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Arthur Veis - One of the best experts on this subject based on the ideXlab platform.

  • chondroitin sulfate is involved in the hypercalcification of the organic matrix of bovine Peritubular Dentin
    Archives of Oral Biology, 2016
    Co-Authors: Jason R Dorvee, Alix C Deymierblack, Lauren Gerkowicz, Sara Bahmanyar, Arthur Veis
    Abstract:

    Apatitic mineral of Dentin forms within the collagenous matrix (intertubular Dentin, ITD) secreted from the odontoblastic processes (OP). Highly calcified mineral (Peritubular Dentin, PTD) is deposited at the interface between the ITD and each process membrane, creating a tubular system penetrating the Dentin that extends from the Dentino-enamel junction to the preDentin-Dentin junction. We focus on determining the composition of the PTD both with regard to its organic matrix and the inorganic phase. A laser capture technique has been adapted for the isolation of the mineralized PTD free from the ITD, and for the analysis of the PTD by SEM, TEM, and energy dispersive spectrometry (EDS), these data were subsequently compared with similar analyses of intact Dentin slices containing ITD bounded-PTD annuli. Elemental line scans reveal clearly marked boundaries between ITD, PTD, and OP components, and illustrate the differences in composition, and topographical surface roughness. The organic matrix of the PTD was shown to be sulfur rich, and further antibody labeling showed the sulfated organic component to be chondroitin sulfate [corrected]. In this PTD organic matrix the S/Ca and Ca/P ratios were distinctly higher than in the ITD, indicating that polysaccharide bound S supplies the anionic counterion facilitating the formation of the apatitic PTD mineral.

  • bovine and equine Peritubular and intertubular Dentin
    Acta Biomaterialia, 2014
    Co-Authors: Stuart R Stock, Alix C Deymierblack, Arthur Veis, Alvin Telser
    Abstract:

    Abstract Dentin contains 1–2 μm diameter tubules extending from the pulp cavity to near the junction with enamel. Peritubular Dentin (PTD) borders the tubule lumens and is surrounded by intertubular Dentin (ITD). Differences in PTD and ITD composition and microstructure remain poorly understood. Here, a (∼200 nm)2, 10.1 keV synchrotron X-ray beam maps X-ray fluorescence and X-ray diffraction simultaneously around tubules in 15–30 μm thick bovine and equine specimens. Increased Ca fluorescence surrounding tubule lumens confirms that PTD is present, and the relative intensities in PTD and ITD correspond to carbonated apatite (cAp) volume fraction of ∼0.8 in PTD vs. 0.65 assumed for ITD. In the PTD near the lumen edges, Zn intensity is strongly peaked, corresponding to a Zn content of ∼0.9 mg g−1 for an assumed concentration of ∼0.4 mg g−1 for ITD. In the equine specimen, the Zn K-edge position indicates that Zn2+ is present, similar to bovine Dentin (Deymier-Black et al., 2013), and the above edge structure is consistent with spectra from macromolecules related to biomineralization. Transmission X-ray diffraction shows only cAp, and the 00.2 diffraction peak (Miller–Bravais indices) width is constant from ITD to the lumen edge. The cAp 00.2 average preferred orientation is axisymmetric (about the tubule axis) in both bovine and equine Dentin, and the axisymmetric preferred orientation continues from ITD through the PTD to the tubule lumen. These data indicate that cAp structure does not vary from PTD to ITD.

  • Peritubular Dentin a highly mineralized non collagenous component of Dentin isolation and capture by laser microdissection
    Connective Tissue Research, 2014
    Co-Authors: Jason R Dorvee, Alix C Deymierblack, Lauren Gerkowicz, Arthur Veis
    Abstract:

    We demonstrate the capability and technique to perform microdissection and isolation of select regions of untreated, mineralized Dentin using laser capture. Dentin is a complex, non-homogeneous tissue comprised of a mineralized collagenous matrix (intertubular Dentin [ITD]), odontoblastic processes (ODPs), a void space (tubules) that forms within the ITD left behind by the retraction of ODPs during Dentin maturation, and a highly mineralized non-collagenous component that exists at the interface between the tubules and ITD known as Peritubular Dentin (PTD). PTD forms as the Dentin matures. The ODPs retract toward the direction of the pulp; leaving very little PTD at either the DEJ or near the pulp. Statistical analysis of thin cross-sections of coronal bovine Dentin imaged by light microscopy reveal that the area occupied by PTD >50%. To examine the nature of PTD and its relation to both the tubules and ITD, we devised a series of steps to carefully prepare sections of coronal bovine Dentin so that areas of the Dentin tissue could be cut and isolated for further analysis. We demonstrate that it is possible to selectively isolate targeted regions of Dentin for analysis and that high resolution analysis of such sections can be performed using electron microscopy. Results show that the mineralized PTD has a different texture than mineralized ITD and that there is a distinct boundary between the PTD and the ITD. Selective isolation of mineralized tissue components for further analytical study opens the door for the investigation of similar enigmatic mineralized structures.

  • near tubule and intertubular bovine Dentin mapped at the 250 nm level
    Journal of Structural Biology, 2011
    Co-Authors: Stuart R Stock, Arthur Veis, Alvin Telser
    Abstract:

    In this study, simultaneous diffraction and fluorescence mapping with a (250 nm){sup 2}, 10.1 keV synchrotron X-ray beam investigated the spatial distribution of carbonated apatite (cAp) mineral and elemental Ca (and other cations including Zn) around Dentin tubules. In 1 {mu}m thick sections of near-pulp root Dentin, where Peritubular Dentin (PTD) is newly forming, high concentrations of Zn, relative to those in intertubular Dentin (ITD), were observed adjacent to and surrounding the tubule lumens. Some but not all tubules exhibited hypercalcified collars (high Ca signal relative to the surrounding ITD), and, when present, the zone of high Ca did not extend around the tubule. Diffraction rings from cAp 00.2 and 11.2 + 21.1 + 30.0 reflections were observed, and cAp was the only crystal phase detected. Profiles of Ca, Zn and cAp diffracted intensities showed the same transitions from solid to tubule lumen, indicating the same cAp content and organization in ITD far from the tubules and adjacent to them. Further, the matching Ca and diffraction profiles demonstrated that all of the Ca is in cAp or that any noncrystalline Ca was uniformly distributed throughout the Dentin. Variation of 00.2 and 11.2 + 21.1 + 30.0 diffracted intensity was consistentmore » with the expected biaxial crystallographic texture. Extension of X-ray mapping from near 1 {mu}m resolution to the 250 nm level, performed here for Dentin and its tubules, will provide new understanding of other mineralized tissues.« less

  • the composition of bovine Peritubular Dentin matching tof sims scanning electron microscopy and biochemical component distributions new light on Peritubular Dentin function
    Cells Tissues Organs, 2009
    Co-Authors: Bat Ami Gotliv, Arthur Veis
    Abstract:

    Peritubular Dentin (PTD) is a hypermineralized phase within the Dentinal tubules in some vertebrate teeth as an interface between the intertubular Dentin (ITD) and the cell processes. Our aim has been to understand the composition, structure and role of PTD as a mineralized tissue. We have utilized the technique of time of flight secondary ion mass spectrometry (TOF-SIMS) to map the distribution of positive and negative inorganic ions as well as organic components in the fully mineralized, intact PTD structure in bovine tooth cross-sections, and correlated these with scanning electron microscopy (SEM) in standard and backscatter modes. In recent work, we developed a procedure to freeze fracture the teeth and separate PTD from the less dense ITD by the use of aqueous sodium phosphotungstate step density gradients, after degrading the ITD collagen with NaOCl. Here, PTD-containing fragments were characterized by SEM and TOF-SIMS surface structure analysis. The TOF-SIMS data show that the isolated PTD does not contain collagen, but its surface is rich in glutamic acid-containing protein(s). The TOF-SIMS spectra also indicated that the intact PTD fragments contain phospholipids, and chemical analyses showed phosphatidylserine, phosphatidylinositol and phosphatidylcholine as the principal lipid components. In SEM sections, untreated PTD shows as a smooth collar around the tubule, but after digestion with ethylenediamine to remove all organic components, the porous nature of the mineral phase of small, thin platy apatite crystals becomes evident. Thus, the organic matrix of PTD appears to be a proteolipid-phospholipid complex.

