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Scientific Reports Nov 2023To evaluate the biomimetic remineralization capabilities of Moringa oleifera leaves (MOL) extract on coronal dentin and acellular cementum, two different concentrations...
To evaluate the biomimetic remineralization capabilities of Moringa oleifera leaves (MOL) extract on coronal dentin and acellular cementum, two different concentrations (50 and 200 mg/ml) of MOL extract loaded in plain varnish (M1 and M2 groups respectively) were compared to fluoride varnish (FL group) and native surface (C group). Eighty sound premolar teeth were collected. Forty teeth (10 teeth in each group) were used for coronal dentin testing while the other forty (10 teeth in each group) were used for acellular cementum testing. Teeth in M1, M2, and FL groups were etched for 30 s and then received the specific varnish treatment. All samples were immersed in artificial saliva for 14 days and then collected, dried, and examined by scanning electron microscopy and energy dispersive X-ray spectroscopy (EDX). Histologically, FL group showed mineral deposition as discrete vesicular granules of various sizes on the surface of both coronal dentin and acellular cementum. Mineral deposition only occurred on some DTs openings while opened tubules remained. The surface of the acellular cementum revealed regular grooves, micro-fissures, and cracks. In the M1 and M2 groups, mineral deposition appeared as a homogenous continuous layer on coronal dentin and acellular cementum. Only a few DTs and cementum fissures were not filled completely. In L.S. sections of the coronal one-third, the DTs appeared almost sealed with varying lengths of mineral deposition. EDX results statistical analysis showed that the M2 group had the highest phosphate ions (P) and calcium ions (Ca) at%. MOL has an extraordinary effect on the remineralization of coronal dentin and acellular cementum. It would have a promising ability to control dentinal hypersensitivity and formation of biomimetic cementum tissue.
Topics: Dentin; Moringa oleifera; Microscopy, Electron, Scanning; Bicuspid; Fluorides; Minerals
PubMed: 37935743
DOI: 10.1038/s41598-023-46656-1 -
Journal of Dental Research Jul 2022Methylglyoxal (MGO) is an important molecule derived from glucose metabolism with the capacity of attaching to collagen and generating advanced glycation end products...
Methylglyoxal (MGO) is an important molecule derived from glucose metabolism with the capacity of attaching to collagen and generating advanced glycation end products (AGEs), which accumulate in tissues over time and are associated with aging and diseases. However, the accumulation of MGO-derived AGEs in dentin and their effect on the nanomechanical properties of dentinal collagen remain unknown. Thus, the aim of the present study was to quantify MGO-based AGEs in the organic matrix of human dentin as a function of age and associate these changes with alterations in the nanomechanical and ultrastructural properties of dentinal collagen. For this, 12 healthy teeth from <26-y-old and >50-y-old patients were collected and prepared to obtain crown and root dentin discs. Following demineralization, MGO-derived AGEs were quantified with a competitive ELISA. In addition, atomic force microscopy nanoindentation was utilized to measure changes in elastic modulus in peritubular and intertubular collagen fibrils. Finally, principal component analysis was carried out to determine aging profiles for crown and root dentin. Results showed an increased presence of MGO AGEs in the organic matrix of dentin in the >50-y-old specimens as compared with the <26-y-old specimens in crown and root. Furthermore, an increase in peritubular and intertubular collagen elasticity was observed in the >50-y-old group associated with ultrastructural changes in the organic matrix as determined by atomic force microscopy analysis. Furthermore, principal component analysis loading plots suggested different "aging profiles" in crown and root dentin, which could have important therapeutic implications in restorative and adhesive dentistry approaches. Overall, these results demonstrate that the organic matrix of human dentin undergoes aging-related changes due to MGO-derived AGEs with important changes in the nanomechanical behavior of collagen that may affect diagnostic and restorative procedures in older people.
Topics: Aged; Aging; Collagen; Dentin; Elastic Modulus; Humans; Magnesium Oxide; Nanostructures
PubMed: 35130787
DOI: 10.1177/00220345211072484 -
Biology Letters Apr 2022In amniotes, daily rates of dentine formation in non-ever-growing teeth range from less than 1 to over 25 μm per day. The latter value has been suggested to represent...
