-
International Journal of Molecular... May 2024It is remarkable how teeth maintain their healthy condition under exceptionally high levels of mechanical loading. This suggests the presence of inherent mechanical... (Review)
Review
It is remarkable how teeth maintain their healthy condition under exceptionally high levels of mechanical loading. This suggests the presence of inherent mechanical adaptation mechanisms within their structure to counter constant stress. Dentin, situated between enamel and pulp, plays a crucial role in mechanically supporting tooth function. Its intermediate stiffness and viscoelastic properties, attributed to its mineralized, nanofibrous extracellular matrix, provide flexibility, strength, and rigidity, enabling it to withstand mechanical loading without fracturing. Moreover, dentin's unique architectural features, such as odontoblast processes within dentinal tubules and spatial compartmentalization between odontoblasts in dentin and sensory neurons in pulp, contribute to a distinctive sensory perception of external stimuli while acting as a defensive barrier for the dentin-pulp complex. Since dentin's architecture governs its functions in nociception and repair in response to mechanical stimuli, understanding dentin mechanobiology is crucial for developing treatments for pain management in dentin-associated diseases and dentin-pulp regeneration. This review discusses how dentin's physical features regulate mechano-sensing, focusing on mechano-sensitive ion channels. Additionally, we explore advanced in vitro platforms that mimic dentin's physical features, providing deeper insights into fundamental mechanobiological phenomena and laying the groundwork for effective mechano-therapeutic strategies for dentinal diseases.
Topics: Dentin; Humans; Animals; Odontoblasts; Mechanotransduction, Cellular; Biomechanical Phenomena; Dental Pulp; Extracellular Matrix
PubMed: 38891829
DOI: 10.3390/ijms25115642 -
Proceedings of the Finnish Dental... 1992The hydrodynamic theory of dentin sensitivity is based on the premise that sensitive dentin is permeable throughout the length of the tubules. Such a condition may... (Review)
Review
The hydrodynamic theory of dentin sensitivity is based on the premise that sensitive dentin is permeable throughout the length of the tubules. Such a condition may permit the diffusion of bacterial products across dentin to the pulp where they may cause irritation of pulpal soft tissues. However, the slow outward movement of dentinal fluid tends to flush the tubules free of exogenous substances. This balance between the inward diffusion of exogenous substances, whether bacterial or the active ingredients in desensitizing medicaments, and the cleansing action of dentinal fluid flow needs to be examined experimentally.
Topics: Dentin; Dentin Permeability; Dentin Sensitivity; Humans
PubMed: 1508886
DOI: No ID Found -
Caries Research 2015Dentin organic matrix, with type I collagen as the main component, is exposed after demineralization in dentinal caries, erosion or acidic conditioning during adhesive... (Review)
Review
Dentin organic matrix, with type I collagen as the main component, is exposed after demineralization in dentinal caries, erosion or acidic conditioning during adhesive composite restorative treatment. This exposed matrix is prone to slow hydrolytic degradation by host collagenolytic enzymes, matrix metalloproteinases (MMPs) and cysteine cathepsins. Here we review the recent findings demonstrating that inhibition of salivary or dentin endogenous collagenolytic enzymes may provide preventive means against progression of caries or erosion, just as they have been shown to retain the integrity and improve the longevity of resin composite filling bonding to dentin. This paper also presents the case that the organic matrix in caries-affected dentin may not be preserved as intact as previously considered. In partially demineralized dentin, MMPs and cysteine cathepsins with the ability to cleave off the terminal non-helical ends of collagen molecules (telopeptides) may lead to the gradual loss of intramolecular gap areas. This would seriously compromise the matrix ability for intrafibrillar remineralization, which is considered essential in restoring the dentin's mechanical properties. More detailed data of the enzymes responsible and their detailed function in dentin-destructive conditions may not only help to find new and better preventive means, but better preservation of demineralized dentin collagenous matrix may also facilitate true biological remineralization for the better restoration of tooth structural and mechanical integrity and mechanical properties.
