Connective tissue graft plus resin-modified glass ionomer restoration for the treatment of gingival recession associated with non-carious cervical lesions: Microbiological and immunological results

Objectives: It was previously reported the clinical results of placing subgingival resin-modified glass ionomer restoration for treatment of gingival recession associated with non-carious cervical lesions. The aim of this study was to evaluate the influence of this treatment on the subgingival biofilm and gingival crevicular fluid (GCF) inflammatory markers. Materials and methods: Thirty-four patients presenting the combined defect were selected. The defects were treated with either connective tissue graft plus modified glass ionomer restoration (CTG+R) or with connective tissue graft only (CTG). Evaluation included bleeding on probing and probing depth, 5 different bacteria targets in the subgingival plaque assessed at baseline, 45, and 180 days post treatments, and 9 inflammatory mediators were also assessed in the GCF. Results: The levels of each target bacterium were similar during the entire period of evaluation (p > 0. 05), both within and between groups. The highest levels among the studied species were observed for the bacterium associated with periodontal health. Additionally, the levels of all cyto/chemokines analyzed were not statistically different between groups (p > 0. 05). Conclusion: Within the limits of the present study, it can be concluded that the presence of subgingival restoration may not interfere with the subgingival microflora and with GCF inflammatory markers analyzed. Clinical relevance: This approach usually leads to the placement of a subgingival restoration. There is a lack of information about the microbiological and immunological effects of this procedure. The results suggest that this combined approach may be considered as a treatment option for the lesion included in this study. © 2012 Springer-Verlag.

Broadband NIR emission in novel sol-gel Er3+-doped SiO 2-Nb2O5 glass ceramic planar waveguides for photonic applications

This paper reports on the sol-gel preparation and structural and optical characterization of new Er3+-doped SiO2-Nb 2O5 nanocomposite planar waveguides. Erbium-doped (100-x)SiO2-xNb2O5 waveguides were deposited on silica-on-silicon substrates and Si(1 0 0) by the dip-coating technique. The waveguides exhibited uniform refractive index distribution across the thickness, efficient light injection at 1538 nm, and low losses at 632 and 1538 nm. The band-gap values lied between 4.12 eV and 3.55 eV for W1-W5, respectively, showing an excellent transparency in the visible and near infrared region for the waveguides. Fourier Transform Infrared (FTIR) Spectroscopy analysis evidenced SiO2-Nb2O5 nanocomposite formation with controlled phase separation in the films. The HRTEM and XRD analyses revealed Nb2O5 orthorhombic T-phase nanocrystals dispersed in a silica-based host. Photoluminescence (PL) analysis showed a broad band emission at 1531 nm, assigned to the 4I13/2 → 4I15/2 transition of the Er3+ ions present in the nanocomposite, with a full-width at half medium of 48-68 nm, depending on the niobium content and annealing. Hence, these waveguides are excellent candidates for application in integrated optics, especially in EDWA and WDM devices. © 2012 Elsevier B.V. All rights reserved.

In vitro and in vivo investigation of the biological and mechanical behaviour of resin-modified glass-ionomer cement containing chlorhexidine

Objectives: To evaluate: (1) the in vitro antibacterial, cytotoxic and mechanical properties of a resin-modified glass ionomer cement (RMGIC) containing different concentrations of chlorhexidine (CHX) and (2) the in vivo microbiologic action of the best concentration of CHX associated with the RMGIC applied on remaining dentine after indirect pulp treatment (IPT). Methods: For the in vitro studies, RMGIC was associated with 0.2, 0.5, 1.25 and 2.5% CHX. Microbiologic evaluation consisted of an agar diffusion test on cariogenic bacteria for 24 h. Odontoblast-like cell metabolism and morphology analyses measured the cytotoxic effects of the RMGIC groups after 24 h. The same groups were submitted to compressive and diametral tensile strength. The in vivo treatment consisted of IPT using an RMGIC associated with the best CHX concentration. Clinical and microbiologic evaluations were performed before and after 3 months. Results: The use of 1.25% CHX significantly improved the antibacterial effects of the evaluated RMGIC, without causing any detrimental effects to the odontoblast-like cells and on the mechanical properties. This RMGIC and CHX combination completely eliminated mutans streptococci after 3 months of IPT. Conclusion: The RMGIC and 1.25% CHX mixture showed great biological and mechanical behaviour and could be a good treatment against caries progression. Clinical significance: The association of CHX with a liner RMGIC opens a new perspective for arresting residual caries after IPT. © 2012 Elsevier Ltd. All rights reserved.

