Antibacterial activity of composite resin with glass-ionomer filler particles

The formation of cariogenic plaque to contemporary adhesive restorative materials: an in vitro study

The research exploiting the ability of dental materials to induce or prevent secondary caries (SC) development still seems inconclusive. Controlling bacterial adhesion by releasing bacteriostatic ions and improving the surface structure has been suggested to reduce the occurrence of SC. This paper analyses the impact of five distinctively composed dental materials on cariogenic biofilm formation. Forty-five specimens of three composites (CeramX Spectra ST, Admira Fusion, Beautifil II) and two glass-ionomers (Fuji II LC, Caredyne Restore), respectively, were incubated in bacterial suspension composed of Streptococcus mutans, Lactobacillus acidophilus, Streptococcus mitis, Streptococcus sanguinis, and Streptococcus salivarius at pH 7.0 and 5.5. Coverslips were used as a control. Adhered bacteria were collected after 2, 4, 6, 12, 24, and 48 h and analyzed using quantitative polymerase chain reaction (qPCR). Fluoride leakage was measured at each collection. The specimens' surface topography was assessed using interferometry. In the present study, surface roughness seemed to have a partial role in bacterial adhesion and biofilm formation, together with chemical composition of the materials tested. Despite differences in fluoride leakage, biofilm accumulation was similar across materials, but the number of adhered bacteria differed significantly. A release of other ions may also affect adhesion. These variations suggest that certain materials may be more prone to initiating secondary caries.

Transdentinal effects of S-PRG fillers on odontoblast-like cells

OBJECTIVES

To investigate the transdentinal effects of surface reaction-type pre-reacted glass-ionomer (S-PRG) fillers on odontoblast-like cells.

METHODS

An eluate of S-PRG fillers was obtained by dissolving the particles in distilled water (1:1 m/v). Dentin discs with similar permeability were mounted into artificial pulp chambers and MDPC-23 cells were seeded on their pulpal surface. The occlusal surface was treated with (n = 10): ultrapure water (negative control - NC), hydrogen peroxide (positive control - PC), S-PRG eluate exposure for 1 min (S-PRG 1 min), or S-PRG filler eluate exposure for 30 min (S-PRG 30 min). After 24 h, cell viability (alamarBlue) and morphology (SEM) were evaluated. The extract obtained from transdentinal diffusion was applied to MDPC-23 pre-cultured in plates for another 24 h to evaluate viability (alamarBlue, 1, 3, and 7 days), gene expression of Col1a1, Alpl, Dspp, and Dmp1 (RT-qPCR, 1 and 7 days), and mineralization (Alizarin Red, 7 days). Data were analyzed with ANOVA (α = 5 %).

RESULTS

While S-PRG 1 min did not differ from NC, S-PRG 30 min reduced 17.9 % viability of cells from discs. S-PRG treatments resulted in low cell detaching from dentin, and the remaining cells exhibited typical morphology or minor cytoplasmic contraction. S-PRG 30 min slightly increased cell viability (6 %) 1 day after contact with the extract. S-PRG treatments upregulated the expression of the investigated genes, especially after 1 day. S-PRG 30 min stimulated mineralization activity by 39.7 %.

CONCLUSIONS

S-PRG filler eluate does not cause transdentinal cytotoxicity on odontoblast-like cells, and long-term exposure can stimulate their dentinogenic-related mineralization activity.

SIGNIFICANCE

The transdentinal elution of ions from S-PRG fillers is not expected to be harmful to the dental pulp and may exert bioactive effects by inducing dentin matrix deposition through the metabolism of underlying odontoblasts.

Clinical Evaluation of Bioactive Injectable Resin Composite vs Conventional Nanohybrid Composite in Posterior Restorations: An 18-Month Randomized Controlled Clinical Trial

AIM

To evaluate the clinical performance of bioactive injectable resin composite vs nanohybrid resin composite in restoring carious posterior teeth.

MATERIALS AND METHODS

A total of 18 patients with 26 class I and II carious cavities were recruited. Teeth were divided into two groups (n = 13): group I: Bioactive injectable resin composite (Beautifil Flow Plus X F00) while group II: Nanohybrid resin composite (Tetric N-Ceram) and were restored according to the manufacturer's instructions. The restorations were evaluated using the modified USPHS criteria at baseline, 6, 12, and 18 months. Data were tabulated and statistically analyzed with a significant level set at (p ≤ 0.05). Using the Chi-squared test and Cochran's Q test. The survival rate was analyzed using the Kaplan-Meier and Log-rank tests.

RESULTS

Inter- and intra-group comparisons showed no statistically significant difference between bioactive injectable resin composite and nanohybrid resin composite at different time intervals in terms of anatomical form, marginal adaptation, secondary caries, marginal staining, postoperative sensitivity. Moreover, there was no statistically significant difference between both materials regarding the overall survival rate after 18 months.

CONCLUSIONS

The clinical performance of bioactive injectable resin composite and nanohybrid resin composite was similar and found to be clinically acceptable after 18 months of clinical use.

CLINICAL SIGNIFICANCE

Bioactive injectable resin composite can be used to restore occlusal anatomy as a nanohybrid resin composite in restoring posterior cavities with acceptable clinical performance.

TRIAL REGISTRATION

It was registered in (www.

CLINICALTRIALS

gov) database in June 2022, with identification number NCT05499494. How to cite this article: Elderiny HM, Khallaf YS, Akah MM, et al. Clinical Evaluation of Bioactive Injectable Resin Composite vs Conventional Nanohybrid Composite in Posterior Restorations: An 18-Month Randomized Controlled Clinical Trial. J Contemp Dent Pract 2024;25(8):794-802.

Comparative Evaluation of Two Esthetic Full Coronal Restorative Materials for Primary Incisors

Aim

This study was designed to compare the clinical efficacy of two esthetic restorative materials, nanoceramic (Magma NT®) and giomer (Beautifil II®), as full coronal restoration in primary maxillary incisors.

Materials and methods

A total of 15 patients aged 3-5 years presenting with mutilated primary maxillary incisors due to caries or trauma were selected for the study using randomized simple sampling. A total of 40 maxillary incisors were randomly divided into two equal groups, with 20 teeth in each group. Teeth in group I (GP I) were restored with nanoceramic (Magma NT®) and group II (GP II) with giomer (Beautifil II®). The full coronal restorations were done using strip crowns (3M ESPE). The restorations were evaluated for gross fracture, marginal integrity, and secondary caries according to modified Ryge's criteria [United States Public Health Service (USPHS)] at baseline (immediate postoperative), 3, 6, and 9 months. Parental satisfaction with each type of restoration was also evaluated using the Likert 5-point scale.

Results

The data obtained was statistically analyzed using the Chi-squared test, and the level of significance, that is, the p-value, was determined. The Chi-squared test showed no significant changes to all modified USPHS criteria for each material at baseline and 3-month evaluation period. The changes recorded were after a 3-month follow-up between the two materials; nanoceramic (Magma NT®) restoration demonstrated marginally better than giomer (Beautifil II®) in terms of gross fracture and marginal integrity; however, there was no statically significant difference between them (p > 0.05), while giomer (Beautifil II®) was better than nanoceramic in terms of secondary caries (p < 0.05). Parental satisfaction for both entities was comparable in terms of color and durability; however, they were cost-ineffective.

Conclusion

Nanoceramic restoration demonstrated better results in terms of gross fracture and marginal integrity, while giomer was better in terms of secondary caries.

Clinical significance

Nanoceramics and giomers can serve as an alternative to conventional restorative materials in primary anterior teeth because of their improved qualities.

How to cite this article

Dhaker KK, Tandon S, Rathore AS, et al. Comparative Evaluation of Two Esthetic Full Coronal Restorative Materials for Primary Incisors. Int J Clin Pediatr Dent 2024;17(3):321-327.

