-
Dental Materials : Official Publication... Jul 2021To investigate the effectiveness of novel polymeric nanoparticles (NPs) doped with melatonin (ML) in reducing dentin permeability and facilitating dentin...
OBJECTIVES
To investigate the effectiveness of novel polymeric nanoparticles (NPs) doped with melatonin (ML) in reducing dentin permeability and facilitating dentin remineralization after endodontic treatment.
METHODS
The effect of undoped NPs and ML-doped NPs (ML-NPs) was tested in radicular dentin, at 24 h and 6 m. A control group without NPs was included. ML liberation was measured. Radicular dentin was assessed for fluid filtration. Dentin remineralization was analyzed by scanning electron microscopy, AFM, Young's modulus (Ei), Nano DMA-tan delta, and Raman analysis.
RESULTS
ML release ranged from 1.85 mg/mL at 24 h to 0.033 mg/mL at 28 d. Both undoped NPs and ML-NPs treated dentin exhibited the lowest microleakage, but samples treated with ML-NPs exhibited hermetically sealed dentinal tubules and extended mineral deposits onto dentin. ML-NPs promoted higher and durable Ei, and functional remineralization at root dentin, generating differences between the values of tan delta among groups and creating zones of stress concentration. Undoped-NPs produced closure of some tubules and porosities at the expense of a relative mineral amorphization. Chemical remineralization based on mineral and organic assessments was higher in samples treated with ML-NPs. When using undoped NPs, precipitation of minerals occurred; however, radicular dentin was not mechanically reinforced but weakened over time.
SIGNIFICANCE
Application of ML-NPs in endodontically treated teeth, previous to the canal filling step, is encouraged due to occlusion of dentinal tubules and the reinforcement of the radicular dentin structure.
Topics: Dentin; Melatonin; Microscopy, Electron, Scanning; Nanoparticles; Polymers; Tooth Root
PubMed: 33846017
DOI: 10.1016/j.dental.2021.03.007 -
Medical Principles and Practice :... 2021Matrix metalloproteinases (MMPs) are present in radicular dentin and can convert structural matrix proteins into signaling molecules; thus, these enzymes play an...
OBJECTIVE
Matrix metalloproteinases (MMPs) are present in radicular dentin and can convert structural matrix proteins into signaling molecules; thus, these enzymes play an essential role in dentin biomineralization and tissue regeneration therapies. Their expression on radicular dentin may be affected by the irrigation solutions used during root canal treatments. This study aimed to evaluate the effects of the most common irrigants on radicular dentin MMP expression.
MATERIALS AND METHODS
The experimental solutions were distilled water (control), 5% sodium hypochlorite (NaOCl), 18% ethylenediaminetetraacetic acid (EDTA), and 2% chlorhexidine (CHX). Samples were prepared from extracted human teeth. For zymography analysis, root sections were powderized, and dentin proteins were extracted to observe gelatinolytic activity. Root dentin slices were treated with the experimental solutions for immunohistochemical analysis using anti-MMP-2 and anti-MMP-9 antibodies. ANOVA and the Tukey test were performed.
RESULTS
Zymograms revealed the presence of MMP-2, MMP-8, and MMP-20 in the control group and the EDTA-treated group. Immunohistochemistry confirmed the presence of MMP-2 and MMP-9 mainly associated with the dentinal tubule lumens and occasionally with intertubular dentin. NaOCl- and CHX-treated groups showed lower expression of MMPs than the control group. Immuno-staining for both proteinases in the EDTA-treated group showed higher expression compared to the other experimental groups.
CONCLUSION
Our results showed that most common irrigants affect MMP expression on radicular dentin. Treatment with NaOCl and chlorhexidine resulted in lower expression of MMPs, while EDTA increased their expression in root canal dentin.
