1
|
Vidal CMP, Carrilho MR. Dentin Degradation: From Tissue Breakdown to Possibilities for Therapeutic Intervention. CURRENT ORAL HEALTH REPORTS 2023; 10:99-110. [PMID: 37928132 PMCID: PMC10624336 DOI: 10.1007/s40496-023-00341-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/09/2023] [Indexed: 11/07/2023]
Abstract
Purpose of the Review Presently, dental materials science is driven by the search for new and improved materials that can trigger specific reactions from the affected tissue to stimulate repair or regeneration while interacting with the oral environment to promote or maintain oral health. In parallel, evidence from the past decades has challenged the exclusive role of bacteria in dentin tissue degradation in caries, questioning our understanding of caries etiopathogenesis. The goal of this review is to recapitulate the current evidence on the host and bacterial contributions to degradation, inflammation, and repair of the dentin-pulp complex in caries. Recent Findings Contrasting findings attribute dentin breakdown to the activity of endogenous enzymes, such as matrix metalloproteinases (MMPs) and cathepsins, while the role of bacteria and their by-products in the destruction of dentin organic matrix and pulp inflammation has been for decades supported as an incontestable paradigm. Aiming to better understand the mechanisms involved in collagen degradation by host enzymes in caries, studies have showed that these proteinases are expressed in the mature dentin (i.e., after dentin formation) and become activated by the low pH in the acidic environment resulted by bacterial metabolism in caries. However, different host sources other than dentin-bound proteinases seem to also contribute to caries progression, such as saliva and pulp. Interestingly, studies evaluating pulp responses to bacteria invasion and inflammation in caries report higher levels of MMPs and cathepsins in inflamed tissue, but also showed MMP potential to resolve inflammation and stimulate wound healing. Notably, as reported for other tissues, MMPs exert dual roles in the dentin-pulp complex in caries, participating or regulating both degradative and reparative mechanisms. Summary The specific roles of host and bacteria and their by-products in caries progression have yet to be clarified. The complex interactions between inflammation and repair in caries pose challenges to a clear understanding of the dentin-pulp complex responses and changes to bacteria invasion. However, it opens new venues for the development of novel therapies and dental biomaterials based on the modulation of specific mechanisms to favor tissue repair and healing.
Collapse
Affiliation(s)
- Cristina M. P. Vidal
- Department of Operative Dentistry, College of Dentistry, The University of Iowa, 801 Newton Road, DSB S245, Iowa City, IA 52242, USA
| | | |
Collapse
|
2
|
Toledano M, Osorio E, Osorio MT, Aguilera FS, Toledano R, Romero EF, Osorio R. Dexamethasone-doped nanoparticles improve mineralization, crystallinity and collagen structure of human dentin. J Dent 2023; 130:104447. [PMID: 36754111 DOI: 10.1016/j.jdent.2023.104447] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 02/01/2023] [Accepted: 02/04/2023] [Indexed: 02/09/2023] Open
Abstract
OBJECTIVES Bioactive materials have been used for functionalization of adhesives to promote dentin remineralization. This study aims to evaluate bonding ability and both mechanical and chemical behavior of demineralized dentin infiltrated with polymeric nanoparticles doped with dexamethasone (Dex-NPs). METHODS Dentin conditioned surfaces were infiltrated with NPs, Dex-NPs or Dex-Zn-NPs. Bonded interfaces were also created and stored for 24 h or 21d, and then submitted to microtensile bond strength testing. Dentin remineralization was analyzed by Nanohardness, Young's modulus and Raman analysis. RESULTS At 21d of storage, dentin treated with undoped-NPs attained the lowest nanohardness and Young's modulus. Dex-NPs and Zn-Dex-NPs increased dentin nanohardness and Young's modulus after 21d Raman analysis showed high remineralization, crystallinity, crosslinking and better structure of collagen when functionalized Dex-NPs were present at the dentin interface. CONCLUSIONS Infiltration of dentin with Dex-NPs promoted functional remineralization as proved by nanomechanical and morpho-chemical evaluation tests. Dexamethasone in dentin facilitated crystallographic maturity, crystallinity and improved maturity and secondary structure of dentin collagen. CLINICAL SIGNIFICANCE Using dexamethasone-functionalized NPs before resin infiltration is a clear option to obtain dentin remineralization, as these NPs produce the reinforcement of the dentin structure, which will lead to the improvement of the longevity of resin restorations.
