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Anatomia, Histologia, Embryologia Dec 2013The aim of this study was to describe the dentine morphology of sloths (Bradypus tridactylus). The sloth teeth were removed and prepared for light microscopy (LM) and...
The aim of this study was to describe the dentine morphology of sloths (Bradypus tridactylus). The sloth teeth were removed and prepared for light microscopy (LM) and scanning electron microscopy analyses (SEM). LM revealed two patterns of tubular dentins: an outer with dentinary tubules over the all tooth length and one in the inner part with larger diameter and more spaced tubules, when compared to those present in the outer dentine. These findings were confirmed by SEM, which revealed a tubular pattern in the outer dentine like in humans. The inner dentine displayed pared grouped tubules that were characterized as vascular channels. It can be concluded that this sloth species present two types of dentins: an inner dentin (ortodentin) and an outer dentin characterized as a vascular dentin. This suggests a partial evolutive/adaptive process of this dental tissue, as compared to other mammalian species.
Topics: Animals; Biological Evolution; Dental Enamel; Dental Pulp Cavity; Dentin; Diet; Female; Male; Mastication; Microscopy, Electron, Scanning; Sloths; Tooth
PubMed: 23410180
DOI: 10.1111/ahe.12029 -
IET Nanobiotechnology Dec 2011The resistance of nanoporous dentin biomaterial to CO₂ laser irradiation was investigated by experiment and simulation for potential tooth hypersensitivity treatment....
The resistance of nanoporous dentin biomaterial to CO₂ laser irradiation was investigated by experiment and simulation for potential tooth hypersensitivity treatment. The controlled parameters including laser power of 0.03-0.150 W, scanning speeds of 11.4-34.2 mm/s and focus/defocus modes were used for studying interaction between laser energy and dentin of human tooth. Most of the dentin specimens were etched after CO₂ laser irradiation with the power larger than 0.12 W at a scanning speed of 11.4 mm/s. Compared with the simulation results of temperature distribution, the maximum temperature at laser powers from 0.12 to 0.15 W is increased from 1961 to 2245°C, which exceeded the melting point (1570°C) of dentin's main content hydroxyapatite (HA). Increasing scanning speed can reduce the linear density of laser output energy for just locally melting porous microstructure of dentin surface without etching. Varying focus mode can also improve the damage of nanoporous dentin microstructure. At parameters of 0.150 W power and 34.2 mm/s scanning speed under defocus operation, laser treatment was successfully performed on the nano-HA coated dentin with well-molten sealing on tubules of porous microstructure at a simulate surface temperature of about 574°C, which was the potential for dentin hypersensitivity cure application.
Topics: Computer Simulation; Dentin; Durapatite; Hot Temperature; Humans; Lasers, Gas; Microscopy, Electron, Scanning; Models, Biological; Nanostructures; Porosity; Transition Temperature
PubMed: 22149872
DOI: 10.1049/iet-nbt.2011.0025 -
Archives of Oral Biology Nov 2020To determine the rate of fluid flow through human dentine due to electroosmosis during iontophoresis of either 2 % lignocaine with epinephrine, Ringer's solution,...
OBJECTIVE
To determine the rate of fluid flow through human dentine due to electroosmosis during iontophoresis of either 2 % lignocaine with epinephrine, Ringer's solution, epinephrine, or distilled water.
DESIGN
Experiments were carried out on 24 intact extracted human premolars. Dentine was exposed at the tip of the buccal cusp. The cavity was filled with one of the test solutions and the pulp cavity, with Ringer's solution at a pressure of 11 mm Hg. Fluid flow through the dentine was measured using a capillary connected to the pulp cavity. Current was passed between a stainless-steel electrode in the cavity and one in the pulp cavity. The results were analysed using repeated measures, three-way ANOVA, with Bonferroni pairwise comparisons where this showed a significant effect.
RESULTS
The current passed produced a significant flow of fluid through the dentine but neither the composition of the test solution nor etching had a significant effect on the flow. During iontophoresis of 2 % lignocaine with epinephrine for example, currents of 0.2, 0.4, and 0.6 mA applied with the cavity electrode as anode produced inward flow rates of 2.25 ± 0.87, 5.00 ± 1.62, 8.60 ± 1.97 (mean ± s.d.) nL/s/mm² respectively, and applying the currents in the opposite direction caused outward flows of 0.76 ± 0.72, 1.00 ± 1.01, 1.12 ± 1.18 nL/s/mm² respectively.
