METHODS: VE-TPGS was added to RF-solution, at RF/VE-TPGS (w/w) ratios of 0.125/0.250 and 0.125/0.500. Demineralized dentine beams were used (10wt.% phosphoric acid), rinsed using deionized-water and analysed using ELISA (Human MMP2 ELISA; Human CTSK/Cathepsin-K for MMP2 and Cathepsin K analysis). AFM of dentine collagen-fibrils structure was done before and after dentine specimens' placement in mineralization solution and tested after 14days in artificial saliva/collagenase (AS/Co) solution. The specimens were tested after 24h in mineralization solution for surface/bulk elastic modulus. Nano-indentation was carried out for each specimen on intertubular-dentine with lateral spacing of 400nm. Reduced elastic-modulus and nano-hardness were calculated and collagen content was determined using hydroxyproline-assay. Micro-Raman were performed. TEM was carried out to study structural variations of dentine-collagen in artificial-saliva (collagenase). Data were presented as mean±standard deviation and analyzed by SPSS v.15, by analysis of variance.
RESULTS: Synergetic effect of VE-TPGS was observed with RF through higher structural integrity of dentine collagen-fibrils shown by TEM/AFM. Superior surface/bulk mechanical stability was shown by nano-indentation/mechanical testing. Improvement in collagenase degradation resistance for hydroxyproline release was observed and lower endogenous-protease release of MMP-2/Cathepsin-K. Raman-analysis analysed chemical interactions between RF and collagen confirming structural-integrity of collagen fibrils after crosslinking. After 24h mineralization, AFM showed mineral depositions in close association with dentine-collagen fibrils with RF/VE-TPGS formulations.
SIGNIFICANCE: Potential synergetic effect of RF/VE-TPGS was observed by reflection of higher structural integrity and conformational-stability of dentine-collagen fibrils.
METHODS: The interaction between HIFU waves and dentin-surface in terms of structural, mechanical and chemical variations were investigated by SEM, TEM, AFM, nano-indentation and Raman-analysis. The bonding between HIFU-treated dentin and two-step, etch-and-rinse, adhesive was preliminary explored by characterizing dentin-bound proteases activities, resin-dentin interfacial morphology and bond-durability with HIFU exposure at different time-points of 60, 90 and 120 s compared to conventional acid-etching technique.
RESULTS: With the increase in HIFU exposure-time from 60-to-120 s, HIFU waves were able to remove the smear-layer, expose dentinal-tubules and creating textured/rough dentin surface. In addition, dentin surfaces showed a pattern of interlocking ribbon-like minerals-coated collagen-fibrils protruding from the underlaying amorphous dentin-background with HIFU exposure for 90 s and 120 s. This characteristic pattern of dentin-surface showing inorganic-minerals associated/aligned with collagen-fibrils, with 90-to-120 s HIFU-treatment, was confirmed by the Raman-analysis. HIFU-treated specimens showed higher nano-indentation properties and lower concentrations of active MMP-2 and Cathepsin-K compared to the acid-etched specimens. The resin-dentin bonded interface revealed the partial/complete absence of the characteristic hybrid-layer formed with conventional etch-and-rinse bonding strategy. Additionally, resin-infiltration and resin-tags formation were enhanced with the increase in HIFU exposure-time to 120 s. Although, all groups showed significant decrease in bond-strength after 12 months compared to 24 h storage in artificial saliva, groups exposed to HIFU for 90 s and 120 s showed significantly higher μTBS compared to the control acid-etched group.
SIGNIFICANCE: The implementation of HIFU-technology for dental hard-tissues treatment could be of potential significance in adhesive/restorative dentistry owing to its ability of controlled, selective and localised combined tissue alteration/ablation effects.
METHODS: TPAu nanoparticles were fabricated from 0.31-g tetrachloroauric acid and 0.38-g of N-(2-mercaptopropionyl) glycine (2.4-mmol). Then co-dissolved using 35-mL of 6:1 methanol/acetic acid and mixed using NaBH4. EDC (0.3-M) was conjugated to TPAu nanoparticles at TPAU/EDC-0.25:1, and TPAU/EDC-0.5:1 treatment formulations ratios. Dentin specimens treated with 0.3-M EDC solution alone or left untreated were used as control. Nanoparticles formulations were characterized in term of particles morphology and size, Zeta potential, thermogravimetric analysis and small-angle X-ray scattering. Dentin substrates were characterized in term of TEM investigation, dentin proteases characterization, hydroxyproline liberation, elastic modulus measurement, Raman analysis and confocal microscopy viewing.
