biofilms adherence, initial colonization and maturation. Material and Methods: a reference UA 159 and a clinical S. mutans (SM6) strain were used. Bovine enamel specimens were randomly allocated into the groups (n=5): toothpastes containing 0%; 1%; 5%; 20%; 30% S-PRG; positive control dentifrice (NaF+triclosan); and negative control (distilled water). For biofilm development, samples were placed in a 24-well plate containing artificial saliva (4h), followed by adding 1mL of artificial saliva, BHI broth and 225uL of S. mutans suspension. Treatments with toothpastes were applied previously or after 4h and 24h of biofilm formation. Samples were incubated for 48h at 37°C in 5%CO2 and biofilm was detached and seeded in Petri dishes for determining the number of viable cells. Data were analyzed by ANOVA and Tukey test (5%). Results: significantly lower microorganisms’ adherence (p&lt;0.05) was obtained for all S-PRG toothpastes, with similar results to NaF+triclosan for SM6 and 20 and 30%S-PRG groups exhibiting higher inhibition effect than the NaF+Triclosan for UA159. Antibacterial effect on the early-stage biofilm was also observed for the S-PRG groups, but was not superior to the NaF+Triclosan toothpaste. For the mature biofilm, the effective antimicrobial potential of S-PRG toothpastes was observed only for the SM6 clinical strain, but was not higher than the positive control. Conclusion: experimental S-PRG toothpastes were effective to inhibit S. mutans biofilm growth by exhibiting antimicrobial activity, being promising agents to prevent cariogenic biofilm development. KEYWORDS Biofilm; Dental enamel; Giomer; Streptococcus mutans, S-PRG.

Optimal Surface Pre-Reacted Glass Filler Ratio in a Dental Varnish Effective for Inhibition of Biofilm-Induced Root Dentin Demineralization.

A unique type of dental varnish (DV) containing surface pre-reacted glass (S-PRG) fillers of different concentrations was evaluated to determine the unpresented optimal ratio for inhibiting root dentin bio-demineralization. S-PRG DVs (10% to 40%)-10%-S, 20%-S, 30%-S, and 40%-S-were applied to bovine root dentin blocks and compared with controls-0%-f (no S-PRG) and 5%-NaF (5%-NaF). The Streptococcus mutans biofilm challenge was executed inside and outside an oral biofilm reactor for 7 days. The specimens were examined using a confocal laser scanning microscope and swept-source optical coherence tomography. Furthermore, they were observed using a scanning electron microscope and analyzed using energy-dispersive X-ray spectroscopy. The roughness (SzJIS) due to leaching of DV materials and demineralization depth were significantly less in the S-PRG groups than the control groups (p &lt; 0.05). Complete or partially plugged dentinal tubules (DTs) were observed in 20%-S, 30%-S, and 40%-S, while wide-open DTs were observed more in controls. Cylindrical tags were present in groups containing more than 20% S-PRG. F, Na, Al, and Sr were detected in a higher percentile ratio in the 20%-S, 30%-S, and 40%-S groups compared to 0%-f and 10%-S. Nonetheless, it is suggested that incorporating 20% to 30% S-PRG fillers in DVs would be effective enough as an anti-demineralization coating, together with supplementing minerals; further evaluation is required to validate these findings.

Effect of Surface Pre-Reacted Glass Ionomer Containing Dental Sealant on the Inhibition of Enamel Demineralization.

The effect of a surface pre-reacted glass ionomer (S-PRG)-containing sealant on the demineralization inhibition and remineralization of intact enamel adjacent to the sealant material was investigated. BeautiSealant (BTS, S-PRG sealant, Shofu), Teeth Mate F-12.0 (TMF, fluoride-releasing sealant, Kuraray Noritake Dental), and an experimental silica-filler sealant were investigated. After pH cycling for 10 days, the enamel surface adjacent to the sealant material was observed using confocal laser microscopy and scanning electron microscopy. The polymerized sealant disks were immersed in a demineralized solution (pH: 4.3) to measure pH change. The enamel specimens with polymerized sealant disks were additionally immersed in demineralized solution, followed by energy-dispersive X-ray spectroscopy. The demineralized area of BTS was significantly smaller than that of TMF and SS (p &lt; 0.05). The surfaces adjacent to the sealant of TMF and SS were demineralized, while the surface of BTS was comparatively intact. An increase in pH values were observed in the BTS and TMF groups. Enamel surfaces presented an inhibition of demineralization for BTS and TMF, but not for SS. Fluoride uptake from the polymerized sealant was greater for BTS than for TMF. The S-PRG-containing sealant showed a buffering ability, demineralization inhibition, promotion of remineralization, and it can be advised for clinical applications.

