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Archives of Oral Biology 1994The classical hydrodynamic theory implicated fluid movement as a transducing mechanism in the production of dental sensitivity. This theory assumes that sensitive... (Review)
Review
The classical hydrodynamic theory implicated fluid movement as a transducing mechanism in the production of dental sensitivity. This theory assumes that sensitive dentine must be permeable. Various measurements of dentine permeability are discussed, including: (1) factors that influence diffusive permeation across dentine; (2) factors that influence convective fluid movement across dentine; (3) osmotic activities of solutions; (4) comparison of evaporative and convective fluid movement; (5) the interaction between outward convective fluid flux on the inward diffusive flux of molecules; and (6) the importance of pulpal blood flow in the clearance of noxious substances from dentine and pulp, a balance concept. The variables involved in achieving good penetration of desensitizing agents in the presence of outward movement of dentinal fluid are also discussed, along with the presentation of a new hypothesis which emphasizes the importance of dentine as a dynamic physiological barrier that works in harmony with neurovascular elements in the pulp in an attempt to maintain the health of the pulp-dentine complex.
Topics: Animals; Body Fluids; Dental Pulp; Dentifrices; Dentin; Dentin Permeability; Dentin Sensitivity; Humans; Hydrostatic Pressure; Rheology
PubMed: 7702470
DOI: 10.1016/0003-9969(94)90191-0 -
Gerodontology Dec 1995With changes in the age structure and oral health in the population, changes in the pulpo-dentinal complex are becoming more relevant clinically. Age-related changes in... (Review)
Review
With changes in the age structure and oral health in the population, changes in the pulpo-dentinal complex are becoming more relevant clinically. Age-related changes in the structure of dentine and pulp are reviewed. The influence of these changes on restorative dentistry are considered with particular emphasis on endodontics and the use of adhesive restorative materials.
Topics: Adult; Age Factors; Aged; Aging; Dental Bonding; Dental Cementum; Dental Pulp; Dental Pulp Calcification; Dental Restoration, Permanent; Dentin; Dentin, Secondary; Humans; Middle Aged; Odontoblasts; Root Canal Therapy
PubMed: 9084291
DOI: 10.1111/j.1741-2358.1995.tb00132.x -
Proceedings of the Finnish Dental... 1992Dentinal sensitivity is a common complaint of patients. Removal of cementum or enamel leaves the dentin exposed allowing various stimuli to produce fluid movement... (Review)
Review
Dentinal sensitivity is a common complaint of patients. Removal of cementum or enamel leaves the dentin exposed allowing various stimuli to produce fluid movement through the dentinal tubules. These fluid movements are believed to activate pulpal sensory nerves leading to pain. Various therapeutic approaches have been investigated to treat this problem. Resins, fluoride compounds and oxalate solutions have been used to block the dentinal tubules. KNO3 and SrCl2 are active ingredients in desensitizing tooth pastes but neither compound reduces the permeability of dentine. The ability of various solutions to decrease hypertonic (3M NaCl) evoked nerve activity was tested in the canine teeth of anesthetized cats. Excitatory and desensitizing solutions were placed into a deep dentinal cavity prepared over the incisal pulp horn. An electrode used to record nerve activity was also placed into this deep cavity. KNO3 and other K+ ion containing solutions elicit a biphasic effect on nerve activity. Immediately following application of these solutions into the deep dentinal cavity there is a brief burst of high frequency spike activity. Following this brief period of excitation, the intradental nerves are silent and respond weakly to hypertonic NaCl. CaCl2 and other divalent cation solutions also inhibit hypertonic NaCl induced nerve activity, but have a weaker effect than that exerted by K+. These observations can be explained based on the effects of various ions on nerve excitability. Increasing the K+ ion concentration in the vicinity of the dentinal nerve terminal depolarize and activates the nerve fibers. Following a prolonged period of depolarization the action potential mechanism is inactivated. Divalent cation solutions stabilize the nerve membrane without changing the membrane potential. Desensitizing solutions do not decrease nerve activity by an effect on pulpal blood flow. This experimental model does not entirely explain the clinical action of these desensitizing agents. The role of inflammation in hypersensitivity and dental pain is currently being investigated.