Dual-Stable-Isotope-Probed Raman microspectroscopy reveals the metabolic dynamic of Streptococcus mutans

Streptococcus mutans (S. mutans) is regarded as a cariogenic pathogen with the ability to metabolize sugars and form organic acids. However, its actual timely level of glucose consumption and cellular vitality in a polymicrobial culture system remains largely unknown. To tackle this challenge, we employed the S. mutans UA159 as a model and developed a dual-stable-isotope-probed Raman microspectroscopy method (Dual SIP-Raman) to simultaneously profile the general metabolic activity and glucose assimilative activity in situ. (i) Mono-SIP substrate feeding revealed that 0.5% 13C-glucose and 30% D2O were proper doses in the medium to obtain prominent and quantitative band shifts along with the 13C or D2O incorporation. In addition, the intensity of the 13C peak of phenylalanine (Phe) is proposed as a Raman-based biomarker for glucose utilization in a cell. (ii) The state of dual SIP substrate incorporation of 13C-glucose and D2O could be visualized by the corresponding spectral "red shifts" of Raman-scattered emissions; moreover, we also demonstrated that 13C/12C analysis was closely correlated with the C-D ratio. (iii) The application of the dual 13C-glucose and D2O feeding approach on a mock microbiota of S. mutans UA159 and C. albicans ATCC14053 revealed a stimulatory effect of fungus on both the glucose intake rate and general metabolic vitality of S. mutans UA159 (p < 0.05). Therefore, the 13C-glucose and D2O dual-feeding Raman Microspectroscopy approach is a valuable new tool for evaluating the glucose intake rate and general metabolic levels in situ, tracing the changing trend of the above metabolic activities, which is helpful to clarify the changes in the cariogenicity of oral microorganisms caused by the external environment at the single-cell level.

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

BACKGROUND

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 0.5 g of 4 different types of toothpastes: 5 wt % S-PRG filler, 1400 ppm F AmF (amine fluoride), 1500 ppm F NaF (sodium fluoride), and MFP (monofluorophosphate) containing toothpaste.

METHODS

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 2 min. At first, 1.0 and 0.5 g of 20 wt % S-PRG filler toothpastes were used to compare, then followed by 0.5 g of 0 (control), 1, and 5 wt % S-PRG toothpastes, respectively. The participants spat out once and rinsed with 15 mL of distilled water for 5 s. Saliva was collected for 3 min each at different time intervals of 0 (baseline), 5, 10, 15, 30, 60, 120, and 180 min 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 0.5 g of 5 wt % S-PRG filler toothpaste, followed by NaF, MFP, and AmF toothpastes.

RESULTS

Since there were no statistical differences between using 1.0 and 0.5 g of 20 wt % S-PRG toothpastes in salivary fluoride concentrations as well as the AUC value throughout the 180 min measurement, the volume was set as 0.5 g for the following studies. Concentrations of 5 and 20 wt % S-PRG toothpastes retained 0.09 ppm F or more in saliva even after 180 min. 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 (0.06 ppm F at 180 min) and the AUC value (24.6 ppm‧min), whereas 5 wt % S-PRG toothpaste (0.15 ppm F at 180 min, 92.3 ppm‧min) displayed retention on par with AmF toothpaste which appeared to result in higher values (0.17 ppm F at 180 min, 103 ppm‧min), compared to NaF toothpaste (0.12 ppm F at 180 min, 49.3 ppm‧min).

CONCLUSIONS

The salivary fluoride concentrations following toothbrushing with 0.5 g of 5 wt % S-PRG filler containing toothpaste showed retention similar to the best performing 1400 ppm F AmF toothpaste even 180 min after toothbrushing.

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

OBJECTIVE

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.

METHODS

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).

RESULTS

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 600 N 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).

SIGNIFICANCE

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.

Effect of laser bleaching, ultrasonic scaling and powered tooth brushing on surface roughness and bacterial adherence of class V composite restorations

Objective

To evaluate and compare the effect of diode laser assisted bleaching, ultrasonic scaling and powered tooth brushing on surface roughness and bacterial adherence on class V cavities restored with composites.

Materials and methods

A total of one hundred and twenty samples (40 samples each of Brilliant Everglow, Beautifil II and Heytec-N) were prepared in standardized stainless steel molds. The samples were further subdivided into four subgroups i.e. one control group (without any intervention) and three experimental groups - diode laser assisted bleaching, ultrasonic scaling and powered tooth brushing consisting of 10 sample each. Surface roughness was measured quantitatively with the help of 3D Optical Profilometer. For bacterial adherence analysis S. mutans strain (ATCC 25175) was cultured in BHI medium and samples were evaluated for the presence of viable bacteria using the Colony Forming Unit (CFU) count. Results obtained were then tabulated and subjected to statistical analysis.

Results

Diode laser bleaching caused a significant increase in surface roughness and bacterial adherence with lowest mean change exhibited by Heytec-N followed by Beautifil II and highest by Brilliant Everglow group. Similarly, Ultrasonic scaling increased the surface roughness of all the three tested samples with significant difference between the groups. Powered tooth brushing had no effect on the surface roughness and bacterial adherence of the tested composites.

Conclusion

Diode assisted laser bleaching and ultrasonic caused significantly higher surface roughness and bacterial adherence values for all the tested composites. It may therefore be recommended to do finishing and polishing of restorations after such procedures.

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 (BO₃^3-), fluoride (F^-), sodium (Na⁺), silicate (SiO₃^2-), 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.

Comparison of the shear bond strength in Giomer and resin-modified glass ionomer in class V lesions

Introduction

There are several cosmetic, restorative materials to restore non-carious Cervical Lesions (NCCLs). The aim of this study was to specify and compare the shear bond strength of Giomer and resin-modified glass ionomer in Class V lesions so that whether Giomer showed a better shear bond strength, it could be used instead of RMGI to restore NCCLs because of its better esthetic.

Method

ology: 20 maxillary and 20 mandibular intact premolars were collected. Each group of 20 samples was divided into two 10-tooth subgroups of A and B. A class V preparation was made on the buccal surface of the samples with 2*2*3 mm dimensions using a diamond bur. Also, the crossing path of the universal machine chisel was prepped with 2 mm depth up to incisal edge. For group A, after applying BeautiBond and curing it, Beautifil II Giomer was placed in nylon cylinders and the cylinders were placed in the middle cervical region and cured for 20 s. For group B, 1 spoon powder of Fuji II RMGI was mixed with two drops of its liquid and transported to nylon cylinders and placed in the middle cervical region, then cured for 20 s. The nylon cylinders were removed from all 40 samples. Then, all teeth were thermocycled and then tested using a universal machine with the force of 20 MPa and the speed of 1 mm/min until they fractured to assess their shear bond strength. The obtained data was analyzed using SPSS v.26. The significance level was considered 0.05.

Results

There was no significant difference between Giomer (4.97 ± 2.36) and the resin-modified glass ionomer (3.41 ± 2.71) groups as regards their shear strength (p = 0.059). Likewise, there was no significant difference in shear bond strength between Giomer and RMGI groups as regards jaw type (P = 0.326).

Conclusion

The paper suggests that Giomer and resin-modified glass ionomer groups did not differ significantly in terms of their shear bond strength and that both can be utilized to treat Class V lesions. Furthermore, there was no significant difference between the shear bond strength in terms of jaw type.

In vitro investigation of the impact of contemporary restorative materials on cariogenic bacteria counts and gene expression

OBJECTIVES

The aim of this study was to compare the antibacterial effect of different fluoride-containing and bioactive restorative materials, and their effect on the expression of specific biofilm-associated genes and therefore the caries process.

MATERIALS AND METHODS

The restorative materials utilized in this study included: 1. Filtek Z250, 2. Fuji II LC, 3. Beautifil II, 4. ACTIVA, and 5. Biodentine. For each material, disc-shaped specimens were prepared. The inhibitory effects against Streptococcus mutans, Lactobacillus acidophilus, and Leptotrichia shahii were tested. After incubation for 24 hours and 1 week, colony-forming units (CFUs) were enumerated. From the plates dedicated for biomass quantification and RNA purification, the target glucosyltransferase B (gtfB) and glucan-binding protein B (gbpB) genes were chosen for S. mutans. For L. acidophilus, a gene involved in exopolysaccharide synthesis (epsB) was chosen.

RESULTS

Except for Filtek Z250, all four materials showed statistically significant inhibitory effects on the biofilms of all three species. When biofilms were grown in the presence of the same four materials, the expression of S. mutans gtfB and gbpB genes, was significantly reduced. For L. acidophilus, the decrease in the expression of gtfB gene in the presence of ACTIVA was the highest change seen. The epsB gene expression also decreased. Compared to fluoride-releasing materials, bioactive materials had more inhibitory effect against L. acidophilus, both at 24 hours and 1 week.

CONCLUSIONS

Both fluoride releasing and bioactive materials exhibited a significant inhibitory effect on the biofilm growth. The expression of the targeted biofilm-associated genes was downregulated by both material groups.

CLINICAL SIGNIFICANCE

The findings from this study give insight into the antibacterial effect of fluoride-containing and bioactive materials which would help to reduce the chances for secondary caries and therefore increase the lifetime of dental restorations placed for patients.

