This study examined the release of cetylpyridinium chloride and benzalkonium chloride from fatty ... more This study examined the release of cetylpyridinium chloride and benzalkonium chloride from fatty acid chelate temporary dental cement and their antimicrobial effects. The cement was Cavex Temporary, and either cetylpyridinium chloride or benzalkonium chloride was added (1% or 5% by mass), incorporating into the base paste. Release of the additives was determined by reverse-phase high-performance liquid chromatography. Possible chemical interactions between the cement components and additives were examined by Fourier transform infrared (FTIR) spectroscopy. Antimicrobial effects were assessed by measuring the zone of inhibition around sample discs after 24 h in a Streptococcus mutans culture. FTIR spectroscopy showed no interaction with cement components. For both additives, release was by diffusion for approximately the first 6 hours, with equilibration after about 2 weeks. Diffusion coefficients were 1.76 m 2 s ½ to 8.05 × 10 −12 m 2 s ½ and total release was 10.3 to 44.7% of additive loading. Zones of inhibition with additive were significantly larger than those for control discs. In conclusion, the antimicrobial properties of Cavex temporary cement are improved by the addition of the antimicrobial compounds cetylpyridium chloride and benzalkonium chloride, which are released by a diffusion process.
The purpose of this study was to investigate the enamel remineralization potential of two toothpa... more The purpose of this study was to investigate the enamel remineralization potential of two toothpastes, one of which was based on Recaldent (CPP- ACP) and the other on NovaMin (Calcium-sodium-phosphosilicate). Human permanent molar teeth were subjected to three consecutive demineralization cycles. These cycles were followed by remineralization of the experimental groups by toothpastes containing Recalden and NovaMin respectively. The samples were analyzed by Scanning Electron Microscope, (SEM) and energy-dispersive X-ray spectroscopy analysis (EDX). Extensive demineralization was noted in the control group (without remineralization) while the groups treated with the dentifices demonstrated various degrees of remineralization, as shown by formation of different types of deposits on the enamel surface. The EDX analysis showed increased amounts of Ca, P Si and Zn in the enamel of the experimental groups, compared to the control one. Toothpastes containing Recalden and especially NovaMin have the potential to remineralize enamel, a property which might be important in finding a substitute to pit and fissure sealing.
Conventional glass-ionomer cements (GICs) are popular restorative materials, but their use is lim... more Conventional glass-ionomer cements (GICs) are popular restorative materials, but their use is limited by their relatively low mechanical strength. This paper reports an attempt to improve these materials by incorporation of 10 wt% of three different types of nanoparticles, aluminum oxide, zirconium oxide, and titanium dioxide, into two commercial GICs (ChemFil ® Rock and EQUIA ™ Fil). The results indicate that the nanoparticles readily dispersed into the cement matrix by hand mixing and reduced the porosity of set cements by filling the empty spaces between the glass particles. Both cements showed no significant difference in compressive strength with added alumina, and ChemFil ® Rock also showed no significant difference with zirconia. By contrast, ChemFil ® Rock showed significantly higher compressive strength with added titania, and EQUIA ™ Fil showed significantly higher compressive strength with both zirconia and titania. Fewer air voids were observed in all nanoparticle-containing cements and this, in turn, reduced the development of cracks within the matrix of the cements. These changes in microstructure provide a likely reason for the observed increases in compressive strength, and overall the addition of nanoparticles appears to be a promising strategy for improving the physical properties of GICs.
Background: The aim of this study was to determine the effects of bleaching on the structure of t... more Background: The aim of this study was to determine the effects of bleaching on the structure of the enamel layer of teeth and the potential of the commercial bioactive glass NovaMinÒ in two different toothpastes to remineralize such regions of the enamel. Three aspects were considered: the extent and nature of the alterations in the enamel after application of the bleaching agents; the extent of remineralization after application of two commercial toothpastes containing bioactive glass; and whether or not there were differences between the toothpastes in terms of their effectiveness in promoting remineralization. Methods: Bleaching agent based on 16% carbamide peroxide was applied to the enamel surface of freshly extracted human molars for 8 minutes, once a day for 7 days. After the bleaching cycles, the enamel surface was analysed by SEM and EDX. Results: The results obtained in the study lead to the conclusion that application of 16% carbamide peroxide causes distinct morphological changes to the enamel surface which vary from mild to severe. Subsequent treatment with either of the toothpastes containing the bioactive glass NovaMinÒ resulted in the formation of a protective layer on the enamel surface, consisting of bioactive glass deposits, with only slight differences between the two brands. Application of these dentifrices also caused increases in the Ca and P content of the enamel layer, returning it to that of undamaged enamel. Conclusions: Remineralizing toothpastes should be used after bleaching, in order to repair any damage to the mineral tissue caused by these procedures.