Giant enhancement of phonon-assisted one-photon excited frequency upconversion in a Nd3+-doped tellurite glass

Changing the sample's temperature from 200 K to 535 K, we observed 670-fold enhancement of a phonon-assisted upconversion emission at ≈754 nm obtained from a Nd3+-doped tellurite glass excited by 5 ns laser pulses at 805 nm. A rate-equation model, including the relevant energy levels and temperature dependent transition rates, is proposed to describe the process. The results fit well with the data when one considers the nonradiative transitions contributing for the 754 nm luminescence are promoted by an effective phonon mode with energy of 700 cm-1. © 2013 American Institute of Physics.

Upconversion luminescence in Er3+ doped Ga10Ge 25S65 glass and glass-ceramic excited in the near-infrared

The infrared-to-visible frequency upconversion was investigated in Er 3+-doped Ga10Ge25S65 glass and in the transparent glass-ceramic obtained by heat-treatment of the glass above its glass-transition temperature. Continuous-wave and pulsed lasers operating at 980 nm and 1480 nm were used as excitation sources. The green (2H 11/2 → 4I15/2; 4S3/2 → 4I15/2) and red (4F9/2 → 4I15/2) photoluminescence (PL) signals due to the Er3+ ions were characterized. The PL decay times were influenced by energy transfer among Er3+ ions, by cross-relaxation processes and by energy transfer from the Er3+ ions to the host material. The PL from the Er3+ ions hosted in the crystalline phase was distinguished only when the glass-ceramic was excited by the 1480 nm pulsed laser. The excitation pathways responsible for the green and red PL bands are discussed to explain the differences between the spectra observed under continuous-wave and pulsed excitation. © 2013 American Institute of Physics.

Infrared to visible up-conversion emission in Er3+/Yb 3+ codoped fluoro-phosphate glass-ceramics

Erbium Er3+ and ytterbium Yb3+ codoped fluoro-phosphate glasses belonging to the system NaPO3-YF 3-BaF2-CaF2 have been prepared by the classical melt-quenching technique. Glasses containing up to 10 wt% of erbium and ytterbium fluorides have been obtained and characterized using differential scanning calorimetry (DSC) and UV-visible and near-infrared spectroscopy. Transparent and homogeneous glass-ceramics have been then reproducibly synthetized by appropriate heat treatment above glass transition temperature of a selected parent glass. Structural investigations of the crystallization performed through X-ray diffractometry (XRD) and scanning electron microscopy (SEM) have evidenced the formation of fluorite-type cubic crystals based during the devitrification process. Finally, infrared to visible up-conversion emission upon excitation at 975 nm has been studied on the Er3+ and Yb 3+ codoped glass-ceramics as a function of thermal treatment time. A large enhancement of intensity of the up-conversion emissions-about 150 times- has been observed in the glass-ceramics if compared to the parent glass one, suggesting an incorporation of the rare-earth ions (REI) into the crystalline phase. © 2012 The American Ceramic Society.

Glass foam of macroporosity using glass waste and sodium hydroxide as the foaming agent

Glass foams using float glass waste and sodium hydroxide were produced. The influence of the sodium hydroxide amount in the foam formulation was studied. Titanium dioxide was used as a strengthening agent. The variations of temperature, heating rate and sintering time were investigated during the synthesis process. Open porosity was estimated using mercury porosimetry. The morphology of the glass foams was evaluated using scanning electron microscopy, phase formation was studied using X-ray diffraction, and chemical composition was estimated using X-ray fluorescence. As a result, glass foams with macroporosity were obtained. Since the glass foams used glass waste as reactant, the results suggest the development of an alternative route for glass recycling. © 2012 Elsevier Ltd and Techna Group S.r.l.

Comparison of the caries-preventive effect of a glass ionomer sealant and fluoride varnish on newly erupted first permanent molars of children with and without dental caries experience

Purpose: This longitudinal clinic study evaluated the effect of a glass ionomer sealant (GIS) and a fluoride varnish (FV) in the prevention of dental decay on newly erupted permanent molars of children with and without caries experience. Materials and methods: Eighty children, aged 6-8 years, with all four newly erupted first permanent molars, were divided into two groups. Group 1 consisted of 53 children without caries experience and group 2 consisted of 27 children with dental caries experience. Permanent molars of the right side were sealed with GIS and the fluoride varnish was applied on the other two permanent first molars. Evaluation of GIS retention and the effectiveness of both materials in the prevention of dental caries were performed after 6, 12 and 18 months. Results: After 18 months, of the 299 teeth, 271 (91%) showed no caries lesions and 28 presented caries lesions (9%). Teeth sealed with GIS had more carious lesions (15) than teeth with fluoride varnish (13). Most of the teeth (70%) that presented carious lesions were in group 2. Of the 138 sealed teeth, only one showed GIS to be totally present, 95 were partially present and 42 teeth were absent. Conclusion: The caries-preventive effect was very similar between both treatments. The presence of dental caries prevailed in the children with caries experience. © 2013 Informa Healthcare.