Effects of a co-stimulation with S-PRG filler eluate and muramyl dipeptide (MDP) on matrix metalloproteinase-1 production by human dental pulp fibroblast-like cells

The present study investigated the effects of a co-stimulation with surface reaction-type pre-reacted glass-ionomer (S-PRG) filler eluate and muramyl dipeptide (MDP) on matrix metalloproteinase (MMP)-1 production by human dental pulp fibroblast-like cells (hDPFs). S-PRG filler eluate contains 6 ions (F, Na, Al, B, Sr, and Si) released from S-PRG filler. Each S-PRG filler eluate and MDP stimulation enhanced MMP-1 production by hDPFs. The co-stimulation with S-PRG filler eluate and MDP enhanced MMP-1 production more than the MDP stimulation alone. A similar stimulation induced the phosphorylation of ERK 1/2. The increased secretion of MMP-1 and enhanced phosphorylation of ERK 1/2 by the co-stimulation with S-PRG filler eluate and MDP were suppressed by the selective and potent CaSR antagonist NPS 2143. Since strontium binds to CaSR, these results suggest that the enhanced production of MMP-1 by the co-stimulation with S-PRG filler eluate and MDP was due to the effects of strontium.

The inhibitory effects of various ions released from S-PRG fillers on dentin protease activity

This study investigates the effect of ions released from S-PRG fillers on host-derived enzymatic degradation of dentin collagen matrices. Dentin beams (n=80) were demineralized and distributed to eight groups following baseline dry mass and total MMP activity assessments. Each group treated with boron, fluoride, sodium, silicone, strontium, aluminium, or S-PRG eluate solutions for 5 min. Untreated beams served as control. After pre-treatment, MMP activity was reassessed, beams were incubated in complete medium for 1 week, dry mass was reassessed. Incubation media were analyzed for MMP and cathepsin-K-mediated degradation fragments. Data were analyzed with ANOVA and Tukey's test. All pretreatment groups showed significant reduction in total MMP activity (p<0.05) that was sustainable after incubation in all groups except for boron and silicone groups (p<0.05). Cathepsin-K activity did not differ between control or treatment groups. The results indicated that ions released from S-PRG fillers have the potential to partly inhibit MMP-mediated endogenous enzymatic activity.

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.

Clinical Evaluation of Low-shrinkage Bioactive Material Giomer Versus Nanohybrid Resin Composite Restorations: A Two-year Prospective Controlled Clinical Trial

This study evaluated the clinical performance of low-shrinkage bioactive resin composite compared with a conventional nanohybrid resin composite. A total of 35 patients (18 males, 17 females; mean age: 29±9 years old) received, randomly, 35 pairs of fillings restored with either low-shrinkage bioactive material employing Giomer filler technology (Beautifil II LS, Shofu Inc, Kyoto, Japan) or conventional nanohybrid resin composite (Clearfil Majesty Posterior, Kuraray, Japan) in Class I and Class II cavities. Two operators made all the restorations using the corresponding adhesive resins: FL-Bond II (Shofu Inc) and Clearfil SE Bond (Kuraray), according to each manufacturer's instructions. Two calibrated operators evaluated the restorations two weeks after placement (baseline), at six months, and at one and two years using FDI criteria (Scores 1-5). Data were analyzed using the McNemar test (α=0.05). Mean observation time was 27.4 ± 4.1 months (min=20.8; max=33.7). In both groups, according to FDI criteria, the restorations were mostly rated with best scores (Score 1 or 2) for biological, functional, and optical parameters. For one filling in the group restored with nanohybrid resin composite, a small and localized secondary caries lesion was observed and monitored at the one- and two-year follow-ups. One restoration in the low-shrinkage Giomer restorative group was accepted as a failure due to retention loss. Over the two-year follow-up, both the Giomer and the nanohybrid resin composite restorations' performance was clinically acceptable.

Prospects on Tuning Bioactive and Antimicrobial Denture Base Resin Materials: A Narrative Review

Denture base resin (DBR) materials are used in dentistry in constructing removable dentures and implant-supported prostheses. A plethora of evidence has demonstrated that DBR materials are associated with a high risk of denture stomatitis, a clinical complication where the soft oral tissues underneath the resin-based material are inflamed. The prevalence of denture stomatitis among denture wearers is high worldwide. Plaque accumulation and the infiltration of oral microbes into DBRs are among the main risk factors for denture stomatitis. The attachment of fungal species, mainly Candida albicans, to DBRs can irritate the underneath soft tissues, leading to the onset of the disease. As a result, several attempts were achieved to functionalize antimicrobial compounds and particles into DBRs to prevent microbial attachment. This review article explored the advanced approaches in designing bioactive and antimicrobial DBR materials. It was reported that using monomer mixtures, quaternary ammonium compounds (QACs), and organic and inorganic particles can suppress the growth of denture stomatitis-related pathogens. This paper also highlighted the importance of characterizing bioactive DBRs to be mechanically and physically sustainable. Future directions may implement a clinical translational model to attempt these materials inside the oral cavity.

Effect of Self-cured Universal Adhesive System on Shear Bond Strengths of Conventional and Bulk-fill Composites

ABSTRACT Effect of Self-cured Universal Adhesive System on Shear Bond Strengths of Conventional and Bulk-fill Composites Ihsan HUBBEZOGLU1, Serra KUTLU2, Ayşegül KARAARSLAN3 1 Sivas Cumhuriyet University, Faculty of Dentistry, Department of Restorative Dentistry, Sivas, Turkey 2 Niğde Oral and Dental Center, Niğde, Turkey 3 Sivas Oral and Dental Center, Sivas, Turkey Aim: The aim of this study was to investigate the effect of self-cured universal adhesive system on shear bond strengths of two conventional and two bulk-fill composites to dentin. Material-method: In this study, four groups were formed: two conventional condensable composites[G-aenial posterior(GC), Palfique Estelite Paste(Tokuyama)], and two bulk-fill composites[Estelite Bulk Fill Flow(Tokuyama), Beautifil Bulk Restorative(Shofu)]. Each group was divided into two subgroups; G-premio bond (control group) ve self-cured Universal Bond (Tokuyama). 32 human third molar human teeth were prepared to expose dentin surfaces. After the preparation, the teeth were randomly divided into 4 main groups and 2 subgroups (n = 8), composites were applied to the surfaces with the help of cylindrical silicone transparent mold with a diameter of 4 mm and a height of 4 mm. Results: In this study, when both adhesive systems are evaluated; the highest shear bond strength value was Palfique Estelite Paste, while the lowest shear bond strength value was Beautifil Bulk Restorative. While the difference between Palfique Estelite Paste and Estelite bulk-fill flow, Beautifil Bulk Restorative was found to be statistically significant (p&lt;0.05), the difference with G-aenial posterior was not significant (p&gt;0.05). The difference between G-aenial posterior and Beautifil Bulk Restorative was found to be statistically significant (p&lt;0.05). When adhesive systems are compared; G-premio bond was found to be higher in all composite groups compared to self-cured Universal Bond, but the difference between them was statistically insignificant (p&gt;0.05). Conclusion: While conventional composites exhibited high shear bond strengths, bulk-fill composites showed values close to these values. The self-cured adhesive system we used showed near values of shear bond strength to the light-polymerized adhesive system. In terms of bond strength self-cured adhesive systems can be recommended for use in areas where light can be difficult to reach in clinical applications. It is advisable to use self-cured adhesive systems for use in areas where light can be difficult to access in clinical applications. Keywords: shear bond strength, bulk-fill composites, self-cured adhesive systems ÖZET Geleneksel ve Bulk-fill Kompozitlerin Makaslama Bağlanma Dayanımlarına Işıksız Adeziv Sistemin Etkisi Amaç: Çalışmamızın amacı, iki geleneksel ve iki bulk-fill kompozitlerin dentine makaslama bağlanma dayanımlarına ışıksız adeziv sistemin etkisinin incelenmesidir. Materyal-metod: Çalışmamızda iki geleneksel kondanse edilebilen kompozit [G-aenial posterior(GC), Palfique Estelite Paste(Tokuyama)], kütlesel yerleştirilebilen iki bulk-fill kompozit [Estelite Bulk Fill Flow(Tokuyama), Beautifil Bulk Restorative(Shofu)] olarak 4 grup oluşturuldu. Her grup iki alt gruba ayrıldı; G-premio bond (Kontrol grubu) ve ışıksız Universal Bond (Tokuyama). 32 adet insan üçüncü molar insan dişi dentin yüzeyleri açığa çıkacak şekilde prepare edildi. Preparasyonun ardından dişler rastgele 4 ana, 2 alt gruba ayrıldı(n=8), yüzeylere 4 mm çapında ve 4 mm yüksekliğindeki silindirik silikon şeffaf kalıp yardımıyla kompozitler uygulandı. Tüm grupların makaslama bağlanma değerleri universal test cihazında ölçüldü, kuvvet birimi ise “newton” (=N) olarak kalibre edildi. Bulgular: Çalışmamızda her iki adeziv sistem kullanıldığında da, en yüksek makaslama bağlanma dayanım değerini Estelite Paste gösterirken, en düşük makaslama bağlanma dayanım değerini Beautifil Bulk Restorative göstermiştir. Estelite pasteile; Bulk-fill flow ve Beautifil Bulk Restorative arasındaki fark istatistiksel olarak anlamlı bulunurken (P&lt;0,05), G-aenial posterior ile arasındaki fark anlamsız bulunmuştur(P&gt;0,05). G-aenial posterior ile Beautifil Bulk Restorative arasındaki fark istatistiksel olarak önemli bulunmuştur(P&lt;0,05). Adeziv sistemler kıyaslandığında; tüm kompozit gruplarında G-premio bond, Işıksız Universal Bonda göre daha yüksek bağlanma sağlarken, aralarındaki fark istatistiksel olarak anlamsız bulunmuştur (P&gt;0,05). Sonuçlar: Geleneksel kompozitler, yüksek makaslama bağlanma dayanımları sergilerken, bulkfill kompozitler bu değerlere yakın değerler göstermiştir. Kullandığımız ışıksız adeziv sistem, ışıkla polimerize edilen adeziv sisteme yakın bağlanma değerleri sergilemiştir. Işıksız adeziv sistemler, klinik kullanımlarda ışığın zor olabileceği bölgelerde bağlanma dayanımı açısından kullanılması önerilebilir. Anahtar kelimeler: makaslama bağlanma dayanımı, bulkfill kompozitler, ışıksız adezivler

