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Objectives: The aim of this study was to evaluate the effect of removing excess of resin-based materials applied to eroded enamel, subjected to erosive challenge.Methods: Bovine enamel blocks were immersed in HCl 0.01M, pH 2.3, for 30s under agitation at 50 rpm in room temperature, in order to form a softened erosion lesion. The blocks were then randomly divided into eight groups (n=12) and treated as follows: Cn- and Ce-control without treatment, Hn- and He-fissure resin sealant (Helioseal Clear(®)), An- and Ae-self-etch adhesive (Adhese(®)), In- and Ie-infiltrant (Icon(®)); being n-with excess removal and e-without excess removal of the material. After application of the materials, the blocks were immersed in HCl for 2 min, followed by immersion in artificial saliva for 120 min. This cycle was repeated four times a day for five days. Material thickness and enamel wear were assessed using profilometry. Data were analyzed by two-way ANOVA and Tukey's test (P<0.05).Results: Groups He, Ae, and Ie resulted in the formation of a layer of material over enamel, being similar effective in inhibiting erosion progression (P>0.05). Groups Hn, An, and In (with excess removal) were similar to controls (Cn, Ce) and resulted in near enamel loss after application and after erosive challenge (P>0.05).Conclusions: Resin-based materials are able to protect enamel against erosion only when they are present over enamel, as a physical barrier.Clinical Significance: The resin-based materials demonstrated potential to prevent the progression of erosion lesions when the material remains on the dental surface. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to create prototype glass ionomer cements (GICs) incorporating a concentrated paste of chlorhexidine-hexametaphosphate (CHX-HMP), and to investigate the long-term release of soluble chlorhexidine and the mechanical properties of the cements. The purpose is the design of a glass ionomer with sustained anticaries efficacy.Methods: CHX-HMP paste was prepared by mixing equimolar solutions of chlorhexidine digluconate and sodium hexametaphosphate, adjusting ionic strength, decanting and centrifuging. CHX-HMP paste was incorporated into a commercial GIC in substitution for glass powder at 0.00, 0.17, 0.34, 0.85 and 1.70% by mass CHX-HMP. Soluble chlorhexidine release into artificial saliva was observed over 436 days using absorbance at 255nm. Diametral tensile and compressive strength were measured after 7 days' setting (37°C, 100% humidity) and tensile strength after 436 days' aging in artificial saliva. 0.34% CHX-HMP GICs were tested for their ability to inhibit growth of Streptococcus mutans in vitro.Results: GICs supplemented with CHX-HMP exhibited a sustained dose-dependent release of soluble chlorhexidine. Diametral tensile strength of new specimens was unaffected up to and including 0.85% CHX-HMP, and individual values of tensile strength were unaffected by aging, but the proportion of CHX-HMP required to adversely affect tensile strength was lower after aging, at 0.34%. Compressive strength was adversely affected by CHX-HMP at substitutions of 0.85% CHX-HMP and above.Conclusions: Supplementing a GIC with CHX-HMP paste resulted in a cement which released soluble chlorhexidine for over 14 months in a dose dependent manner. 0.17% and 0.34% CHX-HMP did not adversely affect strength at baseline, and 0.17% CHX-HMP did not affect strength after aging. 0.34% CHX-HMP GICs inhibited growth of S. mutans at a mean distance of 2.34mm from the specimen, whereas control (0%) GICs did not inhibit bacterial growth.Clinical Significance: Although GICs release fluoride in vivo, there is inconclusive evidence regarding any clinical anticaries effect. In this study, GICs supplemented with a paste of chlorhexidine-hexametaphosphate (CHX-HMP) exhibited a sustained release of chlorhexidine over at least 14 months, and small additions of CHX-HMP did not adversely affect strength. [ABSTRACT FROM AUTHOR]

Objectives: To introduce a new interproximal mineralisation model and to investigate the effectiveness of novel toothpaste and dual phase gel formulations to remineralise acid softened enamel in a simulated interproximal environment. Methods: Specimens were positioned opposite each other with an approximately 100 µm space between enamel surfaces to simulate an interproximal environment. Target specimens were demineralised in 1% (w/v) citric acid, pH3.75. Specimens were daily immersed in artificial saliva (AS) for 1h, treated with formulations, re-immersed in AS for 6h, re-treated and reimmersed in AS for a further 1h. Study 1 evaluated prototype calcium silicate/phosphate fl uoride toothpaste formulations. Study 2 evaluated novel calcium silicate/phosphate fl uoride toothpaste and dual phase gel formulations. Both studies contained fluoridated and non-fluoridated controls. The surface microhardness of each target enamel block was measured following demineralisation and following days three, seven and fourteen for study one and after days one, three and seven for study two. Results: This new mineralisation model was able