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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 -
Journal of Oral Biosciences Mar 2023Bone, platelet concentrate, and tooth-derived dentin/cementum have been used as autologous materials in regenerative medicine Dentin materials were first recycled in... (Review)
Review
OBJECTIVES
Bone, platelet concentrate, and tooth-derived dentin/cementum have been used as autologous materials in regenerative medicine Dentin materials were first recycled in 2002 for bone regeneration in humans, although bone autografts were noted in the 19th century, and auto-platelet concentrates were developed in 1998. Dentin/cementum-based material therapy has been applied as an innovative technique for minimally invasive bone surgery, while bone autografts are associated with donor site morbidity.
METHODS
In October 2021, PubMed, Google Scholar, Scopus, and the Cochrane Library databases from 1980 to 2020 were screened.
RESULTS
The demineralized dentin/cementum matrix (DDM) had better performance in bone induction and bone regeneration than mineralized dentin.
CONCLUSIONS
Unlike cell culture therapy, DDM is a matrix-based therapy that includes growth factors. A matrix-based system is a realistic and acceptable treatment, even in developing countries. The aim of this review was to summarize the evidence related to both animal studies and human clinical cases using human dentin materials with a patch of cementum, especially DDM.
Topics: Animals; Humans; Dentin; Bone Regeneration; Animals, Laboratory; Dental Cementum
PubMed: 36336319
DOI: 10.1016/j.job.2022.10.003 -
Archives of Oral Biology Aug 2023Dentin, enamel and the transition zone, called the dentin-enamel junction (DEJ), have an organization and properties that play a critical role in tooth resilience and in...
OBJECTIVE
Dentin, enamel and the transition zone, called the dentin-enamel junction (DEJ), have an organization and properties that play a critical role in tooth resilience and in stopping the propagation of cracks. Understanding their chemical and micro-biomechanical properties is then of foremost importance. The aim of this study is to apply Brillouin microscopy on a complex biological structure, that is, the DEJ, and to compare these results with those obtained with Raman microscopy.
DESIGN
Both techniques allow noncontact measurements at the microscopic scale. Brillouin microscopy is based on the interaction between acoustic phonons and laser photons and gives a relation between the frequency shift of the scattered light and the stiffness of the sample. Raman spectra contain peaks related to specific chemical bonds.
RESULTS
Comparison of the Brillouin and Raman cartographies reveals correlations between mechanical and chemical properties. Indeed, the shapes of the phosphate content and stiffness curves are similar. The two spectroscopies give compatible values for the mean distance between two tubules, i.e., 4-6 µm. Moreover, for the first time, the daily cross striations of enamel could be studied, indicating a relationship between the variation in the phosphate concentration and the variation in the rigidity within the enamel prisms.
CONCLUSIONS
We demonstrate here the possibility of using Brillouin scattering microscopy to both study complex biological materials such as the enamel-dentin junction and visualize secondary structures. Correlations between the chemical composition and mechanical properties could help in better understanding the tissue histology.
Topics: Dentin; Microscopy; Dental Enamel; Tooth
PubMed: 37247560
DOI: 10.1016/j.archoralbio.2023.105733 -
Journal of Bone and Mineral Research :... Feb 2022Considerable amount of research has been focused on dentin mineralization, odontoblast differentiation, and their application in dental tissue engineering. However, very...
Considerable amount of research has been focused on dentin mineralization, odontoblast differentiation, and their application in dental tissue engineering. However, very little is known about the differential role of functionally and spatially distinct types of dental epithelium during odontoblast development. Here we show morphological and functional differences in dentin located in the crown and roots of mouse molar and analogous parts of continuously growing incisors. Using a reporter (DSPP-cerulean/DMP1-cherry) mouse strain and mice with ectopic enamel (Spry2 ;Spry4 ), we show that the different microstructure of dentin is initiated in the very beginning of dentin matrix production and is maintained throughout the whole duration of dentin growth. This phenomenon is regulated by the different inductive role of the adjacent epithelium. Thus, based on the type of interacting epithelium, we introduce more generalized terms for two distinct types of dentins: cementum versus enamel-facing dentin. In the odontoblasts, which produce enamel-facing dentin, we identified uniquely expressed genes (Dkk1, Wisp1, and Sall1) that were either absent or downregulated in odontoblasts, which form cementum-facing dentin. This suggests the potential role of Wnt signalling on the dentin structure patterning. Finally, we show the distribution of calcium and magnesium composition in the two developmentally different types of dentins by utilizing spatial element composition analysis (LIBS). Therefore, variations in dentin inner structure and element composition are the outcome of different developmental history initiated from the very beginning of tooth development. Taken together, our results elucidate the different effects of dental epithelium, during crown and root formation on adjacent odontoblasts and the possible role of Wnt signalling which together results in formation of dentin of different quality. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
Topics: Animals; Cell Differentiation; Dentin; Epithelium; Extracellular Matrix Proteins; Incisor; Mice; Odontoblasts; Odontogenesis
PubMed: 34783080
DOI: 10.1002/jbmr.4471 -
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 -
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 -
Operative Dentistry Mar 2023This study evaluated the etching pattern, surface microhardness, and bond strength for enamel and dentin submitted to treatment with phosphoric, glycolic, and ferulic...