CONCLUSIONS
It is concluded that electroosmosis can be produced in human dentine, it can enhance the effect of iontophoresis in transporting charged molecules through dentine, particularly large molecules, and it could also enable uncharged molecules to be carried through dentine into the pulp.
Topics: Dentin; Electroosmosis; Epinephrine; Humans; In Vitro Techniques; Iontophoresis; Lidocaine
PubMed: 32905886
DOI: 10.1016/j.archoralbio.2020.104885 -
Journal of Dentistry Jul 2013This paper reviews a number of studies in oral biology and endodontics that deal with the reactivity of the pulpo-dentine complex in response to mechanical and... (Review)
Review
This paper reviews a number of studies in oral biology and endodontics that deal with the reactivity of the pulpo-dentine complex in response to mechanical and immunological stimuli. It can be hypothesized that these reactions could also apply to changes in dentine sensitivity following periodontal procedures. Some of these changes involve neurogenic inflammation of the pulp under exposed open tubules; this increases the rate of outward fluid flow through the tubules, making the overlying exposed dentine more sensitive. Other changes may be due to inflammation-related nerve sprouting of pulpal nerves, which can lead to innervation of more tubules than normal. Changes may also involve upregulation of new, more sensitive ion channels in the membranes of these nerves. The goal of the paper is to increase awareness of the complex issues involved in dentine sensitivity, so that future investigators may develop agents or techniques to stimulate mechanisms that mitigate dentine sensitivity, or to block mechanisms that aggravate the condition, for therapeutic effect.
Topics: Dental Pulp; Dentin; Dentin Permeability; Dentin Sensitivity; Dentinal Fluid; Humans; Inflammation Mediators; Ion Channels; Neurogenic Inflammation; Smear Layer
PubMed: 23929645
DOI: 10.1016/S0300-5712(13)70006-X -
Wiadomosci Lekarskie (Warsaw, Poland :... 2018Introduction: The condition of hard teeth tissues while choosing treatment method becomes particularly important due to the large development of adhesive technologies...
OBJECTIVE
Introduction: The condition of hard teeth tissues while choosing treatment method becomes particularly important due to the large development of adhesive technologies and the choice of filling materials. The quality of adhesion is one of the key factors that affects effectiveness of the entire range of therapeutic interventions, that determines the success of therapeutic treatment and the reliability of therapeutic restorations fixation. The aim of the work is to study the condition of hard teeth tissues in carious and non-carious pathology for further rationale of the choice of filling material and adhesive system.
PATIENTS AND METHODS
Materials and methods: A thorough examination included teeth that were removed according to the indications. The age of patients, whose teeth were examined, was 25-55 years old according to the classification of age periods adopted at the International Symposium on the Age Periodization (Moscow, 1965). We conducted a morphological study of enamel and dentin of teeth with carious and non-carious lesions (increased erasability, cuneal defects), by obtaining chips and microsections of teeth, followed by examination of the number of enamel prisms, dentinal tubules,their diameter, the thickness of the gaps between these structures. The studies were carried out using a scanning electron microscope (SEM) "Mira 3 LMU" ("Tescan", Czech Republic) with a maximum resolution of 1 nm and a maximum magnification of 1,000,000. Dentally removed teeth were washed in running water, cleaned of plaque, dried by filter paper and crushed by vice, that was followed by the selection of the wreckage for the study. Then, markings in the dentine and enamel zones were made to fix the sizes of enamel prisms and dentinal tubules.
RESULTS
Results: After the completion of the determination of enamel prisms and dentinal tubules diameter, counting of their number was carried out according to the method proposed by I.M. Tkachenko, by obtaining a series of digital images of the examined tooth's enamel and dentin with varying degrees of magnification. The number of prisms per unit area characterized the enamel density, on which permeability, hardness, tissue resistance to fracture, bending and modulus of elasticity depends. The number of dentinal tubules characterized the density of dentin and the peculiarities of trophic processes that occur in dentin. Also, in our opinion, the amount of dentinal tubules determines the damping properties of dentin and strength enamel values.
CONCLUSION
Conclusions: Thus, the structure of enamel and dentin has peculiarities of the morphological structure at various clinical conditions of hard teeth tissues. This peculiarity can be associated with a decrease of enamel density, that is associated with a decrease in the number of prisms in the non-carious teeth pathology and an increase of the gaps between them.