to show increased remineralisation from calcium silicate/phosphate fl uoride prototype formulations over fluoridated formulations alone, after three and seven days of treatment. Using this new model, the combined application of novel calcium silicate/phosphate fl uoride toothpaste and novel calcium silicate/phosphate fluoride dual phase gel showed the greatest amount of remineralisation, which was significantly greater than sodium fluoride and non-fluoride controls. Conclusions: Employing a new interproximal mineralisation model successfully determined the remineralisation potential of novel calcium silicate/phosphate fluoride oral healthcare formulations. Clinical significance: Modifying a mineralisation model to include specimens positioned in an interproximal environment allows us to better understand the remineralisation potential of oral healthcare products. It is important to minimise mineral loss at interproximal sites as the enamel within these areas is thinner than the rest of the crown. [ABSTRACT FROM AUTHOR]

Objectives: Various formulations of artificial saliva are present in the literature and little guidance is available on the standardization of type of saliva for use in in vitro protocols for erosive studies. The aim of this study was to evaluate the remineralizing capacity of different formulations of artificial saliva on initial enamel erosive lesion. Methods: Bovine enamel blocks were subjected to short-term acidic exposure by immersion in citric acid 0.05 M (pH 2.5) for 15 s, resulting in surface softening without tissue loss. Then 90 selected eroded enamel blocks were randomly and equally divided into 6 groups according to saliva formulation (n = 15): Saliva 1 (contain mucin); Saliva 2 (Saliva 1 without mucin); Saliva 3; Saliva 4; Saliva 5 (contain sodium carboxymethyl cellulose) and control (C) (deionized water). After demineralization enamel blocks were subjected to remineralization by immersion in the saliva's formulations for 2 h. Enamel remineralization was measured by superficial hardness test (% superficial hardness change). The data were tested using ANOVA and Tukey's test ( p < 0.05). Results: All the tested formulations of artificial saliva resulted in significantly higher enamel remineralization compared to control ( p < 0.001). Saliva 3 showed higher percentage of enamel remineralization than Saliva 5 ( p < 0.05). Conclusions: Besides the variety of artificial saliva for erosion in vitro protocols, all the formulations tested were able to partially remineralize initial erosive lesions. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this in vitro study was to evaluate the influence of infiltrant composition and application frequency on micro-hardness and lesion progression after resin infiltration of artificial enamel lesions. Methods: In each of 100 bovine enamel samples, three artificial caries lesions were created (pH = 4.95, 50 days). After etching two of the lesions (37% phosphoric acid) specimens were randomly allocated to five infiltrants (four experimental infiltrants with different monomer and solvent compositions and penetration coefficients, and one commercial infiltrant [Icon, DMG]). Lesions were then infiltrated and light-cured, and infiltration repeated afterwards for one of the lesions. Infiltrated samples were cut into halves, with one half being demineralised for further 50 days. Micro-hardness (VHN) and integrated mineral loss (?Z) were evaluated at baseline and after second demineralisation. Repeated measures ANOVA and paired t-tests were used to analyse influence of material composition and application frequency on micro-hardness and lesion progression (integrated mineral loss difference ??Z). Results: Resin infiltration significantly increased micro-hardness and reduced lesion progression compared to untreated artificial lesions ( p < 0.05, t-test). Neither micro-hardness nor lesion progression were significantly influenced by material composition ( p > 0.05, ANOVA). In contrast, twice application resulted in significantly increased micro-hardness and demineralisation resistance of infiltrated lesions ( p < 0.05, ANOVA). Conclusion: Resin infiltration significantly improves micro-hardness and demineralisation resistance of enamel lesions; these effects are significantly enhanced if resins are applied twice. Experimental resins did not outperform the commercial infiltrant. Clinical significance: This in vitro study demonstrated that resin infiltration significantly increases both micro-hardness and demineralisation resistance of enamel caries lesions. Twice application of the infiltrant seems to increase these effects. In contrast, the composition of the infiltrant had no significant influence on investigated parameters. [ABSTRACT FROM AUTHOR]