In amniotes, daily rates of dentine formation in non-ever-growing teeth range from less than 1 to over 25 μm per day. The latter value has been suggested to represent the upper limit of odontoblast activity in non-ever-growing teeth, a hypothesis supported by the lack of scaling between dentine apposition rates and body mass in Dinosauria. To determine the correlates and potential controls of dentine apposition rate, we assembled a dataset of apposition rates, metabolic rates and body masses for 80 amniote taxa of diverse ecologies and diets. We used phylogenetic regression to test for scaling relationships and reconstruct ancestral states of daily dentine apposition across Amniota. We find no relationship between body mass and daily dentine apposition rate (DDAR) for non-ever-growing teeth in Amniota as a whole or within major clades. Metabolic rate, the number of tooth generations, diet and habitat also do not predict or correspond with DDARs. Similar DDARs are found in large terrestrial mammals, dinosaurs and marine reptiles, whereas primates, cetaceans and some smaller marine reptiles independently evolved exceptionally slow rates. Life-history factors may explain the evolution of dentine apposition rates, which evolved rapidly at the origin of major clades.
Topics: Animals; Dentin; Dinosaurs; Mammals; Phylogeny; Reptiles; Tooth
PubMed: 35472282
DOI: 10.1098/rsbl.2022.0092 -
Dental Update Nov 2015Dentine becomes infected as a result of caries lesion formation on root surfaces and when lesions progress following cavitation of enamel lesions. However, this...
Dentine becomes infected as a result of caries lesion formation on root surfaces and when lesions progress following cavitation of enamel lesions. However, this infection is unimportant because the driving force for lesion formation and progression is the overlying biofilm. This explains why root surface caries can be controlled by mechanical plaque control and fluoride, and restorations are not needed to arrest these lesions. Similarly, the infected dentine in cavitated coronal lesions does not have to be removed to arrest the lesion. If the lesion is either accessible or opened for cleaning by the patient or parent, the lesion can be arrested. Sealing of infected dentine within the tooth, either by a Hall crown in the primary dentition or by partial caries removal prior to placing a well-sealed filling, will also arrest the lesion. When restoring deep lesions in symptomless, vital teeth, vigorous excavation of infected dentine is likely to expose the pulp and make root canal treatment necessary. Thus complete excavation'is not needed and should be avoided. CPD/CLINICAL RELEVANCE: Root surface caries can be arrested by cleaning and fluoride application. Restorations are not essential. Vigorous excavation of softened dentine in deep cavities of symptomless, vital teeth is contra-indicated. It is not needed and increases the risk of pulp exposure.
Topics: Bacteria; Biofilms; Cariostatic Agents; Dental Caries; Dental Pulp; Dental Pulp Exposure; Dental Restoration, Permanent; Dentin; Dentin, Secondary; Disease Progression; Fluorides; Humans; Pulpitis; Root Caries; Tooth Remineralization; Toothbrushing; Toothpastes
PubMed: 26749788
DOI: 10.12968/denu.2015.42.9.802 -
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 -
Monographs in Oral Science 2023Pathology is the science of how a tissue changes during the process of the disease. The pathology is of important knowledge for understanding subsequent treatment... (Review)
Review
Pathology is the science of how a tissue changes during the process of the disease. The pathology is of important knowledge for understanding subsequent treatment concepts of a disease. In the cariology field, pathological features of caries are often presented using tooth sections, whereby the sequence and spread can be monitored. It is optimal to describe such changes using thin undecalcified tooth sections as an overview can be given of both enamel demineralization and pulp-dentine reactions. Also, an optimal understanding is achieved if the clinical status of carious lesion activity is known. Different studies using human teeth have shown the principle changes in progressive stages of carious lesions; the growth of the enamel lesion reflects the growth condition of the cariogenic biofilm. Surprisingly, the pulp (the odontoblast) is aware of the cariogenic stimuli even before mineral alteration has taken place within the dentine. The microorganisms mainly invade the dentine during enamel cavitation. In this chapter, the current improvement of knowledge on advanced carious lesions has been assessed in detail both histologically and radiographically. From a radiographic point of view, well-defined deep and extremely deep carious lesions and their difference are presented. Recent advances in artificial intelligence (AI) in medicine have raised the possibility of increasing the accuracy and speed of histopathological examination techniques. However, the literature involving AI-based histopathological features of hard and soft dentinal tissue pathologic changes is still scarce.