Topics: Chlorhexidine; Dentin; Edetic Acid; Humans; Matrix Metalloproteinase 2; Sodium Hypochlorite
PubMed: 34153965
DOI: 10.1159/000517887 -
European Cells & Materials Jul 2021Dentineogenesis starts on odontoblasts, which synthesise and secrete non-collagenous proteins (NCPs) and collagen. When dentine is injured, dental pulp... (Review)
Review
Dentineogenesis starts on odontoblasts, which synthesise and secrete non-collagenous proteins (NCPs) and collagen. When dentine is injured, dental pulp progenitors/mesenchymal stem cells (MSCs) can migrate to the injured area, differentiate into odontoblasts and facilitate formation of reactionary dentine. Dental pulp progenitor cell/MSC differentiation is controlled at given niches. Among dental NCPs, dentine sialophosphoprotein (DSPP) is a member of the small integrin-binding ligand N-linked glycoprotein (SIBLING) family, whose members share common biochemical characteristics such as an Arg-Gly-Asp (RGD) motif. DSPP expression is cell- and tissue-specific and highly seen in odontoblasts and dentine. DSPP mutations cause hereditary dentine diseases. DSPP is catalysed into dentine glycoprotein (DGP)/sialoprotein (DSP) and phosphoprotein (DPP) by proteolysis. DSP is further processed towards active molecules. DPP contains an RGD motif and abundant Ser-Asp/Asp-Ser repeat regions. DPP-RGD motif binds to integrin αVβ3 and activates intracellular signalling via mitogen-activated protein kinase (MAPK) and focal adhesion kinase (FAK)-ERK pathways. Unlike other SIBLING proteins, DPP lacks the RGD motif in some species. However, DPP Ser-Asp/Asp-Ser repeat regions bind to calcium-phosphate deposits and promote hydroxyapatite crystal growth and mineralisation via calmodulin-dependent protein kinase II (CaMKII) cascades. DSP lacks the RGD site but contains signal peptides. The tripeptides of the signal domains interact with cargo receptors within the endoplasmic reticulum that facilitate transport of DSPP from the endoplasmic reticulum to the extracellular matrix. Furthermore, the middle- and COOH-terminal regions of DSP bind to cellular membrane receptors, integrin β6 and occludin, inducing cell differentiation. The present review may shed light on DSPP roles during odontogenesis.
Topics: Cell Differentiation; Dental Pulp; Dentin; Extracellular Matrix Proteins; Odontoblasts; Phosphoproteins; Sialoglycoproteins
PubMed: 34275129
DOI: 10.22203/eCM.v042a04 -
FEBS Open Bio Jan 2023Biomimetic nanohydroxyapatite (nHAp) has long been used as a biocompatible material for bone repair, bone regeneration, and bone reconstruction due to its low toxicity...
Biomimetic nanohydroxyapatite (nHAp) has long been used as a biocompatible material for bone repair, bone regeneration, and bone reconstruction due to its low toxicity to local or systemic tissues. Various cross-linkers have been employed to maintain the structure of collagen; these include epigallocatechin-3-gallate (EGCG), which can fortify the mechanical properties of collagen and withstand the degradation of collagenase. We hypothesized that EGCG combined with nHAp may promote resin-dentin bonding durability. Here, we examined the effect of epigallocatechin-3-gallate-encapsulated nanohydroxyapatite/mesoporous silica (EGCG@nHAp@MSN) on thermal stability and remineralization capability of dentin collagen. Dentin slices (2 × 2 × 1 mm ) were obtained and completely demineralized in a 10% phosphoric acid water solution. The resulting dentin collagen matrix was incubated with deionized water, EGCG, nHAp@MSN, and EGCG@nHAp@MSN. The collagen thermal degradation temperature was assessed utilizing differential scanning calorimetry analysis, which indicated that EGCG, nHAp@MSN, and EGCG@nHAp@MSN reinforced collagen's capability to resist thermal degradation. EGCG@nHAp@MSN resulted in the highest increase in denaturation temperature. Thermogravimetric analysis showed that both nHAp@MSN and EGCG@nHAp@MSN achieved a higher residual mass than the EGCG and control groups. Fourier transform infrared spectroscopy was performed to examine the interaction between EGCG@nHAp@MSN and dentin collagen. The EGCG@nHAp@MSN sample exhibited stronger dentin microhardness and uppermost bond strength after thermocycling. EGCG significantly enhanced collagen's capability to resist thermal degradation. In summary, EGCG and nHAp@MSN may work together to assist the exposed collagen to improve resistance to thermal cycling and promote remineralization while also strengthening the durability of resin-dentin bonds.
Topics: Dentin; Silicon Dioxide; Collagen; Water
PubMed: 36350226
DOI: 10.1002/2211-5463.13521 -
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 -
Advanced Healthcare Materials Jul 2023Dentin hypersensitivity (DH) is triggered by external stimuli irking fluid flow through exposed dentinal tubules (DTs). Three commercially available desensitizing agents...
