Article

Comparative biological assessments of endodontic root canal sealer containing surface pre-reacted glass-ionomer (S-PRG) filler or silica filler

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Abstract

Surface pre-reacted glass-ionomer (S-PRG) filler releases several ions, such as fluoride, borate and strontium ions, to exert bioactive effects. We fabricated an endodontic root canal sealer containing S-PRG fillers (S-PRG sealer) and then evaluated the antibacterial and anti-inflammatory properties of S-PRG sealer compared with sealer containing conventional silica fillers (silica sealer). Antibacterial tests showed that S-PRG sealer significantly reduced the turbidity of Enterococcus faecalis compared with silica sealer. Implantation of S-PRG or silica sealer blocks in rat subcutaneous tissue showed that S-PRG sealer decreased the proinflammatory response compared with silica sealer at 10 days post-implantation. In addition, immunostaining revealed that infiltration of CD68- and peroxidase-positive cells around the S-PRG sealer was significantly lower than that in silica sealer. Therefore, it was suggested that S-PRG sealer exhibits antibacterial and anti-inflammatory effects.

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... A S-PRG eluate effectively inhibits the growth and in vitro cariogenicity of S. mutans (10). Miyaji et al. (11) described the preparation of a surface pre-reacted glass ionomer (S-PRG) filler from a fluoro-boro-alumino-silicate glass having sample. The ICP converts elements into ions which can be then detected by the mass spectrometer (MS). ...
... While the fluoride ion primarily assists with remineralization of the enamel (15), the released strontium, boron, and silicon ions are antibacterial and have osteogenic potential (16)(17)(18) to improve endodontic outcomes. The prototype S-PRG sealer has shown to exhibit antibacterial and anti-inflammatory effects (11), induce osteogenesis in apical bone (19), and avoid collapse of the dentinal tubule because of its neutral pH (12). Silicon ions are known to promote bone formation and tooth remineralization (20). ...
... The speed of boron and silicon ion release from both sealers was constant (Fig. 1a, 1b). (24), and found that, due to its release of antibacterial ions such as boron and strontium, S-PRG sealer exhibited more significant antibacterial effects against E. faecalis than a silica-filled sealer (11). Boron also has been associated with anti-inflammatory effects resulting in the prevention of bone loss (25) and the ability to stimulate osteoblastic activity, thereby promoting bone formation (26). ...
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Objective: Bioactive ions, when incorporated in an endodontic sealer, can contribute to the long-term success of endodontic therapy by combating the re-infection of a tooth and promoting the healing of the periapical bone. The objective of this study was to measure the release of boron, strontium, and silicon ions from surface pre-reacted glass ionomer (S-PRG) filler containing prototype endodontic sealer over a sustained period in comparison to EndoSequence BC sealer in a simulated clinical model using extracted human teeth in vitro. Methods: Twelve extracted human anterior teeth were instrumented using ProTaper Next (Dentsply Sirona, Johnson City, TN, USA) files up to size X3 (#30/variable taper) with copious 2.5% NaOCl irrigation. Teeth were obturated using a single-cone technique with a matching size tapered gutta-percha point and one of two endodontic sealers: prototype S-PRG (Shofu Inc., Kyoto, Japan) or EndoSequence BC (Brasseler, Savannah, GA, USA). The teeth were soaked in phosphate-buffered saline (PBS) solution for 336 hours. Periodically, 1-mL samples of the PBS were analyzed via an inductively coupled plasma mass spectrometer to determine the concentrations of ions released by the sealers. Results: The average (S.D.) cumulative release (ng/ml) of boron, silicon, and strontium ions over 2 weeks for the prototype S-PRG sealer was 8614.9 (1264.3), 35758.9 (5986.5), and 3965.2 (145.6), and for EndoSequence BC sealer was 1860.5 (82.7), 164648.7 (16468.1), and 227.7 (4.7). Generalized linear mixed model analysis showed significant differences in ion concentration among boron, silicon, and strontium over time between the two sealer groups (Boron: P<0.0001, Silicon: P=0.010, Strontium: P=0.028). Of the three ions, strontium had the lowest amount of release for both sealers. The prototype S-PRG sealer showed a rapid initial burst followed by a slow, continuous release of strontium ions. Conclusion: The prototype S-PRG sealer released boron and strontium ions in higher cumulative concentrations over 2 weeks compared to the EndoSequence BC sealer. Both the prototype S-PRG and EndoSequence BC sealers released silicon ions, although significantly more were eluted from the EndoSequence BC sealer. Antimicrobial and osteogenic ion release from sealers is expected to positively influence the post-treatment control of microbial infections to improve periapical healing.
... This filler is currently incorporated into various dental materials, for example resin composites 3) or a root canal sealer 4) . The latter has been reported to exhibit possible effects of osteogenesis induction and periodontal tissue recovery 5,6) . Ions slowly released from sealants containing S-PRG fillers have also been reported to show potential effects of enhancing tooth remineralisation 7,8) . ...
... Ishigure et al. 24) reported that ALP activity of hDPSC increased with the addition of the S-PRG filler eluate, which contained a higher amount of B than other ions. The results in this study suggest 6 Dent Mater J 2024; : that S-PRG filler-derived B contributes to an increase in ALP activity. Ying et al. 31) reported that B has promoting effects on bone marrow stromal cell differentiation and osteogenesis. ...
Article
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Surface pre-reacted glass-ionomer (S-PRG) filler is a bioactive glass filler capable of releasing various ions. A culture medium to which was added an S-PRG filler eluate rich in boron was reported to enhance alkaline phosphatase (ALP) activity in human dental pulp-derived stem cells (hDPSC). To clarify the role of boron eluted from S-PRG fillers, the modified S-PRG filler eluate with different boron concentrations was prepared by using an anion exchange material. Therefore, elemental mapping analysis of anion exchange material, adsorption ratio, hDPSCs proliferation and ALP activity were evaluated. For statistical analysis, Kruskal-Wallis test was used, with statistical significance determined at p<0.05. ALP activity enhancement was not observed in hDPSC cultured in the medium that contained the S-PRG filler eluate from which boron had been removed. The result suggested the possibility that an S-PRG filler eluate with controlled boron release could be useful for the development of novel dental materials.
... Therefore, endodontic filling materials capable of eliminating residual bacteria inside root canals have been proposed as a possible solution to this problem. An experimental zinc oxide-based endodontic sealer containing S-PRG filler demonstrated the sustained release of multiple ions (i.e., Sr 2+ , BO 3 3− , F − , Na + , SiO 3 2− , and Al 3+ ) [40] and antibacterial effects against E. faecalis and P. gingivalis [69,70]. ...
... The eluate obtained from experimental root canal sealer containing S-PRG filler was reported to downregulate mRNA expression levels of proinflammatory cytokines, such as interleukin (IL)-1α, IL-6, and TNF-α, in LPS-stimulated RAW264.7 cells, suggesting its anti-inflammatory effects [71]. Moreover, an experimental sealer containing S-PRG filler can promote the healing of periapical lesions in vivo [70,72,73]. ...
Article
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Surface Pre-Reacted Glass-ionomer (S-PRG) filler, which releases strontium (Sr2+), borate (BO33−), fluoride (F−), sodium (Na+), silicate (SiO32−), and aluminum (Al3+) ions at high concentrations, is a unique glass filler that are utilized in dentistry. Because of its multiple-ion releasing characteristics, S-PRG filler exhibits several bioactivities such as tooth strengthening, acid neutralization, promotion of mineralization, inhibition of bacteria and fungi, inhibition of matrix metalloproteinases, and enhancement of cell activity. Therefore, S-PRG filler per se and S-PRG filler-containing materials have the potential to be beneficial for various dental treatments and care. Those include restorative treatment, caries prevention/management, vital pulp therapy, endodontic treatment, prevention/treatment of periodontal disease, prevention of denture stomatitis, and perforation repair/root end filling. This review summarizes bioactive functions exhibited by S-PRG filler and its possible contribution to oral health.
... GICs are used clinically in restorative dentistry as long-term temporary restorations, definitive restorations for deciduous and permanent teeth, core build-ups, liners and bases, pulp capping agents, root surface and root end fillings, endodontic sealers, luting agents, fissure sealants, and adhesives in orthodontic brackets [12][13][14][15][16][17][18]. In addition, high-viscosity GIC (HVGIC) is the adhesive material of choice for the atraumatic restorative treatment (ART) technique [3,13,19]. ...
... In addition, CPP-ACP interacts with fluoride ions released from GIC to form a stabilised amorphous calcium fluoride phosphate complex, and this further augments its anticariogenic potential [38,84,85]. The various strategies that have been used so far in promoting the remineralisation of GICs are summarised in Table 1 [5,15,16,[35][36][37][38][55][56][57][58][59][62][63][64][65]68,76,86]. The inclusion of sol-gel derived BAG (10-30%) additives to glass-ionomer promoted the induction of apatite mineral deposits on the surface and produced higher cell viability, without compromising the DTS. ...
Article
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The prospect of repair, regeneration, and remineralisation of the tooth tissue is currently transitioning from the exploratory stages to successful clinical applications with materials such as dentine substitutes that offer bioactive stimulation. Glass-ionomer or polyalkenoate cements are widely used in oral healthcare, especially due to their ability to adhere to the tooth structure and fluoride-releasing capacity. Since glass-ionomer cements exhibit an inherent ability to adhere to tooth tissue, they have been the subject of modifications to enhance bioactivity, biomineralisation, and their physical properties. The scope of this review is to assess systematically the modifications of glass-ionomer cements towards bioactive stimulation such as remineralisation, integration with tissues, and enhancement of antibacterial properties.