Topics: Adult; Dental Caries; Dental Enamel; Dentin; Humans; Middle Aged
PubMed: 30176630
DOI: No ID Found -
Caries Research 2015Demineralization in dentinal caries and erosion exposes dentine organic matrix. This exposed matrix, containing type I collagen and non-collagenous proteins, is then... (Review)
Review
Demineralization in dentinal caries and erosion exposes dentine organic matrix. This exposed matrix, containing type I collagen and non-collagenous proteins, is then degraded by host collagenolytic enzymes, matrix metalloproteinases (MMPs) and cysteine cathepsins. The knowledge of the identities and function of these enzymes in dentine has accumulated only within the last 15 years, but has already formed a field of research called 'dentine degradomics'. This research has demonstrated the role of endogenous collagenolytic enzymes in caries and erosion development. In demineralized dentine, the enzymes degrade triple-helical collagen molecules, leading to the gradual loss of collagen matrix. Even before that, they can cleave off the terminal non-helical ends of collagen molecules called telopeptides, leading to the structural changes at the intramolecular gap areas, which may affect or even prevent intrafibrillar remineralization, which is considered essential in restoring the dentine's mechanical properties. They may also cause the loss of non-collagenous proteins that could serve as nucleation sites for remineralization. Here we review the findings demonstrating that inhibition of salivary or dentine endogenous MMPs and cysteine cathepsins may provide preventive means against the progression of caries or erosion. Furthermore, we also suggest the future directions for the new experimental preventive research to gain more knowledge of the enzymes and their function during and after dentine demineralization, and the pathways to find the clinically acceptable means to prevent the functional activity of these enzymes.
Topics: Cathepsins; Collagen Type I; Collagenases; Dental Caries; Dentin; Humans; Matrix Metalloproteinase Inhibitors; Matrix Metalloproteinases; Peptide Hydrolases; Phosphoproteins; Tooth Erosion
PubMed: 25871416
DOI: 10.1159/000380885 -
Journal of Biomaterials Science.... Jun 2017The occlusion of dentinal tubules is an effective method to alleviate the symptoms of dentin hypersensitivity. In this paper, we successfully modified...
The occlusion of dentinal tubules is an effective method to alleviate the symptoms of dentin hypersensitivity. In this paper, we successfully modified nano-hydroxyapatite (n-HAP) with carboxyl-terminated polyamidoamine dendrimers by an aqueous-based chemical method and verified by fourier transform infrared spectroscopy (FTIR) and transmission electron microscope (TEM). Then the demineralization dentin discs were randomly divided into 4 groups, corresponding to subsequent brushing experiments: deionized water and kept in artificial saliva (AS), dendrimer-functionalized n-HAP and stored in AS, n-HAP and saved in AS, dendrimer-functionalized n-HAP and stored in deionized water. After 7 days of simulated brushing, dentin discs followed the in vitro characterization using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy and microhardness test. These data suggested that dendrimer-functionalized n-HAP could crosslink with collagen fibers and resulted in effective dentinal tubule occlusion. Moreover, the new material can induce the HAP formation with the help of superficial carboxyl and fill the spaces in dentinal tubules furtherly. The microhardness of dendrimer-functionalized n-HAP-treated specimens was significantly higher than others. In summary, dendrimer-functionalized n-HAP can be a new therapeutic material for the treatment of dentin hypersensitivity.
Topics: Collagen; Cross-Linking Reagents; Dendrimers; Dentin; Dentin Sensitivity; Durapatite; Humans; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Nanocomposites; Polyamines; Saliva, Artificial; Spectrometry, X-Ray Emission; Spectroscopy, Fourier Transform Infrared; Surface Properties
PubMed: 28325103
DOI: 10.1080/09205063.2017.1308654 -
Dental Update Sep 1998Clinical success with resin-based bonding systems depends upon meticulous attention to detail at each stage of the bonding process. Cavity margins placed in enamel... (Review)
Review
Clinical success with resin-based bonding systems depends upon meticulous attention to detail at each stage of the bonding process. Cavity margins placed in enamel wherever possible and etched for at least 15 to 30 seconds will ensure a reliable peripheral seal. Dentine conditioning should be brief--a maximum of 15 seconds for surface demineralization only. Diffusion of primers into the full extent of dentinal demineralization is enhanced by application of multiple coats. Any solvent or moisture remaining on a primed dentine surface will prevent adaptation of bonding resin, resulting in non-attachment. Adhesive bonding resin provides a valuable elastic intermediate layer for absorption of stresses of polymerization shrinkage--but it should be of uniform thickness and not air-thinned. Incremental insertion of resin composite will reduce polymerization stresses and ensure a fully cured restoration.