Five-year clinical performance of two fluoride-releasing giomer resin materials in occlusal restorations

OBJECTIVE

To evaluate and compare the clinical performance of two nano-hybrid giomer restorative composite materials after 5 years.

MATERIALS AND METHODS

Forty-four pairs of restorations (total n = 88) of a flowable giomer (Beautifil Flow Plus F00; Shofu Inc., Kyoto, Japan) and a conventional nano-hybrid giomer restorative material (Beautifil II; Shofu Inc.) were placed in Class I cavities after the application of a dentin adhesive (FL-Bond II; Shofu Inc.) and a flowable liner (Beautifil Flow Plus F03; Shofu Inc). After 5 years, 32 pairs of restorations were assessed using the modified United States Public Health Service criteria. Both tested materials were compared using Fisher's exact test and each tested clinical criterion for each material was analyzed separately with respect to different follow-up periods using Friedman's test (a = 0.05).

RESULTS

None of the restorations showed complete retention loss, post-operative sensitivity, secondary caries or color change. There were no significant changes to any of the clinical criteria for each material during the 5-year evaluation period (p > 0.05) and no significant differences between the two materials in all clinical parameters after 5 years (p > 0.05).

CONCLUSIONS

Five-year clinical performance of both two nano-hybrid giomer restorative materials was comparably acceptable and not significantly different for any of the parameters evaluated.

CLINICAL SIGNIFICANCE

Nano-hybrid giomer-based materials are clinically acceptable for the restoration of occlusal cavities as they demonstrate excellent performance after 5 years.

Effect of brushing on surface roughness, fluoride release, and biofilm formation with different tooth-colored materials

Background/purpose

Tooth brushing, material mechanical ageing procedure, is the most effective way in removing biofilm. The purpose of this study was to investigate the surface roughness, fluoride-release, and S. mutans biofilm formation on various tooth-colored restorative materials before and after brushing.

Materials and methods

Discs of materials, a nanocomposite (Filtek Z350XT; CO), a giomer (Beautifil II; GIOMER), a resin-modified glass-ionomer material (Fuji II LC; RMGI), and a conventional glass-ionomer material (Fuji IX GP Extra; GI), were prepared, polished with abrasive discs (SofLex), and divided into brushed and not brushed groups. The surface roughness of specimens was observed using a contact profilometer, fluoride-release was measured using a fluoride-specific ion electrode, and S. mutans biofilm formation, biovolume and live/dead cells, was observed under a confocal laser scanning microscope.

Results

Higher roughness was observed on GI and RMGI than on CO and GIOMER. Brushing had no effect on the roughness. The fluoride-release of GI and RMGI was higher than that of GIOMER. The fluoride-release decreased after brushing in all materials. The biovolume of S. mutans was not significantly different between GIOMER, RMGI and GI, while CO showed the highest. Brushing resulted in a higher biovolume for all materials, except CO, which showed no change. After brushing, all the tested materials demonstrated identical biovolumes. There were no significant differences in live/dead cells among all groups.

Conclusion

Brushing demonstrated a negative effect on the fluoride-release and biovolume of S. mutans biofilms for all tested materials except nanocomposites.

S-PRG-based toothpastes compared to NaF toothpaste and NaF varnish on dentin permeability in vitro

Objectives

To analyze the effect of 5 toothpastes containing different percentages of S-PRG fillers compared to NaF toothpaste and NaF varnish on the dentin hydraulic conductance (Lp).

Methodology

Dentin disks (1.0±0.2 mm thickness) were cut from third molars, and their Lp values were evaluated using Flodec. The specimens were allocated into 7 groups (n=8). The minimum (smear layer) and the maximum (after acid etching) Lp values were recorded. Lp was also assessed after treatment with either a 0wt.%, 1wt.%, 5wt.%, 20wt.%, or 30wt.% S-PRG toothpaste, a NaF toothpaste, or a NaF varnish. Toothpastes were applied by brushing for 15 s, allowing it to settle for 1 min, and rinsing with deionized water. The NaF varnish was applied for 4 min and was removed with a probe. Specimens were exposed to citric acid (6%, pH 2.1, 1 min) and their final Lp was recorded. The pH of all products was recorded (n=3) and specimens from each group were analyzed by Laser Scanning Confocal Microscopy (LSCM). Data were subjected to 2-way repeated measures ANOVA and post-hoc Bonferroni (a=0.05).

Results

The highest Lp reduction was noticed for the 5wt.% S-PRG toothpaste, NaF toothpaste, and NaF varnish. However, the toothpastes containing 5wt.%, 20wt.%, and 30wt.% of S-PRG were similar to all toothpastes but differed from the NaF varnish. After erosion, all groups retrieved their maximum Lp values, except for the NaF varnish. The LSCM evidenced deposits on the surface of specimens treated with 5%, 20%, and 30% S-PRG-based toothpastes and NaF toothpaste. Even more deposits were observed for the NaF varnish. After the erosive challenge, the deposits were diminished in all groups.

Conclusion

Toothpastes containing 5wt.%, 20wt.%, and 30wt.% of S-PRG fillers behaved similarly to a conventional NaF toothpaste, even after an erosive challenge. The NaF varnish promoted better reduction of the Lp, but its effect was also diminished after erosion.

Comparative evaluation of antibacterial efficacy different bioactive smart composites: An in vitro study

BACKGROUND

Composites are the widely used restorative materials, and over the year, newer restorative composites have been introduced to eliminate the drawbacks of previous ones. The recent advance in restorative dentistry is bioactive restorative materials. However, bacterial plaque formation on these restorations is the primary reason for secondary caries.

AIMS AND OBJECTIVES

The purpose of this study was to do the comparative evaluation of bioactive restorative composites (Beautifil Flow Plus, Activa BioACTIVE, and Filtek Z250 XT as control) for their antibacterial efficacy under in vitro conditions.

MATERIALS AND METHOD

Thirty material blocks were used for this evaluation. Antibacterial efficacy was checked against Streptococcus mutans and observed under confocal laser scanning microscopy.

RESULTS

The results showed that Activa BioACTIVE shows maximum number of dead bacteria on the material surface compared to other groups.

CONCLUSION

It can be concluded as it has maximum antibacterial efficacy among tested materials.

Effects of S-PRG filler eluate on MMP-1 and MMP-3 secretion by human gingival fibroblasts

The aim of this study was to investigate the effects of surface reaction-type pre-reacted glass-ionomer (S-PRG) filler eluate on Matrix metalloproteinase (MMP)-1 and MMP-3 secretion by human gingival fibroblasts (HGF). The S-PRG filler eluate contains 6 ions (F, Na, Al, B, Sr and Si) released from the S-PRG filler. The S-PRG filler eluate stimulation induced a slight secretion of MMP-1 and MMP-3 by HGF. It also enhanced the phosphorylation of p38 and ERK. The increase in MMP-1 and MMP-3 secretion by the inflammatory cytokine TNF-α was suppressed by the S-PRG filler eluate. TNF-α-induced increases in the phosphorylation of ERK were slightly enhanced by S-PRG filler eluate. These findings may prompt the development of new therapeutic agents for oral inflammation with materials composed of S-PRG filler eluate.