... These dental materials have been clinically applied, with no reports of harm to the human body. In addition, 1% of S-PRG filler was less toxic to osteoblastic cell lines than 1% of silica filler 29 . When S-PRG filler-containing sealer or silica fillercontaining sealer was implanted in rat subcutaneous tissue, the accumulation of inflammatory cells was lower www.nature.com/scientificreports/ ...
... When S-PRG filler-containing sealer or silica fillercontaining sealer was implanted in rat subcutaneous tissue, the accumulation of inflammatory cells was lower www.nature.com/scientificreports/ www.nature.com/scientificreports/ in the case of S-PRG filler-containing sealer than that of silica filler-containing sealer 29 . Furthermore, the safety of S-PRG filler has been demonstrated by administration experiments using the silkworm, which has similar susceptibility to chemical compounds as humans 30 . ...
Article
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Surface pre-reacted glass-ionomer (S-PRG) filler is a bioactive functional glass that releases six different ions. Although several dental materials containing S-PRG filler have been developed, few self-care products containing S-PRG filler have been reported. We investigated the inhibitory effects of PRG gel paste containing S-PRG filler on Streptococcus mutans, a major pathogen of dental caries. PRG gel paste inhibited bacterial growth of S. mutans in a concentration-dependent manner, and all S. mutans were killed in the presence of ≥ 1% PRG gel paste. Additionally, it was difficult for S. mutans to synthesize insoluble glucan from sucrose in the presence of 0.1% PRG gel paste. A biofilm formation model was prepared in which slices of bovine enamel were infected with S. mutans after treatment with or without PRG gel paste. Biofilm formation was inhibited significantly more on the enamel treated with PRG gel paste than on enamel without PRG gel paste (P < 0.001). The inhibitory effects on bacterial growth and biofilm formation were more prominent with PRG gel paste than with S-PRG-free gel paste, suggesting that PRG gel paste may be effective as a self-care product to prevent dental caries induced by S. mutans.
... Fujita et al. [18] also reported an increase in the number and ALP activity of human dental pulp cells extracted from deciduous teeth when exposed to a certain amount of S-PRG cement extract. The biocompatibility of S-PRG filler was also recently confirmed by other researchers on different cell lineages [16,19,27]. The slight differences in the findings of these studies are attributed to different methodologies, materials, concentrations of the eluate, and the use of different cell lines. ...
... However, most of these studies relate the positive biological effect of S-PRG filler to the release of different types of bioactive ions, such as Sr, B, Si, F, and Al. The effect of each ion has been previously reported: Sr and B ions are postulated to downregulate inflammatory responses [27], the former ion also promotes bone formation [28,29], and the latter has been reported to induce osteogenesis and odontogenic differentiation [30]. Si ions exhibit antioxidant activity and enhance bone formation [31]. ...
Article
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.
... The preparation of S-PRG is simple, by acid-base reaction of fluoro-boroalumino-silicate glass and polyacrylic acid in an aqueous solution. 10 Interestingly, there occurs a ligand exchange mechanism in prereacted hydrogel, which enables subsidization of S-PRG barriers programmed to release and recharge fluoride. Accordingly, S-PRG is developed to manage multiple ions such as Al 3+ , B 3+ , Na + , BO 3 , and Sr 2+ with competence in mineral induction. ...
... It is a facultative anaerobe that has evolved to survive in the harsh conditions of the gastrointestinal, vaginal, and oral cavities (22) . It has also been discovered to occur sometimes in primary root canal infections (23) . E. faecalis is one of the most resistant bacteria that is associated with endodontic treatment failure as it is frequently found in root filled teeth with a prevalence ranging from 30% to 90%. ...
Article
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Introduction: When Enterococcus faecalis is present in sufficient amounts, resin sealer can be degraded by esterase-like activity. E. faecalis has potential ability to penetrate the methacrylate-tooth interface, enter the root canal, causing secondary infections. Adhesion of the sealer to dentin and gutta percha was measured by push out bond strength using universal testing machine and adaptation using scanning electron microscope. Aim: This study aims to determine the effect of E. faecalis on push out bond strength of AH Plus epoxy resin-based sealer. Material and methods: A total of 40 recently extracted teeth were used in this experiment. After chemo-mechanical preparation of all samples, they were randomly classified into four groups (n=10): Group 1: Root canals inoculated with E. faecalis. Group 2: Root canals with no bacterial inoculation. Group 3: Root canals inoculated with dead bacteria. Group 4: Root canals inoculated with media only. Obturation was performed by single cone obturation technique. Methods of evaluation: The bond strength of the samples of all groups was calculated by dividing the load by bonding area of the filling area. The load was converted to MPa. Results: Control group 2 "no bacteria" and group 4 "media only" showed the highest statistically significant values of push out bond strength both at apical and coronal sections with no statistically significant difference between them. This was followed by group 3 "dead bacteria" then group 1 "with bacteria" which showed the least values of POBS with statistically significant difference between them and with other groups. Conclusion: E. faecalis demonstrated biodegradation of resin
... Although the antibacterial properties of GICs are limited, additives like resin, as used in Vitrebond, make them more antibacterial due to toxic agents released during setting [44]. Also, silver additives and modifications such as surface pre-reacted glass-ionomer fillers may increase their antibacterial properties [45]. GICs are sensitive to moisture during the endodontic procedure, which is not always easy to achieve in the apical region. ...
Article
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Endodontic sealers and cements used in root canal treatment have different compositions and properties. Common to all materials is that their primary goal is to fill gaps and voids, making a permanent seal of the root canal system. Furthermore, aspects such as antibacterial properties, cytotoxicity, setting time, solubility and biocompatibility are also crucial and ought to be considered. Over the years, a shift in the view on the importance of these aspects has ocurred. Whereas the antibacterial properties were considered important when the technical factors in endodontics were less developed, the sealing ability and biocompatibility have later been considered the most critical factors. The introduction of tricalcium silicate cements and sealers has led to a renewed interest in material properties, as these cements seem to have good sealing ability and at the same time combine favourable antimicrobial effects with excellent biocompatibility. This review discusses how the various properties of root canal sealers and cements may conflict with the primary aim of providing a permanent seal of the root canal system.
... Chelating agents include Zinc oxide/Eugenol and salicylatebased sealers that contain calcium hydroxide [2]. Glass ionomers, due to their fluoride-release properties, have also been used but their applications as endodontic sealers have diminished over the last few years [3]. Perhaps, other commonly used polymeric endodontic sealant system are AH-plus [4], an epoxy-based resin sealer, and MTA Fillapex [5], composed of resin and mineral trioxide aggregate (MTA) bioceramic. ...
Article
Background: Antimicrobial photodynamic therapy (aPDT) has been used for the disinfection of root canals. Studies have been carried out on its effect on the bond-strength and penetration of endodontic sealers. The aim of this systematic review is to critically analyze the literature and summarize the outcomes of these studies. Materials and methods: An electronic search was conducted on research databases PubMED/Medline, ISI Web of Knowledge, Embase, Scopus and Europe PMC using the following the medical subject headings (MeSH) terms and keywords: [((endodontic sealer) OR (endodontic sealant) OR (root canal sealer)) AND ((anti-microbial photodynamic therapy) OR (laser-assisted) OR (light-assisted) OR (photosensitive dye) OR (photosensitizer)) AND ((bond-strength) OR (penetration))] for all literature published from inception to September 2022. Clinical studies, animal studies, laboratory investigations and case reports were included. Data was extracted and the quality of the included studies was assessed. Results: Of the 204 studies screen initially, 12 laboratory studies were included in this review. Majority of the outcomes revealed that aPDT does not have an adverse impact on the bond-strength or sealer penetration. Furthermore, AH Plus (an epoxy-based sealer) resulted in higher bond-strengths than other types of sealers (MTA Fillapex, Sealapex and Bioceramics). 11 studies were graded as having 'medium' quality and one study was graded as 'low'. Conclusion: Within the limitations of this review, aPDT does not have a significant impact on the bonding and penetration of endodontic sealers. Future studies should focus on standardization and optimization of aPDT procedures when assessing their impact on the interaction between sealers and dentine.
... They are mostly used as dental materials owing to their antibacterial and anti inflammatory properties. [73] Recently, Dash et al. performed a study to evaluate the osteoregenerative potential of glass ionomer based composite scaffolds. They found that the glass ionmer provides better mechanical strength and porous architecture to the scaffold and hence supports osteogenesis of mesenchymal stem cells. ...
Article
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The intersection of very different, yet complementary fields, stem cells, and nanotechnology, has led to the opening of new horizons in the area of research, giving new hopes, better strategies, and a boost to regenerative medicine, nanotherapeutics, and tissue engineering. Harnessing the stem cell’s ability to self‐renew and differentiate into specific types of functional cells and the unique physico‐chemical properties of the nanomaterials, researchers have optimized the interactions of these with the biological milieu to overcome the hurdles of conventional cell‐based therapies. Here, we highlight and outline various types of nanomaterials and their well‐established significance in redefining the future of human medicine through influencing stem cell research targeting illness of important human organs.
... The S-PRG sealer is presumed to favor osteoblastic differentiation because extracts from the S-PRG sealer induce osteoblastic differentiation and mineralization of Kusa-A1, an osteoblastic cell line, through the calciumsensing receptor-induced activation of extracellular signal-regulated kinase and p38 mitogen-activated protein kinase 16) . Anti-inflammatory properties of the S-PRG sealer have also been described in a recent study: subcutaneous implantation of set S-PRG sealer led to reduced macrophage infiltration, compared with a silica filler-containing (non-SPRG filler-containing) sealer 17) . However, these results could be largely attributed to the difference in biocompatibility between the two materials, and thus anti-inflammatory effects of the S-PRG sealer have not yet been fully evaluated. ...