Objective: The main aim of this in vitro study was to evaluate the influence of Streptococcus mutans on the corrosion of titanium. Methods: S. mutans biofilms were formed on commercially pure titanium (CP-Ti) square samples (10 mm × 10 mm × 1 mm) using a culture medium enriched with sucrose. Open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) measurements were used to evaluate the corrosion behaviour of CP-Ti in the presence of S. mutans in Fusayama's artificial saliva. The corrosion of biofilm-free CP-Ti samples was also evaluated in artificial saliva. Biofilms biomass was measured by spectrophotometry, using crystal violet staining, after 1, 2 and 7 days. Results: The OCP values recorded on CP-Ti in the presence of S. mutans (0.3 0.02 V vs. SCE) was lower than those on biofilm-free CP-Ti (-0.1 ± 0.01 V vs. SCE) after 2 h of immersion in artificial saliva ( p < 0.05). That reveals a high reactivity of titanium in presence of S. mutans. Impedance spectra revealed the formation of a compact passive film on titanium in artificial saliva or in the presence of a 2 days old S. mutans biofilm even though the corrosion resistance of CP-Ti has decreased in presence of a S. mutans biofilm. Conclusion: The presence of bacterial colonies, such as S. mutans, negatively affected the corrosion resistance of the titanium. [ABSTRACT FROM AUTHOR]

Caseinomacropeptide (CMP), the variably phosphorylated and glycosylated forms of the bovine milk protein fragment, k-casein(106-169), is produced during cheese production and has been shown to have a range of antibacterial bioactivities. Objectives: To characterise the biofilm disruptive component of CMP and compare its activity with the known antimicrobial agents chlorhexidine and zinc ions. Methods: Streptococcus mutans biofilms were grown in flow cells with an artificial saliva medium containing sucrose and treated with CMP and the glycosylated forms of k-casein( 106-169) (k-casein glycopeptide, KCG). The biofilms were imaged using confocal laser scanning microscopy (CLSM) and quantified by COMSTAT software analysis. A static biofilm assay and flow cytometric analysis were used to examine the mechanism of action of chlorhexidine and a combination of KCG with the known antimicrobial agent ZnCl2 (KCGZn). Results: CLSM analysis showed that S. mutans produced robust, structured biofilms with an average thickness of 7.37 mm and a biovolume of 3.88 mm3/mm2 substratum after 16 h of incubation in the flow cell system. A single application of 10 mg/mL CMP that contained 2.4 mg/mL KCG significantly reduced total biofilm biovolume and average biofilm thickness by 53% and 61%, respectively. This was statistically the same as a 2.4 mg/mL KCG treatment that reduced the total biovolume and average thickness by 59% and 69%, respectively, suggesting the KCG was the biofilm disruptive component of CMP. Chlorhexidine treatment (0.1%) caused similar effects in the flow cell model. KCG-Zn caused significantly more disruption of the biofilms than either KCG or ZnCl2 treatment alone. In a static biofilm model chlorhexidine was shown to work by disrupting bacterial membrane integrity whilst KCGZn had no effect on membrane integrity. Conclusions: KCG and KCG-Zn may have potential as natural biofilm disruptive agents. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To test sealants to prevent erosive tooth wear caused by extrinsic and intrinsic acids under long-term exposition. Methods: 144 bovine enamel samples were randomly allocated to twelve groups (1–12). Samples of groups 1, 5 and 9 remained unsealed (positive controls), 2, 6 and 10 were sealed with Silicon Seal Nano Mix and 3, 7 and 11 with Seal&Protect. Groups 4, 8 and 12 were sealed with flowable composite (negative controls). Groups 1–4 were immersed in artificial saliva, 5–8 in hydrochloric acid and groups 9–12 in citric acid for 28 days, respectively. After 1, 2, 4, 7, 11, 14, 21 and 28 days, solutions were renewed and enamel wear was quantified by assignation of 32P in the solutions. Results: In all immersion solutions, lowest mineral loss was observed for the negative controls whilst highest loss was observed for unsealed positive controls. In artificial saliva and citric acid, the loss from samples sealed with Seal&Protect was not significantly different compared with negative controls whilst loss in groups sealed with Silicon Seal Nano Mix was significantly higher. In hydrochloric acid, loss from samples sealed with Seal&Protect was not different compared with that of negative controls up to 4 days. Except day 1, the mineral loss in the Seal&Protect group was significantly lower compared with that of the Silicon Seal Nano Mix group. Conclusion: The tested resin based surface sealant is able to significantly reduce the erosive demineralisation of enamel caused by hydrochloric and citric acid even under long-term exposition. [Copyright &y& Elsevier]