Journal of Materials Science: Materials in Medicine, Sep 21, 2013
The original version of this article unfortunately contained a mistake. Figure 4b was incorrect. ... more The original version of this article unfortunately contained a mistake. Figure 4b was incorrect. The corrected figure is given below. The authors apologise for this error and the inconvenience it has caused.
The interaction of three polyacid-modified composite resins (compomers) with various acidic stora... more The interaction of three polyacid-modified composite resins (compomers) with various acidic storage solutions, and also water, over periods of time up to 6 months has been studied and compared with those of a glass-ionomer and a composite resin. This interaction has been shown to vary in a complex way with length of storage and nature of the acid, and citric acid was found to be the most aggressive storage medium for glass-ionomer cement, and also for the compomers. The pure composite resin, by contrast, was relatively unaffected by all of the acid solutions examined. In all acids, the compomers showed a distinct buffering effect, i.e. they increased the pH towards neutral, as did the glass-ionomer. The extent of this also varied with duration of storage and nature of the acid. The biaxial flexure strength was determined and found to be essentially unaffected by the complex chemical interactions with acidic storage solutions. Values obtained for the compomers were lower than those of the composite resin, but above those of the glass-ionomer. Fourier-transform infrared (FT-IR) spectroscopy was employed to study the changes in the compomers following storage in the aqueous media, but bands were broad and no detailed assignments could be made. There were changes in the region of the spectra associated with metal carboxylates however, and this indicates that the secondary acid-base reaction had occurred following water uptake.
Journal of Materials Science: Materials in Medicine, Apr 25, 2012
This study was carried out in order to determine the extent to which ions released from fluoride-... more This study was carried out in order to determine the extent to which ions released from fluoride-containing dental restoratives migrated through the enamel and dentine of extracted teeth. A total of 40 permanent human 3rd molars were used. They were extracted for orthodontic reasons, and employed within 1 month of extraction. A cervical (Class V) cavity was prepared in each tooth, then filled with one of: a conventional glass-ionomer, a resinmodified glass-ionomer, a polyacid-modified composite resin (''compomer'') or a fluoride-releasing resin composite. Ten samples were prepared per material. After 1 month, five specimens per material were prepared and examined under SEM/EDX. Concentrations of sodium, aluminium, strontium, fluorine, magnesium, silicon, phosphorus and calcium were determined within the tooth. After 18 months, the remaining five specimens for each material were prepared and studied in the same way. The greatest extent of ion migration into the tooth was found with the conventional glass-ionomer and least migration was found for the fluoride-releasing composite, which showed no evidence of fluoride migration at all. Levels of migrating ions were generally higher in the 18 month specimens than in the 1 month specimens, and also higher in the dentine than in the enamel. Ions released by restorative dental materials have been shown conclusively for the first time to be capable of migrating into the enamel and dentine surrounding the restoration. The conventional glass-ionomer showed the highest level of ion migration whereas the fluoridated composite resin showed little if any ion migration. This suggests that the conventional glassionomer has the greatest caries inhibiting effects of all the materials tested, and the fluoridated composite the least.
Remineralization of hard dental tissues is thought to be a tool that could close the gap between ... more Remineralization of hard dental tissues is thought to be a tool that could close the gap between prevention and surgical procedures in clinical dentistry. The purpose of this study was to examine the remineralizing potential of different toothpaste formulations: toothpastes containing bioactive glass, hydroxyapatite, or strontium acetate with fluoride, when applied to demineralized enamel. Results obtained by scanning electron microscopy~SEM! and SEM/energy dispersive X-ray analyses proved that the hydroxyapatite and bioactive glass-containing toothpastes were highly efficient in promoting enamel remineralization by formation of deposits and a protective layer on the surface of the demineralized enamel, whereas the toothpaste containing 8% strontium acetate and 1040 ppm fluoride as NaF had little, if any, remineralization potential. In conclusion, the treatment of demineralized teeth with toothpastes containing hydroxyapatite or bioactive glass resulted in repair of the damaged tissue.
Journal of The European Ceramic Society, Apr 1, 2009
... Nichola J. Coleman Corresponding Author Contact Information , a , E-mail The Corresponding Au... more ... Nichola J. Coleman Corresponding Author Contact Information , a , E-mail The Corresponding Author , Alistair H. Bishop a , Samantha E. Booth a and ... and Asiatic cultures and the historic use of silver foils in the surgical treatment of wounds and broken bones is documented. ...
