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Nicklisch N, Hinrichs C, Palaske L, Vach W, Alt KW. Variability in human tooth cementum thickness reflecting functional processes. J Periodontal Res 2024; 59:408-419. [PMID: 38126232 DOI: 10.1111/jre.13226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 11/19/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023]
Abstract
OBJECTIVE The aim of this study was to investigate the thickness of acellular extrinsic fibre cementum (AEFC) at four root positions of anterior and posterior teeth with special focus on functional aspects. Furthermore, the correlations between cementum thickness and chronological age and sex are investigated. BACKGROUND While numerous studies confirm continuous cementum apposition with age, masticatory forces as well as physiological and orthodontically induced tooth movements also have the potential to affect tooth cementum thickness. MATERIALS AND METHODS Undecalcified teeth were embedded in resin and transverse-sectioned in the cervical third of the root. Two sections per root were selected, and digital images at four positions were obtained (mesial, distal, oral, and vestibular) using light microscopy. The AEFC thickness of 99 teeth (anterior = 66, posterior = 33, male = 54, female = 45) were measured in both sections. The differences in mean values between root positions and the association of root position variation with tooth type, age, sex, and subject as well as the overall effects of age and sex were analysed using a mixed model. RESULTS First incisors and canines showed the greatest mean AFEC thickness, in contrast to premolars which had the lowest values. Differences were found across the four root positions, with a pattern varying considerably between anterior and posterior teeth and between maxilla and mandible in the anterior teeth. An interaction between root position and subject pointed to the existence of an individual component in the variation of AEFC thickness across the four root positions. There was an age trend with an almost linear increase in cementum thickness of 1 μm per year. Overall, females tended to exhibit a significantly lesser AEFC thickness compared to males. CONCLUSIONS Distinct differences in the pattern of thickness values across the four root positions in anterior and posterior teeth support the assumption that the AEFC is strongly affected by functional processes. In addition to sex-specific differences and age-related trends, the root position variation of AEFC thickness varies from individual to individual.
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Affiliation(s)
- Nicole Nicklisch
- Faculty of Medicine and Dentistry, Danube Private University, Krems, Austria
| | | | - Lukas Palaske
- Faculty of Medicine and Dentistry, Danube Private University, Krems, Austria
| | - Werner Vach
- Institute of Prehistory and Archaeological Science, University of Basel, Basel, Switzerland
| | - Kurt W Alt
- Faculty of Medicine and Dentistry, Danube Private University, Krems, Austria
- Institute of Prehistory and Archaeological Science, University of Basel, Basel, Switzerland
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Yang Y, Liu H, Wang R, Zhao Y, Zheng Y, Huang Y, Li W. Autophagy mediates cementoblast mineralization under compression through periostin/β-catenin axis. J Cell Physiol 2023; 238:2147-2160. [PMID: 37475648 DOI: 10.1002/jcp.31075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 06/13/2023] [Accepted: 06/21/2023] [Indexed: 07/22/2023]
Abstract
Repair of orthodontic external root resorption and periodontal tissue dysfunction induced by mechanical force remains a clinical challenge. Cementoblasts are vital in cementum mineralization, a process important for restoring damaged cementum. Despite autophagy plays a role in mineralization under various environmental stimuli, the underlying mechanism of autophagy in mediating cementoblast mineralization remains unclear. Here we verified that murine cementoblasts exhibit compromised mineralization under compressive force. Autophagy was indispensable for cementoblast mineralization, and autophagic activation markedly reversed cementoblast mineralization and prevented cementum damage in mice during tooth movement. Subsequently, messenger RNA sequencing analyses identified periostin (Postn) as a mediator of autophagy and mineralization in cementoblasts. Cementoblast mineralization was significantly inhibited following the knockdown of Postn. Furthermore, Postn silencing suppressed Wnt signaling by modulating the stability of β-catenin. Together our results highlight the role of autophagy in cementoblast mineralization via Postn/β-catenin signaling under compressive force and may provide a new strategy for the remineralization of cementum and regeneration of periodontal tissue.