Abstract: Objectives: This study evaluated the effect of different surface conditioning methods on the tensile bond strength (TBS) and integrity of the amalgam–resin composite interface, using commercially available restoration repair systems. Methods: One hundred and sixty Gamma 2 amalgam specimens were stored in artificial saliva for 2 weeks and then randomly assigned to one of the following conditioning groups (n =20/group): Group 1: air abrasion, alloy primer and ‘Panavia 21’, Group 2: air abrasion and ‘Amalgambond Plus’, Group 3: air abrasion and ‘All-Bond 3’, Group 4: diamond bur, alloy primer and ‘Panavia 21’, Group 5: diamond bur and ‘Amalgambond Plus’, Group 6: diamond bur and ‘All-Bond 3’, Group 7: silica coating technique, and Group 8: non-conditioned amalgam surfaces (control group). Subsequently, resin composite material was added to the substrate surfaces and the amalgam–resin composite specimens were subjected to TBS testing. Representative samples from the test groups were subjected to scanning electron microscopy and surface profilometry. The data was analysed statistically with one-way ANOVA and post hoc Tukey''s tests (α =0.05). Results: The mean TBS of amalgam–resin composite ranged between 1.34 and 5.13MPa and varied with the degree of amalgam surface roughness and the type of conditioning technique employed. Significantly highest TBS values (5.13±0.96MPa) were obtained in Group 1 (p =0.013). Conclusion: Under the tested conditions, significantly greater tensile bond strength of resin composite to amalgam was achieved when the substrate surface was conditioned by air abrasion followed by the application of the Panavia 21 adhesive system. Clinical significance: Effecting a repair of an amalgam restoration with resin composite via the use of air abrasion and application of Panavia 21 would seem to enhance the integrity of the amalgam–resin composite interface. Clinical trials involving the implementation of this technique are indicated to determine the usefulness of this technique. [Copyright &y& Elsevier]

Objectives: The present study aimed to evaluate dentine remineralization through a 7-day period of artificial saliva (AS) storage induced by bioactive glass 45S5 (BAG) and by bioactive glass modified with soda-lime spherical glass.Methods: Partially demineralized dentine disks were treated by BAG or the spherical-glass modified bioactive glass (M-BAG) and subsequently immersed in AS for 7 days. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) was used to quantitatively analyse the mineral variation of the dentine surface by calculating the spectra parameters. X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDX) were performed on completely demineralized dentine to confirm the apatite formation. The roughness of the dentine surface was evaluated by atomic force microscopy (AFM) and the morphology was also examined by scanning electron microscopy (SEM).Results: ATR-FTIR showed a significant increase of the mineral matrix area ratio in dentine specimens treated with the two bioactive glasses subsequent to 7 days of AS storage. The XRD spectrum exhibited apatite growth and mineral elements could be found on completely demineralized samples analysed by EDX after remineralization treatments. The dentine specimens treated with bioactive glass showed lower roughness, and most of the dentinal tubules appeared completely occluded during the AFM and SEM examination.Conclusions: Although the concentration of bioactive glass in the M-BAG is 60% of that contained in the original version, both formulations have similar potential in dentine remineralization. These bioactive powders developed for air-abrasive use may be considered as innovative bioactive materials for therapeutic remineralization of dental hard tissues. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: To investigate the effect of a single application of highly concentrated SnF2 and NaF solutions and a NaF/CaF2 varnish on human enamel subjected to hydrochloric acid erosion and tooth brush abrasion. Methods: Forty enamel samples were prepared from human third molars and NaF (9500ppm, pH 8.0), SnF2 (9500ppm, pH 2.6) solutions; Bifluorid10® varnish (42,500ppm, NaF 5%, CaF2 5%) and deionized water (control) was applied to the enamel. Following this three, six and nine cycles of erosion [1 cycle=erosion (0.01M HCl, pH 2.2, 2min)+artificial saliva (1h, pH 7.0)] and erosion–abrasion [1 cycle=erosion (0.01M HCl, pH 2.2, 2min)+artificial saliva (1h, pH 7.0)+abrasion (120 linear strokes in artificial saliva from Tepe medium soft brushes 200g loading)] were carried out. The fluoride treated enamel was analysed using Knoop microhardness, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Results: For erosion alone, there was significantly less microhardness reduction in the Bifluorid10® group after three and six cycles of erosion (P <0.05), however no other groups showed statistically different hardness (P >0.05). The EDS analysis showed that only the Bifluorid10® group had any detectable fluorine following erosion and erosion–abrasion (0.1wt.% and 0.2wt.% fluorine respectively). The surface fluorine was found to have been removed after erosion and erosion–abrasion for all other surface treatments. Although precipitates were observed after application of the surface treatments, following erosion–abrasion, no visible surface effects from any fluoride preparation remained. Conclusions: Enamel surface precipitates from application NaF, SnF2 solutions appear to not be able to provide protection against gastric erosion and tooth brush abrasion. The NaF/CaF2 varnish provided limited protection against erosion but the role for such varnishes in gastric erosion and tooth brush abrasion remains uncertain. [Copyright &y& Elsevier]