Dentin hypersensitivity (DH) is triggered by external stimuli irking fluid flow through exposed dentinal tubules (DTs). Three commercially available desensitizing agents as control in this study only achieve limited occlusion depths of ≈10 µm in the DTs as well as scarce remineralization of demineralized dentin matrix. Herein, polyelectrolyte-calcium complexes pre-precursor (PCCP) process is proposed for managing DH that demineralized dentin with exposed DTs is rubbed with ultrahighly concentrated polyelectrolyte-calcium suspension (4 g L -5.44 m) followed by phosphate solution (3.25 m), each 10 min, leading to heavy remineralization of demineralized dentin and compact occlusion of the DTs over 200 µm after 1 day of in vitro and in vivo incubation. For the first time, it is demonstrated that the PCCP process relies on the pH-dependent electrostatic attraction between electropositive polyelectrolyte-calcium complexes and electronegative inwalls of DTs comprised of collagen fibrils and hydroxyapatite crystals under alkaline condition. The PCCP process might shed light on a promising dentin desensitizing strategy for DH management via rapid in-depth DT occlusion and remineralization of demineralized dentin.
Topics: Humans; Calcium; Dentin; Dentin Sensitivity; Polyelectrolytes; Microscopy, Electron, Scanning; Tooth Remineralization
PubMed: 36930219
DOI: 10.1002/adhm.202300100 -
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 Journal May 2022The aim of this study was to evaluate the crosslinking effect of the radio-frequency atmospheric-pressure glow discharge (RF-APGD) plasma jet treatment on dentin...
The aim of this study was to evaluate the crosslinking effect of the radio-frequency atmospheric-pressure glow discharge (RF-APGD) plasma jet treatment on dentin collagen. The dentin collagen was treated by an RF-APGD plasma jet with the gas temperature of 4°C under different treatment times, while the control was a non-treatment group. The dentin collagen was characterized in terms of atomic force microscopy-based nanoindentation, differential scanning calorimeter, Raman analysis and X-ray photoelectron spectroscopy (XPS) measurement. The crosslinking effect of the plasma-treated dentin collagen was found compared to that of the control group. The elastic modulus and denaturation temperature of the dentin collagen after plasma treatment for 30 s were significantly higher than those in the control group (p<0.05). The RF-APGD plasma jet treatment can promote the crosslinking of the dentin collagen, which is of great significance to improve its mechanical and thermal stabilities.
Topics: Atmospheric Pressure; Collagen; Dentin; Elastic Modulus; Plasma Gases
PubMed: 35321973
DOI: 10.4012/dmj.2021-207 -
Clinical Oral Investigations Sep 2022This in vitro study aimed to investigate the optical attenuation of light at 405, 660 and 780 nm sent through sound and carious human enamel and dentin, including...
OBJECTIVES
This in vitro study aimed to investigate the optical attenuation of light at 405, 660 and 780 nm sent through sound and carious human enamel and dentin, including respective individual caries zones, as well as microscopically sound-appearing tissue close to a carious lesion.
MATERIALS AND METHODS
Collimated light transmission through sections of 1000-125-µm thickness was measured and used to calculate the attenuation coefficient (AC). The data were statistically analysed with a MANOVA and Tukey's HSD. Precise definition of measurement points enabled separate analysis within the microstructure of lesions: the outer and inner halves of enamel (D1, D2), the translucent zone (TZ) within dentin lesions and its adjacent layers, the enamel side of the translucent zone (ESTZ) and the pulpal side of the translucent zone (PSTZ).
RESULTS
The TZ could be distinguished from its adjacent layers and from caries-free dentin at 125 µm. Sound-appearing dentin close to caries lesions significantly differed from caries-free dentin at 125 µm. While sound and carious enamel exhibited a significant difference (p < 0.05), this result was not found for D1 and D2 enamel lesions (p > 0.05). At 405 nm, no difference was found between sound and carious dentin (p > 0.05).
CONCLUSIONS
Light optical means enable the distinction between sound and carious tissue and to identify the microstructure of dentin caries partially as well as the presence of tertiary dentin formation. Information on sample thickness is indispensable when interpreting the AC.
CLINICAL RELEVANCE
Non-ionising light sources may be suitable to detect lesion progression and tertiary dentin.
Topics: Dental Caries; Dental Enamel; Dentin; Humans
PubMed: 35588022
DOI: 10.1007/s00784-022-04541-7