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Affiliation(s)
- Yuhui Yang
- Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, People's Republic of China
- National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, China
| | - Hao Liu
- Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, People's Republic of China
- National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, China
| | - Ruoxi Wang
- Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, People's Republic of China
- National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, China
| | - Yi Zhao
- Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, People's Republic of China
- National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, China
| | - Yunfei Zheng
- Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, People's Republic of China
- National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, China
| | - Yiping Huang
- Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, People's Republic of China
- National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, China
| | - Weiran Li
- Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, People's Republic of China
- National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, China
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Atarbashi-Moghadam F, Rezai Rad M, Sijanivandi S, Khodayari P, Mahmoum M. Growth Factors in Periodontal Complex Regeneration. Chin J Dent Res 2022; 25:85-92. [PMID: 35686588 DOI: 10.3290/j.cjdr.b3086335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The ultimate goal of periodontal treatments is the regeneration of all lost periodontal tissues including bone, cementum and the periodontal ligament (PDL). Until now, the clinical methods for periodontal regeneration have been associated with significant failure or incomplete success. Various studies have reported the promising effects of growth factors/cytokines on periodontal regeneration. Growth factors/cytokines include proteins or steroid hormones that bind to cellular receptors, known as signalling molecules, and that trigger cellular responses that eventually stimulate cell proliferation and differentiation. The present review aims to provide an overview of the main growth factors that play an important role in and have been used in the regeneration of periodontal components.
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Pérez-Barbería FJ, Guinness FE, López-Quintanilla M, García AJ, Gallego L, Cappelli J, Serrano MP, Landete-Castillejos T. What do rates of deposition of dental cementum tell us? Functional and evolutionary hypotheses in red deer. PLoS One 2020; 15:e0231957. [PMID: 32343718 PMCID: PMC7188284 DOI: 10.1371/journal.pone.0231957] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 04/04/2020] [Indexed: 12/20/2022] Open
Abstract
Cementum is a bone connective tissue that provides a flexible attachment for the tooth to the alveolar bone in many mammalian species. It does not undergo continuous remodelling, unlike non-dental bone, which combined with its growth pattern of seasonal layering makes this tissue uniquely suitable as a proxy for tracking changes in body repair investment throughout an animal´s life. We tested functional and sexual selection hypotheses on the rate of cementum deposition related to the highly polygynous mating strategy of red deer. We used a sample of 156 first lower molars from wild Scottish red deer of known age between 1 and 17 years old, approximately balanced by sex and age class. Cementum deposition on the inter-radicular pad increased with age at a constant average rate of 0.26 mm per year, with no significant differences between sexes. Cementum deposition was independent of (i) tooth wear, other than that associated with age, and (ii) enamel and dentine micro-hardness. The results partially supported the hypothesis that the main function of cementum is the repositioning of the tooth to maintain opposing teeth in occlusion. However, teeth that had more wear or males´ teeth that had faster rates of tooth wear than those of females did not present the expected higher rates of cementum deposition.