Article
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⁺.
... Some resin-modified glass polyalkenoate ("glass ionomer") cements release fluoride and calcium ions. Other related materials denoted as "Giomer" are also glass based but "pre-reacted"; they release up to six ions: fluoride, sodium, strontium, aluminum, silicate and borate (195). Ion release is beneficial in the oral environment for partial or temporary remineralization, fluoride ion exchange. ...
Article
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Calcium silicate cements were identified as excellent materials for dentistry, particularly for dental procedures contacting the dental pulp or root system. Both calcium silicate and calcium aluminate cements cause the biomineralization (precipitation of hydroxyapatite [HA] phenomena and shield dental tissues from the underlying cement (a foreign body material). The cements also elute ions to stimulate cytokines that contribute to the healing of the dental pulp or in the tissue surrounding the root of a tooth. The cements serve as a foundation for other dental restorative materials. This paper reviews the cement phases, properties, in vivo reactions, and clinical benefits from the use of calcium silicate and calcium aluminate ceramic cements.
... Sr incorporation into dental tissues is an endemic issue; it occurs in regions with high Sr concentration in drinking water [75]. In addition, it is a compound of dental dentifrices and restorative materials such as glass ionomer cements [76,77]. SrF 2 addition may be interesting for dental practitioners for two reasons. ...
Article
The purpose of this study was to investigate the influence of different radiopacifiers on the physicochemical and biological properties of novel calcium silicate based endodontic ceramic enriched with bioactive nano-particulated hydroxyapatite – ECHA. Namely, ECHA was used as a basis for mixing with the following radiopacifiers: strontium fluoride (SrF2), zirconium dioxide (ZrO2) and bismuth oxide (Bi2O3). For comparison, Portland cement (PC) and mineral trioxide aggregate (MTA) were used. The following physicochemical characteristics were examined: the radiopacity, setting time, compressive strength, porosity, wettability and pH value. The biocompatibility of the cements was assessed by crystal violet, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) and cell adhesion assays. The highest radiopacity was obtained for the ECHA + Bi2O3 mixture and MTA that were statistically significant in comparison to other materials (p < 0.05). Both initial and final setting times as well as compressive strengths were statistically lower for experimental cements than for PC and MTA (p < 0.05). The lowest total porosity was observed in the ECHA + ZrO2 group when compared with the other two experimental cements (p < 0.05), but not when compared with PC and MTA (p > 0.05). Experimental cements exhibited statistically higher contact angles of glycerol than PC and MTA (p < 0.05). For blood plasma, a statistical difference was found only between ECHA + Bi2O3 and PC (p < 0.05). All investigated materials had alkalization ability. Cell viability assays revealed that the extracts of tested cements did not exhibit cytotoxic effect on L929 cells. Scanning electron microscopy had shown a high degree of cell proliferation and adhesion of cells from apical papilla on experimental cements’ surfaces. Novel endodontic ceramics with nano-hydroxyapatite addition have satisfactory biological and physicochemical properties when compared to MTA and PC controls. Considerable lower setting time of experimental cements might present a huge advantage of these synthesized materials in clinical practice. SrF2 presents a novel promising radiopacifying agent for dental cements manufacturing.
... Such S-PRG fillers have been used in commercial restorative resins and cements. The prototype S-PRG sealer exhibits antibacterial and anti-inflammatory effects, induces osteogenesis in the apical bone [12,13]. ...
Article
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Objectives: This study used micro-computed tomography (µCT) to compare voids and interfaces in single-cone obturation among AH Plus, EndoSequence BC, and prototype surface pre-reacted glass ionomer (S-PRG) sealers and to determine the percentage of sealer contact at the dentin and gutta-percha (GP) interfaces. Materials and methods: Fifteen single-rooted human teeth were shaped using ProTaper NEXT size X5 rotary files using 2.5% NaOCl irrigation. Roots were obturated with a single-cone ProTaper NEXT GP point X5 with AH Plus, EndoSequence BC, or prototype S-PRG sealer (n = 5/group). Results: The volumes of GP, sealer, and voids were measured in the region of 0-2, 2-4, 4-6, and 6-8 mm from the apex, using image analysis of sagittal µCT scans. GP volume percentages were: AH Plus (75.5%), EndoSequence BC (87.3%), and prototype S-PRG (94.4%). Sealer volume percentages were less: AH Plus (14.3%), EndoSequence BC (6.8%), and prototype S-PRG (4.6%). Void percentages were AH Plus (10.1%), EndoSequence BC (5.9%), and prototype S-PRG (1.0%). Dentin-sealer contact ratios of AH Plus, EndoSequence BC, and prototype S-PRG groups were 82.4% ± 6.8%, 71.6% ± 25.3%, and 70.2% ± 9.4%, respectively. GP-sealer contact ratios of AH Plus, EndoSequence BC, and prototype S-PRG groups were 65.6% ± 29.1%, 80.7% ± 25.8%, and 87.0% ± 8.6%, respectively. Conclusions: Prototype S-PRG sealer created a low-void obturation, similar to EndoSequence BC sealer with similar dentin-sealer contact (> 70%) and GP-sealer contact (> 80%). Prototype S-PRG sealer presented comparable filling quality to EndoSequence BC sealer.
... Surface pre-reacted glass-ionomer (S-PRG) filler has been reported as an ion-releasing, biofunctional glass filler to enhance the physical properties and bioactivities of dental materials, such as composite resin and endodontic sealer [7,8,9]. The surface of the core glass of the S-PRG filler possesses a thin glass-ionomer phase, therefore, it can rapidly release ions related to glass-ionomer phase: borate, fluoride, sodium, strontium, aluminum, and silicate [10,11]. ...
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Objectives Surface pre-reacted glass-ionomer (S-PRG) fillers release antibacterial borate and fluoride ions. We fabricated nanoscale S-PRG fillers (S-PRG nanofillers) for antibacterial coating of tooth surfaces and assessed the antibacterial effects of this coating in vitro. In addition, we creating a canine model of periodontitis to evaluate the effectiveness of S-PRG nanofiller application on tooth roots and improvement of periodontal parameters. Methods Human dentin blocks were coated with S-PRG nanofiller (average particle size: 0.48 μm) and then characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDX), and ion-releasing test. Antibacterial effects of dentin blocks coated with S-PRG nanofiller were examined using bacterial strains, Streptococcus mutans and Actinomyces naeslundii. Next, we created an experimental model of periodontitis in furcation of premolars of beagle dogs. Then, S-PRG nanofiller coating was applied onto exposed tooth root surfaces. Periodontal parameters, gingival index (GI), bleeding on probing (BOP), probing pocket depth (PPD), and clinical attachment level (CAL), were measured from baseline until 4 weeks. In addition, bone healing was radiographically and histologically examined. Results SEM and EDX revealed that S-PRG nanofillers uniformly covered the dentin surface after coating. Dentin blocks coated with S-PRG nanofiller showed ion-releasing property, bacterial growth inhibition, and sterilization effects. In the experimental periodontitis model, S-PRG nanofiller coating significantly reduced clinical inflammatory parameters, such as GI (P < 0.01) and BOP (P < 0.05), compared to uncoated samples. In addition, PPD and CAL significantly decreased by S-PRG nanofiller coating (2 weeks: P < 0.05; 3 and 4 weeks: P < 0.01), suggesting the improvement of periodontitis. Micro-CT and histology revealed that bone healing of furcation defects was enhanced by S-PRG nanofiller coating. Conclusion S-PRG nanofiller coating provides antibacterial effects to tooth surfaces and improves clinical parameters of periodontitis.
... In addition, an endodontic root canal sealer containing an S-PRG filler (i.e., S-PRG sealer) exhibited good antibacterial and anti-inflammatory properties. Finally, the implantation of S-PRG sealer into the subcutaneous tissues of rats noticeably decreased their inflammatory responses [19] The primary objective of this study was to examine the inhibitory effects of four products (three well-known GICs and one S-PRG containing coating material) on enamel demineralization to evaluate their anticaries properties. The release ions from GICs and S-RPG fillers and the acid buffering capacity were examined, and the surfaces of bovine enamels were observed by scanning electron microscopy (SEM). ...
Article
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This study was aimed at investigating the protective effects of glass ionomer cement (GIC) and surface pre-reacted glass ionomer (S-PRG) fillers used as dental restorative materials on demineralization of bovine enamel. GlasIonomer FX ULTRA (FXU), Fuji IX GP Extra (FIXE), CAREDYNE RESTORE (CDR) were used as GICs. PRG Barrier Coat (BC) was used as the S-PRG filler. They were incubated in a lactic acid solution (pH = 4.0) for six days at a temperature of 37 °C. The mineral was etched from the enamel surface, and a large number of Ca and P ions were detected in solution. The Al, F, Na, Sr, and Sr ions were released in GICs and S-RPG fillers. The Zn ion was released only in CDR and the B ion was released only in BC. The presence of apparent enamel prism peripheries was observed after six days of treatment for the group containing only enamel blocks. pH values for the FXU, FIXE, CDR, BC, and enamel block groups after six days were 6.5, 6.6, 6.7, 5.9, and 5.1, respectively. Therefore, the observed pH neutralization effect suppressed progression of caries due to the release of several ions from the restoratives.
