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Acta Biomaterialia Jan 2022Aging is a physiological process with profound impact on the biology and function of biosystems, including the human dentition. While resilient, human teeth undergo wear...
Aging is a physiological process with profound impact on the biology and function of biosystems, including the human dentition. While resilient, human teeth undergo wear and disease, affecting overall physical, psychological, and social human health. However, the underlying mechanisms of tooth aging remain largely unknown. Root dentin is integral to tooth function in that it anchors and dissipates mechanical load stresses of the tooth-bone system. Here, we assess the viscoelastic behavior, composition, and ultrastructure of young and old root dentin using nano-dynamic mechanical analysis, micro-Raman spectroscopy, small angle X-ray scattering, atomic force and transmission electron microscopies. We find that the root dentin overall stiffness increases with age. Unlike other mineralized tissues and even coronal dentin, however, the ability of root dentin to dissipate energy during deformation does not decay with age. Using a deconstruction method to dissect the contribution of mineral and organic matrix, we find that the damping factor of the organic matrix does deteriorate. Compositional and ultrastructural analyses revealed higher mineral-to-matrix ratio, altered enzymatic and non-enzymatic collagen cross-linking, increased collagen d-spacing and fibril diameter, and decreased abundance of proteoglycans and sulfation pattern of glycosaminoglycans . Therefore, even in the absence of remodeling, the extracellular matrix of root dentin shares traits of aging with other tissues. To explain this discrepancy, we propose that altered matrix-mineral interactions, possibly mediated by carbonate ions sequestered at the mineral interface and/or altered glycosaminoglycans counteract the deleterious effects of aging on the structural components of the extracellular matrix. STATEMENT OF SIGNIFICANCE: Globally, a quarter of the population will be over 65 years old by 2050. Because many will retain their dentition, it will become increasingly important to understand and manage how aging affects teeth. Dentin is integral to the protective, biomechanical, and regenerative features of teeth. Here, we demonstrate that older root dentin not only has altered mechanical properties, but shows characteristic shifts in mineralization, composition, and post-translational modifications of the matrix. This strongly suggests that there is a mechanistic link between mineral and matrix components to the biomechanical performance of aging dentin with implications for efforts to slow or even reverse the aging process.
Topics: Aged; Dentin; Extracellular Matrix; Humans; Minerals; Proteoglycans; Tooth Root
PubMed: 34740855
DOI: 10.1016/j.actbio.2021.10.051 -
Clinical Oral Investigations Mar 2013The aim of the article was to present an overview of the management strategies of dentin hypersensitivity (DHS) and summarize and discuss the therapeutic options. (Review)
Review
OBJECTIVES
The aim of the article was to present an overview of the management strategies of dentin hypersensitivity (DHS) and summarize and discuss the therapeutic options.
MATERIALS AND METHODS
A PubMed literature search was conducted to identify articles dealing with dentin hypersensitivity prophylaxis and treatment. We focussed on meta-analyses of available or controlled clinical trials.
RESULTS
DHS therapy should start with noninvasive individual prophylactic home-care approaches. In-office therapy follows with nerve desensitizing, precipitating, or plugging agents. If the hypersensitivity persists, depending on the hard and soft tissue components at reevaluation, i.e., presence or absence of cervical lesions and the gingival contour, adhesive restorations including sealing or mucogingival surgery may be an option. They allow for the establishment of a physicomechanical barrier. As the placebo effect may play an important role, adequate patient management strategies and positive reinforcement may improve the management of DHS in the future.
CONCLUSIONS
Lifelong maintenance under the premise of strict control of the causative factors is crucial in the management of DHS.
CLINICAL RELEVANCE
Clinicians are faced with a broad spectrum of therapeutic options. Therapy should not only focus on pain reduction or better elimination but also on the modification of the exposed cervical dentin area based on the defect type.