Evaluation of the anti-inflammatory effects of surface-reaction-type pre-reacted glass-ionomer filler containing root canal sealer in lipopolysaccharide-stimulated RAW264.7 macrophages

A prototype surface-reaction-type pre-reacted glass-ionomer (S-PRG) filler containing root canal sealer (S-PRG sealer) exhibits bioactive potential by releasing multiple ions. This study explored the suppressive effects and modes of action of S-PRG sealer extracts on proinflammatory cytokine expression in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Expression of proinflammatory cytokines was evaluated by RT-qPCR and ELISA. Expression of phosphorylated nuclear factor-kappa B (p-NF-kB) p65 was evaluated by western blotting. S-PRG sealer extracts significantly downregulated mRNA expression levels of interleukin (IL)-1α, IL-6, and TNF-α in LPS-stimulated RAW264.7 cells; the extracts also reduced the levels of IL-6 protein and p-NF-kB. In order to verify that Zn²⁺ was responsible for downregulation of proinflammatory cytokine expression, N,N,N',N'-tetrakis(2-pyridylmethyl) ethylenediamine (TPEN) was used as a heavy metal chelator with strong affinity for Zn²⁺. These effects were mitigated by TPEN. The application of ZnCl₂ reproduced the actions of S-PRG sealer extracts. These data suggest that S-PRG sealer has anti-inflammatory potential involving heavy metal ions such as Zn²⁺.

Dentin anti-demineralization potential of surface reaction-type pre-reacted glass-ionomer filler containing self-adhesive resin cement

OBJECTIVE

To investigate the anti-demineralization potential of a newly developed surface reaction-type pre-reacted glass-ionomer (S-PRG) filler containing self-adhesive resin cement against acidic attacks on the dentin surface.

MATERIALS AND METHODS

A total of 32 bovine teeth were used. Cavities were prepared on crown dentin slaps and filled with three self-adhesive resin cement: (1) S-PRG-based cement, (2) Si-based cement, and (3) RelyX cement. Specimens were then subjected to pH cycling for 28 days, and the depth of demineralization was assessed using swept-source optical coherence tomography (SS-OCT) after 7, 14, 21, and 28 days. Sixty-four root dentin blocks were divided into four groups and then subjected to a pH cycling procedure with the aforementioned three material blocks and one negative control. The mineral loss was observed using transverse microradiography (TMR), and the surface microhardness (SMH) test was conducted to investigate the mechanical properties of treated dentin surfaces.

RESULTS

The depth of demineralization for the S-PRG-based cement was significantly lower than that of the Si-based cement after 7, 21, and 28 days. Conversely, the RelyX cement was not significantly different from the Si-based cement after 7, 14, and 21 days (p < 0.05). Regarding the TMR and SMH test, the S-PRG-based cement showed the least mineral loss with the highest resistance to acidic challenge.

CONCLUSION

The S-PRG filler containing resin cement can reduce mineral loss and promote remineralization of dentin substrate and has the potential to preserve dentin integrity and resist acidic attack. Clinical significance Self-adhesive resin cement containing S-PRG fillers maintained the surface integrity of dentin after exposure to 28 days of acidic challenge with a significant anti-demineralization effect.

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.

Evaluation of antimicrobial properties of nano-silver particles used in orthodontics fixed retainer composites: an experimental in-vitro study

Background. The present study evaluated the antimicrobial efficacy of composite resins containing nano-silver (NAg) particles used in fixed orthodontic retainers. Methods. Nano-composite resin samples with 1%, 2%, and 5% concentrations of NAg were prepared. The antimicrobial effectiveness of NAg was assessed against Streptococcus mutans, Streptococcus sanguis, and Lactobacillus acidophilus by the biofilm inhibition test (three-day-old biofilms), eluted components test (on days 3, 15, and 30), and disk-diffusion agar test after 48 hours. Measures of central tendency and index of dispersion were used to determine colony-forming units. Kruskal-Wallis test and Mann-Whitney U test were also used. Results. The biofilm inhibition test showed a significant decrease in the colonies of S. mutans (87.64%, 96.47%, and 99.76% decrease), S. sanguis (98.13%, 99.47%, and 99.93% decrease), and L. acidophilus (81.59%, 90.90%, and 99.61% decrease) at 1%, 2%, and 5% concentrations of Nag, respectively, compared to the control groups. The colony-forming unit (CFU)/mL of tested microorganisms continuously decreased with increased NAg concentration. In the eluted component test, no significant differences were noted in the 3rd, 15th, and 30th days between the different concentrations of Nag-containing composite resin disks and control samples. According to the disk-diffusion agar test, there was no growth inhibition zone for the composite resin disks containing 1% and 2% concentrations of Nag. However, the growth inhibition zone was seen with a 5% concentration, with a diameter of 9.5±0.71 mm for S. mutans, 8.5±0.71 mm for S. sanguis, and 8±1.41 for L. acidophilus. Conclusion. The incorporation of NAg into composite resins has antibacterial effects, possibly preventing dental caries around fixed orthodontic retainers.

The effect of surface pre-reacted glass-ionomer filler eluate on dental pulp cells and mineral deposition on dentin: In vitro study

The effects of surface pre-reacted glass-ionomer (S-PRG) filler on pulpal cells and on the composition of dentinal deposits were investigated. Proliferation (CCK-8), cytotoxicity (LDH), and differentiation activity (ALP) tests, along with cell morphology observations, were conducted at 6 and 24 h after treatment of pulpal cells with different S-PRG filler eluate concentrations. Dentinal surfaces were immersed in deionized water or S-PRG filler eluate followed by immersion in deionized water or simulated body fluid and observed under scanning electron microscope and elemental analysis using energy dispersive x-ray spectrometer. At 24 h, there were significant differences in CCK-8 and ALP activity values between the groups in a concentration-dependent manner. LDH test data were not significantly different among the groups. Cell morphology was not altered at either exposure time. However, decreased cellular density was observed with the highest eluate concentration. Crystalline deposits and occluded dentinal tubules were observed in samples immersed in S-PRG filler with a later immersion in simulated body fluid, which also showed higher concentrations of certain ions compared to surfaces that were not initially treated with S-PRG filler. The lowest two eluate concentrations did not show significant toxicity. S-PRG enhanced the effect of simulated body fluid in the formation of mineral deposits.

Evaluation of surface characteristic and bacterial adhesion of low-shrinkage resin composites

This study aimed to examine the surface characteristics of low shrinkage composites and adhesion of Streptococcus mutans and Streptococcus mitis to these materials. Control material (glass) and three low shrinkage composites (Charisma Diamond, Kalore GC, Beatiful II LS) were used. After polishing procedure was applied to composite specimens, surface roughness (SR), surface free energy (SFE), and contact angle measurements were performed. Surfaces of composite were analyzed using scanning electron microscope and energy-dispersive X-ray spectroscopy. After pellicle formation with artificial saliva, S. mutans and S. mitis biofilms were incubated in 5% CO₂ for 24 h at 37°C and were analyzed using confocal laser scanning microscopy. The lowest SR and highest SFE values were found in the control group. While the contact angle of control was statistically lower than composites, statistically difference was not found between composite groups. S. mutans adhesion of composites was significantly lower than control group, but there was no significant difference between composites. S. mitis adhesion of all groups was statistically similar. SR did not affect the S. mutans and S. mitis adhesion. Less adherence of S. mutans to low shrinkage composites was associated with low SFE and high contact angle values. Even though the highest SR was observed in the Charisma Diamond, no difference was found between the composites in terms of bacterial adhesion.

[Evaluation of wear property of Giomer and universal composite in vivo]

OBJECTIVE

To observe the wear performance of Giomer and universal composite for posterior restorations by 3D laser scan method, in order to guide the material selection in clinic.

METHODS

In this study, 48 patients (108 teeth) were selected according to the inclusion and exclusion criteria. All the patients in need of a minimum of 2 Class Ⅰ and/or Class Ⅱ restorations were invited to join the study. The teeth were restored with Giomer (Beautifil Ⅱ, BF) and universal composite (Filtek Z350, Z350) randomly. The restorations were evaluated at baseline and after 6-, 18-, 48-month using the modified United States Public Health Service (USPHS) criteria for clinical performance. The in vivo images and gypsum replicas were taken at each recall. A 3D-laser scanner and Geomagic Studio 12 were used to analyze the wear depth quantitatively. Statistical analysis was performed with SPSS 20.0.