M Giannini - One of the best experts on this subject based on the ideXlab platform.

  • Decreased Dentin tubules density and reduced thickness of Peritubular Dentin in hyperbilirubinemia-related green teeth
    Journal of Clinical and Experimental Dentistry, 2017
    Co-Authors: R Neves-silva, M Giannini, Af Paes-leme, Fábio De Abreu Alves, Alberto Nogueira Da Gama Antunes, Mario Fernando De Goes, Maria Dânia Holanda Tenório, José Lécio Machado, Márcio Ajudarte Lopes, Alan Roger Santos-silva
    Abstract:

    BACKGROUND It is stated anecdotally that patients with liver diseases in childhood who develop green teeth have increased risk for rampant caries, which may be secondary to changes in dental structure. The aim of this study was to test the hypothesis that hyperbilirubinemia affects the Dentin morphology of green teeth. MATERIAL AND METHODS Sixteen primary teeth were prepared and divided into two groups (green teeth, n = 8 and control, n = 8), which were transversely fractured across the cervical third of the dental crowns; Dentin was prepared and sputter-coated with gold, and examined under a scanning electron microscope. The mean density and mean diameter of Dentin tubules, as well as the thickness of Peritubular Dentin, were compared. RESULTS Hyperbilirubinemia was associated with a decrease in the density of the Dentin tubules (p< .01) and the thickness of Peritubular Dentin of green teeth (p< .01). CONCLUSIONS There was a correlation between childhood hyperbilirubinemia and changes in the Dentin morphology, including a decrease in the density of the Dentin tubules and a reduction in the thickness of Peritubular Dentin in green teeth. Key words:Hyperbilirubinemia, liver disease, childhood, Dentin tubules, human teeth, scanning electron microscopy.

  • Decreased Dentin tubules density and reduced thickness of Peritubular Dentin in hyperbilirubinemia-related green teeth
    Journal of Clinical and Experimental Dentistry, 2017
    Co-Authors: R Neves-silva, Fa Alves, A Antunes, Mf Goes, M Giannini, Md Tenorio, Jl Machado, Af Paes-leme, Ma Lopes
    Abstract:

    It is stated anecdotally that patients with liver diseases in childhood who develop green teeth have increased risk for rampant caries, which may be secondary to changes in dental structure. The aim of this study was to test the hypothesis that hyperbilirubinemia affects the Dentin morphology of green teeth. Sixteen primary teeth were prepared and divided into two groups (green teeth, n = 8 and control, n = 8), which were transversely fractured across the cervical third of the dental crowns; Dentin was prepared and sputter-coated with gold, and examined under a scanning electron microscope. The mean density and mean diameter of Dentin tubules, as well as the thickness of Peritubular Dentin, were compared. Hyperbilirubinemia was associated with a decrease in the density of the Dentin tubules (p< .01) and the thickness of Peritubular Dentin of green teeth (p< .01). There was a correlation between childhood hyperbilirubinemia and changes in the Dentin morphology, including a decrease in the density of the Dentin tubules and a reduction in the thickness of Peritubular Dentin in green teeth

  • effect of partially demineralized Dentin beneath the hybrid layer on Dentin adhesive interface micromechanics
    Journal of Biomechanics, 2015
    Co-Authors: M Giannini, Rodolfo Bruniera Anchieta, Lucas Silveira Machado, Renato Herman Sundfeld, Andre Figueiredo Reis, Marco Antonio Luersen, Malvin N Janal, Eduardo Passos Rocha
    Abstract:

    Abstract Objective To investigate the presence of non-infiltrated, partially demineralized Dentin (PDD) beneath the hybrid layer for self-etch adhesive systems, and its effect on micromechanical behavior of Dentin–adhesive interfaces (DAIs). This in-vitro laboratory and computer simulation study hypothesized that the presence of non-infiltrated PDD beneath the hybrid layer does not influence the mechanical behavior of the DAI of self-etch adhesive systems. Methods Fifteen sound third molars were restored with composite resin using three adhesive systems: Scotchbond Multipurpose (SBMP), Clearfil SE Bond (CSEB) and Adper Promp L-Pop (APLP). The thickness and length of all DAIs were assessed using scanning electron microscopy, and used to generate three-dimensional finite element models. Elastic moduli of the hybrid layer, adhesive layer, intertubular Dentin, Peritubular Dentin and resin tags were acquired using a nano-indenter. Finite element software was used to determine the maximum principal stress. Mixed models analysis of variance was used to verify statistical differences (P Results Elastic moduli and morphology were found to differ between the adhesive systems, as well as the presence and extension of PDD. Significance Both self-etch adhesive systems (APLP and CSEB) had PDD. The DAI stress levels were higher for the one-step self-etch adhesive system (APLP) compared with the etch-and-rinse adhesive system (SBMP) and the self-etch primer system (CSEB).