Topics: Dental Bonding; Dentin; Dentin Desensitizing Agents; Dentin Sensitivity; Gingiva; Humans; Tooth Cervix
PubMed: 23274415
DOI: 10.1007/s00784-012-0912-0 -
Acta Biomaterialia Jun 2021Dental pulp is a highly vascularized tissue, situated in an inextensible environment surrounded by rigid dentinal walls. The pulp receives its blood supply solely from...
Dental pulp is a highly vascularized tissue, situated in an inextensible environment surrounded by rigid dentinal walls. The pulp receives its blood supply solely from the small apical foramen of a tooth root. Due to the unique anatomy that controls nutrition supply, regeneration of pulp tissue in a full-length tooth root has long been a challenge in regenerative endodontics. In this study, we designed and synthesized a multifunctional peptide-conjugated, pH-sensitive, non-viral gene vector for fast revascularization and pulp regeneration in a full-length human tooth root. The multifunctional peptide was designed to have distinctive features, including a cell-penetrating peptide to enhance cellular uptake, a nuclear localization signal peptide to assist in the translocation of an angiogenic gene into the nucleus, and a fluorescent tryptophan residue to visualize and quantify the transfection efficiency. Furthermore, a pH-sensitive dimethylmaleic anhydride (DMA) was integrated with the multifunctional peptide to enhance the transfected gene complex to escape from endosomes/lysosomes after internalization. In vitro experiments showed that the multifunctional non-viral gene vector significantly increased internalization and gene transfection efficiency as well as reduced cytotoxicity. After dental pulp stem cells (DPSCs) were transfected with the multifunctional gene vector/pVEGF complexes, the expression of VEGF from the DPSCs was upregulated for more than eight folds, which in turn greatly enhanced endothelial cell migration and vascular-like tube formation. Six weeks after implantation, the VEGF-transfected DPSCs accelerated new blood vessel formation and the regenerated pulp tissue occupied most of the area in the canal of a full-length human tooth root. The multifunctional peptide conjugated non-viral gene delivery is a safe and effective approach for regenerative endodontics. STATEMENT OF SIGNIFICANCE: Pulp regeneration in a full-length tooth root canal has long been a challenge in regenerative endodontics. This is due to the unique root anatomy that allows the blood supply of the tooth root only from a small apical foramen (< 1 mm), leading to a severe barrier for revascularization during pulp regeneration. In this work, we designed a multifunctional peptide-conjugated, pH-sensitive, non-viral gene vector to address this challenge. Our work shows that the peptide-conjugated system was an excellent carrier for fast revascularization and pulp tissue regeneration in a full-length toot root. This study will interest the multidisciplinary readership in gene delivery, biomaterials, and dental/craniofacial tissue engineering community.
Topics: Dental Pulp; Humans; Peptides; Regeneration; Tissue Engineering; Tooth Root
PubMed: 33813092
DOI: 10.1016/j.actbio.2021.03.059 -
Frontiers in Bioscience (Elite Edition) Jan 2011Hard tissue is difficult to repair especially dental structures. Tooth enamel is incapable of self-repairing whereas dentin and cementum can regenerate with limited... (Review)
Review
Hard tissue is difficult to repair especially dental structures. Tooth enamel is incapable of self-repairing whereas dentin and cementum can regenerate with limited capacity. Enamel and dentin are commonly under the attack by caries. Extensive forms of caries destroy enamel and dentin and can lead to dental pulp infection. Entire pulp amputation followed by the pulp space disinfection and filling with an artificial rubber-like material is employed to treat the infection -- commonly known as root canal or endodontic therapy. Regeneration of dentin relies on having vital pulps; however, regeneration of pulp tissue has been difficult as the tissue is encased in dentin without collateral blood supply except from the root apical end. With the advent of modern tissue engineering concept and the discovery of dental stem cells, regeneration of pulp and dentin has been tested. This article will review the recent endeavor on pulp and dentin tissue engineering and regeneration. The prospective outcomes of current advancements and challenges in this line of research are discussed.