Freshly-mixed and partially-cured ordinary Portland cement (OPC) pastes have been shown to exhibi... more Freshly-mixed and partially-cured ordinary Portland cement (OPC) pastes have been shown to exhibit good biological compatibility with a range of cells and tissue-types; particularly those associated with bone formation. Formulations based on OPC have been used as dental restoratives and are now being investigated for their potential use in orthopaedic repair. Despite the current clinical interest in OPCs, very little is known about their chemistry in the physiological environment. In this respect, research to investigate aspects of the interactions between a white Portland cement (WPC) paste and simulated body fluid (SBF) has been carried out in vitro. Exposure to SBF has been found to promote the precipitation of a layer of 'bone-like' hydroxyapatite on the surface of WPC paste which underpins its ability to integrate with living tissue. The dissolution of portlandite and formation of calcite were also observed on contact with SBF.
The aim of this study was to investigate the adaptation of different types of restorations toward... more The aim of this study was to investigate the adaptation of different types of restorations towards deciduous and young permanent teeth. Materials and Methods: Class V cavities were prepared in deciduous and young permanent teeth and filled with different materials (a conventional glass-ionomer, a resin-modified glass-ionomer, a poly-acid-modified composite resin and a conventional composite resin). Specimens were aged in artificial saliva for 1, 6, 12 and 18 months, then examined by SEM. Results: The composite resin and the polyacid-modified composite had better marginal adaptation than the glassionomers, though microcracks developed in the enamel of the tooth. The glass-ionomers showed inferior marginal quality and durability, but no microcracking of the enamel. The margins of the resin-modified glass-ionomer were slightly superior to the conventional glass-ionomer. Conditioning improved the adaptation of the composite resin, but the type of tooth made little or no difference to the performance of the restorative material. All materials were associated with the formation of crystals in the gaps between the filling and the tooth; the quantity and shape of these crystals varied with the material. Conclusions: Resinbased materials are generally better at forming sound, durable margins in deciduous and young permanent teeth than cements, but are associated with microcracks in the enamel. All fluoride-releasing materials give rise to crystalline deposits.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of Materials Science: Materials in Medicine, Apr 25, 2008
This study examined the release of aluminium and fluoride from restorative materials placed in ei... more This study examined the release of aluminium and fluoride from restorative materials placed in either deciduous or young permanent immature teeth stored in artificial saliva for 1 month. Cavities were prepared in extracted teeth, then filled with a fluoride releasing restorative (glass-ionomer, compomer or composite resin), with and without conditioning as appropriate. The teeth were then stored in artificial saliva for 1 month, after which the amount of aluminium and fluoride released was determined spectrophotometrically. With all materials tested, both aluminium and fluoride were released in all cases. Young immature teeth were associated with lower level of ion release which was attributed to the absorption of ions by the enamel. However, unconditioned samples were usually associated with similar ion release to conditioned ones, suggesting that the loss of mineral phase on conditioning has only a marginal effect on the capacity for ion uptake. The ratio of aluminium to fluoride released varied with the type of tooth, deciduous conditioned teeth generally absorbing proportionately less aluminium than young immature teeth. The overall conclusion is that interaction with ions released by restorative materials is influenced by type of tooth.
Antikariogeni efekat ispuna koje oslobađaju fluoride u direktnoj je korelaciji sa količinom oslob... more Antikariogeni efekat ispuna koje oslobađaju fluoride u direktnoj je korelaciji sa količinom oslobođenih fluorida, ali očito mnogo vie od dugotrajnosti ovog oslobađanja. Pored fluorida, glas-jonomer cementi oslobađaju i druge jone koji sudeluju u formiranju matriksa. Između ovih jona, ...
Gel-derived CaO-SiO 2 binary glasses of CaO mole fractions 0.2, 0.3 and 0.4 have been prepared an... more Gel-derived CaO-SiO 2 binary glasses of CaO mole fractions 0.2, 0.3 and 0.4 have been prepared and characterised. Pore diameter, specific pore volume, skeletal density and porosity were found to increase with increasing CaO-content, whereas a concomitant decrease in specific surface area was observed. 29 Si NMR indicated that the 0.2 CaO mole fraction glass consisted of highly polymerized Q 4 and Q 3 silicate species, with some Q 2 units. With increasing CaO mole fraction, these silicate species became progressively depolymerised such that isolated SiO 4 tetrahedra were detected within the 0.4 CaO glass matrix. Unusually, the glasses retained a proportion of Q 4 and Q 3 species as the CaO mole fraction was increased. All glass formulations exhibited in vitro bioactivity. The rate of hydroxyapatite precipitation followed the order 0.2 CaO > 0.4 CaO > > 0.3 CaO, an effect that is attributed to differences in the rate of dissolution of calcium from these glasses. This, in turn, appears to be dependent upon the proportion of Ca 2+ participating in the formation of the glassy network.