Objectives: The lack of durability in resin-dentine bonds led to the use of chlorhexidine as MMP-inhibitor to prevent the degradation of hybrid layers. Biomimetic remineralisation is a concept-proven approach in preventing the degradation of resin-dentine bonds. The purpose of this study is to examine the integrity of aged resin-dentine interfaces created with a nanofiller-containing etch-and-rinse adhesive after the application of these two approaches.Methods: The more established MMP-inhibition approach was examined using a parallel in vivo and in vitro ageing design to facilitate comparison with the biomimetic remineralisation approach using an in vitro ageing design. Specimens bonded without chlorhexidine exhibited extensive degradation of the hybrid layer after 12 months of in vivo ageing.Results: Dissolution of nanofillers could be seen within a water-rich zone within the adhesive layer. Although specimens bonded with chlorhexidine exhibited intact hybrid layers, water-rich regions remained in those hybrid layers and degradation of nanofillers occurred within the adhesive layer. Specimens subjected to in vitro biomimetic remineralisation followed by in vitro ageing demonstrated intrafibrillar collagen remineralisation within hybrid layers and deposition of mineral nanocrystals in nanovoids within the adhesive.Conclusions: The impact was realized by understanding the lack of an inherent mechanism to remove water from resin-dentine interfaces as the critical barrier to progress in bonding with the etch-and-rinse technique. The experimental biomimetic remineralisation strategy offers a creative solution for incorporating a progressive hydration mechanism to achieve this goal, which warrants its translation into a clinically applicable technique. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Besides the use of saliva substitutes, patients suffering from hyposalivation are instructed to apply fluoride products to prevent caries. Some saliva substitutes have been shown to demineralise enamel; an effect that might be counteracted by the application of fluoride gels or mouthrinses. Combined use of these products with remineralising or neutral saliva substitutes might result in more pronounced remineralisation. Methods: Demineralised bovine enamel specimens were either stored in mineral water [W, control; saturation with respect to octacalcium phosphate ( S OCP): 0.7], an experimental demineralising carboxymethylcellulose (CMC)-based solution (C, S OCP: 0.3), or in a modified ( S OCP) saliva substitute [Saliva natura (SN), S OCP: 1.6] for five weeks (37°C). After two weeks half of the exposed surfaces were nail varnished. The following treatments were applied twice daily for 10min each time (n =14-18/group): 1: no treatment, 2: Meridol mouthrinse, 3: Elmex sensitive mouthrinse, 4: ProSchmelz fluoride gel, and 5: Elmex gelée. Mineral parameters before and after storage were evaluated from microradiographs. Results: Specimens stored in C showed significantly higher mineral loss compared to W and SN (p <0.05; ANOVA). For C additional use of fluorides resulted in less demineralisation (p <0.05) compared to C alone. SN in combination with ProSchmelz led to significantly higher remineralisation compared to all other groups (p <0.05). Conclusions: Use of fluorides reduces the detrimental effects of the demineralising solution. Treatment with ProSchmelz in combination with storage in a saliva substitute supersaturated with respect to OCP yielded to most pronounced remineralisation under the conditions chosen. [Copyright &y& Elsevier]

Objectives: The exposure of dentinal tubules causes fluid movement and dentinal hypersensitivity. This study aimed at evaluating the dentine permeability after prophylactic measures performed on exposed dentine after immersion in artificial saliva and citric acid challenge. Confocal microscopy was performed to evaluate the percentage of occluded tubules (OCT%) and the changes in dentine morphology.Methods: Prophy-powders and pastes were tested in this study. An oxalic acid liner was used as a positive control. Dentine discs from human third molars were treated with each material and the dentine permeability was evaluated using a fluid filtration system working at 20cm H(2)O. Artificial saliva and citric acid were used for the determination of changes in dentine permeability. The percentage of tubule occlusion capability (OCT%) was evaluated using confocal microscopy.Results: All the products used in this study were able to significantly reduce the dentine permeability of acid-etched specimens. The use of the bioactive glass and sodium bicarbonate showed the highest values in dentine permeability reduction. However, the air-polishing procedures performed with Sylc bioactive glass powder created a dentine surface resistant to citric acid attack.Conclusion: Bioactive glass is suitable for treatment of dentinal hypersensitivity by creating a dentine surface resistant to citric acid attack. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The purpose of this study was to evaluate the in vitro effectiveness of a new bioglass-containing and two commercial desensitising toothpastes on dentinal tubule occlusion after citric acid challenge or artificial saliva (AS) immersion. Methods: One hundred dentin discs from human third molars were used. Specimens were randomly divided into five groups (n =20), Group 1: EDTA-treated dentin; Group 2: brushing with distilled water; Group 3: brushing with Novamin; Group 4: brushing with Sensodyne Freshmint; Group 5: brushing with Colgate Sensitive. In each group, samples were then equally split into two subgroups (n =10) to test two post-treatments: 6% citric acid challenge or 24h immersion in artificial saliva. Dentine permeability of each specimen was measured before and after each treatment using a hydrostatic device working at 20cm H2O pressure. Data were analysed by two-way repeated measures ANOVA to determine if there were any significant differences within or between groups. Dentine morphology and surface deposits were observed by SEM. Results: All three desensitising toothpastes significantly reduced dentine permeability and created precipitates on the treated dentine surfaces. Moreover, the reductions in dentine permeability showed partial recovery after a citric acid and artificial saliva immersion. Sensodyne showed significant resistant to acid attack and Novamin exhibited the lowest permeability after artificial saliva immersion for 24h. Conclusions: The application of the three toothpastes resulted in effective dentinal tubule occlusion. However, the new bioglass-containing toothpaste (Novamin) represented excellent occlusion effects after brushing treatment and AS immersion, while Sensodyne demonstrated more reduction in permeability when citric acid challenged. [Copyright &y& Elsevier]

Abstract: Objectives: The aim of this in vitro study was to assess the effects of saliva substitutes (modified with respect to calcium, phosphates, and fluorides) in combination with a high-concentrated fluoride toothpaste on demineralised dentin. Methods: Before and after demineralisation of bovine dentin specimens (subsurface lesions; 37°C, pH 5.0, 5 d), one-quarter of each specimen''s surface was covered with nail varnish (control of sound/demineralised tissue). Subsequently, specimens were exposed to original Saliva natura (saturation with respect to octacalciumphosphate [S OCP]: 0.03; SN 0), or to three lab-produced Saliva natura modifications (S OCP: 1, 2, and 3; SN 1–3) for 2 and 5 weeks (37°C). An aqueous solution (S OCP: 2.5) served as positive control (PC). Two times daily (2min each), Duraphat toothpaste (5000ppmF−; Colgate)/saliva substitute slurry (ratio 1:3) was applied gently. Differences in mineral losses (ΔΔZ) and lesion depths (ΔLD) between values before and after exposure were microradiographically evaluated. Results: After both treatment periods specimens immersed in SN 0 revealed significantly higher mineral losses (lower ΔΔZ values) and lesion depths (lower ΔLD) compared to PC (p <0.05; ANOVA). After 5 weeks, specimens stored in SN 1 and 2 showed significantly higher mineral losses compared to PC (p <0.05), while those stored in SN 3 showed similar results (p >0.05). No differences in mineral loss could be observed between SN 2 and 3 (p >0.05). Conclusions: Under the conditions of this limited protocol, the combination of Saliva natura solutions slightly saturated with respect to OCP in combination with a high-concentrated fluoride toothpaste enabled remineralisation of dentin in vitro. [Copyright &y& Elsevier]

Abstract: Objectives: The aim of this study is to compare the wear resistance and hardness of two dental nanohybrid composites and to evaluate the influence of artificial saliva storage on those properties. Methods: Specimens were made from two commercial nanohybrid dental composites (Esthet-X®-Dentsply and Filtek Supreme®-3M). Abrasion tests were carried out in a ball-cratering machine (three body abrasion) and microscopic analysis of the wear surfaces was made using optical and scanning electron microscopy; hardness was quantified by Vickers hardness test. Those tests were repeated on specimens stored in artificial saliva. Results: Results show that the wear rate of the studied materials is within 10−7 mm3/Nmm range, one of the composites presenting wear rate twice as large as the other. After storage in artificial saliva, the wear resistance increases for both materials. Microhardness of the composites is around 52 and 64HV, Esthet-X® presents higher hardness values than Filtek Supreme®. After storage in artificial saliva, the microhardness of both materials decreases. Data were analyzed using ANOVA test, p ≤0.05. Conclusions: Artificial saliva storage increases the materials’ wear resistance, suggesting that in both materials bulk post-cure takes place and saliva absorption occurs only on the surface of the composites. This effect was confirmed by comparing the Vickers hardness before and after artificial saliva treatment and FTIR analyses. Surface microhardness of the composites decreases after storage in artificial saliva whereas bulk microhardness of the materials increases. [Copyright &y& Elsevier]