... In addition, an endodontic root canal sealer containing an S-PRG filler (i.e., S-PRG sealer) exhibited good antibacterial and anti-inflammatory properties. Finally, the implantation of S-PRG sealer into the subcutaneous tissues of rats noticeably decreased their inflammatory responses [17]. ...
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We investigated the protective effects of glass ionomer cement (GIC) and surface pre-reacted glass ionomer (S-PRG) fillers used as dental restorative materials on the demineralization of bovine enamel during the incubation in a lactic acid solution with pH = 4.0 conducted for 6 d at a temperature of 37 °C. Scanning electron microscopy images of the specimen surfaces from the group containing only enamel blocks revealed the presence of apparent enamel prism peripheries after 6 d of treatment. The mineral was etched from the enamel surface, and a large number of Ca ions were detected in solution. In contrast, the enamel blocks incubated together with discs of GIC or S-PRG fillers did not exhibit demineralized surfaces, owing to the neutralization of the acid solution by the fillers within the first 3 h of the incubation process. The observed pH neutralization effect was attributed to the release of different ions from the fillers and could be utilized for suppressing the progression of caries.
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Objectives: To assess whether the dissolution products of S53P4 bioactive glass (BG) affect cellular response of macrophages and clinically relevant peri-implant cell populations to dental implant particles in vitro. Cells chosen were human gingival fibroblasts (HGFs), osteoblasts and bone marrow derived stromal cells (HBMSCs). Methods: Melt-derived S53P4 bioactive glass were prepared. HGFs, Saos-2 human osteoblastic cell line, HBMSCs and macrophages, derived from THP-1 human monocytic cell line, were cultured in the presence of particles from commercially pure titanium (Ti-CP4), grade 5 titanium alloy (Ti-6Al-4V), titanium-zirconium alloy (Ti-15Zr) or zirconia (Zr) (with respective diameters of 34.1 ± 3.8, 33.3 ± 4.4, 97.8 ± 8.2 and 71.3 ± 6.1 µm) with or without S53P4 dissolution products (conditioned media contained 327.30 ± 2.01 ppm Ca, 51.34 ± 0.41 ppm P and 61.48 ± 1.17 ppm Si, pH 8.01 ± 0.21). Inflammatory and macrophage polarisation markers including TNF-ɑ, IL-1, IL-6 and CD206 were quantified using enzyme-linked immunosorbent assay (ELISA). Results: The presence of Ti-6Al-4V implant particles significantly induced the expression of pro-inflammatory markers in all tested cell types. S53P4 BG dissolution products regressed the particle induced up-regulation of pro-inflammatory markers and, appeared to suppress M1 macrophage polarisation. Conclusions: Implant particles, Ti-6Al-4V in particular, resulted in significant inflammatory responses from cells. S53P4 BG may possess anti-inflammatory properties and potentially mediate macrophage polarisation behaviour. Clinical significance: The findings highlight that the use and benefits of BG is a promising field of study. Authors believe more collective efforts are required to fully understand the reliability, efficiency and exact mechanisms of action of BG in the search for new generation of treatment modalities in dentistry.
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Objectives Surface pre-reacted glass-ionomer (S-PRG) nanofiller, an antibacterial ion-releasing bioactive glass, has been shown to adhere to tooth surfaces and reported to improve inflammatory parameters in experimental periodontitis. In this study, cementum substrate was irrigated ultrasonically with dispersion to examine in-vitro nanofiller adhesion and antibacterial activity. Moreover, periodontal pockets in a beagle dog were ultrasonically irrigated with dispersion to assess periodontal healing. Methods The morphology of human cementum irrigated with S-PRG nanofiller dispersion was examined by scanning electron microscopy and energy dispersive X-ray spectrometry. The antibacterial activity of the treated cementum was tested using Actinomyces naeslundii. In addition, experimentally formed periodontal pockets in beagle dog were ultrasonically irrigated with S-PRG nanofiller dispersion. Periodontal parameters (gingival index, bleeding on probing, probing pocket depth, and clinical attachment level) were measured from baseline (0 weeks) through 12 weeks. Moreover, the effects of irrigation with S-PRG nanofiller on changes in periodontal microflora and bone healing were analyzed. Results After ultrasonic irrigation, S-PRG nanofiller adhered to the cementum and exhibited antibacterial activity. The periodontal parameters were shown to improve following ultrasonic irrigation with S-PRG nanofiller dispersion. Analysis by next-generation sequencing revealed that the ratio of red-complex species decreased in the pockets irrigated with S-PRG nanofiller dispersion. In addition, the S-PRG nanofiller showed the potential to promote bone healing. Conclusions Ultrasonic irrigation with S-PRG nanofiller dispersion using an ultrasonic scaler system permitted delivery of the S-PRG nanofiller to the root surface, providing improved parameters in experimental periodontitis and modifying the composition of subgingival periodontal microflora.
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Numerous studies have shown that the sustained release of ions from dental restorative materials have acid buffering capacity, prevents tooth enamel demineralization, and inhibits bacterial adhesion. Herein, the release behavior and bioresponsiveness of ions released from surface pre-reacted glass-ionomer (S-PRG) fillers were investigated in different types of media based on human dental pulp-derived stem cell (hDPSC) responses. The hDPSCs were cultured for 1–7 days in S-PRG eluates diluted with varying amounts of cell culture media. S-PRG released several types of ions, such as F⁻, Sr²⁺, Na⁺, Al³⁺, BO3³⁻, and SiO3²⁻. The balance of eluted ions differed depending on the dilution and solvent, which in turn affected the cytotoxicity, cell morphology, cell proliferation, and alkane phosphatase activity of hDPSCs, among other properties. The results suggest that tailored S-PRG filler eluates could be designed and prepared for application in dental practice.
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Aim: To evaluate the efficacy of a prototype root canal dressing containing surface pre-reacted glass-ionomer (S-PRG) fillers on repairing induced periapical lesions in a rat model. Calcium hydroxide [Ca(OH)2 ] was applied as a comparison in the healing process. Methodology: The pulp chambers of the maxillary first molars in 64 male Wistar rats aged 16 weeks were opened to induce periapical lesions. After 28 days, the mesial canal of each tooth was prepared, irrigated with 2.5% sodium hypochlorite only (control group: irrigation) or followed by the respective dressing [Ca(OH)2 group, irrigation + Ca(OH)2 ; S-PRG group, irrigation + S-PRG] and restored with composite resin for 3 or 7 days (10/group). Four rats with healthy molars were used as blank controls. Descriptive analysis of the periapical radiographs, haematoxylin and eosin staining and immunohistochemical observation was performed 3 and 7 days after treatment. The periapical grey value, CD68 macrophages and osteoclasts (cathepsin-K) were quantified and statistically analysed with Tukey's honest significant difference test. A significant difference was achieved when P values were <0.05. Results: S-PRG and Ca(OH)2 dressings were associated with increased periapical grey values and inhibited osteoclast activity at 3 and 7 days; a significant difference in radiographic results and the number of osteoclasts was obtained at 3 and 7 days compared with the control group (P < 0.05). Reparative tissue was observed histologically in the space of the periapical resorbed necrotic area after S-PRG and Ca(OH)2 treatment for 3 and 7 days. The number of macrophages was significantly decreased at 3 and 7 days in the S-PRG and Ca(OH)2 specimens when compared with the controls (P < 0.05). Conclusions: In a rat experimental model, the S-PRG root canal dressing was comparable to Ca(OH)2 in promoting the healing of experimentally induced periapical lesions. S-PRG paste has the potential to be used as an alternative intracanal dressing in teeth with apical periodontitis.
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In an attempt to combat the possibility of bacterial infection and insufficient bone growth around metallic, surgical implants, bioactive glasses may be employed as coatings. In this work, silica-based and borate-based glass series were synthesized for this purpose and subsequently characterized in terms of antibacterial behavior, solubility and cytotoxicity. Borate-based glasses were found to exhibit significantly superior antibacterial properties and increased solubility compared to their silica-based counterparts, with BRT0 and BRT3 (borate-based glasses with 0 and 15 mol% of titanium dioxide incorporated, respectively) outperforming the remainder of the glasses, both borate and silicate based, in these respects. Atomic Absorption Spectroscopy confirmed the release of zinc ions (Zn²⁺), which has been linked to the antibacterial abilities of glasses SRT0, BRT0 and BRT3, with inhibition effectively achieved at concentrations lower than 0.7 ppm. In vitro cytotoxicity studies using MC3T3-E1 osteoblasts confirmed that cell proliferation was affected by all glasses in this study, with decreased proliferation attributed to a faster release of sodium ions over calcium ions in both glass series, factor known to slow cell proliferation in vitro.
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Severe periodontal diseases cause root exposure, and there is no established method for the protection of exposed root surfaces. PRG Barrier Coat is a coating material with bioactive prereacted glass ionomer filler (hereafter, filler). However, the material can be detached in some clinical situations. We evaluated the effects of PRG Barrier Coat removal on root dentin demineralization under simulated oral cavity pH conditions. Five extracted human teeth were prepared, and three 200-μm-thick single sections were obtained from each tooth. The polished surfaces, except the outer surface, were covered with a wax coating. PRG Barrier Coat (BC group) or Fuji III (FIII group), a glass ionomer cement, was applied to the root surfaces of one section each from each tooth and removed after 24 h. The remaining sections were included as a control group. Then, all specimens were subjected to pH cycling (pH 6.8-4.5) for 6 weeks. All specimens were observed using transverse microradiography images obtained weekly during pH cycling, which were used for integrated mineral loss assessments. Fluoride and calcium levels in each specimen were also evaluated at 5 weeks using a proton-induced gamma emission/proton-induced X-ray emission system. The control group surfaces and the BC and FIII group subsurfaces showed demineralization at 5 weeks, while an outer surface remineralization layer formed in the BC group. In the BC group, subsurface demineralization was observed at week 1, and it disappeared at week 6. There were no significant differences in IML values before and during pH cycling in the BC and FIII groups. Furthermore, fluorides penetrated the root surfaces of specimens in both groups. These findings suggest that PRG Barrier Coat and FIII supplemented the root surface with fluoride and inhibited demineralization, which can facilitate caries prevention for approximately 1 to 6 months.