RESULTS: TEM evaluation of tiopronin protected gold nanoparticles dispersion revealed nano-clusters formations in both groups. However, based on our TEM measurements, the particle-size was ranging from ˜20 to 50 nm with spherical core-shape which were almost similar for both TPAu/EDC ratios (0.5:1 and 0.25:1). Zeta potential measurements indicate negative nanoparticles surface charge. SAXS profiles for both formulations, suggest a typical profile for uni-lamellar nanoparticles. Superior dentin collagen cross-linking effect was found with the TPAu/EDC nanoparticles formulations compared to the control and EDC treated groups.
SIGNIFICANCE: Cross-linking of dentin collagen using TPAu coupled with EDC through TPAu/EDC nanoparticles formulations is of potential significance in improving the biodegradation resistance, proteases inhibition, mechanical and structural stability of demineralized dentin substrates. In addition, the cross-linking effect is dependent on TPAu/EDC ratio, whereas higher cross-linking effect was found at TPAu/EDC ratio of 0.5:1.
METHODS: Root canal preparation was performed using stainless steel K-files™ and F4 size protaper with irrigation protocols of 6% NaOCl + 2% CHX; 3.5% QIS; 2% QIS and sterile saline. Biofilms were prepared using E. faecalis adjusted and allowed to grow for 3 days, treated with irrigants, and allowed to grow for 7 days. AFM was performed and surface free energy calculated. MC3T3 cells were infected with endo irrigant treated E. faecalis biofilms. Raman spectroscopy of biofilms were performed after bacterial re-growth on root dentine and exposed to different irrigation protocols and collagen fibers analysed collagen fibers using TEM. Antimicrobial potency against E. faecalis biofilms and cytoxicity against 3T3 NIH cells were also. Resin penetration and MitoTracker green were also evaluated for sealer penetration and mitochondrial viability. Data were analysed using One-way ANOVA, principal component analysis and post-hoc Fisher's least-significant difference.
RESULTS: Elastic moduli were maintained amongst control (5.5 ± 0.9) and 3.5% QIS (4.4 ± 1.1) specimens with surface free energy higher in QIS specimens. MC3T3 cells showed reduced viability in 6%NaOCl+2%CHX specimens compared to QIS specimens. DNA/purine were expressed in increased intensities in control and 6% NaOCl + 2% CHX specimens with bands around 480-490 cm-1 reduced in QIS specimens. 3.5% QIS specimens showed intact collagen fibrillar network and predominantly dead bacterial cells in confocal microscopy. 3.5% QIS irrigant formed a thin crust-type surface layer with cytoplasmic extensions of 3T3NIH spread over root dentine. Experiments confirmed MitoTracker accumulation in 3.5% treated cells.
SIGNIFICANCE: Novel QIS root canal irrigant achieved optimum antimicrobial protection inside the root canals facilitating a toxic effect against the Enterococcus faecalis biofilm. Root dentine substrates exhibited optimum mechanical properties and there was viability of fibroblastic mitochondria.
METHODS: Dentin slabs were treated with 0.1% riboflavin-5-phosphate modified (powder added slowly while shaking and then sonicated to enhance the dispersion process) Universal Adhesive Scotch Bond and Zipbond™ along with control (non-modified) and experimental adhesives, photoactivated with blue light for 20s. Hydroxyproline (HYP) release was assessed after 1-week storage. Elastic-modulus testing was evaluated using universal testing machine at 24 h. Resin-dentin interfacial morphology was assessed with scanning electron-microscope, after 6-month storage. 0.1% rhodamine dye was added into each adhesive and analyzed using CLSM. Detection of free amino groups was carried out using ninhydrin and considered directly proportional to optical absorbance. Collagen molecular confirmation was determined using spectropolarimeter to evaluate and assess CD spectra. For molecular docking studies with riboflavin (PDB ID file), the binding pocket was selected with larger SiteScore and DScore using Schrodinger PB software. After curing, Raman shifts in Amide regions were obtained at 8 μm levels. Data were analyzed using Two-way analysis of variance (ANOVA, p ≤ 0.05) and Tukey-Kramer multiple comparison post hoc tests.
RESULTS: At baseline, bond strength reduced significantly (p ≤ 0.05) in control specimens. However, at 6 months' storage, UVA Zipbond™ had significantly higher μTBS. Resin was able to diffuse through the porous demineralized dentin creating adequate hybrid layers in both 0.1%RF modified adhesives in CLSM images. In riboflavin groups, hybrid layer and resin tags were more pronounced. The circular dichroism spectrum showed negative peaks for riboflavin adhesive specimens. Best fitted poses adopted by riboflavin compound are docked with MMP-2 and -9 proteases. Amide bands and CH2 peaks followed the trend of being lowest for control UA Scotch bond adhesive specimens and increasing in Amides, proline, and CH2 intensities in 0.1%RF modified adhesive specimens. All 0.1%RF application groups showed statistically significant (p
METHODS: Dentine surfaces were etched with 37% phosphoric acid, bonded with respective in vitro ethanol and acetone adhesives modified with (m/m, 0, 1%, 2% and 3% ribose), restored with restorative composite-resin, and sectioned into resin-dentine slabs and beams to be stored for 24h or 12 months in artificial saliva. Bond-strength testing was performed with bond failure analysis. Pentosidine assay was performed on demineralized ribose modified dentine specimens with HPLC sensitive fluorescent detection. The structural variations of ribose-modified dentine were analysed using TEM and human dental pulpal cells were used for cell viability. Three-point bending test of ribose-modified dentine beams were performed and depth of penetration of adhesives evaluated with micro-Raman spectroscopy. The MMP-2 and cathepsin K activities in ribose-treated dentine powder were also quantified using ELISA. Bond strength data was expressed using two-way ANOVA followed by Tukey's test. Paired T tests were used to analyse the specimens for pentosidine crosslinks. The modulus of elasticity and dentinal MMP-2 and cathepsin K concentrations was separately analyzed using one-way ANOVA.