Collapse
Affiliation(s)
- Manuel Toledano
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - Estrella Osorio
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - María T Osorio
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - Fátima S Aguilera
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain.
| | - Raquel Toledano
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - Enrique Fernández- Romero
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - Raquel Osorio
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| |
Collapse
|
3
|
Abstract
Fibromodulin (FMOD) is an archetypal member of the class II small leucine-rich proteoglycan family. By directly binding to extracellular matrix structural components, such as collagen and lysyl oxidase, FMOD regulates collagen cross-linking, packing, assembly, and fibril architecture via a multivalent interaction. Meanwhile, as a pluripotent molecule, FMOD acts as a ligand of various cytokines and growth factors, especially those belonging to the transforming growth factor (TGF) β superfamily, by interacting with the corresponding signaling molecules involved in cell adhesion, spreading, proliferation, migration, invasion, differentiation, and metastasis. Consequently, FMOD exhibits promigratory, proangiogenic, anti-inflammatory, and antifibrogenic properties and plays essential roles in cell fate determination and maturation, progenitor cell recruitment, and tissue regeneration. The multifunctional nature of FMOD thus enables it to be a promising therapeutic agent for a broad repertoire of diseases, including but not limited to arthritis, temporomandibular joint disorders, caries, and fibrotic diseases among different organs, as well as to be a regenerative medicine candidate for skin, muscle, and tendon injuries. Moreover, FMOD is also considered a marker for tumor diagnosis and prognosis prediction and a potential target for cancer treatment. Furthermore, FMOD itself is sufficient to reprogram somatic cells into a multipotent state, creating a safe and efficient cell source for various tissue reconstructions and thus opening a new avenue for regenerative medicine. This review focuses on the recent preclinical efforts bringing FMOD research and therapies to the forefront. In addition, a contemporary understanding of the mechanism underlying FMOD's function, particularly its interaction with TGFβ superfamily members, is also discussed at the molecular level to aid the discovery of novel FMOD-based treatments.
Collapse
Affiliation(s)
- Z. Zheng
- David Geffen School of Medicine,
University of California, Los Angeles, CA, USA
- School of Dentistry, University of
California, Los Angeles, CA, USA
| | - H.S. Granado
- Department of Orthodontics, School of
Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - C. Li
- Department of Orthodontics, School of
Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
4
|
Yuan H, Suzuki S, Terui H, Hirata-Tsuchiya S, Nemoto E, Yamasaki K, Saito M, Shiba H, Aiba S, Yamada S. Loss of IκBζ Drives Dentin Formation via Altered H3K4me3 Status. J Dent Res 2022; 101:951-961. [PMID: 35193410 DOI: 10.1177/00220345221075968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Enforced enrichment of the active promoter marks trimethylation of histone H3 lysine 4 (H3K4me3) and acetylation of histone H3 lysine 27 (H3K27ac) by inhibiting histone demethylases and deacetylases is positively associated with hard tissue formation through the induction of osteo/odontogenic differentiation. However, the key endogenous epigenetic modulator of odontoblasts to regulate the expression of genes coding dentin extracellular matrix (ECM) proteins has not been identified. We focused on nuclear factor (NF)-κB inhibitor ζ (IκBζ), which was originally identified as the transcriptional regulator of NF-κB and recently regarded as the NF-κB-independent epigenetic modulator, and found that IκBζ null mice exhibit a thicker dentin width and narrower pulp chamber, with aged mice having more marked phenotypes. At 6 mo of age, dentin fluorescent labeling revealed significantly accelerated dentin synthesis in the incisors of IκBζ null mice. In the molars of IκBζ null mice, marked tertiary dentin formation adjacent to the pulp horn was observed. Mechanistically, the expression of COL1A2 and COL1A1 collagen genes increased more in the odontoblast-rich fraction of IκBζ null mice than in wild type in vivo, similar to human odontoblast-like cells transfected with small interfering RNA for IκBζ compared with cells transfected with control siRNA in vitro. Furthermore, the direct binding of IκBζ to the COL1A2 promoter suppressed COL1A2 expression and the local active chromatin status marked by H3K4me3. Based on whole-genome identification of H3K4me3 enrichment, ECM and ECM organization-related gene loci were selectively activated by the knockdown of IκBζ, which consistently resulted in the upregulation of these genes. Collectively, this study suggested that IκBζ is the key negative regulator of dentin formation in odontoblasts by inhibiting dentin ECM- and ECM organization-related gene expression through an altered local chromatin status marked by H3K4me3. Therefore, IκBζ is a potential target for epigenetically improving the clinical outcomes of dentin regeneration therapies such as pulp capping.