Svrha ovog istraživanja bila je ispitati kako djeluje pomicanje vode po površini dentina vezanog ... more Svrha ovog istraživanja bila je ispitati kako djeluje pomicanje vode po površini dentina vezanog za konvencionalne stakleno-ionomerne cemente. Materijal i postupci: Na ekstrahiranim trećim molarima bili su pripremljeni kaviteti petog razreda ispunjeni konvencionalnim stakleno-ionomernim cementom Fuji IX. Zatim je dio uzoraka bio jedan mjesec uronjen u umjetnu slinu, a dio 18 mjeseci. Nakon toga roka razrezani su longitudinalno i analizirani SEM-om (sekundarnim i "backscattered" načinom) te EDAX-om. Rezultati: Nakon 18 mjeseci u materijalu su bile uočene sferične strukture kod spoja tvrdog dentina. Prazni prostori u blizini spoja tradicionalnih stakleno-ionomera i dentina uglavnom su bili u obliku "ljuske jajeta" (iako je bilo i čvrstih). To je najvjerojatnije rezultat daljnjeg stvrdnjavanja u praznim prostorima originalnog polialkenoatnog matriksa, a događa se zbog difuzije vode iz vlažnog dentina. EDAX-ovom analizom potvrđeno je da su te formacije sastavljene od velike količine stroncija, silikata i aluminijia. Zaključak: Opisane sferične formacije mogle bi poboljšati kompresivne snage uočene kod starijih ispuna s konvencionalnim stakleno-ionomernim cementom. Ključne riječi stakleno-ionomerni cementi; stomatološki materijali; dentin 1 Klinika za dječju i preventivnu stomatologiju Stomatološkog fakulteta Sveučilišta "
Journal of Materials Science: Materials in Medicine, Mar 16, 2021
Release kinetics for sodium, silicon, aluminium, calcium and phosphorus from conventional glass-i... more Release kinetics for sodium, silicon, aluminium, calcium and phosphorus from conventional glass-ionomer dental cement has been studied in neutral and acid conditions. Specimens (6 mm height × 4 mm diameter) were made from AquaCem (Dentsply, Konstanz, Germany), 6 per experiment. They were matured (37°C, 1 h), then placed in 5 cm 3 storage solution at 20-22°C. In the first experiment, deionised water, changed daily for 28 days, was used. In the second, deionised water, changed monthly for 21 months, was used. In the third, lactic acid (20 mmol dm −3 , pH: 2.7 ± 0.1), changed monthly for 21 months was used. After storage each solution was analyzed by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results showed that in neutral conditions, no calcium was released, but in acid, significant amounts were released. The other elements (Na, Al, Si and P) were released in neutral as well as acid conditions, with greater amounts in acid. More frequent changes of water gave greater release. In neutral conditions, release over 21 months followed the equation: [E] c = [E] 1 t/(t + t ½) + β√t ([E] c is the cumulative release of the element). In acid conditions, this became: [E] c = [E] 1 t/(t + t ½) + αt. Hence release of all elements was shown to occur in two steps, a rapid initial one (half-life: 12-18 h) and a longer second one. In neutral conditions, the longer step involves diffusion; in acid it involves erosion. These patterns influence the material's bioactivity.
... J. Endod. 2003, 29, 442446. [24] MATT GD, THORPE JR ... [28] BORTOLUZZI EA, BROON NJ, BRAMAN... more ... J. Endod. 2003, 29, 442446. [24] MATT GD, THORPE JR ... [28] BORTOLUZZI EA, BROON NJ, BRAMANTE CM, GARCIA RB, DE MORAES IG, BERNARDINELI N.: Sealing abil− ity of MTA and radiopaque Portland cement with or without calcium chloride for root−end filling. ...
The kinetics of fluoride uptake by synthetic hydroxyapatite from aqueous solution has been studie... more The kinetics of fluoride uptake by synthetic hydroxyapatite from aqueous solution has been studied. Experiments involved exposing 0.1 g of synthetic hydroxyapatite to 5 cm 3 of sodium fluoride solution in the concentration range 100-1000 ppm fluoride and determining fluoride concentration at regular time intervals with a fluoride ion-selective electrode. In all cases, uptake was found to follow pseudo-second order kinetics with correlation coefficients of at least 0.998; all systems equilibrated by 24 hours with equilibrium uptake values that varied with the initial fluoride concentration. The kinetic results differ from those previously reported for much lower concentrations of fluoride, but in the present case, the concentrations were of clinical relevance, as they are those used in fluoride-containing dental products. Further work is necessary to determine how well these findings model uptake by natural hydroxyapatite and hence the extent to which they might apply in vivo.