Topics: Dental Pulp; Dentin; Humans; Regeneration; Stem Cells; Tissue Engineering
PubMed: 21196351
DOI: 10.2741/e286 -
Matrix Biology : Journal of the... 2016Membrane-type matrix metalloproteinase 1 (MT1-MMP) is a transmembrane zinc-endopeptidase that breaks down extracellular matrix components, including several collagens,...
Membrane-type matrix metalloproteinase 1 (MT1-MMP) is a transmembrane zinc-endopeptidase that breaks down extracellular matrix components, including several collagens, during tissue development and physiological remodeling. MT1-MMP-deficient mice (MT1-MMP(-/-)) feature severe defects in connective tissues, such as impaired growth, osteopenia, fibrosis, and conspicuous loss of molar tooth eruption and root formation. In order to define the functions of MT1-MMP during root formation and tooth eruption, we analyzed the development of teeth and surrounding tissues in the absence of MT1-MMP. In situ hybridization showed that MT1-MMP was widely expressed in cells associated with teeth and surrounding connective tissues during development. Multiple defects in dentoalveolar tissues were associated with loss of MT1-MMP. Root formation was inhibited by defective structure and function of Hertwig's epithelial root sheath (HERS). However, no defect was found in creation of the eruption pathway, suggesting that tooth eruption was hampered by lack of alveolar bone modeling/remodeling coincident with reduced periodontal ligament (PDL) formation and integration with the alveolar bone. Additionally, we identified a significant defect in dentin formation and mineralization associated with the loss of MT1-MMP. To segregate these multiple defects and trace their cellular origin, conditional ablation of MT1-MMP was performed in epithelia and mesenchyme. Mice featuring selective loss of MT1-MMP activity in the epithelium were indistinguishable from wild type mice, and importantly, featured a normal HERS structure and molar eruption. In contrast, selective knock-out of MT1-MMP in Osterix-expressing mesenchymal cells, including osteoblasts and odontoblasts, recapitulated major defects from the global knock-out including altered HERS structure, short roots, defective dentin formation and mineralization, and reduced alveolar bone formation, although molars were able to erupt. These data indicate that MT1-MMP activity in the dental mesenchyme, and not in epithelial-derived HERS, is essential for proper tooth root formation and eruption. In summary, our studies point to an indispensable role for MT1-MMP-mediated matrix remodeling in tooth eruption through effects on bone formation, soft tissue remodeling and organization of the follicle/PDL region.
Topics: Animals; Dentinogenesis; Gene Expression Regulation, Developmental; Gene Knockout Techniques; Matrix Metalloproteinase 14; Mesoderm; Mice; Mutation; Tissue Distribution; Tooth Eruption; Tooth Root
PubMed: 26780723
DOI: 10.1016/j.matbio.2016.01.002 -
Caries Research 2022While the ultrastructure of the enamel pellicle and its erosion protective properties are well studied, the dentin pellicle is still neglected in dental research....
While the ultrastructure of the enamel pellicle and its erosion protective properties are well studied, the dentin pellicle is still neglected in dental research. Therefore, the ultrastructure and erosion protective properties of a pellicle formed on bovine dentin specimens were investigated in the present study. The dentin pellicle was formed in situ for 3, 30, 120, and 360 min at buccal or palatal oral sites of 3 subjects and analyzed by transmission electron microscopy. In order to clarify the impact of an erosive challenge to the ultrastructure of the pellicle and the underlying dentin, specimens were exposed to the oral cavity and eroded in vivo with 0.1% or 1% citric acid either immediately or after 30 min of pellicle formation. Specimens that were eroded without exposure to the oral cavity served as control. In another trial, specimens with a 30-min pellicle were exposed to the oral cavity for a further 60 min after the erosive challenge to investigate the effect of saliva on the impaired pellicle and dentin. Transmission electron micrographs reveal a globular and granular structured pellicle layer, which was thicker when the pellicle was formed buccally or with longer formation times. Erosion with citric acid reduced the thickness of the pellicle and interrupted its continuity. The dentin was also affected by erosion, which was represented by a lower electron density and formation of demineralized lacunae. These were infiltrated by a granular structured material when specimens were exposed to the oral cavity. After further intraoral exposure, the infiltration was more pronounced, indicating a significant impact of saliva on the demineralized dentin. A reformation of the dentin pellicle on the other hand did not occur. In conclusion, the dentin pellicle is neither acid-resistant nor able to effectively protect dentin from erosion.