Collapse
Affiliation(s)
- H Yuan
- Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - S Suzuki
- Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - H Terui
- Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - S Hirata-Tsuchiya
- Department of Biological Endodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - E Nemoto
- Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - K Yamasaki
- Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - M Saito
- Department of Restorative Dentistry, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - H Shiba
- Department of Biological Endodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - S Aiba
- Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - S Yamada
- Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai, Japan
| |
Collapse
|
5
|
FONSÊCA JM, MARTINS MD, VARGAS PA, SILVA WG, NORMANDO AGC, PALMIER NR, RIBEIRO ACP, BRANDÃO TB, LOPES MA, GOES MFD, SANTOS-SILVA AR. Preservation of immunoexpression of type I collagen, BSP and BMP4 in the dentin-pulp complex of head and neck cancer patients after radiotherapy. Braz Oral Res 2022; 36:e012. [DOI: 10.1590/1807-3107bor-2022.vol36.0012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 07/14/2021] [Indexed: 11/22/2022] Open
|
6
|
Sadyrin E, Swain M, Mitrin B, Rzhepakovsky I, Nikolaev A, Irkha V, Yogina D, Lyanguzov N, Maksyukov S, Aizikovich S. Characterization of Enamel and Dentine about a White Spot Lesion: Mechanical Properties, Mineral Density, Microstructure and Molecular Composition. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E1889. [PMID: 32967152 PMCID: PMC7560001 DOI: 10.3390/nano10091889] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/10/2020] [Accepted: 09/17/2020] [Indexed: 11/17/2022]
Abstract
The study focuses on in vitro tracing of some fundamental changes that emerge in teeth at the initial stage of caries development using multiple approaches. The research was conducted on a mostly sound maxillary molar tooth but with a clearly visible natural proximal white spot lesion (WSL). Values of mineral density, reduced Young's modulus, indentation hardness and creep as well as the molecular composition and surface microstructure of the WSL and bordering dentine area were studied. The results obtained were compared to those of sound enamel and dentine on the same tooth. A decrease of mechanical properties and mineral density both for the WSL and bordering dentine was detected in comparison to the sound counterparts, as well as increase of creep for the enamel WSL. Differences in molecular composition and surface microstructure (including the indenter impressions) were found and described. WSL induces a serious change in the state of not only the visually affected enamel but also surrounding visually intact enamel and dentine in its vicinity. The results provide the basis for future studies of efficacy of minimal invasive treatments of caries.
Collapse
Affiliation(s)
- Evgeniy Sadyrin
- Research and Education Center “Materials”, Don State Technical University, Gagarin Square 1, 344000 Rostov-on-Don, Russia; (M.S.); (B.M.); (A.N.); (V.I.); (S.A.)
| | - Michael Swain
- Research and Education Center “Materials”, Don State Technical University, Gagarin Square 1, 344000 Rostov-on-Don, Russia; (M.S.); (B.M.); (A.N.); (V.I.); (S.A.)