In vitro and in vivo performance of self-conditioning sealants with pre-reacted glass for caries prevention

Bioactive materials capable of preventing the development of caries lesions can be an important preventive strategy. This study aims to evaluate in vitro the alkalizing potential, fluoride release, shear bond strength (SBS), and Knoop microhardness (HK) of self-conditioning sealants with pre-reacted glass (S-PRG) and in vivo their retention, quality and caries prevention using the randomized clinical trial (RCT). Dental sealants FS-conventional (Fluoroshield-Dentsply) and BS self-etching (BeautiSealant-Shofu) were evaluated. Sealants samples (n = 5 per group) were performed to verify the alkalizing potential and fluoride release at neutral and acid pH. For mechanical evaluation of both sealants, twenty bovine incisors were used for SBS test, and twenty sealant samples were performed for HK under 50 g load for 15 s. All measurements were taken after 24h and 30 d. A split-mouth RCT including 28 volunteers (10–14 years) with erupted permanent molars and initial enamel caries lesions was conducted to evaluate BS and FS behavior. Sealant retention (total, partial and total loss) and quality scores were analyzed after 30 d. In vitro and in vivo tests were assessed by T-test, and χ2 & Fisher tests (α = 0.05). BS demonstrated higher alkalinizing potential at neutral and acid pH and lower SBS and HK at 24h and 30 d (p < 0.05). However, the FS had greater fluoride release at neutral and acid pH. Clinically, BS also showed lower retention than FS (p = 0.02), but no sealant quality difference was observed. Both sealants contributed to the remission or non-evolution of caries. After 1 month, the bioactive S-PRG sealant showed in vitro a higher alkalizing potential and lower fluoride release, retention, and microhardness, while in vivo, despite the lower retention, the non-evolution of caries lesions was verified.

Obliteration of Dentinal Tubules by Desensitizing Agents Based on Silver Fluoride/Potassium Iodide or Pre-Reacted Glass Particles: An in Vitro Study

Obliteration of Dentinal Tubules by Desensitizing Agents Based on Silver Fluoride/Potassium Iodide or Pre-Reacted Glass Particles: An in Vitro Study

49 - Can S-PRG Fillers in Different Vehicles Act on Dentin Permeability?

The exposure of dentin to the oral environment often leads to the development of dentin hypersensitivity (DH) partially due to the permeability of this mineralized tissue. Among the strategies to relief its symptoms, ions that minimize demineralization and reinforce mineralized tissues are often employed. Recently, one light-curing varnish containing surface pre-reacted glass (S-PRG) fillers (PRG Barrier Coat) was developed with this purpose. Furthermore, it presents aluminum, which is attributed to the clinical relief of DH. However, due to the presence of these fillers in a light-curing resinous matrix, the effect of the matrix cannot be disregarded. Therefore, the aim of this study was to investigate the effect of a S-PRG-based varnish, a toothpaste containing 30 wt.% of S-PRG fillers, a resin infiltrant (Icon) and a NaF-based varnish (Duraphat) on the dentin permeability in vitro. The permeability of the dentin disks (1.0 0.2 mm) was evaluated using Flodec. The specimens were distributed in 4 groups (n=8) and the minimum (pMin, with smear layer) and maximum (pMax, without smear layer) were recorded. Thereafter, each specimen was treated with one of the designated product and the permeability after treatment (pTreat) was recorded. Then, specimens were subjected to a 1-min erosive challenge and the final permeability (pEro) was recorded. The data was transformed in Log10 and analyzed using 2-way repeated measures ANOVA (alpha=0.05). The results evidenced no difference between groups for the pMin and pMax values, assuring a standardized baseline for all tested conditions. There was no difference in pTreat when comparing the two S-PRG-based vehicles. For pTreat and pEro, the lowest permeability was seen for the group treated with the resin infiltrant, reaching values closest to pMin. Likely, its homogeneous TEGDMA layer constituted a mechanical barrier. NaF varnish also effectively reduced dentin permeability after treatment. Therefore, it can be concluded that S-PRG-based products vehicle did not reduce the dentin permeability in vitro, so its effective action for DH might be attributed to other mechanisms rather than by an obliterating process.

Biological properties of lithium-containing surface pre-reacted glass fillers as direct pulp-capping cements

ObjectiveSurface pre-reacted glass fillers (S-PRG) can release different types of ions and in our previous study, we modified these fillers with lithium chloride (S-PRG/Li-100 mM) to induce reparative dentin formation by activating the Wnt/β-catenin signaling pathway. Here, we assessed the biological performance of S-PRG/Li-100 mM and compared it with that of mineral trioxide aggregate (MTA) and S-PRG without additives. MethodsIn vivo studies were conducted on male Wistar rats using Masson’s trichrome staining in pulp-capped molars. The test materials were implanted subcutaneously to evaluate their capacity for vascularization and biocompatibility. The ability of the test materials to form apatite was tested by immersing them in simulated body fluid. Rhodamine-B staining was conducted to assess their sealing ability in bovine teeth, while their antibacterial activity was evaluated against Streptococcus mutans and Lactobacillus casei in terms of colony-forming units and by live/dead staining. ResultsMasson’s trichrome staining and tissue-implantation tests confirmed the biocompatibility of S-PRG/Li-100 mM and it was similar to that of MTA and S-PRG; inflammation regression was observed 14 days after operation in the subcutaneous tissues. S-PRG/Li-100 mM promoted the formation of apatite on its surface. Both the S-PRG groups showed higher sealing capability and bactericidal/bacteriostatic activity against oral bacterial biofilms than MTA. SignificanceLithium-containing surface pre-reacted glass cements exhibit better antibacterial and sealing capabilities than MTA, suggesting their potential as high-performance direct pulp-capping materials.