This study examined the release of cetylpyridinium chloride and benzalkonium chloride from fatty ... more This study examined the release of cetylpyridinium chloride and benzalkonium chloride from fatty acid chelate temporary dental cement and their antimicrobial effects. The cement was Cavex Temporary, and either cetylpyridinium chloride or benzalkonium chloride was added (1% or 5% by mass), incorporating into the base paste. Release of the additives was determined by reverse-phase high-performance liquid chromatography. Possible chemical interactions between the cement components and additives were examined by Fourier transform infrared (FTIR) spectroscopy. Antimicrobial effects were assessed by measuring the zone of inhibition around sample discs after 24 h in a Streptococcus mutans culture. FTIR spectroscopy showed no interaction with cement components. For both additives, release was by diffusion for approximately the first 6 hours, with equilibration after about 2 weeks. Diffusion coefficients were 1.76 m 2 s ½ to 8.05 × 10 −12 m 2 s ½ and total release was 10.3 to 44.7% of additive loading. Zones of inhibition with additive were significantly larger than those for control discs. In conclusion, the antimicrobial properties of Cavex temporary cement are improved by the addition of the antimicrobial compounds cetylpyridium chloride and benzalkonium chloride, which are released by a diffusion process.
The purpose of this study was to investigate the enamel remineralization potential of two toothpa... more The purpose of this study was to investigate the enamel remineralization potential of two toothpastes, one of which was based on Recaldent (CPP- ACP) and the other on NovaMin (Calcium-sodium-phosphosilicate). Human permanent molar teeth were subjected to three consecutive demineralization cycles. These cycles were followed by remineralization of the experimental groups by toothpastes containing Recalden and NovaMin respectively. The samples were analyzed by Scanning Electron Microscope, (SEM) and energy-dispersive X-ray spectroscopy analysis (EDX). Extensive demineralization was noted in the control group (without remineralization) while the groups treated with the dentifices demonstrated various degrees of remineralization, as shown by formation of different types of deposits on the enamel surface. The EDX analysis showed increased amounts of Ca, P Si and Zn in the enamel of the experimental groups, compared to the control one. Toothpastes containing Recalden and especially NovaMin have the potential to remineralize enamel, a property which might be important in finding a substitute to pit and fissure sealing.
Conventional glass-ionomer cements (GICs) are popular restorative materials, but their use is lim... more Conventional glass-ionomer cements (GICs) are popular restorative materials, but their use is limited by their relatively low mechanical strength. This paper reports an attempt to improve these materials by incorporation of 10 wt% of three different types of nanoparticles, aluminum oxide, zirconium oxide, and titanium dioxide, into two commercial GICs (ChemFil ® Rock and EQUIA ™ Fil). The results indicate that the nanoparticles readily dispersed into the cement matrix by hand mixing and reduced the porosity of set cements by filling the empty spaces between the glass particles. Both cements showed no significant difference in compressive strength with added alumina, and ChemFil ® Rock also showed no significant difference with zirconia. By contrast, ChemFil ® Rock showed significantly higher compressive strength with added titania, and EQUIA ™ Fil showed significantly higher compressive strength with both zirconia and titania. Fewer air voids were observed in all nanoparticle-containing cements and this, in turn, reduced the development of cracks within the matrix of the cements. These changes in microstructure provide a likely reason for the observed increases in compressive strength, and overall the addition of nanoparticles appears to be a promising strategy for improving the physical properties of GICs.
Background: The aim of this study was to determine the effects of bleaching on the structure of t... more Background: The aim of this study was to determine the effects of bleaching on the structure of the enamel layer of teeth and the potential of the commercial bioactive glass NovaMinÒ in two different toothpastes to remineralize such regions of the enamel. Three aspects were considered: the extent and nature of the alterations in the enamel after application of the bleaching agents; the extent of remineralization after application of two commercial toothpastes containing bioactive glass; and whether or not there were differences between the toothpastes in terms of their effectiveness in promoting remineralization. Methods: Bleaching agent based on 16% carbamide peroxide was applied to the enamel surface of freshly extracted human molars for 8 minutes, once a day for 7 days. After the bleaching cycles, the enamel surface was analysed by SEM and EDX. Results: The results obtained in the study lead to the conclusion that application of 16% carbamide peroxide causes distinct morphological changes to the enamel surface which vary from mild to severe. Subsequent treatment with either of the toothpastes containing the bioactive glass NovaMinÒ resulted in the formation of a protective layer on the enamel surface, consisting of bioactive glass deposits, with only slight differences between the two brands. Application of these dentifrices also caused increases in the Ca and P content of the enamel layer, returning it to that of undamaged enamel. Conclusions: Remineralizing toothpastes should be used after bleaching, in order to repair any damage to the mineral tissue caused by these procedures.