RESULTS

After 4 years, 89.6% patients were recalled. The survival rate of both materials was 95.8% (Kaplan-Meier survival analysis). Seven restorations of the two materials failed due to loss of restoration, bulk fracture, secondary caries and pulp necrosis. The wear patterns of restorations were divided into 2 classes. Pattern Ⅰ: occlusal contact areas showed the deepest and fastest wear depth; pattern Ⅱ: the wear depth was slow and uniform. Both materials showed a rapid wear in the first 6 months. Then the wear rate was decreased. The occlusal wear depth after 4 years were (58±22) μm and (54±16) μm for BF group and Z350 group respectively, which were in accordance with the American Dental Association (ADA) guidelines (wear depth for 3 years < 100 μm). No significant differences (P>0.05) were observed between the two groups. Regarding the restorations with wear pattern Ⅰ, the wear depth of BF group was higher than Z350 group at 6- and 48-month (P < 0.05), while there was no significant difference between restorations with wear pattern Ⅱ (P>0.05).

CONCLUSION

Within the limitation of the study, after 4 years, the survival rate and wear resistance of Giomer met ADA guidelines for tooth-colored restorative materials for posterior teeth. When the two materials were applied in occlusal contact areas, wear resistance of Giomer was slightly lower than universal composite resin. No significant difference was found when they were applied in none of the occlusal contact areas.

Efficacy of S-PRG filler containing varnishes on enamel demineralization prevention

This study evaluated the efficacy of S-PRG vanishes on preventing enamel demineralization. Bovine enamel specimens were obtained, polished and the baseline Knoop microhardness was evaluated. Specimens were stratified into six groups (n = 15), according to the varnish applied: S10—experimental varnish containing 10% of S-PRG fillers, S20—20% of S-PRG fillers, S30—30% of S-PRG fillers; S40—40% of S-PRG fillers; PC (positive control)—5% of NaF; NC (negative control)—no treatment was performed. Half of enamel surfaces were protected to work as a control and varnishes were applied over the unprotected area. A demineralizing pH-cycling was performed, and surface and cross-sectional microhardness were measured. The percentage of microhardness of the treated area was calculated comparing with the untreated area. Statistical analysis was performed by one-way ANOVA and Tukey’s test (p = 5%). All experimental S-PRG varnishes protected against demineralization in relation to no treatment, but S40 was the most effective on the surface. For all depths, S30 and S40 were superior in enamel demineralization prevention than other S-PRG filler concentrations and 5% NaF. It was concluded that S-RPG filler containing varnishes were effective to prevent enamel demineralization. The higher concentrated products were more effective than 5% sodium fluoride on surface demineralization prevention.

Efficacy of S-PRG filler containing varnishes on enamel demineralization prevention

This study evaluated the efficacy of S-PRG vanishes on preventing enamel demineralization. Bovine enamel specimens were obtained, polished and the baseline Knoop microhardness was evaluated. Specimens were stratified into six groups (n = 15), according to the varnish applied: S10—experimental varnish containing 10% of S-PRG fillers, S20—20% of S-PRG fillers, S30—30% of S-PRG fillers; S40—40% of S-PRG fillers; PC (positive control)—5% of NaF; NC (negative control)—no treatment was performed. Half of enamel surfaces were protected to work as a control and varnishes were applied over the unprotected area. A demineralizing pH-cycling was performed, and surface and cross-sectional microhardness were measured. The percentage of microhardness of the treated area was calculated comparing with the untreated area. Statistical analysis was performed by one-way ANOVA and Tukey’s test (p = 5%). All experimental S-PRG varnishes protected against demineralization in relation to no treatment, but S40 was the most effective on the surface. For all depths, S30 and S40 were superior in enamel demineralization prevention than other S-PRG filler concentrations and 5% NaF. It was concluded that S-RPG filler containing varnishes were effective to prevent enamel demineralization. The higher concentrated products were more effective than 5% sodium fluoride on surface demineralization prevention.

Effects of a surface prereacted glass-ionomer filler coating material on biofilm formation and inhibition of dentin demineralization

OBJECTIVES

This study investigated the ability of a surface prereacted glass-ionomer (S-PRG) coating material to inhibit the biofilm formation and demineralization of dentin.

METHODS AND MATERIALS

Dentin specimens were randomly divided into three groups: (1) no coating (control), (2) S-PRG filler-containing coat, and (3) a nonS-PRG filler-containing coat. Streptococcus mutans biofilms were grown on the dentin surfaces in a microcosm for 20 h. Then, the quantity of bacteria and water-insoluble glucan in the retained biofilm on the dentin surface were measured. Regarding demineralization inhibition test, specimens were demineralized for 5 days then sectioned into halves and observed under confocal laser scanning microscope (CLSM). One-way ANOVA and Tukey's HSD were used for statistical analysis.

RESULTS

The estimated mean surface roughness for specimens in the S-PRG group was statistically significantly higher than the estimates for both the nonS-PRG and the control group specimens. The quantity of bacteria and water-insoluble glucan/mm² revealed that the S-PRG group prevented biofilm formation and bacterial adhesion to the dentin surface compared with the control and nonS-PRG groups. The S-PRG group recorded the highest acid-resistance ability with no surface loss.

CONCLUSION

Application of S-PRG barrier coat on dentin surfaces can inhibit biofilm formation as well as protecting the dentin surface against demineralization.

CLINICAL SIGNIFICANCE

Coating material containing S-PRG fillers might be used for caries prevention, through inhibiting biofilm formation, enhancing mineralization, and reducing acidic attack by cariogenic bacteria.

Optimal dilutions of S-PRG filler eluate for experiments on human gingival fibroblasts in vitro

The present study attempted to identify the optimal dilution at which at which the effects of surface reaction-type pre-reacted glass-ionomer (S-PRG) filler eluate on human gingival fibroblasts (HGF) may be safely examined in vitro. S-PRG filler is a material that releases six ions and exerts strong caries-suppressing effects. We prepared S-PRG filler eluate in which S-PRG filler and α-MEM were mixed as a medium for HGF. This eluate contains six ions that are released from S-PRG filler. All cells died in proliferation experiments on HGF using S-PRG filler eluate, which demonstrated that unless S-PRG filler eluate was diluted, the ion concentration was strongly cytotoxic. S-PRG filler eluate diluted by 1/100 or more with the addition of 2% or more of FBS was safe for use. We herein successfully established the optimal dilution of S-PRG filler eluate at which HGF may be safely examined in vitro.

Silver nanoparticles in orthodontics, a new alternative in bacterial inhibition: in vitro study

BACKGROUND

The purpose of the study is to assess the antiadherent and antibacterial properties of surface-modified different orthodontic brackets with silver nanoparticles against Streptococcus mutans and Streptococcus sobrinus, using radiomarker.

METHODS

In this study evaluated quantitatively the adherence of Streptococci to orthodontic brackets, 300 samples of orthodontic brackets were selected and classified in to 10 groups as follow: GIn (InVu-Roth), GIIn (System-AlexanderLTS), GIIIn (Gemini-Roth), GIVn (NuEdge-Roth), GVn (Radiance plus-Roth), GVI (InVu-Roth), GVII (System-AlexanderLTS), GVIII (Gemini-Roth), GIX (NuEdge-Roth), GX (Radiance plus-Roth). All the samples were sonicated and Streptococci were cultivated by gender. A radioactive marker (3H) was used to codify the bacteria and measure them. After that, the brackets were submerged in a radiolabelled solution, and the radiation was measured. The statistical analysis was calculated with ANOVA test (Sheffè post hoc).

RESULTS

The results showed significant differences were found among the groups. GIIIn shown the lowest scores for both bacteria; in contrast, GIX for Streptococcus mutans and GVI for Streptococcus sobrinus were the highest values.

CONCLUSIONS

Surface modification of orthodontic brackets with silver nanoparticles can be used to prevent the accumulation of dental plaque and the development of dental caries during orthodontic treatment.