Clinical Evaluation of Glass-Lonomer Cement and Giomer for the Management of Cervical Caries

Background: Giomer is a unique class of restorative material has been introduced as the true hybridization of Glass Ionomer (GI) and composite resin and has the distinguishing feature of a stable surface pre-reacted glass ionomer. Glass Ionomer Cements (GIC) are also unique restorative materials with many uses in clinical practice and provide for caries-protective fluoride releasing at the margins of restorations, as well as their ability to have the fluoride within their chemical matrix recharged by outside exposure to other fluoride-containing materials. The present study aim at clinically evaluate the comparison between the glass Ionomer cement and Giomer for the management of cervical caries.&#x0D; Materials and methods: The study was a cross sectional comparative study which was carried out from 01 December 2018 to 31 November 2019 in the Department of Conservative Dentistry and Endodontics, Bangladesh Dental College, Dhanmondi, Dhaka. Total number of cases was 80. The patients were divided into two groups, half of the patient (Group-1) was treated with Glass Ionomer cement and half of the patient (Group-2) was treated with Giomer restoration. The post-operative sensitivity discoloration, dislodgement of filling material and secondary caries formation were recorded. All the patients were assigned and the data were analyzed statistically by SPSS version 21. p-value &lt; 0.05 was taken as significant.&#x0D; Results: The study reveals 60% of the study population was within 41 to 50 years of age group (Group-1) and 62.5% were 51 to 60 years (Group-2) 45% in (Group-1) and 10% in (Group-2) had history of post filling sensitivity, 12% in (Group-1) and 5% in (Group-2) had discoloration after restoration, 2.5% had history of dislodgement of the filling in (Group-1), no history of dislodgement of the filling in (Group-2), 2.5% had history of secondary caries formation in (Group-1) and no history of Secondary caries formation in (Group-2).&#x0D; Conclusion: Patients were more approachable for Giomer restoration than Glass ionomer for the management of cervical caries over a period of 12 month.&#x0D; Chatt Maa Shi Hosp Med Coll J; Vol.20 (2); July 2021; Page 60-64

Bioactive self-etching sealant on newly erupted molars: A split-mouth clinical trial

ObjectivesThis randomized clinical trial compares retention, survival rate, and evolution of caries of newly erupted permanent molars sealed with bioactive self-etching sealants with pre-reacted glass ionomer (S-PRG). MethodsA split-mouth clinical trial was conducted with 56 permanent second molars in stages 2 and 3 of crown eruption; ICDAS (International Caries Detection and Assessment System) was between 0 and 2. The molars were randomized and blinded in relation to the side (right or left) that would receive the sealants; the conventional resin sealant (FS), Fluroshield (Dentsply), or bioactive self-etch sealant (BS), BeautiSealant with S-PRG (Shofu). The sealants were compared in terms of retention, quality of sealant remnant (anatomical shape, marginal adaptation, surface texture, and marginal discoloration), and development of caries by ICDAS after 1, 6, and 12 months. The Wilcoxon, x² of independence, Kaplan–Meier, and Mantel–Cox survival statistical tests were applied (α = 5%). ResultsThe total retention was higher for FS (57.1%) at all periods, and there was no difference in the quality of sealants at all periods. The ICDAS decreased after 6 (p = 0.025) and 12 months (p = 0.027) for both materials. Despite the lower retention of BS, the clinical quality of sealants over 12 months were similar. ConclusionTeeth sealed with BS presented higher sound teeth predominance (ICDAS 0) compared to FS sealant, even with a higher loss of material. Clinical relevanceEruption of permanent molars is a relevant period, and the prevention/management of initial caries is essential in these critical stages. Sealants can be an important prevention strategy. After 12 months of follow-up, there was a major failure of the bioactive sealant but without the development of caries lesions.

Evaluation of bonding performance and multi-ion release of S-PRG fillercontaining self-adhesive resin composite.

The bonding performance of a surface pre-reacted glass ionomer (S-PRG) filler-containing self-adhesive flowable resin composites to enamel and dentin were evaluated using a tensile bond test with thermal cycling. Also, the quantities of various ions released from the materials were measured using ICP atomic emission spectrometry and a fluoride ion electrode. The initial bond strengths of the materials were approximately 6 MPa, and decreased after thermal cycling. The S-PRG filler-containing self-adhesive flowable resin composites materials exhibited much higher ion release compared with the commercial self-adhesive flowable resin composite possibly due to different acidic monomers contained. It was suggested that the S-PRG filler containing self-adhesive flowable resin composites should be limited as a lining material or to restore small cavities in non-stress bearing areas.