Journal of Materials Science: Materials in Medicine, Sep 21, 2013
The original version of this article unfortunately contained a mistake. Figure 4b was incorrect. ... more The original version of this article unfortunately contained a mistake. Figure 4b was incorrect. The corrected figure is given below. The authors apologise for this error and the inconvenience it has caused.
The interaction of three polyacid-modified composite resins (compomers) with various acidic stora... more The interaction of three polyacid-modified composite resins (compomers) with various acidic storage solutions, and also water, over periods of time up to 6 months has been studied and compared with those of a glass-ionomer and a composite resin. This interaction has been shown to vary in a complex way with length of storage and nature of the acid, and citric acid was found to be the most aggressive storage medium for glass-ionomer cement, and also for the compomers. The pure composite resin, by contrast, was relatively unaffected by all of the acid solutions examined. In all acids, the compomers showed a distinct buffering effect, i.e. they increased the pH towards neutral, as did the glass-ionomer. The extent of this also varied with duration of storage and nature of the acid. The biaxial flexure strength was determined and found to be essentially unaffected by the complex chemical interactions with acidic storage solutions. Values obtained for the compomers were lower than those of the composite resin, but above those of the glass-ionomer. Fourier-transform infrared (FT-IR) spectroscopy was employed to study the changes in the compomers following storage in the aqueous media, but bands were broad and no detailed assignments could be made. There were changes in the region of the spectra associated with metal carboxylates however, and this indicates that the secondary acid-base reaction had occurred following water uptake.
Journal of Materials Science: Materials in Medicine, Apr 25, 2012
This study was carried out in order to determine the extent to which ions released from fluoride-... more This study was carried out in order to determine the extent to which ions released from fluoride-containing dental restoratives migrated through the enamel and dentine of extracted teeth. A total of 40 permanent human 3rd molars were used. They were extracted for orthodontic reasons, and employed within 1 month of extraction. A cervical (Class V) cavity was prepared in each tooth, then filled with one of: a conventional glass-ionomer, a resinmodified glass-ionomer, a polyacid-modified composite resin (''compomer'') or a fluoride-releasing resin composite. Ten samples were prepared per material. After 1 month, five specimens per material were prepared and examined under SEM/EDX. Concentrations of sodium, aluminium, strontium, fluorine, magnesium, silicon, phosphorus and calcium were determined within the tooth. After 18 months, the remaining five specimens for each material were prepared and studied in the same way. The greatest extent of ion migration into the tooth was found with the conventional glass-ionomer and least migration was found for the fluoride-releasing composite, which showed no evidence of fluoride migration at all. Levels of migrating ions were generally higher in the 18 month specimens than in the 1 month specimens, and also higher in the dentine than in the enamel. Ions released by restorative dental materials have been shown conclusively for the first time to be capable of migrating into the enamel and dentine surrounding the restoration. The conventional glass-ionomer showed the highest level of ion migration whereas the fluoridated composite resin showed little if any ion migration. This suggests that the conventional glassionomer has the greatest caries inhibiting effects of all the materials tested, and the fluoridated composite the least.
Remineralization of hard dental tissues is thought to be a tool that could close the gap between ... more Remineralization of hard dental tissues is thought to be a tool that could close the gap between prevention and surgical procedures in clinical dentistry. The purpose of this study was to examine the remineralizing potential of different toothpaste formulations: toothpastes containing bioactive glass, hydroxyapatite, or strontium acetate with fluoride, when applied to demineralized enamel. Results obtained by scanning electron microscopy~SEM! and SEM/energy dispersive X-ray analyses proved that the hydroxyapatite and bioactive glass-containing toothpastes were highly efficient in promoting enamel remineralization by formation of deposits and a protective layer on the surface of the demineralized enamel, whereas the toothpaste containing 8% strontium acetate and 1040 ppm fluoride as NaF had little, if any, remineralization potential. In conclusion, the treatment of demineralized teeth with toothpastes containing hydroxyapatite or bioactive glass resulted in repair of the damaged tissue.
Journal of The European Ceramic Society, Apr 1, 2009
... Nichola J. Coleman Corresponding Author Contact Information , a , E-mail The Corresponding Au... more ... Nichola J. Coleman Corresponding Author Contact Information , a , E-mail The Corresponding Author , Alistair H. Bishop a , Samantha E. Booth a and ... and Asiatic cultures and the historic use of silver foils in the surgical treatment of wounds and broken bones is documented. ...