Topics: Acid Etching, Dental; Composite Resins; Dental Bonding; Dental Marginal Adaptation; Dental Restoration, Permanent; Dentin; Dentin-Bonding Agents; Humans; Resin Cements
PubMed: 10478022
DOI: No ID Found -
Lasers in Medical Science Sep 2019The proanthocyanidin (PA)-rich grape seed extract (GSE) is a collagen cross-linking agent that can perform a chemical bond with the dentin's collagen. The objective of...
The proanthocyanidin (PA)-rich grape seed extract (GSE) is a collagen cross-linking agent that can perform a chemical bond with the dentin's collagen. The objective of this study was to evaluate the influence on shear bond strength (SBS) of the pre-conditioning of GSE, on human dentin surfaces conditioned with Er,Cr:YSGG laser. The sample consisted of 64 non-carious human teeth, divided into eight groups, four groups conditioned with Er,Cr:YSGG laser (4.5 W, 50 Hz, 50 μs, 70% air, 90% water) and four prepared with conventional methods (control). In both groups, a GSE solution was applied before using the two adhesives tested: Clearfil SE Bond (CSE) and Scotchbond Universal (SU). Subsequently, a SBS test, a scanning electron microscopy, and a statistical analysis were performed. In the laser groups, the best SBS mean (20.08 ± 4.01 MPa) was achieved in the group treated with GSE and CSE. The control group with the application of CSE showed the highest SBS mean (24.27 ± 10.28 MPa), and the group treated with laser and SU showed the lowest SBS mean (12.94 ± 6.51 MPa). Between these two groups there was a statistically significant difference (p = 0.05). However, this was not observed among the laser or control groups. The type of dentin surface preparation can influence the SBS. The CSE showed better SBS in laser and control groups. The presence of GSE did not improve the adhesion on surfaces conditioned with laser, but more studies should be carried out in the future to confirm this conclusion.
Topics: Dental Bonding; Dental Cements; Dentin; Grape Seed Extract; Humans; Lasers, Solid-State; Surface Properties
PubMed: 30830558
DOI: 10.1007/s10103-019-02749-w -
Monographs in Oral Science 2013Dentine hypersensitivity (DH) is a common, painful dental condition with a multi-factorial aetiology. The hydrodynamic mechanism theory to explain dentine sensitivity... (Review)
Review
Dentine hypersensitivity (DH) is a common, painful dental condition with a multi-factorial aetiology. The hydrodynamic mechanism theory to explain dentine sensitivity also appears to fit DH: lesions exhibiting large numbers of open dentinal tubules at the surface and patent to the pulp. By definition, DH can only occur when dentine becomes exposed (lesion localisation) and tubules opened (lesion initiation), thus permitting increased fluid flow in tubules on stimulation. Erosion, particularly from dietary acids appears to play a dominant role in both processes. Toothbrushing with most toothpaste products alone cause clinically insignificant wear of enamel but are additive, even synergistic, to erosive enamel loss. Additionally, toothbrushing with toothpaste is implicated in 'healthy' gingival recession. Toothbrushing with most toothpastes removes the smear layer to expose tubules and again can exacerbate erosive loss of dentine. These findings thereby implicate toothbrushing with toothpaste in the aetiology of DH. Management of the condition should have secondary prevention at the core of treatment and therefore, must consider first and foremost the aetiology. Fluoride toothpaste at present appears to provide little primary or secondary preventive benefits to DH; additional ingredients can provide therapeutic benefits. Potassium-based products to block pulpal nerve response have caused much debate and are considered by many as unproven, which should not translate to ineffective. Several toothpaste technologies formulated to block tubules are from studies in vitro, in situ and controlled clinical trials considered proven for the treatment of DH.
Topics: Dentin; Dentin Desensitizing Agents; Dentin Sensitivity; Dentinal Fluid; Humans; Smear Layer; Tooth Erosion; Toothbrushing; Toothpastes
PubMed: 23817061
DOI: 10.1159/000350477