- Biomaterials and Bioengineering department, Faculty of Dentistry, The University of Sydney, Camperdown, Sydney NSW 2006, Australia
| | - Boris Mitrin
- Research and Education Center “Materials”, Don State Technical University, Gagarin Square 1, 344000 Rostov-on-Don, Russia; (M.S.); (B.M.); (A.N.); (V.I.); (S.A.)
| | - Igor Rzhepakovsky
- Institute of Life Sciences, North Caucasus Federal University, Pushkin Street 1, 355009 Stavropol, Russia;
| | - Andrey Nikolaev
- Research and Education Center “Materials”, Don State Technical University, Gagarin Square 1, 344000 Rostov-on-Don, Russia; (M.S.); (B.M.); (A.N.); (V.I.); (S.A.)
| | - Vladimir Irkha
- Research and Education Center “Materials”, Don State Technical University, Gagarin Square 1, 344000 Rostov-on-Don, Russia; (M.S.); (B.M.); (A.N.); (V.I.); (S.A.)
- Federal Research Centre The Southern Scientific Centre of the Russian Academy of The Sciences, Chehova Street 41, 344006 Rostov-on-Don, Russia
| | - Diana Yogina
- Department of dentistry, Rostov State Medical University, Nakhichevansky Lane 29, 344022 Rostov-on-Don, Russia; (D.Y.); (S.M.)
| | - Nikolay Lyanguzov
- Faculty of Physics, Southern Federal University, Bolshaya Sadovaya Street 105/42, 344090 Rostov-on-Don, Russia;
| | - Stanislav Maksyukov
- Department of dentistry, Rostov State Medical University, Nakhichevansky Lane 29, 344022 Rostov-on-Don, Russia; (D.Y.); (S.M.)
| | - Sergei Aizikovich
- Research and Education Center “Materials”, Don State Technical University, Gagarin Square 1, 344000 Rostov-on-Don, Russia; (M.S.); (B.M.); (A.N.); (V.I.); (S.A.)
| |
Collapse
|
7
|
Horsophonphong S, Sercia A, França CM, Tahayeri A, Reddy AP, Wilmarth PA, Surarit R, Smith AJ, Ferracane JL, Bertassoni LE. Equivalence of human and bovine dentin matrix molecules for dental pulp regeneration: proteomic analysis and biological function. Arch Oral Biol 2020; 119:104888. [PMID: 32932150 DOI: 10.1016/j.archoralbio.2020.104888] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 08/13/2020] [Accepted: 08/21/2020] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To compare proteomics and biological function of human dentin matrix molecules (hDMMs) and bovine dentin matrix molecules (bDMMs). DESIGN Dentin powder from human or bovine teeth (n = 4) was demineralized in 10% (v/v) ethylenediaminetetraacetic acid for 7 days. The extracts were dialyzed, lyophilized and proteins were characterized using liquid chromatography-tandem mass spectrometry and shotgun proteomic analysis. To study biological function, mouse-derived undifferentiated dental pulp cells (OD21) were treated with 0.01, 0.1 or 1 μg/mL of hDMMs or bDMMs and proliferation was measured after 24 hours and 48 hours using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell migration was assessed after 24 hours using a Boyden chamber. Alizarin Red S staining was used to evaluate mineral formation. RESULTS There were 307 proteins identified, of which 93 proteins were common to both species. Gene Ontology functional analysis demonstrated similar pattern of biological process in both species which consisted mainly of tissue development and biomineralization. hDMMs and bDMMs both enhanced cell proliferation. After 24 hours, all concentrations of bDMMs promoted cell proliferation (p ≤ 0.05), while hDMMs did not affect proliferation. After 48 hours, groups with 1μg/mL of bDMMs and 0.01μg/mL of hDMMs had increased cell proliferation compared to control (p ≤ 0.0001). All concentrations of hDMMs and bDMMs enhanced cell migration and mineralization (p ≤ 0.0001). CONCLUSION bDMMs has similar biological functions as hDMMs. Moreover, bDMMs stimulated cell proliferation, migration and differentiation similar to hDMMs.