The effect of ionizing radiation on properties of fluoride-releasing restorative materials

The purpose of this study was to evaluate the effect of ionizing radiation from high energy X-ray on fluoride release, surface roughness, flexural strength, and surface chemical composition of the materials. The study groups comprised five different restorative materials: Beautifil II, GCP Glass Fill, Amalgomer CR, Zirconomer, and Fuji IX GP. Twenty disk-shaped specimens (8x2 mm) for fluoride release and 20 bar-shaped specimens (25 x 2x 2 mm) for flexural strength were prepared from each material. Each material group was divided into two subgroups: irradiated (IR) and non-irradiated (Non-IR). The specimens from IR groups were irradiated with 1.8 Gy/day for 39 days (total IR = 70.2 Gy). The amount of fluoride released into deionized water was measured using a fluoride ion-selective electrode and ion analyzer after 24 hours and on days 2, 3, 7, 15, 21, 28, 35, and 39 (n = 10). The flexural strength was evaluated using the three-point bending test (n = 10). After the period of measurement of fluoride release, seven specimens (n = 7) from each group were randomly selected to evaluate surface roughness using AFM and one specimen was randomly selected for the SEM and EDS analyses. Data were analyzed with two-way ANOVA and Tukey tests (p = 0.05). The irradiation significantly increased fluoride release and surface roughness for Amalgomer CR and Zirconomer groups (p < 0.05). No significant change in flexural strength of the materials was observed after irradiation (p > 0.05). The ionizing radiation altered the amount of fluoride release and surface roughness of only Amalgomer CR and Zirconomer. The effect could be related to the chemical compositions of materials.

Cutting-edge filler technologies to release bio-active components for restorative and preventive dentistry

Advancements in materials used for restorative and preventive treatment is being directed toward "bio-active" functionality. Incorporation of filler particles that release active components is a popular method to create bio-active materials, and many approaches are available to develop fillers with the ability to release components that provide "bio-protective" or "bio-promoting" properties; e.g. metal/calcium phosphate nanoparticles, multiple ion-releasing glass fillers, and non-biodegradable polymer particles. In this review paper, recent developments in cutting-edge filler technologies to release bio-active components are addressed and summarized according to their usefulness and functions, including control of bacterial infection, tooth strengthening, and promotion of tissue regeneration.

Comparison of Flexural Properties of Bulk-fill Restorative/Flowable Composites and Their Conventional Counterparts

The objectives of the study were to compare the flexural modulus and strength of restorative and flowable bulk-fill resin-based composites (RBCs) to their conventional counterparts and to determine the effects of conditioning environment on their flexural properties. The materials evaluated included three conventional RBCs (Filtek Z350, Tetric N Ceram, and Beautifil II), three restorative bulk-fill RBCs (Filtek Bulk-Fill Restorative, Tetric N Ceram Bulk-Fill, and Beautifil Bulk-fill Restorative), as well as three flowable bulk-fill RBCs (Filtek Bulk-Fill Flowable, Tetric N Flow Bulk-Fill, and Beautifil Bulk-Fill Flowable). Specimens were fabricated using customized stainless-steel molds, finished, measured, and randomly divided into four groups. The various RBCs were conditioned in the following mediums (n=10) for seven days at 37°C: air, artificial saliva (SAGF), 0.02 N citric acid, and 50% ethanol-water solution. After conditioning, the specimens were rinsed, blotted dry, measured, and subjected to flexural testing using a universal testing machine. Data were subjected to statistical analysis using analysis of variance and the Tukey test at a significance level of α = 0.05. Significant differences in flexural properties were observed between materials and conditioning mediums. Bulk-fill restorative RBCs exhibited higher flexural modulus than their bulk-fill flowable and conventional counterparts. With the exception of Filtek Bulk-Fill Flowable, bulk-fill flowable RBCs had significantly higher flexural strength than bulk-fill restorative and conventional RBCs. Flexural properties were highest when RBCs were conditioned in air and generally the lowest after exposure to ethanol.

Lithium-containing surface pre-reacted glass fillers enhance hDPSC functions and induce reparative dentin formation in a rat pulp capping model through activation of Wnt/β-catenin signaling

Surface pre-reacted glass (S-PRG) fillers are new bioactive molecules used in dental clinic work to fill tooth defects. These fillers release various types of ions (Al⁺³, BO^-3, Na⁺, SiO₃^-2, Sr⁺² and F^-) and exhibit high biocompatibility, antibacterial capability, reduced plaque accumulation, and enhanced osteoblast differentiation. We previously showed that cement of S-PRG fillers could induce tertiary dentin formation in rat models. Previous work also showed that lithium ions can activate the Wnt/β-catenin signaling pathway in vitro and induce dentin formation in pulpotomized teeth in vivo. In the current study, we sought to enhance the effect of S-PRG cement by incorporating LiCl. We show that treatment of human dental pulp stem cells with eluates from S-PRG/LiCl combination cements leads to an upregulation in cell migration, differentiation, and mineralization in vitro. In pulp-capping animal trials, we found that S-PRG/LiCl cements could induce tertiary dentin formation 28-days post-capping. At 7 days post-capping, we identified both β-catenin and Axin2 expression using immunofluorescence, indicative of Wnt/β-catenin signaling activity. In conclusion, S-PRG/LiCl cement is highly effective in promoting human dental pulp stem cells profiles and in enhancing reparative dentin formation in rat teeth through activation of the Wnt/β-catenin canonical signaling pathway. STATEMENT OF SIGNIFICANCE: This is the first study to assess the behavior of S-PRG fillers containing lithium ions on human dental pulp stem cells. We show that this new combination cement promotes positive cell responses by activating the endogenous Wnt/β-catenin signaling pathway in the pulp. The Wnt/β-catenin canonical signaling pathway is involved in many developmental and wound healing processes. The released lithium ions from the S-PRG cement were systematically detected <0.01 mmol/L in our rat model. But it was efficient to induce tertiary dentin formation at the defect site. Since this novel bioactive cement is potentially a promising material for clinical pulp regenerative therapy, future human clinical trials will be needed.

Surface Pre-Reacted Glass Filler Contributes to Tertiary Dentin Formation through a Mechanism Different Than That of Hydraulic Calcium-Silicate Cement

The induction of tissue mineralization and the mechanism by which surface pre-reacted glass-ionomer (S-PRG) cement influences pulpal healing remain unclear. We evaluated S-PRG cement-induced tertiary dentin formation in vivo, and its effect on the pulp cell healing process in vitro. Induced tertiary dentin formation was evaluated with micro-computed tomography (μCT) and scanning electron microscopy (SEM). The distribution of elements from the S-PRG cement in pulpal tissue was confirmed by micro-X-ray fluorescence (μXRF). The effects of S-PRG cement on cytotoxicity, proliferation, formation of mineralized nodules, and gene expression in human dental pulp stem cells (hDPSCs) were assessed in vitro. μCT and SEM revealed that S-PRG induced tertiary dentin formation with similar characteristics to that induced by hydraulic calcium-silicate cement (ProRoot mineral trioxide aggregate (MTA)). μXRF showed Sr and Si ion transfer into pulpal tissue from S-PRG cement. Notably, S-PRG cement and MTA showed similar biocompatibility. A co-culture of hDPSCs and S-PRG discs promoted mineralized nodule formation on surrounding cells. Additionally, S-PRG cement regulated the expression of genes related to osteo/dentinogenic differentiation. MTA and S-PRG regulated gene expression in hDPSCs, but the patterns of regulation differed. S-PRG cement upregulated CXCL-12 and TGF-β1 gene expression. These findings showed that S-PRG and MTA exhibit similar effects on dental pulp through different mechanisms.

Oroactive dental biomaterials and their use in endodontic therapy

Dental biomaterials have revolutionized modern therapies. Untreated dental caries remains the major etiological factor for endodontic treatment, and together with a decreasing rate of tooth loss escalates the importance of continuously improving the materials used for endodontic therapies. Endodontic biomaterials are used for vital pulp therapies, irrigation, intracanal medicaments, obturation and regenerative procedures. These materials offer several functions including: antimicrobial activity, mechanical reinforcement, aesthetics, and therapeutic effects. Vital pulp therapies have seen an improvement in clinical results with an incremental approach to build on the strengths of past materials such as calcium hydroxide and calcium silicates. While sodium hypochlorite remains the gold standard for canal irrigation, numerous nanoparticle formulations have been developed to promote sustained antimicrobial action. Gutta-percha based bulk fillers remain the most common materials for root filling. However, while multiple studies focus on the development of novel formulations containing drugs, glass derivatives or ionic-, polymeric-, or drug- loaded nanoparticles, a lack of reliable and long-term clinical evidence obligates further study as experienced clinicians prefer to use what has worked for decades. This review delves in to the biochemistry of the materials to scrutinize their shortcomings, and where opportunity lies to further enhance their efficacy in endodontic practice. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:201-212, 2020.