Topics: Humans; Dentin; Artificial Intelligence; Dental Caries Susceptibility; Dental Caries; Dental Pulp
PubMed: 37364550
DOI: 10.1159/000530557 -
Archives of Oral Biology Apr 2022The aims of the study were to evaluate the roles of odontoblast apoptosis in the progression of tubular sclerosis of teeth from donors at different ages and assess its...
OBJECTIVES
The aims of the study were to evaluate the roles of odontoblast apoptosis in the progression of tubular sclerosis of teeth from donors at different ages and assess its correlation to chemical composition and mechanical properties.
DESIGN
Healthy human teeth were obtained and divided into young (age ≤ 25, n = 12) and old (age ≥ 60, n = 12) groups. Odontoblasts were counted with standard hematoxylin and eosin staining. Odontoblast apoptosis within dentinal tubules was determined by cleaved caspase-3 immunostaining. Teeth in each group were evaluated by dynamic nanoindentation and energy-dispersive X-ray spectroscopy (EDS).
RESULTS
The number of odontoblasts decreased significantly with age. The most prominent change occurred in the apical third of roots. Odontoblastic apoptosis was visualized within dentinal tubules. The apoptosis staining fraction was significantly higher in the outer and inner dentin of old teeth when compared with young teeth (p < 0.05). EDS showed increased calcium content in peritubular dentin but a decrease in the intertubular dentin with increasing age. Scanning based nanoindentation showed that the old intertubular dentin exhibited a significantly higher elastic modulus.
CONCLUSIONS
Odontoblast apoptosis, starting at the cell extension in dentinal tubules and proceeding from outer to inner dentin, contributes to the stoichiometric Ca/P ratio in peritubular dentin, which is potentially responsible for intratubular mineralization due to an imbalance of calcium and phosphorous ions.
Topics: Aging; Apoptosis; Dentin; Dentin, Secondary; Humans; Odontoblasts
PubMed: 35183920
DOI: 10.1016/j.archoralbio.2022.105371 -
Dental Materials : Official Publication... Jul 2022The conventional radiotherapy protocol to treat head-and-neck cancer is usually followed by tooth-decay onset. Radiation impact on mineralized tooth structures is not... (Review)
Review
OBJECTIVES
The conventional radiotherapy protocol to treat head-and-neck cancer is usually followed by tooth-decay onset. Radiation impact on mineralized tooth structures is not well-understood. This systematic review aimed to collect the recorded effects of therapeutic radiation on tooth chemical, structural and mechanical properties, in relation with their means of investigation.
DATA
Systematic search (January 01 2012 - September 30 2021) terms were "Radiotherapy", "Radiation effects", "Dental enamel", "Dentin", "Human" and "Radiotherapy" NOT "Laser".
SOURCES
PubMed, DOSS and Embase databases were searched.
STUDY SELECTION
Selected studies compared dental enamel, coronal and root dentin properties before and after in vitro or in vivo irradiation up to 80 Gy.
RESULTS
The systematic search identified 353 different articles, with 28 satisfying inclusion criteria. Their reference lists provided two more. Twenty-two studies evaluated dental enamel evolution, nine assessed coronal dentin and eight concerned root dentin. Coronal and root dentin results indicate a major impact of the radiation on their organic matrix. Dental enamel's chemical properties are less modified. Enamel and root dentin's hardness are decreased by therapeutic radiation, but no consensus arises for coronal dentin.
CONCLUSIONS
Our findings revealed some interesting information about enzymatic degradation mechanisms of dentin organic matrix and highlighted that dental hard-tissue characterization requires highly specific expertise in materials science. That scientific knowledge is necessary to design suitable protocols, adequately analyze the obtained data, and, thus, provide relevant conclusions.
CLINICAL SIGNIFICANCE STATEMENT
Better knowledge and understanding of the mechanisms involved in the degradation of enamel and dentin would enable development of new preventive and therapeutic methods for improved medical care of patients undergoing radiotherapy.