Abstract: Objectives: The present study evaluated the effects of various calcium and phosphate concentrations and ratios of carboxymethylcellulose (CMC)-based solutions on the mineral loss of predemineralised bovine enamel in vitro. Methods: Bovine enamel specimens were prepared, polished and partly covered with nail varnish, thus serving as control of sound enamel. After demineralisation (37°C; pH 5.0; 14 days) the specimens were exposed to CMC-based solutions (20g/l) with various saturations with respect to apatites containing 0.1mM NaF, CaCl2 (0–32mM) and KH2PO4 (0–52mM) at two different pH values (5.5 or 6.5). A fluoride-free solution served as control, and four commercially available products were tested as well. The differences in mineral loss (ΔΔZ) between the values prior to (ΔZ Demin) and after storage (ΔZ Effect) in the various solutions were evaluated from microradiographs of thin sections (100μm). Results: The general linear model revealed a significant dependency for ΔΔZ on ‘calcium’ (p <0.001), ‘phosphate’ (p =0.023), ‘fluoride’ (p =0.002) and ‘pH’ (p <0.001). With increasing calcium and phosphate concentrations an increase in ΔΔZ could be observed up to the solution containing the third highest saturation with respect to octacalciumphosphate (3.2), showing a significant remineralisation (p <0.05; t-test). The commercially available products as well as the control groups revealed significantly reduced ΔΔZ values compared to this group (p <0.01; Bonferroni). Conclusions: A saturation with respect to octacalciumphosphate of 3.2 and a pH of 6.5 enables CMC-based solutions to remineralise bovine enamel in vitro. [Copyright &y& Elsevier]

Abstract: Objectives: This in vitro study assessed the effect of an experimental 4%TiF4 varnish on enamel erosion. Methods: Sixty bovine enamel blocks were randomly allocated to each type of varnish: Duraphat®-D (NaF, 2.26%F), Duofluorid®-F (NaF, 2.71% F), TiF4-T (2.45%F) and no-fluoride-P. After application of the varnishes, the blocks were subjected to six sequential pH cycles (cola drink for 10min and artificial saliva for 50min, each) per day, during 4 days. After the pH cycles, the blocks were maintained in artificial saliva for 18h. Enamel alterations were determined in the 2nd and 4th days, using profilometry (wear) and microhardness (%SMHC) tests. Data were tested using ANOVA and Tukey''s tests (p <0.05). Results: The mean %SMHC (±S.D.) at the 2nd and 4th day was, respectively, D (−77.26±5.04a and −88.59±5.11A), F (−76.79±7.82a and −88.78±6.10A), T (−88.28±3.19b and −92.04±2.54A,B) and P (−87.96±2.23b and −94.15±1.14B). The mean wear (μm±S.D.) at the 2nd and 4th day was, respectively, D (3.16±0.32a and 7.56±0.90A), F (3.35±0.78a,b and 7.92±0.98A), T (3.81±0.43b and 7.69±0.76A) and P (3.43±1.13a,b and 7.31±0.53A). Conclusions: The NaF varnishes reduced the softening, but had no effect on the reduction of the wear. The TiF4 varnish was not able to reduce the softening and wear. [Copyright &y& Elsevier]

Objectives: To assess sorption and solubility of several bulk-fill and conventional resin-composites after one-year storage in water and artificial saliva (AS)., Methods: Six bulk-fill (SureFil SDR, Venus Bulk Fill, X-tra base, Filtek Bulk Fill flowable, Sonic Fill, and Tetric EvoCeram Bulk Fill) and eight conventional resin-composites (Grandioso Flow, Venus Diamond Flow, XFlow, Filtek Supreme XTE, Grandioso, Venus Diamond, TPH Spectrum, and Filtek Z250) were tested. Disc shaped samples (n=5) were randomly immersed into distilled water and AS for one-year period and weighed at different time intervals. Data were analysed using repeated measures ANOVA, one-way ANOVA, and Tukey's post hoc test (α=0.05)., Results: In water, all materials (with the exception of X-Flow) reached a stable mass within three months with a slow increase observed in AS up to one year. Sorption values in water and AS for most materials were not significantly different (p≥0.2). Sorption and solubility values in water ranged from (6.5 μg/mm(3) and -1.77 μg/mm(3) respectively) for X-tra base to (78.8 μg/mm(3) and 44.77 μg/mm(3) respectively) for X-Flow (p<0.005). Sorption of the polymer matrix in water ranged from 1.18% for XB to 9.95 % for XF., Conclusions: Water sorption and solubility of resin-composites are material-dependent and highly affected by the filler loading and hydrophilicity of the resin matrix. BisEMA and UDMA-BisEMA based resins appeared to be more hydrophobic than BisGMA based systems. Water and AS, are generally comparable as storage media in terms of water sorption., Clinical Significance: Bulk-fill materials and conventional resin-composites tested varied in terms of sorption and solubility but both were considered stable in longterm water storage. The composition of each material is critical and can affect the long-term clinical performance of either type of resincomposites., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Objectives: Evaluate the effect of different storage conditions on bleached enamel using Knoop microhardness (KHN) and colour variation., Methods: Forty-eight tooth blocks were divided into four groups (n=12), based on storage media (SM): purified water (PW), artificial saliva (AS), natural saliva (NS), in