Topics: Humans; Cattle; Animals; Dental Enamel; Dental Pellicle; Tooth Erosion; Citric Acid; Dentin
PubMed: 36310018
DOI: 10.1159/000527775 -
Journal of the Indian Society of... 2022This study aimed to systematically review available literature of in vitro studies on apical extrusion of debris through rotary instrumentation in comparison to manual... (Review)
Review
AIM
This study aimed to systematically review available literature of in vitro studies on apical extrusion of debris through rotary instrumentation in comparison to manual instrumentation in pediatric endodontics, and also to perform a comparison between various rotary instrumentation systems for assessment of debris extrusion.
MATERIALS AND METHODS
A comprehensive search was conducted on PubMed, Medline, Cochrane Library, Embase, Scopus, and Google Scholar without any language restriction and year of publication. A planned search strategy was made for PubMed and applied to other databases. After full-text reading, 7 articles were selected for quantitative synthesis. Modified CONSORT checklist of items for reporting in vitro studies of dental materials was used for quality assessment of included studies.
RESULTS
Root canal preparation with rotary instrumentation led to lesser apical debris extrusion than manual instrumentation. Self-adjusting file system was associated with the least debris extrusion among all included studies, followed by ProTaper Next, Kedo-S, ProTaper, K3, Mtwo, Revo-S, and Wave One.
CONCLUSION
More apical debris extrusion was seen with manual instrumentation than rotary instrumentation. Furtrhermore, variance in debris extrusion was seen with different rotary file systems.
Topics: Child; Dental Pulp Cavity; Humans; Root Canal Preparation; Tooth Apex; Tooth, Deciduous
PubMed: 35439877
DOI: 10.4103/jisppd.jisppd_298_21 -
Acta Biomaterialia Jul 2012The prevention and treatment of dental caries are major challenges occurring in dentistry. The foundations for modern management of this dental disease, estimated to... (Review)
Review
The prevention and treatment of dental caries are major challenges occurring in dentistry. The foundations for modern management of this dental disease, estimated to affect 90% of adults in Western countries, rest upon the dependence of ultrafine interactions between synthetic polymeric biomaterials and nanostructured supramolecular assemblies that compose the tooth organic substrate. Research has shown, however, that this interaction imposes less than desirable long-term prospects for current resin-based dental restorations. Here we review progress in the identification of the nanostructural organization of the organic matrix of dentin, the largest component of the tooth structure, and highlight aspects relevant to understating the interaction of restorative biomaterials with the dentin substrate. We offer novel insights into the influence of the hierarchically assembled supramolecular structure of dentin collagen fibrils and their structural dependence on water molecules. Secondly, we review recent evidence for the participation of proteoglycans in composing the dentin organic network. Finally, we discuss the relation of these complexly assembled nanostructures with the protease degradative processes driving the low durability of current resin-based dental restorations. We argue in favour of the structural limitations that these complexly organized and inherently hydrated organic structures may impose on the clinical prospects of current hydrophobic and hydrolyzable dental polymers that establish ultrafine contact with the tooth substrate.
Topics: Adhesiveness; Animals; Biocompatible Materials; Dental Restoration Repair; Dentin; Extracellular Matrix; Humans; Nanoparticles
PubMed: 22414619
DOI: 10.1016/j.actbio.2012.02.022 -
BMC Oral Health Jun 2021The concept of instrumentation beyond the apical foramen by small flexible file to prevent apical blockage is apical patency. However, this procedure might endow... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
The concept of instrumentation beyond the apical foramen by small flexible file to prevent apical blockage is apical patency. However, this procedure might endow postoperative pain, thus to maintain apical patency or not is the matter of dilemma. Hence, the primary objective of this study was to compare postoperative pain between apical patency and non-patency groups and secondary objective was to evaluate the influence of number of visits, vitality of teeth, group of teeth and preoperative pain on post-operative pain.