Topics: Animals; Cations; Dentin; Dentin Sensitivity; Humans; Neurons; Potassium
PubMed: 1508896
DOI: No ID Found -
Journal of Dental Research Jul 2013The aim of this study was to investigate the diffusion dynamics of 25% hydrogen peroxide (H2O2) through enamel-dentin layers and to correlate it with dentin's structural...
The aim of this study was to investigate the diffusion dynamics of 25% hydrogen peroxide (H2O2) through enamel-dentin layers and to correlate it with dentin's structural alterations. Micro-Raman Spectroscopy (MRS) and Fourier Transform Infrared Photoacoustic Spectroscopy (FTIR-PAS) were used to measure the spectra of specimens before and during the bleaching procedure. H2O2 was applied to the outer surface of human enamel specimens for 60 minutes. MRS measurements were performed on the inner surface of enamel or on the subsurface dentin. In addition, H2O2 diffusion dynamics from outer enamel to dentin, passing through the dentin-enamel junction (DEJ) was obtained with Raman transverse scans. FTIR-PAS spectra were collected on the outer dentin. MRS findings revealed that H2O2 (O-O stretching ยต-Raman band) crossed enamel, had a more marked concentration at DEJ, and accumulated in dentin. FTIR-PAS analysis showed that H2O2 modified dentin's organic compounds, observed by the decrease in amides I, II, and III absorption band intensities. In conclusion, H2O2 penetration was demonstrated to be not merely a physical passage through enamel interprismatic spaces into the dentinal tubules. H2O2 diffusion dynamics presented a concentration gradient determined by the chemical affinity of the H2O2 with each specific dental tissue.
Topics: Adolescent; Adult; Amides; Biochemical Phenomena; Carbon; Child; Color; Dental Enamel; Dentin; Diffusion; Humans; Hydrogen; Hydrogen Peroxide; Microspectrophotometry; Oxygen; Photoacoustic Techniques; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman; Time Factors; Tooth Bleaching Agents; Young Adult
PubMed: 23632810
DOI: 10.1177/0022034513488893 -
Journal of Huazhong University of... Aug 2017This study evaluated the effects of sodium hypochlorite (NaOCl) with different concentrations and exposure time on the structural, compositional and mechanical...
This study evaluated the effects of sodium hypochlorite (NaOCl) with different concentrations and exposure time on the structural, compositional and mechanical properties of human dentin in vitro. Sixty dentin slabs were obtained from freshly extracted premolars, randomly distributed into four groups (n=15), and treated with 1%, 5%, 10% NaOCl and distilled water (control group), respectively, for a total of 60 min. Attenuated total reflection infrared (ATR-IR) spectroscopy, Raman spectroscopy and X-ray diffraction (XRD) were carried out before, 10 min and 60 min after the treatment. Scanning electron microscopy (SEM) and flexural strength test were conducted as well. The results showed that dentins experienced morphological alterations in the NaOCl groups, but not in the control group. Two-way repeated-measures analysis of variance revealed that the carbonate:mineral ratio (C:M), Raman relative intensity (RRI), a-axis, c-axis length and full width at half maximum (FWHM) with the increase of time and concentration in the NaOCl groups were not significantly different from those in the control group (P>0.05). Nevertheless, the mineral:matrix ratio (M:M) increased and the flexural strength declined with the increase of concentration and the extension of time in the NaOCl groups (P<0.05). Additionally, it was found that the M:M and the flexural strength remained unchanged after 1% NaOCl treatment (P>0.05), and the morphology changes were unnoticeable within 10 min in 1% NaOCl group. These results indicated that NaOCl has no significant effects on the inorganic mineral of human dentin; but it undermines and eliminates the organic content concentration- and time-dependently, which in turn influences the flexural strength and toughness of dentins. In addition, an irrigation of 1% NaOCl within 10 min can minimize the effects of NaOCl on the structural and mechanical properties of dentin during root canal treatment.