Freshly-mixed and partially-cured ordinary Portland cement (OPC) pastes have been shown to exhibi... more Freshly-mixed and partially-cured ordinary Portland cement (OPC) pastes have been shown to exhibit good biological compatibility with a range of cells and tissue-types; particularly those associated with bone formation. Formulations based on OPC have been used as dental restoratives and are now being investigated for their potential use in orthopaedic repair. Despite the current clinical interest in OPCs, very little is known about their chemistry in the physiological environment. In this respect, research to investigate aspects of the interactions between a white Portland cement (WPC) paste and simulated body fluid (SBF) has been carried out in vitro. Exposure to SBF has been found to promote the precipitation of a layer of 'bone-like' hydroxyapatite on the surface of WPC paste which underpins its ability to integrate with living tissue. The dissolution of portlandite and formation of calcite were also observed on contact with SBF.
The aim of this study was to investigate the adaptation of different types of restorations toward... more The aim of this study was to investigate the adaptation of different types of restorations towards deciduous and young permanent teeth. Materials and Methods: Class V cavities were prepared in deciduous and young permanent teeth and filled with different materials (a conventional glass-ionomer, a resin-modified glass-ionomer, a poly-acid-modified composite resin and a conventional composite resin). Specimens were aged in artificial saliva for 1, 6, 12 and 18 months, then examined by SEM. Results: The composite resin and the polyacid-modified composite had better marginal adaptation than the glassionomers, though microcracks developed in the enamel of the tooth. The glass-ionomers showed inferior marginal quality and durability, but no microcracking of the enamel. The margins of the resin-modified glass-ionomer were slightly superior to the conventional glass-ionomer. Conditioning improved the adaptation of the composite resin, but the type of tooth made little or no difference to the performance of the restorative material. All materials were associated with the formation of crystals in the gaps between the filling and the tooth; the quantity and shape of these crystals varied with the material. Conclusions: Resinbased materials are generally better at forming sound, durable margins in deciduous and young permanent teeth than cements, but are associated with microcracks in the enamel. All fluoride-releasing materials give rise to crystalline deposits.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of Materials Science: Materials in Medicine, Apr 25, 2008
This study examined the release of aluminium and fluoride from restorative materials placed in ei... more This study examined the release of aluminium and fluoride from restorative materials placed in either deciduous or young permanent immature teeth stored in artificial saliva for 1 month. Cavities were prepared in extracted teeth, then filled with a fluoride releasing restorative (glass-ionomer, compomer or composite resin), with and without conditioning as appropriate. The teeth were then stored in artificial saliva for 1 month, after which the amount of aluminium and fluoride released was determined spectrophotometrically. With all materials tested, both aluminium and fluoride were released in all cases. Young immature teeth were associated with lower level of ion release which was attributed to the absorption of ions by the enamel. However, unconditioned samples were usually associated with similar ion release to conditioned ones, suggesting that the loss of mineral phase on conditioning has only a marginal effect on the capacity for ion uptake. The ratio of aluminium to fluoride released varied with the type of tooth, deciduous conditioned teeth generally absorbing proportionately less aluminium than young immature teeth. The overall conclusion is that interaction with ions released by restorative materials is influenced by type of tooth.
Antikariogeni efekat ispuna koje oslobađaju fluoride u direktnoj je korelaciji sa količinom oslob... more Antikariogeni efekat ispuna koje oslobađaju fluoride u direktnoj je korelaciji sa količinom oslobođenih fluorida, ali očito mnogo vie od dugotrajnosti ovog oslobađanja. Pored fluorida, glas-jonomer cementi oslobađaju i druge jone koji sudeluju u formiranju matriksa. Između ovih jona, ...
Gel-derived CaO-SiO 2 binary glasses of CaO mole fractions 0.2, 0.3 and 0.4 have been prepared an... more Gel-derived CaO-SiO 2 binary glasses of CaO mole fractions 0.2, 0.3 and 0.4 have been prepared and characterised. Pore diameter, specific pore volume, skeletal density and porosity were found to increase with increasing CaO-content, whereas a concomitant decrease in specific surface area was observed. 29 Si NMR indicated that the 0.2 CaO mole fraction glass consisted of highly polymerized Q 4 and Q 3 silicate species, with some Q 2 units. With increasing CaO mole fraction, these silicate species became progressively depolymerised such that isolated SiO 4 tetrahedra were detected within the 0.4 CaO glass matrix. Unusually, the glasses retained a proportion of Q 4 and Q 3 species as the CaO mole fraction was increased. All glass formulations exhibited in vitro bioactivity. The rate of hydroxyapatite precipitation followed the order 0.2 CaO > 0.4 CaO > > 0.3 CaO, an effect that is attributed to differences in the rate of dissolution of calcium from these glasses. This, in turn, appears to be dependent upon the proportion of Ca 2+ participating in the formation of the glassy network.