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Graphene oxide (GO) consisting of a carbon monolayer has been widely investigated for tissue engineering platforms because of its unique properties. For this study, we fabricated a GO-applied scaffold and assessed the cellular and tissue behaviors in the scaffold. A preclinical test was conducted to ascertain whether the GO scaffold promoted bone induction in dog tooth extraction sockets. For this study, GO scaffolds were prepared by coating the surface of a collagen sponge scaffold with 0.1 and 1 µg/mL GO dispersion. Scaffolds were characterized using scanning electron microscopy (SEM), physical testing, cell seeding, and rat subcutaneous implant testing. Then a GO scaffold was implanted into a dog tooth extraction socket. Histological observations were made at 2 weeks postsurgery. SEM observations show that GO attached to the surface of collagen scaffold struts. The GO scaffold exhibited an interconnected structure resembling that of control subjects. GO application improved the physical strength, enzyme resistance, and adsorption of calcium and proteins. Cytocompatibility tests showed that GO application significantly increased osteoblastic MC3T3-E1 cell proliferation. In addition, an assessment of rat subcutaneous tissue response revealed that implantation of 1 µg/mL GO scaffold stimulated cellular ingrowth behavior, suggesting that the GO scaffold exhibited good biocompatibility. The tissue ingrowth area and DNA contents of 1 µg/mL GO scaffold were, respectively, approximately 2.5-fold and 1.4-fold greater than those of the control. Particularly, the infiltration of ED2-positive (M2) macrophages and blood vessels were prominent in the GO scaffold. Dog bone-formation tests showed that 1 µg/mL GO scaffold implantation enhanced bone formation. New bone formation following GO scaffold implantation was enhanced fivefold compared to that in control subjects. These results suggest that GO was biocompatible and had high bone-formation capability for the scaffold. The GO scaffold is expected to be beneficial for bone tissue engineering therapy.
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Boron is absorbed by the digestive and respiratory system, and it was considered that it is converted to boric acid (BA), which was distributed to all tissues above 90 %. The biochemical essentiality of boron element is caused by boric acid because it affects the activity of several enzymes involved in the metabolism. DNA damage repair mechanisms and oxidative stress regulation is quite important in the transition stage from normal to cancerous cells; thus, this study was conducted to investigate the protective effect of boric acid on DNA damage and wound healing in human epithelial cell line. For this purpose, the amount of DNA damage occurred with irinotecan (CPT-11), etoposide (ETP), doxorubicin (Doxo), and H2O2 was determined by immunofluorescence through phosphorylation of H2AX(Ser139) and pATM(Ser1981) in the absence and presence of BA. Moreover, the effect of BA on wound healing has been investigated in epithelial cells treated with these agents. Our results demonstrated that H2AX(Ser139) foci numbers were significantly decreased in the presence of BA while wound healing was accelerated by BA compared to that in the control and only drug-treated cells. Eventually, the results indicate that BA reduced the formation of DNA double strand breaks caused by agents as well as improving the wound healing process. Therefore, we suggest that boric acid has important therapeutical effectiveness and may be used in the treatment of inflammatory diseases where oxidative stress and wound healing process plays an important role.
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Osteoclasts are bone-specific multinucleated cells generated by the differentiation of monocyte/macrophage lineage precursors. Regulation of osteoclast differentiation is considered an effective therapeutic approach to the treatment of bone-lytic diseases. Periodontitis is an inflammatory disease characterized by extensive bone resorption. In this study, we investigated the effects of sodium fluoride (NaF) on osteoclastogenesis induced by Porphyromonas gingivalis, an important colonizer of the oral cavity that has been implicated in periodontitis. NaF strongly inhibited the P. gingivalis-induced alveolar bone loss. That effect was accompanied by decreased levels of cathepsin K, interleukin (IL)-1β, matrix metalloproteinase 9 (MMP9), and tartrate-resistant acid phosphatase, which were up-regulated during P. gingivalis-induced osteoclastogenesis. Consistent with the in vivo anti-osteoclastogenic effect, NaF inhibited osteoclast formation caused by the differentiation factor RANKL (receptor activator of nuclear factor κB ligand) and macrophage colony-stimulating factor (M-CSF). The RANKL-stimulated induction of the transcription factor nuclear factor of activated T cells (NFAT) c1 was also abrogated by NaF. Taken together, our data demonstrate that NaF inhibits RANKL-induced osteoclastogenesis by reducing the induction of NFATc1, ultimately leading to the suppressed expression of cathepsin K and MMP9. The in vivo effect of NaF on the inhibition of P. gingivalis-induced osteoclastogenesis strengthens the potential usefulness of NaF for treating periodontal diseases.
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Development of tools to be used for in vivo bone tissue regeneration focuses on cellular models and differentiation processes. In searching for all the optimal sources, adipose tissue-derived mesenchymal stem cells (hADSCs or preadipocytes) are able to differentiate into osteoblasts with analogous characteristics to bone marrow mesenchymal stem cells, producing alkaline phosphatase (ALP), collagen, osteocalcin, and calcified nodules, mainly composed of hydroxyapatite (HA). The possibility to influence bone differentiation of stem cells encompasses local and systemic methods, including the use of drugs administered systemically. Among the latter, strontium ranelate (SR) represents an interesting compound, acting as an uncoupling factor that stimulates bone formation and inhibits bone resorption. The aim of our study was to evaluate the in vitro effects of a wide range of strontium (Sr 2+ ) concentrations on proliferation, ALP activity, and mineralization of a novel finite clonal hADSCs cell line, named PA20-h5. Sr 2+ promoted PA20-h5 cell proliferation while inducing the increase of ALP activity and gene expression as well as HA production during in vitro osteoinduction. These findings indicate a role for Sr 2+ in supporting bone regeneration during the process of skeletal repair in general, and, more specifically, when cell therapies are applied.
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Background: Side effects of anti-inflammatory agents are a major problem during clinical use. The development of a newer, effective, and safe anti-inflammatory agent should be considered. Boron-containing compounds are found effective as anti-inflammatory agents with relatively low side effects. We aimed to evaluate the anti-inflammatory activity of boron in animal models of chronic and granulomatous inflammation. Methods: Sixty-six Wistar rats were allocated into five groups; 1st (6 rats) treated with vehicle only without induction as a negative control; 2nd (12 rats) allocated into two subgroups, treated with vehicle only, with induction of chronic and granulomatous inflammation, as appositive control. 3rd group (24 rats) allocated into four subgroups, treated with different doses of boron (3 and 6 mg/kg) in both models. Fourth group (12 rats) treated with dexamethasone (1 mg/kg) in the same models. 5th group (12 rats used) treated with boron (3 mg/kg) with dexamethasone (1 mg/kg) in the same models. Results: Boron, in a dose-dependent pattern significantly decreases inflammation in rat models of chronic and granulomatous inflammation. Combination of boron with dexamethasone significantly suppresses inflammation in both models, which is significantly higher than all of the effects produced by other approaches of treatment. Conclusion: Boron, in a dose-dependent pattern, effectively suppresses formaldehyde-induced chronic inflammation and cotton pellet-induced granuloma in rats when used alone or as an adjuvant with dexamethasone. It may be considered as a potential treatment for chronic inflammatory conditions.
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A composite resin containing surface pre-reacted glass ionomer(S-PRG) has become widely used as filler or other dental materials in dental treatment. In this mini-review, we briefly summarizethe antibacterial activities of S-PRG on different oral bacteria. The inhibitory effect of S-PRG on plaque formation in the oral cavity has been observed. Streptococcus mutans adherence has been shown to be inhibited by S-PRG. S-PRG is also considered to be effective in caries prevention because S-PRG eluate could inhibit biofilm formation and disrupt salivary mature polymicrobial biofilm. S-PRG eluate has suppressed the protease and gelatinase activities of Porphyromonas gingivalis, which is one of the most important periodontopathic bacteria. Coaggregation by P. gingivali sand Fusobacterium nucleatum was also inhibited by S-PRG eluate. Other work has shown that an endodontic sealer containing S-PRGhad an antibacterial effect on some endodontic bacteria. Oral rinsing with S-PRG eluate was also effective in reducing oral malodor production. In this way, S-PRG has antibacterial effect, and it will be further applied for various dental materials and contribute to preventing oral diseases.