A randomized controlled evaluation of posterior resin restorations of an altered resin modified glass-ionomer cement with claimed bioactivity

OBJECTIVE

The objective of this randomized controlled prospective clinical trial was to evaluate the short time clinical behaviour of an altered resin modified glass-ionomer cement (RMGIC), which is claimed to possess bioactivity, in posterior restorations and to compare it intraindividually with a nanofilled resin composite.

METHODS

Totally 78 pairs Class II and 4 pairs Class I restorations were placed in 29 female and 38 male participants with a mean age of 58.3 years (range 37-86). Each patient received at random at least one pair of, as similar as possible, Class II or Class I restorations. In the first cavity of each pair, the modified flowable RMGIC (ACTIVA Bioactive; AB) was placed after phosphoric acid etching of the cavity and without adhesive, according to the instructions of the manufacturer. In the other cavity a well established nanofilled resin composite (CeramX; RC) with a single step self-etch adhesive (Xeno Select) was placed. The restorations were evaluated using slightly modified USPHS criteria at baseline, 6 and 12 months. Caries risk and parafunctional habits of the participants were estimated.

RESULTS

158 restorations, 8 Class I and 150 Class II, were evaluated at the one year recalls. At baseline two failed restorations were observed (2AB), at 6 months six failures (5AB, 1RC) and at 12 months another thirteen failed restorations were observed (12AB, 1RC). This resulted in annual failure rates of 24.1% for the AB and 2.5% for RC (p<0.0001). The main reasons for failure for AB were lost restorations (5), postoperative symptoms (4) and secondary caries (3). Do to the unacceptable very high one-year failure frequency, the clinical study was stopped and no further evaluation will be performed.

SIGNIFICANCE

The use of the AB restorative in Class II cavities, applied as instructed by the manufacturer after a short phosphoric acid pretreatment but without adhesive system, resulted in a non-acceptable very high failure frequency after a one year period. Further studies should be conducted using a bonding agent.

Effect of a coating material containing surface reaction-type pre-reacted glass-ionomer filler on prevention of primary enamel demineralization detected by optical coherence tomography

We used optical coherence tomography to examine the effect of a coating material containing surface reaction-type pre-reacted glass-ionomer (S-PRG) filler on primary enamel demineralization in 18 extracted human primary teeth. The pulp was removed, and each tooth was ultrasonically cleaned with distilled water. Six teeth were treated with 0.1-M lactic acid buffer solution (De group). In the second group (n = 6), a thin film of coating material was applied before demineralization (PRG group). A third group (Control group; n = 6) was maintained in artificial saliva. Using optical coherence tomography, we measured peak signal intensity (dB) and width at 1/e² (µm) at predetermined locations on the enamel surface and calculated integrated values. All data were analyzed with ANOVA and the Tukey-Kramer test (α = 0.05). Although changes in integrated values differed between groups, there was a small but significant increase in the Control group and a small but significant decrease in the De group. In the PRG group, integrated values were significantly higher at 7 days after the start of the experiment and significantly increased thereafter. Our findings indicate that a coating material containing S-PRG fillers may prevent primary enamel demineralization.

Application of a direct pulp capping cement containing S-PRG filler

OBJECTIVES

To evaluate new pulp capping cements containing surface pre-reacted glass ionomer (S-PRG) filler and to investigate ion release kinetics and pH shift of eluates from the cement.

MATERIALS AND METHODS

Molars of Wistar rats were directly pulp capped using three kinds of cement containing S-PRG filler and mineral tri-oxide aggregate (MTA) was used as a control. After 1, 2, or 4 weeks, histological evaluation was performed and differences of tertiary dentin formation were analyzed. Release of Sr²⁺, BO₃^3-, SiO₃^2-, Na⁺, and Al³⁺ ions was determined by inductively coupled plasma-atomic emission spectrometry, and F^- ion release was measured using a fluoride ion selective electrode. The pH of the eluate from each cement after mixing was measured with a pH electrode.

RESULTS

One of S-PRG cements promoted tertiary dentin formation to the same extent as the control (p > 0.05) and it showed a tendency of less inflammatory response. This cement released more BO₃^3- and SiO₃^2-, but less Sr²⁺, Na⁺, and F^- than other S-PRG specimens. Each cement recovered nearly neutral compared with glass ionomer cement.

CONCLUSIONS

S-PRG cement induced tertiary dentin formation based on multiple ion releases, suggesting that it is suitable as a pulp capping material.

CLINICAL RELEVANCE

This new material can be an alternative pulp capping agent to MTA.

Effect of incorporation of surface pre-reacted glass ionomer filler in tissue conditioner on the inhibition of Candida albicans adhesion

We investigated the effects of incorporation of surface pre-reacted glass ionomer (S-PRG) filler in tissue conditioner (TC) on Candida albicans adhesion. We prepared specimens containing 0, 5, 10, or 20 wt% of S-PRG filler, and measured the amount of C. albicans on the surface using a colony forming unit (CFU) assay and scanning electron microscopic images. In addition, we measured the consistency, penetration depth, and surface roughness (Ra). CFU values for 10 and 20 wt% were significantly lower than that for the control (p<0.05). Hyphal density on the surface was greater in the control. The 10 and 20 wt% specimens showed significantly higher consistency and Ra, lower penetration depth ratio than control (p<0.05). These results suggest that incorporation of S-PRG filler may reduce C. albicans adhesion onto TC surface; however, the optimal amount of filler is dictated by the influence of filler incorporation on mechanical and surface characters of TC.

Viscoelastic Properties of Contemporary Bulk-fill Restoratives: A Dynamic-mechanical Analysis

This study investigated the viscoelastic properties of contemporary bulk-fill restoratives in distilled water and artificial saliva using dynamic mechanical analysis. The materials evaluated included a conventional composite (Filtek Z350), two bulk-fill composites (Filtek Bulk-fill and Tetric N Ceram), a bulk-fill giomer (Beautifil-Bulk Restorative), and two novel reinforced glass ionomer cements (Zirconomer [ZR] and Equia Forte [EQ]). The glass ionomer materials were also assessed with and without resin coating (Equia Forte Coat). Test specimens 12 × 2 × 2 mm of the various materials were fabricated using customized stainless-steel molds. After light polymerization/initial set, the specimens were removed from the molds, finished, measured, and conditioned in distilled water or artificial saliva at 37°C for seven days. The materials (n=10) were then subjected to dynamic mechanical testing in flexure mode at 37°C and a frequency of 0.1 to 10 Hz. Storage modulus, loss modulus, and loss tangent data were subjected to normality testing and statistical analysis using one-way analysis of variance/Dunnett's test and t-test at a significance level of p < 0.05. Mean storage modulus ranged from 3.16 ± 0.25 to 8.98 ± 0.44 GPa, while mean loss modulus ranged from 0.24 ± 0.03 to 0.65 ± 0.12 GPa for distilled water and artificial saliva. Values for loss tangent ranged from 45.7 ± 7.33 to 134.2 ± 12.36 (10^-3). Significant differences in storage/loss modulus and loss tangent were observed between the various bulk-fill restoratives and two conditioning mediums. Storage modulus was significantly improved when EQ and ZR was not coated with resin.

Inhibitory effect of resin composite containing S-PRG filler on Streptococcus mutans glucose metabolism

OBJECTIVES

Resin composites containing surface pre-reacted glass-ionomer (S-PRG) fillers have been reported to inhibit Streptococcus mutans growth on their surfaces, and their inhibitory effects were attributed to BO₃^3- and F^- ions. The aim of this study was to evaluate S. mutans acid production through glucose metabolism on resin composite containing S-PRG fillers and assess inhibitory effects of BO₃^3- and F^- on S. mutans metabolic activities.

METHODS

The pH change through S. mutans acid production on experimental resin composite was periodically measured after the addition of glucose. Inhibitory effects of BO₃^3- or F^- solutions on S. mutans metabolism were evaluated by XTT assays and measurement of the acid production rate.

RESULTS

The pH of experimental resin containing S-PRG fillers was significantly higher than that of control resin containing silica fillers (p < 0.05). OD₄₅₀ values by XTT assays and S. mutans acid production rates significantly decreased in the presence of BO₃^3- and F^- compared with the absence of these ions (p < 0.05).

CONCLUSIONS

pH reduction by S. mutans acid production was inhibited on resin composite containing S-PRG fillers. Moreover, S. mutans glucose metabolism and acid production were inhibited in the presence of low concentrations of BO₃^3- or F^-.

CLINICAL SIGNIFICANCE

BO₃^3- or F^- released from resin composite containing S-PRG fillers exhibits inhibitory effects on S. mutans metabolism at concentrations lower than those which inhibit bacterial growth.