RESULTS: The incorporation of RB in the experimental two-step etch-and-rinse adhesive at 1% improved the adhesive bond strength without adversely affecting the degree of polymerisation. The newly developed adhesive increases the resistance of dentine collagen to degradation by inhibiting endogenous matrix metalloproteinases and cysteine cathepsins. The application of RB to acid-etched dentine helps maintain the mechanical properties.
SIGNIFICANCE: The incorporation of 1%RB can be considered as a potential candidate stabilizing resin dentine bond.
METHODS: Root canal was prepared using stainless steel K-files™ and ProTaper™ and subjected to manual and ultrasonic irrigation using 6% NaOCl+2% CHX, 6% NaOCl+2% QAS and saline as control. For confocal-microscopy, Raman spectroscopy and SEM analysis before and after treatment, Enterococcus faecalis cultured for 7 days. Raman spectroscopy analysis was done across cut section of gutta percha/sealer-dentine to detect resin infiltration. Indentation of mechanical properties was evaluated using a Berkovich indenter. The contact angle of irrigants and surface free energy were evaluated. Mineralization nodules were detected through Alazarin red after 14 days.
RESULTS: Control biofilms showed dense green colonies. Majority of E. faecalis bacteria were present in biofilm fluoresced red in NaOCl+2% QAS group. There was reduction of 484cm-1 Raman band and its intensity reached lowest with NaOCl+2% QAS. There was an increase in 1350-1420cm-1 intensity in the NaOCl+2% CHX groups. Gradual decrease in 1639cm-1 and 1609cm-1 Raman signal ratios were seen in the resin-depth region of 17μm>, 14.1μm> and 13.2μm for NaOCl+2% QAS, NaOCl+2% CHX and control groups respectively. All obturated groups showed an intact sealer/dentine interface with a few notable differences. 0.771 and 83.5% creep indentation distance for NaOCl+2% QAS ultrasonic groups were observed. Highest proportion of polar component was significantly found in the NaOCl+2% QAS groups which was significantly higher as compared to other groups. Mineralized nodules were increased in NaOCl+2% QAS.
SIGNIFICANCE: Favorable antimicrobial and endodontic profile of the NaOCl+2% QAS solution might suggest clinical use for it for more predictable reduction of intracanal bacteria.
PURPOSE/OBJECTIVE: To analyze function of new K21 molecule in the invasive process of oral squamous cell carcinoma (OSCC) cell line.
MATERIALS & METHODS: The Fusobacterium (ATCC 23726) streaks were made, and pellets were resuspended in Cal27 (ATCC CRL-2095) OSCC cell line spheroid cell microplate. Cells were seeded and Lysotracker staining performed for CathepsinK red channel. Cell and morphology were evaluated using Transmission Electron microscopy. Thiobarbituric acid assay was performed. OSCC was analyzed for Mic60. Raman spectra were collected from the cancer cell line. L929 dermal fibroblast cells were used for Scratch Assay. ELISA muti arrays were used for cytokines and matrix molecules. Internalization ability of fibroblast cells were also analyzed. Structure of K21 as a surfactant molecule with best docked poses were presented.
RESULTS: Decrease in lysosomal staining was observed after 15 and 30 min of 0.1% treatment. Tumor clusters were associated with cell membrane destruction in K21 primed cells. There was functional silencing of Mic60 via K21, especially with 1% concentration with reduced cell migration and invasiveness. Raman intensity differences were seen at 700 cm-1, 1200 cm-1 and 1600 cm-1 regions. EVs were detected within presence of fibroblast cells amongst K21 groups. Wound area and wound closure showed the progress of wound healing.
CONCLUSION: Over expression of CatK can be reduced by a newly developed targeted K21 based drug delivery system leading to reduced migration and adhesion of oral squamous cell carcinoma cells. The K21 drug formulation can have great potential for cancer therapies due to targeting and cytotoxicity effects.