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Aseptic loosening is a common cause of joint implant failure in humans. In order to enhance implant stability, we need to develop a new material that not only promotes the wear resistance of components of an artificial joint, but also possesses the pharmaceutical efficacy of protecting patients against aseptic loosening. Strontium-doped calcium polyphosphate (SCPP) has been found to have this potential ability. The goal of this study is to respectively quantify the levels of TNF-α (for macrophages), receptor activator of NF-kB ligand (RANKL) and osteoprotegerin (OPG) (for osteoblasts) when osteoblasts and macrophages are challenged with various particles (including SCPP). In this study, the osteoblasts ROS 17/2.8 and macrophages RAW 264.7 were challenged with various wear particles (8% SCPP, the molar percentage of Sr in SCPP is 8%, UHMWPE, hydroxyapatite (HA) and CPP). The secretion of TNF-α (from RAW 264.7), OPG and RANKL protein (from ROS 17/2.8) was analyzed by ELISA. The OPG and RANKL mRNA from ROS 17/2.8 was detected by RT-PCR. The data of ELISA indicated that the amount of TNF-α challenged with 8% SCPP particles was more than three-fold lower than that of all other test groups. The ratio of OPG/RANKL in the 8% SCPP group was significantly increased compared to that of all other test groups. The results of OPG and RANKL mRNA expression showed the same tendency as the ELISA results. In general, this study showed that 8% SCPP particles can inhibit the expression of TNF-α and RANKL, promote the expression of OPG so that SCPP can inhibit bone resorption and promote bone formation, and then inhibit aseptic loosening. Thus SCPP could be a promising material for the construction of artificial joints.
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The aim of this study was to compare the clinical and radiological outcome of mineral trioxide aggregate (MTA) or epoxy resin as a root canal sealer compared with zinc oxide eugenol sealer. 45 single rooted teeth with periapical index Score 2 or more were allotted to three groups with 15 teeth in each group. Root canal treatment was performed in two visits and obturated with Gutta-percha as obturating material and zinc oxide eugenol as sealer in Group 1, epoxy resin as sealer in Group 2 and MTA mixed with propylene glycol as sealer in Group 3. Visual analog scale, periapical index and VixWin digital Pro image analysis software were used for evaluation. The quantitative data was analyzed by t-test and analysis of variance. Ordinal data was analyzed by Wilcoxon's signed rank test, Mann-Whitney and Kruskall-Wallis test. Results suggested that there exists no statistically significant difference in clinical or radiological outcome of root canal therapy with three different types of sealers used in this study. MTA could be used as a root canal sealer with equal effectiveness compared with epoxy resin and zinc oxide eugenol sealers. Further long-term studies should be carried out to prove the effectiveness.
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New synthetic biomaterials are constantly being developed for wound repair and regeneration. Bioactive glasses (BG) containing strontium have shown successful applications in tissue engineering account of their biocompatibility and the positive biological effects after implantation. This study aimed to assess whether BG-Sr was accepted by the host tissue and to characterize oxidative stress biomarker and antioxidant enzyme profiles during muscle and skin healing. Wistar rats were divided into five groups (six animals per group): the group (I) was used as negative control (T), after ovariectomy, groups II, III, IV and V were used respectively as positive control (OVX), implanted tissue with BG (OVX-BG), BG-Sr (OVX-BG-Sr) and presented empty defects (OVX-NI). Soft tissues surrounding biomaterials were used to estimate superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and malondialdehyde (MDA) concentration. Our results show that 60 days after operation, treatment of rats with BG-Sr significantly increased MDA concentration and caused an increase of SOD, CAT and GPx activities in both skin and muscular tissues. BG-Sr revealed maturation of myotubes followed a normal appearance of muscle regenerated with high density and mature capillary vessels. High wound recovery with complete re-epithelialization and regeneration of skin was observed. The results demonstrate that the protective action against reactive oxygen species (ROS) was clearly observed in soft tissue surrounding BG-Sr. Moreover, the potential use of BG-Sr rapidly restores the wound skin and muscle structural and functional properties. The BG advantages such as ion release might make BG-Sr an effective biomaterial choice for antioxidative activity.
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This study investigated the effect of a coating material containing S-PRG fillers on the demineralization of bovine enamel and dentin, by measuring changes in the transmitted ultrasonic velocity. Bovine enamel and dentin specimens with and without coating (n=6 for each condition) were cut into blocks, immersed in 0.1 M lactic-acid buffer solution (pH 4.75) for 10 min twice daily throughout the test period, and stored in a demineralising artificial saliva solution (pH 7.0) between treatments. The propagation time of longitudinal ultrasonic waves was measured by a pulser-receiver with a transducer. Data were evaluated using ANOVA followed by Tukey's HSD test (α=0.05). The sonic velocity decreased over time for specimens stored in demineralising solution; however, coated specimens had a significantly higher sonic velocity than those without coating. The coating material containing pre-reacted glass-ionomer fillers therefore appeared to reduce the demineralisation of enamel and dentin.
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The purpose of this study was to evaluate the ability of a coating material containing the surface pre-reacted glass-ionomer (S-PRG) filler to protect the root from demineralization in vitro. The proprietary coating resin containing the S-PRG filler (PRG Barrier Coat) was applied to human root dentin and immersed in acid buffer at pH 4.5 for 3 d. Demineralization was evaluated by micro-CT scanning and the dentin-material interface observed by scanning electron microscopy. The ability of the coating resin to modify acid production by Streptococcus mutans was investigated by monitoring pH using an ion-sensitive field-effect transistor pH electrode. Application of PRG Barrier Coat produced a coating layer with the thickness of approximately 200 µm and completely inhibited demineralization. The bacteria-induced pH fall at the material surface was significantly inhibited. We conclude that S-PRG fillercontaining coating resin may be an effective material for protecting exposed root from both chemical and biological challenges.
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We evaluated the concentration of fluoride release at the initial stage and after recharging the fluoride from a resin-based sealant containing surface reaction-type pre-reacted glass-ionomer (S-PRG) filler and conventional resin-based sealants. The concentration of other ions released from the sealants in the surrounding distilled water was also examined. At the initial stage, fluoride was released from all sealants. For the sealant containing S-PRG filler, a significantly higher amount of Sr and B ions was detected relative to those from other sealants. After sealant samples were soaked in a sodium fluoride solution, a significant amount of fluoride and other ions was released from the sealant containing S-PRG filler. These findings suggest that sealants containing S-PRG filler enhance the enamel demineralization-inhibiting effect and the remineralization-promoting effect for long-term dental care.
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Objective: This study aimed to evaluate a prototype surface reaction-type pre-reacted glass-ionomer (S-PRG) filler-containing endodontic sealer (S-PRG sealer) in terms of its ion-releasing ability and the incorporation of the released ions by root canal dentin. Materials and methods: The concentration of ions in the set S-PRG sealer was measured by ICPS and with a fluoride ion electrode. Element mapping and chemical component bulk analysis of the outermost dentin of the S-PRG sealer-dentin interface were performed by SEM-EPMA. The incorporation depth of the elements in dentin was measured by element line scanning. Results and discussion: Ions released from the S-PRG sealer (Al, B, F, Na, Si, Sr, and Zn) were detected over time. The incorporation of fluoride (F), strontium (Sr), silicon (Si), and boron (B) was observed along the outermost dentin of the S-PRG sealer-dentin interface by EPMA analysis, and the incorporation depth increased with prolonged immersion. Conclusion: The continuous release of ions from the S-PRG sealer and their subsequent incorporation by root canal dentin were confirmed.
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Boron is an essential micronutrient for plants, and it is beneficial for animals. However, at high concentrations boron is toxic to cells although the mechanism of this toxicity is not known. Atr1 has recently been identified as a boron efflux pump whose expression is upregulated in response to boron treatment. Here, we found that the expression of ATR1 is associated with expression of genes involved in amino acid biosynthesis. These mechanisms are strictly controlled by the transcription factor Gcn4 in response to boron treatment. Further analyses have shown that boron impaired protein synthesis by promoting phosphorylation of eIF2α in a Gcn2 kinase dependent manner. The uncharged tRNA binding domain (HisRS) of Gcn2 is necessary for the phosphorylation of eIF2α in the presence of boron. We postulate that boron exerts its toxic effect through activation of the general amino acid control system and inhibition of protein synthesis. Since the general amino acid control pathway is conserved among eukaryotes, this mechanism of boron toxicity may be of general importance.
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Surface attributes of a restoration play an important role in adherence of plaque bacteria. Prophylaxis methods may be involved in modification of or damaging the restoration surface. The aim of the present study was to evaluate the effect of two prophylaxis methods on adherence of Streptococcus mutans to the surface of two restorative materials. A total of 60 specimens were prepared from each material; a microfilled composite resin (HelioProgress) and a giomer (Beautifil II). For each material, the specimens were randomly divided into three groups (n=20). Group 1: no prophylaxis treatment (control); Group 2: prophylaxis with pumice and rubber cup; Group 3: prophylaxis with air-powder polishing device (APD). The surfaces of selected specimens from each group were evaluated under a scanning electron microscope (SEM), and the surface topography formed by the two prophylaxis methods was determined by atomic force microscopy (AFM). Adherence of Streptococcus mutans to the surface of specimens was determined by the plate counting method following immersion in a bacterial innoculum for 4 hours, rinsing and sonication. Data were analyzed by two-way ANOVA and post hoc Tukey test for multiple comparisons. Statistical significance was set at P<0.05. Bacterial adherence was significantly affected by both factors: restorative material type and prophylaxis method (P<0.0005). Mean bacterial adhesion was significantly higher in composite groups compared to corresponding giomer groups. Within each material, bacterial adherence was significantly lower in the control group compared to prophylaxis groups. Prophylaxis with pumice and rubber cup resulted in a significantly lower bacterial adherence compared to prophylaxis with APD. Based on the results of the present study, giomer specimens demonstrated lower bacterial adherence compared to composite resin specimens. In both materials, the highest bacterial adherence was observed with prophylaxis with APD, pumice and rubber cup and the control group, respectively.