Topics: Cathepsins; Collagenases; Cysteine Proteases; Dental Bonding; Dental Caries; Dentin; Humans; Matrix Metalloproteinase Inhibitors; Matrix Metalloproteinases; Tooth Remineralization
PubMed: 25661522
DOI: 10.1159/000363582 -
The Journal of Clinical Dentistry 2010
Review
Topics: Dentin; Dentin Desensitizing Agents; Dentin Sensitivity; Dentinal Fluid; Humans
PubMed: 20669812
DOI: No ID Found -
Advances in Dental Research Nov 1997Dentin sensitivity (DS) is a painful clinical condition which may affect 8-35% of the population. Various treatment modalities have claimed success in relieving DS,... (Review)
Review
Dentin sensitivity (DS) is a painful clinical condition which may affect 8-35% of the population. Various treatment modalities have claimed success in relieving DS, although at present there does not appear to be a universally accepted desensitizing agent. Current opinion based on Brännström's Hydrodynamic Theory would suggest that following exposure of the dentin surface (through attrition, abrasion, or erosion), the presence of open dentinal tubules, patent to the pulp, may be a prerequisite for DS. The concept of tubule occlusion as a method of dentin desensitization, therefore, is a logical conclusion from the hydrodynamic theory. The fact that many of the agents used clinically to desensitize dentin are also effective in reducing dentin permeability tends to support the hydrodynamic theory. This paper reviews the in vitro evaluation of desensitizing agents, the techniques used to characterize their effects on the prepared dentin surface, and the ability of these agents to reduce permeability through tubule occlusion, and presents recent findings from ongoing research based on the Pashley Dentin Disc model. It can be concluded that the use of this model to determine surface characteristics, and reductions in dentin permeability through tubule narrowing or occlusion, provides a useful screening method for evaluating potential desensitizing agents. Interpreting changes observed in vitro is difficult, and extrapolation to the clinical situation must be tempered with caution.
Topics: Animals; Dentifrices; Dentin; Dentin Permeability; Dentin Sensitivity; Humans; Lasers; Models, Biological; Smear Layer; Surface Properties
PubMed: 9470509
DOI: 10.1177/08959374970110041701 -
Archives of Oral Biology Jul 2003In order to understand the mechanism of dentin sensitivity to tactile stimuli, the purpose of this study was to evaluate possible permanent deformation of dentin...
OBJECTIVE
In order to understand the mechanism of dentin sensitivity to tactile stimuli, the purpose of this study was to evaluate possible permanent deformation of dentin produced by scratching dentin surfaces with clinically-relevant forces.
METHODS
Midcoronal dentin was prepared from twenty human teeth and polished to 4000-grit and ultrasonicated. The dentin surface of each specimen was scratched under forces ranging from 30 to 100 centi-Newtons (cN). The depth of the grooves were measured with a profilometer and the overall hardness of dentin in the vicinity of the grooves was measured. Additional dentin specimens were prepared for SEM evaluation.
RESULTS
Dentin hardness was constant and no statistical difference was found among the specimens. Statistically significant differences in groove width and depth were found when increasing force was applied to the dental explorer tip. The depth of the groove ranged from 0.21+/-0.09 microm for the 30 cN group to 1.27+/-0.39 microm for the 100 cN group. The width of the groove ranged from 19.3+/-4.0 microm for the 30 cN group to 43.0 microm for the 10 0 cN group.
CONCLUSIONS
(1). The threshold force necessary to create scratches in dentin with a dental explorer was 30 cN or a compressive stress of 1003 MPa. As this exceeds the crushing strength of dentin, this force produces plastic deformation of dentin; (2). Theoretical calculations indicated that even the highest scratching forces (100 cN) could not induce sufficient fluid flow to activate pulpal mechanoreceptors, although it could induce sufficient elastic deformation to theoretically shift dentinal fluid at a rate sufficient to activate mechanoreceptors; (3). The results of this work may lend support the hydrodynamic theory in that scratching of dentin surfaces causes both elastic and plastic deformation of dentin that may displace dentinal fluid toward the pulp where it could activate mechanoreceptors.