Collapse
Affiliation(s)
- Sivaporn Horsophonphong
- Division of Biomaterials and Biomechanics, Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA; Department of Oral Biology, Faculty of Dentistry, Mahidol University, Bangkok, Thailand; Department of Pediatric Dentistry, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
| | - Ashley Sercia
- Division of Biomaterials and Biomechanics, Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - Cristiane M França
- Division of Biomaterials and Biomechanics, Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - Anthony Tahayeri
- Division of Biomaterials and Biomechanics, Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - Ashok P Reddy
- Proteomics Shared Resource, Oregon Health and & Science University, Portland, OR, 97239, USA
| | - Phillip A Wilmarth
- Proteomics Shared Resource, Oregon Health and & Science University, Portland, OR, 97239, USA
| | - Rudee Surarit
- Department of Oral Biology, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
| | - Anthony J Smith
- School of Dentistry, University of Birmingham, Birmingham, UK
| | - Jack L Ferracane
- Division of Biomaterials and Biomechanics, Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - Luiz E Bertassoni
- Division of Biomaterials and Biomechanics, Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA; Center for Regenerative Medicine, School of Medicine, Oregon Health & Science University, Portland, OR, USA; Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, OR, USA; Cancer Early Detection Advanced Research Center (CEDAR), Knight Cancer Institute, Portland, OR, USA.
| |
Collapse
|
8
|
Glycosaminoglycans accelerate biomimetic collagen mineralization in a tissue-based in vitro model. Proc Natl Acad Sci U S A 2020; 117:12636-12642. [PMID: 32461359 DOI: 10.1073/pnas.1914899117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mammalian teeth are attached to the jawbone through an exquisitely controlled mineralization process: unmineralized collagen fibers of the periodontal ligament anchor directly into the outer layer of adjoining mineralized tissues (cementum and bone). The sharp interface between mineralized and nonmineralized collagenous tissues makes this an excellent model to study the mechanisms by which extracellular matrix macromolecules control collagen mineralization. While acidic phosphoproteins, localized in the mineralized tissues, play key roles in control of mineralization, the role of glycosaminoglycans (GAGs) is less clear. As several proteoglycans are found only in the periodontal ligament, it has been hypothesized that these inhibit mineralization of collagen in this tissue. Here we used an in vitro model based on remineralization of mouse dental tissues to determine the role of matrix GAGs in control of mineralization. GAGs were selectively removed from demineralized mouse periodontal sections via enzymatic digestion. Proteomic analysis confirmed that enzymatic GAG removal does not significantly alter protein content. Analysis of remineralized tissue sections by transmission electron microscopy (TEM) shows that GAG removal reduced the rate of remineralization in mineralized tissues compared to the untreated control, while the ligament remained unmineralized. Protein removal with trypsin also reduced the rate of mineralization, but to a lesser extent than GAG removal, despite a much larger effect on protein content. These results indicate that GAGs promote mineralization in mineralized dental tissues rather than inhibiting mineral formation in the ligament, which may have broader implications for understanding control of collagen mineralization in connective tissues.