  • micromorphology of resin Dentin interfaces using one bottle etch rinse and self etching adhesive systems on laser treated Dentin surfaces a confocal laser scanning microscope analysis
    Lasers in Surgery and Medicine, 2010
    Co-Authors: Marcelo Tavares De Oliveira, Frederick A Rueggeberg, Cesar Augusto Galvao Arrais, Ana Cecilia Correa Aranha, Carlos De Paula Eduardo, Katsuya Miyake, M Giannini
    Abstract:

    Background and Objectives This study evaluated the hybrid layer (HL) morphology created by three adhesive systems (AS) on Dentin surfaces treated with Er:YAG laser using two irradiation parameters. Study Design Occlusal flat Dentin surfaces of 36 human third molars were assigned into nine groups (n = 4) according to the following ASs: one bottle etch&rinse Single Bond Plus (3M ESPE), two-step Clearfil Protect Bond (Kuraray), and all-in-one S3 Bond (Kuraray) self-etching, which were labeled with rhodamine B or fluorescein isothiocyanate–dextran and were applied to Dentin surfaces that were irradiated with Er:YAG laser at either 120 (38.7 J/cm2) or 200 mJ/pulse (64.5 J/cm2), or were applied to untreated Dentin surfaces (control group). The ASs were light-activated following MI and the bonded surfaces were restored with resin composite Z250 (3M ESPE). After 24 hours of storage in vegetable oil, the restored teeth were vertically, serially sectioned into 1-mm thick slabs, which had the adhesive interfaces analyzed with confocal laser microscope (CLSM—LSM 510 Meta). CLSM images were recorded in the fluorescent mode from three different regions along each bonded interface. Results Non-uniform HL was created on laser-irradiated Dentin surfaces regardless of laser irradiation protocol for all AS, while regular and uniform HL was observed in the control groups. “Stretch mark”-like red lines were found within the HL as a result of resin infiltration into Dentin microfissures, which were predominantly observed in 200 mJ/pulse groups regardless of AS. Poor resin infiltration into Peritubular Dentin was observed in most regions of adhesive interfaces created by all ASs on laser-irradiated Dentin, resulting in thin resin tags with neither funnel-shaped morphology nor lateral resin projections. Conclusion Laser irradiation of Dentin surfaces at 120 or 200 mJ/pulse resulted in morphological changes in HL and resin tags for all ASs evaluated in the study. Lasers Surg. Med. 42:662–670, 2010. © 2010 Wiley-Liss, Inc.

R Neves-silva - One of the best experts on this subject based on the ideXlab platform.

  • Decreased Dentin tubules density and reduced thickness of Peritubular Dentin in hyperbilirubinemia-related green teeth
    Journal of Clinical and Experimental Dentistry, 2017
    Co-Authors: R Neves-silva, M Giannini, Af Paes-leme, Fábio De Abreu Alves, Alberto Nogueira Da Gama Antunes, Mario Fernando De Goes, Maria Dânia Holanda Tenório, José Lécio Machado, Márcio Ajudarte Lopes, Alan Roger Santos-silva
    Abstract:

    BACKGROUND It is stated anecdotally that patients with liver diseases in childhood who develop green teeth have increased risk for rampant caries, which may be secondary to changes in dental structure. The aim of this study was to test the hypothesis that hyperbilirubinemia affects the Dentin morphology of green teeth. MATERIAL AND METHODS Sixteen primary teeth were prepared and divided into two groups (green teeth, n = 8 and control, n = 8), which were transversely fractured across the cervical third of the dental crowns; Dentin was prepared and sputter-coated with gold, and examined under a scanning electron microscope. The mean density and mean diameter of Dentin tubules, as well as the thickness of Peritubular Dentin, were compared. RESULTS Hyperbilirubinemia was associated with a decrease in the density of the Dentin tubules (p< .01) and the thickness of Peritubular Dentin of green teeth (p< .01). CONCLUSIONS There was a correlation between childhood hyperbilirubinemia and changes in the Dentin morphology, including a decrease in the density of the Dentin tubules and a reduction in the thickness of Peritubular Dentin in green teeth. Key words:Hyperbilirubinemia, liver disease, childhood, Dentin tubules, human teeth, scanning electron microscopy.

  • Decreased Dentin tubules density and reduced thickness of Peritubular Dentin in hyperbilirubinemia-related green teeth
    Journal of Clinical and Experimental Dentistry, 2017
    Co-Authors: R Neves-silva, Fa Alves, A Antunes, Mf Goes, M Giannini, Md Tenorio, Jl Machado, Af Paes-leme, Ma Lopes
    Abstract:

    It is stated anecdotally that patients with liver diseases in childhood who develop green teeth have increased risk for rampant caries, which may be secondary to changes in dental structure. The aim of this study was to test the hypothesis that hyperbilirubinemia affects the Dentin morphology of green teeth. Sixteen primary teeth were prepared and divided into two groups (green teeth, n = 8 and control, n = 8), which were transversely fractured across the cervical third of the dental crowns; Dentin was prepared and sputter-coated with gold, and examined under a scanning electron microscope. The mean density and mean diameter of Dentin tubules, as well as the thickness of Peritubular Dentin, were compared. Hyperbilirubinemia was associated with a decrease in the density of the Dentin tubules (p< .01) and the thickness of Peritubular Dentin of green teeth (p< .01). There was a correlation between childhood hyperbilirubinemia and changes in the Dentin morphology, including a decrease in the density of the Dentin tubules and a reduction in the thickness of Peritubular Dentin in green teeth

Manuel Toledano - One of the best experts on this subject based on the ideXlab platform.

  • A zinc-doped endodontic cement facilitates functional mineralization and stress dissipation at the Dentin surface.
    Medicina oral patologia oral y cirugia bucal, 2018
    Co-Authors: Manuel Toledano, M-c Pérez-Álvarez, C-d Lynch, Estrella Osorio, R. Osorio, Manuel Toledano-osorio
    Abstract:

    The purpose of this study was to evaluate nanohardness and viscoelastic behavior of Dentin surfaces treated with two canal sealer cements for Dentin remineralization. Dentin surfaces were subjected to: i) 37% phosphoric acid (PA) or ii) 0.5 M ethylenediaminetetraacetic acid (EDTA) conditioning prior to the application of two experimental hydroxyapatite-based cements, containing sodium hydroxide (calcypatite) or zinc oxide (oxipatite), respectively. Samples were stored in simulated body fluid during 24 h or 21 d. The intertubular and Peritubular Dentin were evaluated using a nanoindenter to assess nanohardness (Hi). The load/displacement responses were used for the nano-dynamic mechanical analysis to estimate complex modulus (E*) and tan delta (δ). The modulus mapping was obtained by imposing a quasistatic force setpoint to which a sinusoidal force was superimposed. AFM imaging and FESEM analysis were performed. After 21 d of storage, Dentin surfaces treated with EDTA+calcypatite, PA+calcypatite and EDTA+oxipatite showed viscoelastic discrepancies between Peritubular and intertubular Dentin, meaning a risk for cracking and breakdown of the surface. At both 24 h and 21 d, tan δ values at intertubular Dentin treated with the four treatments performed similar. At 21 d time point, intertubular Dentin treated with PA+oxipatite achieved the highest complex modulus and nanohardness, i.e., highest resistance to deformation and functional mineralization, among groups. Intertubular and Peritubular Dentin treated with PA+oxipatite showed similar values of tan δ after 21 d of storage. This produced a favorable dissipation of energy with minimal energy concentration, preserving the structural integrity at the Dentin surface.