Topics: Dentin; Dentin Sensitivity; Dentinal Fluid; Elasticity; Humans; Mechanoreceptors; Microscopy, Electron, Scanning; Stress, Mechanical
PubMed: 12798156
DOI: 10.1016/s0003-9969(03)00091-8 -
Journal de Biologie Buccale Jun 1990Using the rat incisor as a model, evidence is presented that enamel-related (ERD) and cementum-related (CRD) dentins exhibit differences in composition. Whereas the ERD... (Review)
Review
Using the rat incisor as a model, evidence is presented that enamel-related (ERD) and cementum-related (CRD) dentins exhibit differences in composition. Whereas the ERD is rich in highly phosphorylated phosphoproteins, the CRD is rich in lowly phosphorylated phosphoproteins. These differences are accompanied by and possibly related to differences in composition and physical properties of the mineral phase.
Topics: Animals; Dentin; Dentinogenesis; Phosphoproteins; Proteoglycans; Rats
PubMed: 2211579
DOI: No ID Found -
Journal of the American Dental... May 1993With greater need for treating root surface lesions, dentinal adhesives are more in demand. For successful treatment, all factors--dentin, tooth, patient and... (Review)
Review
With greater need for treating root surface lesions, dentinal adhesives are more in demand. For successful treatment, all factors--dentin, tooth, patient and materials--must be considered.
Topics: Age Factors; Bruxism; Dental Bonding; Dentin; Dentin, Secondary; Dentin-Bonding Agents; Humans; Microscopy, Electron, Scanning; Smear Layer; Tooth Abrasion; Tooth Erosion
PubMed: 8482779
DOI: 10.14219/jada.archive.1993.0104 -
Brazilian Dental Journal 2009Permeability involves the passage of fluids, ions, molecules, particulate matter and bacteria into and through a substance or tissue under different and varying...
Permeability involves the passage of fluids, ions, molecules, particulate matter and bacteria into and through a substance or tissue under different and varying conditions. The permeability of the dentin is essential to support the physiology and reaction patterns of the pulp-dentin organ. Nutrients and impulses are transported from the pulp via the odontoblast process and the contents of its tubules maintain the dentin as a vital tissue. However, the main interest of this paper focuses on penetration from the outside towards the pulp rather than from the pulp towards the outside. The present overview centers on the dentinal tubules; how they are formed and how they change as a result of normal and abnormal function, age, and pathological processes and the effect of these processes on the permeability of dentin. Particular attention is focused on the patency of the dentinal tubules.This overview is largely based on the authors own research, clinical insights and active participation in continuing dental education over the last 50 years. It is not a review of the literature related to the permeability of dentin. Rather it presents interpretation of results related to the permeability of dentin based on experience and opinions acquired over a lifetime in dental research.
Topics: Aging; Dental Bonding; Dental Caries; Dental Pulp; Dentin; Dentin Permeability; Dentin Sensitivity; Dentin, Secondary; Dentin-Bonding Agents; Dentinal Fluid; Dentinogenesis; Humans; Hydrostatic Pressure; Odontoblasts; Smear Layer; Tooth Attrition
PubMed: 19466224
DOI: 10.1590/s0103-64402009000100001 -
Monographs in Oral Science 2014Dentine hypersensitivity is a common oral pain condition affecting many individuals. The aetiology is multifactorial; however, over recent years the importance of... (Review)
Review
Dentine hypersensitivity is a common oral pain condition affecting many individuals. The aetiology is multifactorial; however, over recent years the importance of erosion has become more evident. For dentine hypersensitivity to occur, the lesion must first be localised on the tooth surface and then initiated to exposed dentine tubules which are patent to the pulp. The short, sharp pain symptom is thought to be derived from the hydrodynamic pain theory and, although transient, is arresting, affecting quality of life. This episodic pain condition is likely to become a more frequent dental complaint in the future due to the increase in longevity of the dentition and the rise in tooth wear, particularly amongst young adults. Many efficacious treatment regimens are now available, in particular a number of over-the-counter home use products. The basic principles of treatment are altering fluid flow in the dentinal tubules with tubule occlusion or modifying or chemically blocking the pulpal nerve.
Topics: Dental Pulp; Dentin; Dentin Desensitizing Agents; Dentin Sensitivity; Dentinal Fluid; Humans; Rheology; Tooth Erosion
PubMed: 24993261
DOI: 10.1159/000360749