Tunable plasmon resonance modes on gold nanoparticles in Er 3 +-doped germanium-tellurite glass

Relative to the Er3 +:gold-nanoparticle (Er3 +:Au-NP) axis, the polarization of the gold nanoparticle can be longitudinal (electric dipole parallel to the Er3 +:Au-NP axis) or transverse (electric dipole perpendicular to the Er3 +:Au-NP axis). For longitudinal polarization, the plasmon resonance modes of gold nanoparticles embedded in Er3 +-doped germanium-tellurite glass are activated using laser lines at 808 and 488 nm in resonance with radiative transitions of Er3 + ions. The gold nanoparticles were grown within the host glass by thermal annealing over various lengths of time, achieving diameters lower than 1.6 nm. The resonance wavelengths, determined theoretically and experimentally, are 770 and 800 nm. The absorption wavelength of nanoparticles was determined by using the Frohlich condition. Gold nanoparticles provide tunable emission resulting in a large enhancement for the 2H11/2 → 4I13/2 (emission at 805 nm) and 4S 3/2 → 4I13/2 (emission at 840 nm) electronic transitions of Er3 + ions; this is associated with the quantum yield of the energy transfer process. The excitation pathways, up-conversion and luminescence spectra of Er3 + ions are described through simplified energy level diagrams. We observed that up-conversion is favored by the excited-state absorption due to the presence of the gold nanoparticles coupled with the Er3 + ions within the glass matrix. © 2013 Elsevier B.V.

Hybridization effect on the mechanical properties of curaua/glass fiber composites

The aim of this paper was to evaluate the effect of hybridizing glass and curaua fibers on the mechanical properties of their composites. These composites were produced by hot compression molding, with distinct overall fiber volume fraction, being either pure curaua fiber, pure glass fiber or hybrid. The mechanical characterization was performed by tensile, flexural, short beam, Iosipescu and also nondestructive testing. From the obtained results, it was observed that the tensile strength and modulus increased with glass fiber incorporation and for higher overall fiber volume fraction (%Vf). The short beam strength increased up to %Vf of 30 vol.%, evidencing a maximum in terms of overall fiber/matrix interface and composite quality. Hybridization has been successfully applied to vegetable/synthetic fiber reinforced polyester composites in a way that the various properties responded satisfactorily to the incorporation of a third component. © 2013 Published by Elsevier Ltd. All rights reserved.

Nonlinear optical properties of Bi2O3-GeO2 glass at 800 and 532 nm

The nonlinear (NL) optical properties of glassy xBi2O 3-(1-x) GeO2 with x = 0.72 and 0.82 were investigated. The experiments were performed with lasers at 800 nm (pulses of 150 fs) and 532 nm (pulses of 80 ps and 250 ns). Using the Kerr gate technique, we observed that the NL response of the samples at 800 nm is faster than 150 fs. NL refraction indices, | n 2 | ≈ 5 × 10-16 cm2/W, and two-photon absorption coefficients, α 2, smaller than 0.03 cm/GW, were measured at 800 nm. At 532 nm, we measured the NL transmittance of the samples. From the results obtained, we determined α 2 ≈1 cm/GW and excited-state absorption cross-sections of ≈10-22 cm2 due to free-carriers. © 2013 AIP Publishing LLC.

Study of the glass transition temperature of as-s glasses for the fabrication of chalcogenide optical fibers

Values of glass transition temperature (Tg) and of linear expansion coefficient (α) for Asx S100-x glasses were measured in the range of concentrations 35 × 42. Because of the importance of the glass formation region 35 × 42 for the optical fibers elaboration, special attention was made on high-pure Asx S100-x glasses. For the glass in the range of 35 × 38, we measure Tg with the interval of x equal to 1 at.% of arsenic. We also measured the Tg values with the interval of x equal to 0.5 at.% of As. We obtained nonlinear behavior of Tg, reflecting the change in molecular composition of As-S glass in the glass composition range studied. The control of such parameters is important to produce optical fibers with specific numerical aperture. © 2013 The American Ceramic Society and Wiley Periodicals, Inc.