Topics: Dental Caries; Dental Enamel; Dentin; Head and Neck Neoplasms; Humans; Radiation Injuries; Tooth
PubMed: 35570008
DOI: 10.1016/j.dental.2022.04.014 -
Technology and Health Care : Official... 2023The integrity and stability of collagen are crucial for the dentin structure and bonding strength at dentin-resin interface. Natural plant-derived polypehenols have been... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
The integrity and stability of collagen are crucial for the dentin structure and bonding strength at dentin-resin interface. Natural plant-derived polypehenols have been used as collagen crosslinkers.
OBJECTIVE
The aims of the study were to develop novel chitosan oleuropein nanoparticles (CS-OL-NPs), and to investigate the CS-OL-NPs treated dentin's the resistance to enzymatic degradation and mechanic property.
METHODS
CS-OL-NPs were developed using the ionotropic gelation method. Release and biocompatibility of the CS-OL-NPs were tested. Twenty demineralized dentin collage specimens were randomized into four interventions groups: A, Deionized Water (DW); B, 5% glutaraldehyde solution (GA); C, 1 mg/ml chitosan (CS); and D, 100 mg/L CS-OL-NPs. After 1-min interventions, dentin matrix were evaluated by the micro-Raman spectroscopy for the modulus of elasticity test. Collagen degradation was assessed using hydroxyproline (HYP) assay.
RESULTS
CS-OL-NPs were spherical core-shape with a size of 161.29 ± 8.19 nm and Zeta potential of 19.53 ± 0.26 mV. After a burst release of oleuropein in the initial 6 h, there was a long-lasting steady slow release. CS-OL-NPs showed a good biocompatibility for the hPDLSCs. The modulus of elasticity in the crosslinked groups were significantly higher than that in the control group (P< 0.05 for all). The specimens treated with CS-OL-NP showed a greater modulus of elasticity than those treated with GA and CS (P< 0.05 for both). The release of HYP in the crosslinked group was significantly lower than that in the non-crosslinked groups (P< 0.05 for all).
CONCLUSION
CS-OL-NPs enhanced the dentin mechanical property and resistance to biodegradation, with biocompatibility and potential for clinical application.
Topics: Humans; Chitosan; Collagen; Dentin; Nanoparticles
PubMed: 36093647
DOI: 10.3233/THC-220195 -
Dental Materials : Official Publication... Jan 2018Efforts towards achieving durable resin-dentin bonds have been made for decades, including the understanding of the mechanisms underlying hybrid layer (HL) degradation,... (Review)
Review
OBJECTIVES
Efforts towards achieving durable resin-dentin bonds have been made for decades, including the understanding of the mechanisms underlying hybrid layer (HL) degradation, manufacturing of improved adhesive systems, as well as developing strategies for the preservation of the HL.
METHODS
This study critically discusses the available peer-reviewed research concerning the formation and preservation of the HL, the mechanisms that lead to the degradation of the HL as well as the strategies to prevent it.
RESULTS
The degradation of the HL occurs through two main mechanisms: the enzymatic degradation of its collagen fibrils, and the leaching of the resin from the HL. They are enabled by residual unbound water between the denuded collagen fibrils, trapped at the bottom of the HL. Consequently, endogenous dentinal enzymes, such as the matrix metalloproteinases (MMPs) and cysteine cathepsins are activated and can degrade the denuded collagen matrix. Strategies for the preservation of the HL over time have been developed, and they entail the removal of the unbound water from the gaps between the collagen fibrils as well as different modes of silencing endogenous enzymatic activity.
SIGNIFICANCE
Although there are many more hurdles to be crossed in the field of adhesive dentistry, impressive progress has been achieved so far, and the vast amount of available research on the topic is an indicator of the importance of this matter and of the great efforts of researchers and dental material companies to reach a new level in the quality and longevity of resin-dentin bonds.
Topics: Collagen; Cross-Linking Reagents; Dental Bonding; Dentin; Dentin-Bonding Agents; Matrix Metalloproteinases; Surface Properties
PubMed: 29179971
DOI: 10.1016/j.dental.2017.11.005