situ (IS). Three whitening sessions were carried out using 35% hydrogen peroxide, with a week interval. Colour and KHN measurements were taken before the samples were placed in the SM (t1), after 24h in the SM (t2), and after 24h at the end of the bleaching treatment (t3). Two extra samples from each group were analysed using a scanning electron microscope (SEM). KHN results were analysed by PROC-MIXED and Tukey-Kramer test (α=0.05), and colour changes were evaluated using ΔL, Δa, Δb, ΔE between the different times Δ1(t1-t2), Δ2(t2-t3) using the Kruskal-Wallis test and Dunn's test (α=0.05)., Results: Significant statistical difference was noted in KHN at t3, with the lowest values found for PW. As for colour analysis in ΔE2 and Δb2, IS showed values that were statistically lower when compared to AS. Likewise, there were differences between PW and AS in relation to IS when evaluating ΔL2. In addition, NS showed similar values to IS., Conclusions: The storage conditions had different effects on the physical properties of bleached enamel. NS was the only SM that showed similar behaviour to IS., Clinical Significance: NS proved an effective SM in the protection and recovery of damage caused by bleaching and is a viable SM for in vitro studies., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Abstract: Objectives: Firstly, to evaluate the in vitro anti-erosion efficacy of a new mouthrinse formulation containing 450 ppm fluoride using profilometry and microindentation. Secondly, to compare fluoride uptake by erosive lesions from two mouthrinses containing different fluoride sources using dynamic secondary ion mass spectrometry (DSIMS). Methods: Sound human enamel was treated (60s) with mouthrinses containing different fluoride concentrations, then immersed in 1.0% citric acid pH3.8 for either 300s or 30min (Studies 1 & 2 respectively). Surface roughness and erosion depth were determined profilometrically in Study 1, and surface microhardness monitored as a function of time in Study 2. Lesion rehardening was monitored following a 60 s rinse and immersion in artificial saliva for 48 h (Study 3), whilst Study 4 employed DSIMS to quantify fluoride uptake by lesions treated (60s) with rinses containing either sodium fluoride (NaF) or a NaF/Olaflur/stannous chloride combination. Results: The test rinse (450 ppm fluoride) suppressed surface roughening and bulk tissue loss versus all comparators (p< 0.0001), except in the latter measure for the rinse containing 112 ppm fluoride. The test rinse significantly inhibited enamel surface softening versus the three rinses containing ≤112 ppm fluoride (as NaF) at 30min (p<0.05), but was not statistically significantly different from the 225 ppm fluoride rinse. The test rinse conferred statistically superior lesion rehardening versus all comparators at both 24 and 48 h (p< 0.0001). DSIMS demonstrated statistically significantly higher fluoride uptake by incipient erosive lesions treated with the test rinse versus the NaF/Olaflur/stannous rinse. Conclusions: Anti-erosion efficacy was positively correlated with fluoride concentration. DSIMS showed significantly higher levels of fluoride uptake by incipient erosive lesions treated with the 450 ppm fluoride rinse versus the NaF/Olaflur/stannous rinse. [Copyright &y& Elsevier]

Abstract: Objectives: To assess the relative protective effect of commercial mouthrinses containing 0-450ppm fluoride on erosion progression in enamel using a simulated 5-day in vitro cycling model with concurrent monitoring of surface microhardness (SMH) and bulk tissue loss. Methods: Specimens were randomly assigned to six treatment groups (n=6). The model mimicked morning and evening use with rinse times (30 or 60s) reflecting those prescribed on pack, interspersed with three cycles of demineralisation/remineralisation per simulated day. The latter comprised 1.0% citric acid monohydrate pH3.2 for 300s, with subsequent remineralisation in mucin-free artificial saliva pH7.0 for 120min. SMH was determined by Vickers microindentation and bulk tissue loss using white-light interferometry. Results: From the end of day 1, fluoride-containing mouthrinses conferred statistically significant reductions in bulk tissue loss versus fluoride-free rinses (p<0.05), with lesion depth inversely proportional to fluoride concentration. From day 3, the mean lesion depth of specimens treated with the 450 ppm rinse were statistically significantly lower than all comparator treatment groups (p<0.05). Two distinct trends were apparent when comparing SMH changes in groups treated with fluoride-free versus fluoride-containing mouthrinses. In the latter, SMH levelled out over the final three simulated days in contrast to the former whose SMH continued to fall; differences were statistically significant at day 5 (p< 0.05). Conclusions: Bulk tissue loss is inversely proportional to fluoride concentration in this cycling model. The plateau in SMH reflects stabilisation of mineral density as the study progresses and the number of fluoride binding sites and consequently uptake increases, in turn leading to enhanced lesion remineralisation. [ABSTRACT FROM AUTHOR]