Randomized controlled clinical trial evaluating connective tissue graft plus resin-modified glass ionomer restoration for the treatment of gingival recession associated with non-carious cervical lesion: 2-year follow-up

Background: The aim of this clinical study is to evaluate the 2-year term results of gingival recession (GR) associated with non-carious cervical lesions (NCCLs) treated by connective tissue graft (CTG) alone or in combination with a resin-modified glass ionomer restoration (CTG+R). Methods: Thirty-six patients with Miller Class I buccal GR associated with NCCLs completed the follow-up. The defects were randomly assigned to receive either CTG or CTG+R. Bleeding on probing (BOP), probing depth (PD), relative GR, clinical attachment level (CAL), and cervical lesion height coverage were measured at baseline, 6 months, 1 year, and 2 years after treatment. Results: Both groups showed statistically significant gains in CAL and soft-tissue coverage. The differences between groups were not statistically significant in BOP, PD, relative GR, or CAL after 2 years. Cervical lesion height coverage was 79.31% ± 18.51% for CTG and 71.95% ± 13.25% for CTG+R (P >0.05). Estimated root coverage was 91.56% ± 11.74% for CTG and 93.29% ± 7.97% for CTG+R (P ≥0.05). Conclusions: Within the limits of the present study, it can be concluded that both procedures provide comparable soft tissue coverage after 2 years of follow-up.

Degree of conversion and hardness of two different systems of the vitrebond™ glass ionomer cement light cured with blue LED

This study investigated the physicochemical properties of the new formulation of the glass ionomer cements through hardness test and degree of conversion by infrared spectroscopy (FTIR). Forty specimens (n = 40) were made in a metallic mold (4 mm diameter × 2 mm thickness) with two resin-modified glass ionomer cements, Vitrebond™ and Vitrebond™ Plus (3M/ ESPE). Each specimen was light cured with blue LED with power density of 500 mW/cm2during 30 s. Immediately after light curing, 24h, 48h and 7 days the hardness and degree of conversion was determined. The Vickers hardness was performed by the MMT-3 microhardness tester using load of 50 gm force for 30 seconds. For degree of conversion, the specimens were pulverized, pressed with KBr and analyzed with FT-IR (Nexus 470). The statistical analysis of the data by ANOVA showed that the Vitrebond™ and Vitrebond™ Plus were no difference significant between the same storage times (p > 0.05). For degree of conversion, the Vitrebond™ and Vitrebond™ Plus were statistically different in all storage times after light curing. The Vitrebond™ showed higher values than Vitrebond™ Plus (p < 0.05). The performance of Vitrebond™ had greater results for degree of conversion than Vitrebond™ Plus. The correlation between hardness and degree of conversion was no evidence in this study.

The impact of hydrofluoric acid etching followed by unfilled resin on the biaxial strength of a glass-ceramic

Objectives: To evaluate the null hypotheses that hydrofluoric (HF) acid etching time would neither decrease the biaxial flexural strength of a glass-based veneering ceramic nor enhance it after silane and unfilled resin (UR) applications. Methods: Disc-shaped IPS e.max ZirPress specimens were allocated into 12 groups: G1-control (no-etching), G2-30 s, G3-60 s, G4-90 s, G5-120 s, G6-60 s + 60 s. Groups (G7-G12) were treated in the same fashion as G1-G6, but followed by silane and UR applications. Surface morphology and roughness (Ra and Rq) of the ceramics were assessed by means of scanning electron microscopy (SEM) and profilometry, respectively. Flexural strength was determined by biaxial testing. Data were analyzed by two-way ANOVA and the Sidak test (α = 0.05). Weibull statistics were estimated and finite element analysis (FEA) was carried out to verify the stress concentration end areas of fracture. Results: The interaction (etching time vs. surface treatment) was significant for Ra (p = 0.008) and Rq (0.0075). Resin-treated groups presented significantly lower Ra and Rq than non-treated groups, except for the 60 s group (p < 0.005). SEM revealed that etching affected the ceramic microstructure and that the UR was able to penetrate into the irregularities. A significant effect of etching time (p = 0.029) on flexural strength was seen. G7-G12 presented higher strength than G1-G6 (p < 0.0001). None of experimental groups failed to show 95% confidence intervals of σ 0 and m overlapped. FEA showed lower stress concentration after resin treatment. Significance: HF acid etching time did not show a damaging effect on the ceramic flexural strength. Moreover, the flexural strength could be enhanced after UR treatment. © 2013 Academy of Dental Materials.