This study evaluated the etching pattern, surface microhardness, and bond strength for enamel and dentin submitted to treatment with phosphoric, glycolic, and ferulic acids. Enamel and dentin blocks were treated with phosphoric, glycolic, and ferulic acid to evaluate the surface and adhesive interface by scanning electron microscopy (2000×). Surface microhardness (Knoop) was evaluated before and after etching, and microtensile bond strength was evaluated after application of a two-step adhesive system (Adper Single Bond 2, 3M ESPE) at 24 hours and 12 months storage time points. Analysis of variance (ANOVA) and Tukey's test showed a decrease in the microhardness values for both substrates after application of each acid (p<0.0001). The reduction percentage was significantly higher for enamel treated with phosphoric acid (59.9%) and glycolic acid (65.1%) than for ferulic acid (16.5%) (p<0.0001), and higher for dentin that received phosphoric acid (38.3%) versus glycolic acid (27.8%) and ferulic acid (21.9%) (p<0.0001). Phosphoric and glycolic acids led to homogeneous enamel demineralization, and promoted the opening of dentinal tubules, whereas ferulic acid led to enamel surface demineralization and partially removed the smear layer. The adhesive-enamel interface showed micromechanical embedding of the adhesive in the interprismatic spaces when phosphoric and glycolic acids were applied. Ferulic acid showed no tag formation. Microtensile bond strength at both time points, and for both substrates, was lower with ferulic acid (p=0.0003/E; p=0.0011/D; Kruskal Wallis and Dunn). The bond strength for enamel and dentin decreased when using phosphoric and glycolic acids at the 12-month time evaluation (p<0.05). Glycolic acid showed an etching pattern and microhardness similar to that of phosphoric acid. Ferulic acid was not effective in etching the enamel or dentin, and it did not provide satisfactory bond strength to dental substrates.
Topics: Humans; Dental Bonding; Glycols; Surface Properties; Phosphoric Acids; Dental Enamel; Dentin; Tooth Demineralization; Tensile Strength; Dentin-Bonding Agents; Resin Cements
PubMed: 36656318
DOI: 10.2341/21-143-L -
Archives of Oral Biology Sep 2022The tufts of human dental enamel are structures located at the enamel-dentin junction and whose origin has not been clearly established. Although studies have...
OBJECTIVE
The tufts of human dental enamel are structures located at the enamel-dentin junction and whose origin has not been clearly established. Although studies have highlighted their protein content and hypomineralization, none has been able to shed light on their 3D structure. The aim of this study was to reveal the whole structure using high-resolution conventional microtomography.
DESIGN
Ten adult mandibular first and second molars and two primary mandibular first molars were sectioned and scanned with microcomputed tomography with a resolution between 4.7 and 5 micrometers. By determining the threshold discriminating dentin and tufts, we were able to reconstruct 3D meshes.
RESULTS
We revealed the exact pattern of the tufts in adult molars and discovered their distribution, their dynamics, and the existence of a regular undulation, forming a particular angle of approximately 30 degrees with the dentin surface. A spatial frequency of approximately 160 micrometers would be compatible with the variation in the orientation of groups of dental enamel rods. In contrast, the present setting is not sufficient to extract similar information for primary teeth.
CONCLUSIONS
Enamel tufts have a specific pattern, with an oriented draped form and are regularly spaced. The possible connection between these undulations and the Hunter-Schreger bands (diazonias and parazonias) needs to be studied.
Topics: Adult; Dental Enamel; Dentin; Humans; Molar; Tooth; X-Ray Microtomography
PubMed: 35738023
DOI: 10.1016/j.archoralbio.2022.105487 -
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