Topics: Biomechanical Phenomena; Dentin; Humans; Sodium Hypochlorite; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman; Surface Properties; Time Factors; X-Ray Diffraction
PubMed: 28786056
DOI: 10.1007/s11596-017-1774-0 -
Clinical Oral Investigations Sep 1999The purpose of this in vitro study was to analyze the micromorphological changes caused by Carisolv gel on sound, demineralized, and denatured dentin. Fractured dentinal...
The purpose of this in vitro study was to analyze the micromorphological changes caused by Carisolv gel on sound, demineralized, and denatured dentin. Fractured dentinal surfaces, dentinal surfaces demineralized superficially by phosphoric acid etching and dentinal surfaces denatured due to lactic acid and collagenase pretreatment were exposed to freshly mixed Carisolv gel or 0.25% sodium hypochlorite. No additional mechanical action was exerted during the 20-min exposure of specimens to the Carisolv solution. Specimens were evaluated by transmission electron microscopy. Electron microscopic evaluation did not indicate any ultrastructural changes of the fractured or demineralized dentinal surfaces due to the 20-min Carisolv treatment. Denatured dentin was partially removed within a 20 min period of chemical action of the Carisolv solution leaving only a 1- to 2-micron thick layer of residual denatured dentin on the specimen's surface. In contrast, 0.25% sodium hypochlorite treatment completely dissolved the demineralized as well as denatured dentin layer within 20 min. It is concluded that Carisolv gel (1) does not affect sound fractured dentin, (2) does not dissolve demineralized dentin, and (3) has a limited potential to chemically dissolve denatured dentin.
Topics: Cariostatic Agents; Dentin; Glutamic Acid; Humans; Leucine; Lysine; Microscopy, Electron; Protein Denaturation; Tooth Demineralization
PubMed: 10803128
DOI: 10.1007/s007840050095 -
Archives of Oral Biology Dec 1999In the 1959 premier issue of the Archives of Oral Biology, the first TEM observations were presented of sections of undecalcified human mature dentine produced with... (Review)
Review
In the 1959 premier issue of the Archives of Oral Biology, the first TEM observations were presented of sections of undecalcified human mature dentine produced with diamond knives. The odontoblast process was clearly shown to be a cytoplasmic extension of the odontoblast. The peritubular dentine appeared to be more calcified than the intertubular dentine and contained hydroxyapatite as demonstrated by selective area electron diffraction. In the 40 years which followed, significant progress was made in TEM methodology, including improvements in fixation and embedding, development of ultrastructural cytochemistry and immunocytochemistry, and the use of electron microscope autoradiography. Additionally, we saw the advent of SEM and HRTEM. Thus, better knowledge was gained of (1) the odontoblast and its process and the lamina limitans, (2) the dentinal nerve fibrils and (3) the HRTEM aspects of dentine. Interestingly, to the present day, diamond knives have continued to serve as the best tool for preparing thin sections of non-decalcified mature hard tissue for TEM and HRTEM, not only for dentine but also for bone, enamel and cementum.
Topics: Dentin; Humans; Microscopy, Electron; Microscopy, Electron, Scanning
PubMed: 10669074
DOI: 10.1016/s0003-9969(99)00109-0 -
Australian Endodontic Journal : the... Apr 2002Bacterial invasion of dentinal tubules is critical to the progression of dental caries and the development of pulp and periapical disease, and may also influence the... (Review)
Review
Bacterial invasion of dentinal tubules is critical to the progression of dental caries and the development of pulp and periapical disease, and may also influence the progression of periodontal disease. However, little is known about the host or bacterial mechanisms involved in tubule invasion. Recent work has demonstrated that bacterial interactions with dentine, and salivary and tissue molecules influence invasion. Salivary molecules such as mucin and immunoglobulin G (IgG) co-aggregate with bacterial cells, which inhibits dentine invasion, while deposition of dentinal tubule fluid molecules e.g. albumin, IgG, or fibrinogen within dentinal tubules also inhibits invasion. Dentine invasion by streptococci has been shown to be associated with a bacterial growth response and adhesion to unmineralized collagen, which are mediated by streptococcal cell-surface antigen I/II polypeptides. These adhesins possess diverse binding properties including binding to salivary glycoprotein, other bacteria, and to collagen. Additionally, some antigen I/II polypeptides facilitate species-specific co-invasion between streptococci and obligate anaerobes that lack the ability to invade by themselves. An understanding of the mechanisms involved in bacterial invasion of dentine should allow development of new control strategies.