Svrha ovog istraživanja bila je ispitati kako djeluje pomicanje vode po površini dentina vezanog ... more Svrha ovog istraživanja bila je ispitati kako djeluje pomicanje vode po površini dentina vezanog za konvencionalne stakleno-ionomerne cemente. Materijal i postupci: Na ekstrahiranim trećim molarima bili su pripremljeni kaviteti petog razreda ispunjeni konvencionalnim stakleno-ionomernim cementom Fuji IX. Zatim je dio uzoraka bio jedan mjesec uronjen u umjetnu slinu, a dio 18 mjeseci. Nakon toga roka razrezani su longitudinalno i analizirani SEM-om (sekundarnim i "backscattered" načinom) te EDAX-om. Rezultati: Nakon 18 mjeseci u materijalu su bile uočene sferične strukture kod spoja tvrdog dentina. Prazni prostori u blizini spoja tradicionalnih stakleno-ionomera i dentina uglavnom su bili u obliku "ljuske jajeta" (iako je bilo i čvrstih). To je najvjerojatnije rezultat daljnjeg stvrdnjavanja u praznim prostorima originalnog polialkenoatnog matriksa, a događa se zbog difuzije vode iz vlažnog dentina. EDAX-ovom analizom potvrđeno je da su te formacije sastavljene od velike količine stroncija, silikata i aluminijia. Zaključak: Opisane sferične formacije mogle bi poboljšati kompresivne snage uočene kod starijih ispuna s konvencionalnim stakleno-ionomernim cementom. Ključne riječi stakleno-ionomerni cementi; stomatološki materijali; dentin 1 Klinika za dječju i preventivnu stomatologiju Stomatološkog fakulteta Sveučilišta "
Journal of Materials Science: Materials in Medicine, Mar 16, 2021
Release kinetics for sodium, silicon, aluminium, calcium and phosphorus from conventional glass-i... more Release kinetics for sodium, silicon, aluminium, calcium and phosphorus from conventional glass-ionomer dental cement has been studied in neutral and acid conditions. Specimens (6 mm height × 4 mm diameter) were made from AquaCem (Dentsply, Konstanz, Germany), 6 per experiment. They were matured (37°C, 1 h), then placed in 5 cm 3 storage solution at 20-22°C. In the first experiment, deionised water, changed daily for 28 days, was used. In the second, deionised water, changed monthly for 21 months, was used. In the third, lactic acid (20 mmol dm −3 , pH: 2.7 ± 0.1), changed monthly for 21 months was used. After storage each solution was analyzed by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results showed that in neutral conditions, no calcium was released, but in acid, significant amounts were released. The other elements (Na, Al, Si and P) were released in neutral as well as acid conditions, with greater amounts in acid. More frequent changes of water gave greater release. In neutral conditions, release over 21 months followed the equation: [E] c = [E] 1 t/(t + t ½) + β√t ([E] c is the cumulative release of the element). In acid conditions, this became: [E] c = [E] 1 t/(t + t ½) + αt. Hence release of all elements was shown to occur in two steps, a rapid initial one (half-life: 12-18 h) and a longer second one. In neutral conditions, the longer step involves diffusion; in acid it involves erosion. These patterns influence the material's bioactivity.
... J. Endod. 2003, 29, 442446. [24] MATT GD, THORPE JR ... [28] BORTOLUZZI EA, BROON NJ, BRAMAN... more ... J. Endod. 2003, 29, 442446. [24] MATT GD, THORPE JR ... [28] BORTOLUZZI EA, BROON NJ, BRAMANTE CM, GARCIA RB, DE MORAES IG, BERNARDINELI N.: Sealing abil− ity of MTA and radiopaque Portland cement with or without calcium chloride for root−end filling. ...
The kinetics of fluoride uptake by synthetic hydroxyapatite from aqueous solution has been studie... more The kinetics of fluoride uptake by synthetic hydroxyapatite from aqueous solution has been studied. Experiments involved exposing 0.1 g of synthetic hydroxyapatite to 5 cm 3 of sodium fluoride solution in the concentration range 100-1000 ppm fluoride and determining fluoride concentration at regular time intervals with a fluoride ion-selective electrode. In all cases, uptake was found to follow pseudo-second order kinetics with correlation coefficients of at least 0.998; all systems equilibrated by 24 hours with equilibrium uptake values that varied with the initial fluoride concentration. The kinetic results differ from those previously reported for much lower concentrations of fluoride, but in the present case, the concentrations were of clinical relevance, as they are those used in fluoride-containing dental products. Further work is necessary to determine how well these findings model uptake by natural hydroxyapatite and hence the extent to which they might apply in vivo.
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