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The purpose of this study was to examine the antibacterial activity of composite resin with glass-ionomer filler particles versus that of contemporary commercial composite resins. Three composite resins were used: Beautifil II (containing S-PRG filler), Clearfil AP-X, and Filtek Z250. Resin blocks were bonded to maxillary first molars, and plaque accumulation on the resin block surface was examined after 8 hours. For the antibacterial test, the number of Streptococcus mutans in contact with the composite resin blocks after incubation for 12 hours was determined, and adherence of radiolabeled bacteria was evaluated. Less dental plaque was formed on Beautifil II resin block as compared to the other two materials. Antibacterial test revealed that there were no significant differences in the number of Streptococcus mutans among the three composite resins. However, the adherence of radiolabeled bacteria to the saliva-treated resin surface was significantly (p<0.01) lower in Beautifil II than in the other two materials. These results suggested that Beautifil II could reduce dental plaque formation and bacterial adherence, leading to prevention of secondary caries.
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This study introduces a calcium fluoride (CaF2)-containing composite hydrogel with good biocompatibility and antibacterial properties for multifunctional wound-dressing applications. CaF2 particles were uniformly embedded within a hyaluronic acid (HA) based pure hydrogel using an in situ precipitation process. By varying the CaCl2 and NH4F concentrations used in the precipitation as well as the precipitation time, composite hydrogels with different ion-release profiles were obtained. Colony tests and live/dead assays using Escherichia coli and Staphylococcus aureus revealed a lower density of bacteria on the CaF2 composite hydrogels than on the pure hydrogel for both strains. In addition, improved cellular responses such as cell attachment and proliferation were also observed for the CaF2 composite hydrogels than for the pure hydrogel. Furthermore, the composite hydrogels exhibited excellent wound healing efficiency, as evidenced by an in vitro cell migration assay. Finally, monitoring of the wound closure changes using a full-thickness wound in a rat model revealed the accelerated wound healing capability of the CaF2 composite hydrogels compared with that of the pure hydrogel. Based on our findings, these CaF2 composite hydrogels show great potential for application as advanced hydrogel wound dressings with antibacterial properties and accelerated wound-healing capabilities.
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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 BO33- 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 BO33- 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 BO33- 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 BO33- 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 BO33- or F-. Clinical significance: BO33- 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.
Article
Objective A surface pre-reacted glass-ionomer (S-PRG) filler is a technology of interest for providing bio-functions to restorative materials. Resin composites containing S-PRG filler have been reported to show less plaque accumulation and reduced bacterial attachment. In this study, experimental resin composites containing S-PRG filler at various concentrations were fabricated, and the inhibitory effects on bacterial growth on their surface and the association of ions released from S-PRG filler with antibacterial activity were evaluated. Methods Five kinds of experimental resin composites containing S-PRG filler at 0, 13.9, 27.3, 41.8, or 55.9 (vol.%) were fabricated. Streptococcus mutans was cultured on the cured discs for 18 h to examine the growth of bacteria in contact with the surface of the experimental resins. The concentrations of Al³⁺, BO3³⁻, F⁻, Na⁺, SiO3²⁻, or Sr²⁺ released from each experimental resin into water were measured. The standardized solutions of each ion were prepared at the concentrations determined to be released from the experimental resin, and their inhibitory effects of single ion species on S. mutans growth were evaluated by using each standardized solution. Results Resin composites containing S-PRG filler at 13.9 (vol.%) or greater inhibited S. mutans growth on their surface. When S. mutans was incubated in the presence of six kinds of ions at the concentrations released from the resin composite containing S-PRG filler at 55.9 (vol.%), a significant reduction in bacterial number was observed for BO3³⁻, F⁻, Al³⁺, and SiO3²⁻. Among these four ions, BO3³⁻ and F⁻ demonstrated the strongest inhibitory effect on S. mutans growth. Significance Our findings suggest that resin composites containing S-PRG filler inhibit the growth of S. mutans on their surface. BO3³⁻, F⁻, Al³⁺ and SiO3²⁻ released from S-PRG filler have the ability to inhibit S. mutans growth, and the inhibitory effects are mainly attributed to release of BO3³⁻ and F⁻.
Article
This study focused on the antibacterial activity of the fluoride ions corted titanium. The profile of the elements of the modified material were analyzed with a X-ray photoelectron spectroscopy analysis system. At the same time, in vitro bacteria culture model was established to evaluate the influence of the modified titanium on the colonization and adhesion of Porphyromonas gingivalis (P.g.). It was confirmed by bacterial colony counting assays and SEM observations that fluoride ion-corted titanium could effectively influence the adhesion and growth of P. g. The current results indicated that fluoride ion corting could improve the antibacterial activity of titanium. © 2011 The Hard Tissue Biology Network Association Printed in Japan, All rights reserved.
Article
The buffering capacity and inhibitory effects on enamel demineralization of two commercially available dental sealants were evaluated in this study. The effects of filler particles were also examined. Disks of enamel and cured sealant materials of BeautiSealant (silica or S-PRG filler) or Teethmate F-1 were incubated in lactic acid solutions (pH 4.0) for 1-6 d. The pH changes and amounts of ions released in the solutions were assessed, and enamel surfaces were observed using a scanning electron microscope. The pH of the solution with BeautiSealant (S-PRG filler) was neutralized from pH 4.0 to pH 6.1 (after incubation for 1 d) and from pH 4.0 to pH 6.7 (after incubation for 6 d). In addition, no release of calcium ions was detected and the enamel surface was morphologically intact in scanning electron microscopy images. However, the pH of the solution with Teethmate F-1 remained below pH 4.0 during incubation from days 1 to 6. Calcium release was increased in solutions up to and after 6 d of incubation. Scanning electron microscopy images showed that the structures of hydroxyapatite rods were exposed at the specimen surfaces as a result of demineralization. Ions released from S-PRG filler-containing dental sealant rapidly buffered the lactic acid solution and inhibited enamel demineralization.
Article
There is growing evidence that strontium ranelate (SR; S12911-2, PROTELOS; Institut de Recherches Internationales Servier, Courbevoie, France), a compound containing 2 atoms of stable strontium (Sr), influences bone cells and bone metabolism in vitro and in vivo. We previously reported that SR increases bone mass in rats and mice by stimulating bone formation and inhibiting bone resorption. We also showed that short-term treatment with SR enhances osteoblastic cell recruitment and function in short-term rat calvaria cultures. Because Sr incorporates into the bone matrix, it was of interest to determine whether SR may affect matrix mineralization in long-term culture. To this goal, osteogenic mouse calvaria-derived MC3T3-E1 osteoblastic cells were cultured for up to 14 days in the presence of ascorbic acid and phosphate to induce matrix formation and mineralization. Matrix formation was determined by incorporation of tritiated proline during collagen synthesis. Matrix mineralization was quantified by me
Article
The aim of the present study was to investigate the biological mechanisms of the functional attachment of fluoride-modified titanium implants to cortical bone by studying the association of the pull-out test results with gene expression of osteoblast (runx2, osteocalcin, collagen-I and IGF-I), osteoclast (TRAP, H+-ATPase and calcitonin receptor) and inflammation (TNF-α, IL-6 and IL-10) markers from peri-implant bone tissue using real-time RT–PCR, following a 4- and 8-week healing period. After implant detachment, wound fluid from the implant site was collected for LDH and ALP activity analysis. A new method to study volumetric bone mineral density (vBMD) of sub-implant cortical bone was developed using micro-computed tomography. Our results show lower LDH activity and TRAP mRNA levels in fluoride implants after 4 weeks of healing, yet no differences were found either on the pull-out force or expression of bone formation marker genes. After 8 weeks of healing, both pull-out, vBMD and osteocalcin, runx2 and collage type I gene expression were higher in fluoride implants. In conclusion, fluoride-modified implants seem to modulate both inflammation and bone resorption/formation events at the bone–implant interface, suggesting that these biological effects are an intrinsic part of the clinical performance of this surface.
Article
This study was designed to investigate the effect of strontium on human PDL cells in vitro. Strontium is used to treat osteoporosis because of its bone formation promoting effect on osteoblast cells. This investigation presents evidence that strontium promotes PDL cell proliferation. Simultaneously, strontium suppresses the expression of the inflammation-promoting cytokine IL-6. The observed effect of strontium on PDL cells supports its use it in guided dental tissue regeneration.
Article
Strontium ranelate is a newly approved drug that can reduce the risk of vertebral fracture, which is attributed to its dual function in increasing the bone formation and decreasing the bone resorption. Strontium-containing hydroxyapatite was also demonstrated to stimulate the osteoblast activity and inhibit the osteoclast activity. However, the molecular mechanisms of strontium underlying such beneficial effects were still not fully understood. In this study, we investigated the effects of strontium on the osteogenic differentiation of human mesenchymal stem cells (MSCs) and its related mechanism; its osteogenic potential was also evaluated using a calvarial defect model in rats. We found that strontium could enhance the osteogenic differentiation of the MSCs, with upregulated extracellular matrix (ECM) gene expression and activated Wnt/β-catenin pathway. After transplanting the collagen-strontium-substituted hydroxyapatite scaffold into the bone defect region, histology and computed tomography scanning revealed that in vivo bone formation was significantly enhanced; the quantity of mature and remodeled bone substantially increased and ECM accumulated. Interestingly, strontium induced an increase of β-catenin expression in newly formed bone area. In this study, we showed for the first time that strontium could stimulate the β-catenin expression in vitro and in vivo, which might contribute to the enhanced osteogenic differentiation of MSCs and in vivo bone formation.