  • improved reactive nanoparticles to treat Dentin hypersensitivity
    Acta Biomaterialia, 2018
    Co-Authors: Manuel Toledanoosorio, Estrella Osorio, Manuel Toledano, Fatima S Aguilera, Antonio L Medinacastillo, Raquel Osorio
    Abstract:

    Abstract The aim of this study was to evaluate the effectiveness of different nanoparticles-based solutions for Dentin permeability reduction and to determine the viscoelastic performance of cervical Dentin after their application. Four experimental nanoparticle solutions based on zinc, calcium or doxycycline-loaded polymeric nanoparticles (NPs) were applied on citric acid etched Dentin, to facilitate the occlusion and the reduction of the fluid flow at the Dentinal tubules. After 24 h and 7 d of storage, cervical Dentin was evaluated for fluid filtration. Field emission scanning electron microscopy, energy dispersive analysis, AFM and Nano-DMA analysis were also performed. Complex, storage, loss modulus and tan delta (δ) were assessed. Doxycycline-loaded NPs impaired tubule occlusion and fluid flow reduction trough Dentin. Tubules were 100% occluded in Dentin treated with calcium-loaded NPs or zinc-loaded NPs, analyzed at 7 d. Dentin treated with both zinc-NPs and calcium-NPs attained the highest reduction of Dentinal fluid flow. Moreover, when treating Dentin with zinc-NPs, complex modulus values attained at intertubular and Peritubular Dentin were higher than those obtained after applying calcium-NPs. Zinc-NPs are then supposed to fasten active Dentin remodeling, with increased maturity and high mechanical properties. Zinc-based nanoparticles are then proposed for effective Dentin remineralization and tubular occlusion. Further research to finally prove for clinical benefits in patients with Dentin hypersensitivity using Zn-doped nanoparticles is encouraged. Statement of Significance Erosion from acids provokes Dentin hypersensitivity (DH) which presents with intense pain of short duration. Open Dentinal tubules and demineralization favor DH. Nanogels based on Ca-nanoparticles and Zn-nanoparticles produced an efficient reduction of fluid flow. Dentinal tubules were filled by precipitation of induced calcium-phosphate deposits. When treating Dentin with Zn-nanoparticles, complex modulus values attained at intertubular and Peritubular Dentin were higher than those obtained after applying Ca-nanoparticles. Zn-nanoparticles are then supposed to fasten active Dentin remodeling, with increased maturity and high mechanical properties. Zinc-based nanogels are, therefore, proposed for effective Dentin remineralization and tubular occlusion. Further research to finally prove for clinical benefits in patients with Dentin hypersensitivity using Zn-doped nanogels is encouraged.

  • ions modified nanoparticles affect functional remineralization and energy dissipation through the resin Dentin interface
    Journal of The Mechanical Behavior of Biomedical Materials, 2017
    Co-Authors: Manuel Toledano, Estrella Osorio, Manuel Toledanoosorio, Antonio L Medinacastillo, Raquel Osorio, Fatima S Aguilera
    Abstract:

    Abstract The aim of this study was to evaluate changes in the mechanical and chemical behavior, and bonding ability at Dentin interfaces infiltrated with polymeric nanoparticlesstandard deviations and modes of failure are (NPs) prior to resin application. Dentin surfaces were treated with 37% phosphoric acid followed by application of an ethanol suspension of NPs, Zn-NPs or Ca-NPs followed by the application of an adhesive, Single Bond (SB). Bonded interfaces were stored for 24 h, submitted to microtensile bond strength test, and evaluated by scanning electron microscopy. After 24 h and 21 d of storage, the whole resin-Dentin interface adhesive was evaluated using a Nano-DMA. Complex modulus, storage modulus and tan delta (δ) were assessed. AFM imaging and Raman analysis were performed. Bond strength was not affected by NPs infiltration. After 21 d of storage, tan δ generally decreased at Zn-NPs/resin-Dentin interface, and augmented when Ca-NPs or non-doped NPs were used. When both Zn-NPs and Ca-NPs were employed, the storage modulus and complex modulus decreased, though both moduli increased at the adhesive and at Peritubular Dentin after Zn-NPs infiltration. The phosphate and the carbonate peaks, and carbonate substitution, augmented more at interfaces promoted with Ca-NPs than with Zn-NPs after 21 d of storage, but crystallinity did not differ at created interfaces with both ions-doped NPs. Crosslinking of collagen and the secondary structure of collagen improved with Zn-NPs resin-Dentin infiltration. Ca-NPs-resin Dentin infiltration produced a favorable dissipation of energy with minimal stress concentration trough the crystalline remineralized resin-Dentin interface, causing minor damage at this structure.