Topics: Adhesins, Bacterial; Bacterial Adhesion; Dental Pulp Diseases; Dentin; Enterococcus faecalis; Humans; Salivary Proteins and Peptides; Streptococcus
PubMed: 12360678
DOI: 10.1111/j.1747-4477.2002.tb00363.x -
The Kaohsiung Journal of Medical... Jan 2006The purpose of the present study was to evaluate the combined occluding effects of fluoride-containing dentin desensitizer and neodymium:yttrium aluminum garnet (Nd-YAG)...
The purpose of the present study was to evaluate the combined occluding effects of fluoride-containing dentin desensitizer and neodymium:yttrium aluminum garnet (Nd-YAG) laser irradiation on human dentinal tubules. All six of the groups of dentin samples (A-F) included in this study received applications of fluoride-containing dentin desensitizer. Groups B, D, and F also received Nd-YAG laser irradiation. Groups A and B served as controls, to allow observations of the occluding effects on the dentinal tubules before and after Nd-YAG laser irradiation. Groups C and D were treated with 0.5 M vitamin C solution, whereas groups E and F underwent brushing with an electric toothbrush. Scanning electron microscopy (SEM) revealed that the fluoridated dentinal tubule-occluding agent (FDTOA) formed a fine crystalline deposit on the dentin surface. After soaking in 0.5 M vitamin C solution for 3 hours, the crystalline deposit of the FDTOA was completely dissolved. Furthermore, brushing of the teeth 3,600 times removed most of the occluding agent. When the application of FDTOA was combined with Nd-YAG laser irradiation, the dentin melted and then recrystallized. The occluding agent was thus 'burned into' the dentinal tubules, and could neither be dissolved by vitamin C solution nor removed by brushing. Therefore, we concluded that the FDTOA combined with Nd-YAG laser irradiation burns the occluding agent into the dentinal tubules, thereby resisting the effects of an acidic diet and brushing, and increasing the duration of the desensitizing effect.
Topics: Combined Modality Therapy; Dentin; Dentin Permeability; Dentin Sensitivity; Humans; Laser Therapy; Microscopy, Electron, Scanning; Sodium Fluoride
PubMed: 16570565
DOI: 10.1016/S1607-551X(09)70216-5 -
Journal of Dental Research Oct 1977A scanning electron microscopic examination of the interface between etched dentin and several different commercial resins showed that pretreatment with othophosphoric...
A scanning electron microscopic examination of the interface between etched dentin and several different commercial resins showed that pretreatment with othophosphoric acid enlarged the dentinal tubules facilitating penetration of the resin. The depth of penetration increased from approximately 0.2 mm to 2.0 mm when dentin was dried for 24 hours compared to using the normal clinical protocol. The hydration of dentin and/or the presence of dentinal fluid probably influences the degree of resin penetration. While penetration would provide a means of mechanical retention of resin it would probably do so at the expense of dentin and pulp viability particularly where remaining dentin thickness is less than 1.0 mm. Penetration of toxic resin would account in part for the enhanced inflammatory pulpal response observed following application of acid etch restorative procedures.
Topics: Absorption; Acid Etching, Dental; Composite Resins; Dental Bonding; Dentin; Humans; Phosphoric Acids; Surface Properties
PubMed: 342563
DOI: 10.1177/00220345770560100501