METHODS
Preselected (n = 178) patients based on group of teeth and status of pulp were randomly divided into 2 groups, apical patency and non-patency which was further treated in either single or multiple visits. After exclusion, 160 patients were included. Each group (n = 80) was subdivided in single visit (n = 40) and multiple visits (n = 40), including vital (n = 20) and non-vital teeth (n = 20) and single-rooted (n = 10) and multiple-rooted teeth (n = 10). Apical patency was maintained with a size 10 K-file during conventional hand filing step-back shaping procedure. Intensity of pain was recorded before treatment and on days 1, 2, and 7 after treatment using Numerical Rating Scale (NRS-11). Statistical analysis was done using Mann-Whitney U test, Spearman correlation and Multiple linear regression analysis.
RESULTS
The primary outcome of this study showed statistically significant difference (p < 0.05) in postoperative pain scores between patency and non-patency groups with higher pain scores in patency group on 1st, 2nd and 7th day follow up. The secondary outcome showed postoperative pain in patency-maintained group was influenced by status of the pulp and preoperative pain only. Vital teeth of patency-maintained group treated in multiple visits showed statistically significant (p = 0.02) post-operative pain in day 1 follow up. Pre-operative pain showed positive correlation with postoperative pain with statistically significant difference.
CONCLUSIONS
Our study concluded that maintenance of apical patency increased postoperative pain. Evaluation of influence of number of visits, status of pulp, group of tooth and preoperative pain revealed status of pulp and preoperative pain as influencing factors for postoperative pain in patency group.
Topics: Dental Pulp; Dental Pulp Necrosis; Humans; Pain, Postoperative; Root Canal Therapy; Tooth Apex
PubMed: 34078331
DOI: 10.1186/s12903-021-01632-x -
Medicina Oral, Patologia Oral Y Cirugia... Mar 2021The caveolin-1 protein (structural component of membrane caveolae) plays important roles in several biological functions, such as endocytosis, cell adhesion, and cell...
BACKGROUND
The caveolin-1 protein (structural component of membrane caveolae) plays important roles in several biological functions, such as endocytosis, cell adhesion, and cell signaling. However, this protein has been associated with mechanisms of tumorigenesis in several neoplasms. The expression patterns and roles of caveolin-1 in the oral epithelium and in embryonic and odontogenic tumor tissues are still unclear.
MATERIAL AND METHODS
The expression of caveolin-1 was evaluated in samples of the normal gingival epithelium (n=7), human tooth germ (TG) (n=12), ameloblastoma (AM) (n=83), and ameloblastic carcinoma (AC) (n=9) by immunohistochemistry. Additionally, AM samples were analyzed by qRT-PCR and Western blot.
RESULTS
Most TG (91.7%), AM (73.5%) and AC (100%) samples showed diverse patterns of immunohistochemical positivity for caveolin-1, while only one gingival sample was positive. The transcript levels of cav-1 were significantly upregulated by 14.9-fold in AM tissue (P = 0.0014) compared to those in normal gingival epithelial tissue, as shown by qRT-PCR. Presence of caveolin-1 protein was confirmed by Western blot analysis. The caveolin-1 immunoexpression patterns throughout the stages of TG show its importance during odontogenesis.
CONCLUSIONS
The overexpression of caveolin-1 in AM and AC compared to its expression in normal gingival epithelium (adult tissue) suggests a possible role of caveolin-1 in protumoral events, but due to the similar immunoexpression observed in AM and AC, caveolin-1 may not necessarily participate in the malignant transformation process. However, future studies are needed to clarify and confirm these hypotheses.
Topics: Adult; Ameloblastoma; Carcinoma; Caveolin 1; Humans; Odontogenic Tumors; Tooth Germ
PubMed: 33037799
DOI: 10.4317/medoral.24151