D Arola - One of the best experts on this subject based on the ideXlab platform.

  • importance of age on the dynamic mechanical behavior of intertubular and Peritubular Dentin
    Journal of The Mechanical Behavior of Biomedical Materials, 2015
    Co-Authors: Heonjune Ryou, Elaine Romberg, David H Pashley, D Arola
    Abstract:

    An experimental evaluation of human coronal Dentin was performed using nanoscopic Dynamic Mechanical Analysis (nanoDMA). The primary objectives were to quantify any unique changes in mechanical behavior of intertubular and Peritubular Dentin with age, and to evaluate the microstructure and mechanical behavior of the mineral deposited within the lumens. Specimens of coronal Dentin were evaluated by nanoDMA using single indents and in scanning mode via scanning probe microscopy. Results showed that there were no significant differences in the storage modulus or complex modulus between the two age groups (18–25 versus 54–83 yrs) for either the intertubular or Peritubular tissue. However, there were significant differences in the dampening behavior between the young and old Dentin, as represented in the loss modulus and tanδ responses. For both the intertubular and Peritubular components, the capacity for dampening was significantly lower in the old group. Scanning based nanoDMA showed that the tubules of old Dentin exhibit a gradient in elastic behavior, with decrease in elastic modulus from the cuff to the center of tubules filled with newly deposited mineral.

  • nanoscopic dynamic mechanical properties of intertubular and Peritubular Dentin
    Journal of The Mechanical Behavior of Biomedical Materials, 2012
    Co-Authors: Heonjune Ryou, Elaine Romberg, David H Pashley, D Arola
    Abstract:

    An experimental evaluation of intertubular and Peritubular Dentin was performed using nanoindentation and Dynamic Mechanical Analysis (DMA). The objective of the investigation was to evaluate the differences in dynamic mechanical behavior of these two constituents and to assess if their response is frequency dependent. Specimens of hydrated coronal Dentin were evaluated by DMA using single indents over a range in parametric conditions and using scanning probe microscopy. The complex (E*), storage (E’) and loss moduli (E”) of the intertubular and Peritubular Dentin were evaluated as a function of the dynamic loading frequency and static load in the fully hydrated condition. The mean complex E* (19.6 GPa) and storage E’ (19.2 GPa) moduli of the intertubular Dentin were significantly lower than those quantities of Peritubular Dentin (E* = 31.1 GPa, p 0.05), both constituents exhibited a significant increase in E” with dynamic load frequency and reduction in the quasi-static component of indentation load. The largest difference in dynamic behavior of the two tissues was noted at small quasi-static indentation loads and the highest frequency.

  • nanoscopic dynamic mechanical properties of intertubular and Peritubular Dentin
    Journal of The Mechanical Behavior of Biomedical Materials, 2012
    Co-Authors: Heonjune Ryou, Elaine Romberg, David H Pashley, D Arola, Franklin R Tay
    Abstract:

    An experimental evaluation of intertubular and Peritubular Dentin was performed using nanoindentation and Dynamic Mechanical Analysis (DMA). The objective of the investigation was to evaluate the differences in dynamic mechanical behavior of these two constituents and to assess whether their response is frequency dependent. Specimens of hydrated coronal Dentin were evaluated by DMA using single indents over a range of parametric conditions and using scanning probe microscopy. The complex (E∗), storage (E') and loss moduli (E″) of the intertubular and Peritubular Dentin were evaluated as a function of the dynamic loading frequency and static load in the fully hydrated condition. The mean complex E∗ (19.6 GPa) and storage E' (19.2 GPa) moduli of the intertubular Dentin were significantly lower than those for Peritubular Dentin (E∗ = 31.1 GPa, p 0.05), both constituents exhibited a significant increase in E″ with dynamic load frequency and reduction in the quasi-static component of indentation load. The largest difference in dynamic behavior of the two tissues was noted at small quasi-static indentation loads and the highest frequency.