Collapse
|
9
|
Alania Y, Creighton J, Trevelin LT, Zamperini CA, Bedran-Russo AK. Regional contribution of proteoglycans to the fracture toughness of the dentin extracellular matrix. J Biomech 2020; 101:109633. [PMID: 32035660 DOI: 10.1016/j.jbiomech.2020.109633] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 01/06/2020] [Accepted: 01/12/2020] [Indexed: 12/11/2022]
Abstract
This study investigated the contribution of small leucine rich proteoglycans (SLRPs) to the fracture toughness of the dentin extracellular matrix (ECM) by enzymatically-assisted selective removal of glycosaminoglycan chains (GAGs) and proteoglycans (PGs) core protein. We adapted the Mode III trouser tear test to evaluate the energy required to tear the dentin ECM. Trouser-shaped dentin specimens from crown and root were demineralized. Depletion of GAGs and PGs followed enzymatic digestion using chondroitinase ABC (c-ABC) and matrix metalloproteinase 3 (MMP-3), respectively. The legs from specimen were stretched under tensile force and the load at tear propagation was determined to calculate the tear energy (T, kJ/m2). SLRPs decorin and biglycan were visualized by immunohistochemistry and ECM tear pattern was analyzed in SEM. Results showed T of crown ECM was not affected by PGs/GAGs depletion (p = 0.799), whereas the removal of PGs significantly reduced T in root dentin ECM (p = 0.001). Root dentin ECM exhibited higher T than crown (p < 0.03), however no regional difference are present after PG depletion (p = 0.480). Immunohistochemistry confirmed removal of GAGs and PGs. SEM images showed structural modifications after PGs/GAGs removal such as enlargement of dentinal tubules, increased interfibrillar spaces and presence of untwisted fibrils with increased diameter. Findings indicate that the capacity of the PGs to unfold and untwist contribute to the dentin ECM resistance to tear, possibly influencing crack growth propagation. The regional differences are likely an evolutionary design to increase tooth survival, that undergoes repetitive mechanical loading and load stress dissipation over a lifetime of an individual.
Collapse
Affiliation(s)
- Yvette Alania
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 801 South Paulina St, Chicago, IL 60612, USA
| | - Johnathon Creighton
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 801 South Paulina St, Chicago, IL 60612, USA
| | - Livia T Trevelin
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 801 South Paulina St, Chicago, IL 60612, USA; Department of Restorative Dentistry, School of Dentistry, Municipal University of São Caetano do Sul, Rua Santo Antônio 50, São Caetano do Sul, São Paulo 09521-160, Brazil
| | - Camila A Zamperini
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 801 South Paulina St, Chicago, IL 60612, USA
| | - Ana K Bedran-Russo
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 801 South Paulina St, Chicago, IL 60612, USA.
| |
Collapse
|
10
|
Bertassoni LE. Dentin on the nanoscale: Hierarchical organization, mechanical behavior and bioinspired engineering. Dent Mater 2017; 33:637-649. [PMID: 28416222 PMCID: PMC5481168 DOI: 10.1016/j.dental.2017.03.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 03/09/2017] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Knowledge of the structural organization and mechanical properties of dentin has expanded considerably during the past two decades, especially on a nanometer scale. In this paper, we review the recent literature on the nanostructural and nanomechanical properties of dentin, with special emphasis in its hierarchical organization. METHODS We give particular attention to the recent literature concerning the structural and mechanical influence of collagen intrafibrillar and extrafibrillar mineral in healthy and remineralized tissues. The multilevel hierarchical structure of collagen, and the participation of non-collagenous proteins and proteoglycans in healthy and diseased dentin are also discussed. Furthermore, we provide a forward-looking perspective of emerging topics in biomaterials sciences, such as bioinspired materials design and fabrication, 3D bioprinting and microfabrication, and briefly discuss recent developments on the emerging field of organs-on-a-chip. RESULTS The existing literature suggests that both the inorganic and organic nanostructural components of the dentin matrix play a critical role in various mechanisms that influence tissue properties. SIGNIFICANCE An in-depth understanding of such nanostructural and nanomechanical mechanisms can have a direct impact in our ability to evaluate and predict the efficacy of dental materials. This knowledge will pave the way for the development of improved dental materials and treatment strategies. CONCLUSIONS Development of future dental materials should take into consideration the intricate hierarchical organization of dentin, and pay particular attention to their complex interaction with the dentin matrix on a nanometer scale.
Collapse
Affiliation(s)
- Luiz E Bertassoni
- Division of Biomaterials and Biomechanics, Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, USA; Center for Regenerative Medicine, Oregon Health and Science University, School of Medicine, Portland, OR, USA; Department of Biomedical Engineering, Oregon Health and Science University, School of Medicine, Portland, OR, USA.
| |
Collapse
|