Article
The purpose of this study was to analyze the ions released from a surface pre-reacted glass ionomer (S-PRG) filler in distilled water or lactic acid solution. S-PRG filler was mixed with either solution at 1000:1, 100:1, 10:1, and 1:1 ratios by weight. By means of inductively coupled plasma atomic emission spectroscopy and a fluoride electrode, elements released from S-PRG filler were identified to be Al, B, Na, Si, Sr, and F. To investigate the effect of solution pH on ion release, the pH values of the solutions before mixing and after 24 hours' mixing with S-PRG were measured. After 24 hours' mixing, the pH values of solutions at all ratios became more neutral or weakly alkaline regardless of their initial pH levels before mixing. In conclusion, results showed that S-PRG filler released several types of ions, and that ion release was influenced by the mixing ratio of the solution rather than the initial pH of the solution.
Article
Alendronate is a known inhibitor of root resorption and the development of alendronate paste would enhance its utilization as intracanal medication. Therefore, this study aimed to investigate the biocompatibility of experimental alendronate paste in subcutaneous tissue of rats, for utilization in teeth susceptible to root resorption. The study was conducted on 15 male rats, weighing approximately 180-200 grams. The rats' dorsal regions were submitted to one incision on the median region and, laterally to the incision, the subcutaneous tissue was raised and gently dissected for introduction of two tubes, in each rat. The tubes were sealed at one end with gutta-percha and taken as control. The tubes were filled with experimental alendronate paste. The animals were killed at 7, 15 and 45 days after surgery and the specimens were processed in laboratory. The histological sections were stained with hematoxylin-eosin and analyzed by light microscopy. Scores were assigned to the inflammatory process and statistically compared by the Tukey test (P < 0.05). Alendronate paste promoted severe inflammation process at 7 days, with statistically significant difference compared to the control (P < 0.05%). However, at 15 days, there was a regression of inflammation and the presence of connective tissue with collagen fibers, fibroblasts and blood vessels was observed. After 45 days, it was observed the presence of well-organized connective tissue, with collagen fibers and fibroblasts, and few inflammatory cells. No statistical difference was observed between the control and experimental paste at 15 and 45 days. The experimental alendronate paste was considered biocompatible with subcutaneous tissue of rat.
Article
The cytotoxicity of six different zinc oxide-eugenol root canal sealers was tested by determining the incorporation of [L-14C]leucine in human gingival fibroblasts that had been in contact with root canal sealers after setting for 24 and 48 h. The biopsies were obtained from healthy patients. In some cases there was a significant difference shown in the fibroblasts' protein synthesis ([L-14C]leucine incorporation) between the group that was coveted with fibroblasts 24 h and the group that was covered 48 h after mixing (p less than 0.05). The fibroblasts were cultured with the different sealers for 21 days. In the 24-h group, Pulp Canal Sealer showed initially moderate cytotoxic potential but, after 13 days, fibroblast recovery was noticeable. Tubli-Seal, Endoseal, Hermetic, Proco-Sol, and Wach's Formula showed slight recovery at the end phase of the test. Hermetic and Endoseal showed also in the 48-h group a similar development as in the 24-h group. A relative low cytotoxicity was observed with Tubli-Seal, Proco-Sol, Pulp Canal Sealer, and Wach's Formula at the beginning of the test period. Pulp Canal Sealer showed at the middle phase of the trial a toxic increase, but after the 15th day recovery of the fibroblasts was noticed. In this group constant toxic potential increase was observed with Wach's Formula and Tubli-Seal.
Article
The number of discrete, three-dimensional bone nodules formed in vitro from a class of osteoprogenitor cells present in fetal rat calvaria cell populations (RC cells) is linearly related to the number of cells plated, implying that this system functions as a colony assay for the expression of osteoprogenitor cells. To determine the effect of fluoride on the expression of these cells, primary RC cells were grown for periods of up to 21 days in alpha-MEM (minimal essential medium) containing 5-15% heat-inactivated fetal bovine serum (FBS), 50 micrograms/ml ascorbic acid, 10 mM Na beta-glycerophosphate, and NaF at concentrations from 10 microM to 5 mM. The continuous presence of NaF resulted in an increase in the number of bone nodules with maximal response occurring at 500 microM (p less than 0.001). A similar response at 500 microM NaF was observed also with regard to alkaline phosphatase activity. NaF levels up to 500 microM did not affect the growth of the mixed RC cell population, however, higher concentrations (1 mM) significantly reduced cell numbers (p less than 0.001) suggestive of cytotoxicity. Plating efficiency tests for colony formation in the presence of 0.5 to 2 mM NaF showed that the decreases in nodule formation observed at concentrations above 500 microM correlated with cytotoxicity. NaC1 at 1 mM had no effect on nodule formation, alkaline phosphatase activity, or cell growth. The results show that NaF stimulates osteoprogenitor cell number in vitro and that the maximal effect occurs at concentrations close to toxic levels.
Article
A new root canal sealer based on calcium hydroxide has been developed and two properties, sealing ability and biocompatibility, have been investigated in this study. Sealing ability was assessed by the extent of dye penetration along root fillings in extracted teeth. The sealing ability was good and similar to that of a control zinc oxide-eugenol sealer. Biocompatibility was assessed by histological examination of the periapical tissues of monkey teeth, either 1 or 6 months, after vital pulpectomy and immediate root filling with gutta-percha and sealer. Zinc oxide-eugenol was used as the control sealer. Normal periapical tissues were observed around all 24 teeth filled with the experimental root canal sealer. The study established that the new root canal sealer had acceptable properties of biocompatibility and sealing ability.
Article
Fluoride is widely used as a highly effective anticaries agent. Although it is felt that its anticaries action is related mainly to effects on mineral phases of teeth and on the process of remineralization, fluoride also has important effects on the bacteria of dental plaque, which are responsible for the acidification of plaque that results in demineralization. The results of recent studies have shown that fluoride can affect bacterial metabolism through a set of actions with fundamentally different mechanisms. It can act directly as an enzyme inhibitor, for example for the glycolytic enzyme enolase, which is inhibited in a quasi-irreversible manner. Direct action seems also to occur in inhibition of heme-based peroxidases with binding of fluoride to heme. The flavin-based peroxidases of many oral bacteria are insensitive to fluoride. Another mode of action involves formation of metal-fluoride complexes, most commonly AlF4-. These complexes are responsible for fluoride inhibition of proton-translocating F-ATPases and are thought to act by mimicking phosphate to form complexes with ADP at reaction centers of the enzymes. However, the actions of fluoride that are most pertinent to reducing the cariogenicity of dental plaque are those related to its weak-acid character. Fluoride acts to enhance membrane permeabilities to protons and compromises the functioning of F-ATPases in exporting protons, thereby inducing cytoplasmic acidification and acid inhibition of glycolytic enzymes. Basically, fluoride acts to reduce the acid tolerance of the bacteria. It is most effective at acid pH values. In the acidic conditions of cariogenic plaque, fluoride at levels as low as 0.1 mM can cause complete arrest of glycolysis by intact cells of Streptococcus mutans. Overall, the anticaries actions of fluoride appear to be complex, involving effects both on bacteria and on mineral phases. The antibacterial actions of fluoride appear themselves to be complex but to be dominated by weak-acid effects.
Article
In this study a new epoxy-resin-based endodontic sealer, AH Plus, was tested in vitro for apical leakage. The conventional sealer AH26, for which information is already available, was used as the control. The root canals of 72 single-rooted teeth were prepared biomechanically using a stepback technique before lateral condensation of gutta-percha with one of the two sealers. Teeth were immersed in 5% methylene blue dye for 2, 4 or 10 days. The roots were split longitudinally so that the extent of dye penetration could be measured with a stereomicroscope. The mean extent at 2 days was 0.4 mm for AH26 and 1.4 mm for AH Plus. Neither material produced a complete apical seal and leakage increased with the duration of immersion in dye. The differences between observation periods as well as between materials with respect to dye penetration were statistically significant ANOVA, (P < 0.005).
Article
Enterococcus faecalis is a microorganism commonly detected in asymptomatic, persistent endodontic infections. Its prevalence in such infections ranges from 24% to 77%. This finding can be explained by various survival and virulence factors possessed by E. faecalis, including its ability to compete with other microorganisms, invade dentinal tubules, and resist nutritional deprivation. Use of good aseptic technique, increased apical preparation sizes, and inclusion of 2% chlorhexidine in combination with sodium hypochlorite are currently the most effective methods to combat E. faecalis within the root canal systems of teeth. In the changing face of dental care, continued research on E. faecalis and its elimination from the dental apparatus may well define the future of the endodontic specialty.
Antiinflammatory effects of boron alone or as adjuvant with dexamethasone in animal models of chronic and granulomatous inflammation
  • Hnm Ameen
  • S A Hussain
  • Z A Ahmed
  • T A Aziz
Ameen HNM, Hussain SA, Ahmed ZA, Aziz TA. Antiinflammatory effects of boron alone or as adjuvant with dexamethasone in animal models of chronic and granulomatous inflammation. Int J Basic Clin Pharmacol 2015; 4: 701-707.
Effective wound healing by antibacterial and bioactive calcium-fluoride-containing composite hydrogel dressings prepared using in situ precipitation
  • J Seol-Ha
  • S Da-Yong
  • K In-Ku
  • Eun - Ho
  • S Jiung
Seol-Ha J, Da-Yong S, In-Ku K, Eun-Ho S, Yun-Jeong S, JiUng P, et al. Effective wound healing by antibacterial and bioactive calcium-fluoride-containing composite hydrogel dressings prepared using in situ precipitation. ACS Biomater Sci Eng 2018; 4: 2380-2389.