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Affiliation(s)
- F. J. Pérez-Barbería
- Game and Livestock Resources Unit, University of Castilla-La Mancha, IDR, IREC, Albacete, Spain
- Wildlife Research Unit UIRCP, Universidad de Córdoba, Córdoba, Spain
| | - F. E. Guinness
- Department of Zoology, Large Animal Research Group, University of Cambridge, Cambridge, United Kingdom
| | - M. López-Quintanilla
- Game and Livestock Resources Unit, University of Castilla-La Mancha, IDR, IREC, Albacete, Spain
| | - A. J. García
- Game and Livestock Resources Unit, University of Castilla-La Mancha, IDR, IREC, Albacete, Spain
| | - L. Gallego
- Game and Livestock Resources Unit, University of Castilla-La Mancha, IDR, IREC, Albacete, Spain
| | - J. Cappelli
- Game and Livestock Resources Unit, University of Castilla-La Mancha, IDR, IREC, Albacete, Spain
| | - M. P. Serrano
- Game and Livestock Resources Unit, University of Castilla-La Mancha, IDR, IREC, Albacete, Spain
| | - T. Landete-Castillejos
- Game and Livestock Resources Unit, University of Castilla-La Mancha, IDR, IREC, Albacete, Spain
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Liu J, Ruan J, Weir MD, Ren K, Schneider A, Wang P, Oates TW, Chang X, Xu HHK. Periodontal Bone-Ligament-Cementum Regeneration via Scaffolds and Stem Cells. Cells 2019; 8:E537. [PMID: 31167434 PMCID: PMC6628570 DOI: 10.3390/cells8060537] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 05/29/2019] [Accepted: 05/29/2019] [Indexed: 12/13/2022] Open
Abstract
Periodontitis is a prevalent infectious disease worldwide, causing the damage of periodontal support tissues, which can eventually lead to tooth loss. The goal of periodontal treatment is to control the infections and reconstruct the structure and function of periodontal tissues including cementum, periodontal ligament (PDL) fibers, and bone. The regeneration of these three types of tissues, including the re-formation of the oriented PDL fibers to be attached firmly to the new cementum and alveolar bone, remains a major challenge. This article represents the first systematic review on the cutting-edge researches on the regeneration of all three types of periodontal tissues and the simultaneous regeneration of the entire bone-PDL-cementum complex, via stem cells, bio-printing, gene therapy, and layered bio-mimetic technologies. This article primarily includes bone regeneration; PDL regeneration; cementum regeneration; endogenous cell-homing and host-mobilized stem cells; 3D bio-printing and generation of the oriented PDL fibers; gene therapy-based approaches for periodontal regeneration; regenerating the bone-PDL-cementum complex via layered materials and cells. These novel developments in stem cell technology and bioactive and bio-mimetic scaffolds are highly promising to substantially enhance the periodontal regeneration including both hard and soft tissues, with applicability to other therapies in the oral and maxillofacial region.
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Affiliation(s)
- Jin Liu
- Key Laboratory of Shannxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an 710004, China.
- Clinical Research Center of Shannxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an 710004, China.
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland Dental School, Baltimore, MD 21201, USA.
| | - Jianping Ruan
- Key Laboratory of Shannxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an 710004, China.
- Clinical Research Center of Shannxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an 710004, China.
| | - Michael D Weir
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland Dental School, Baltimore, MD 21201, USA.
| | - Ke Ren
- Department of Neural and Pain Sciences, School of Dentistry, & Program in Neuroscience, University of Maryland, Baltimore, MD 21201, USA.
| | - Abraham Schneider
- Department of Oncology and Diagnostic Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA.
- Member, Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Ping Wang
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland Dental School, Baltimore, MD 21201, USA.
| | - Thomas W Oates
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland Dental School, Baltimore, MD 21201, USA.
| | - Xiaofeng Chang
- Key Laboratory of Shannxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an 710004, China.
- Clinical Research Center of Shannxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an 710004, China.
| | - Hockin H K Xu
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland Dental School, Baltimore, MD 21201, USA.
- Member, Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
- Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Sprio S, Campodoni E, Sandri M, Preti L, Keppler T, Müller FA, Pugno NM, Tampieri A. A Graded Multifunctional Hybrid Scaffold with Superparamagnetic Ability for Periodontal Regeneration. Int J Mol Sci 2018; 19:E3604. [PMID: 30445700 PMCID: PMC6274723 DOI: 10.3390/ijms19113604] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/07/2018] [Accepted: 11/12/2018] [Indexed: 01/09/2023] Open
Abstract
The regeneration of dental tissues is a still an unmet clinical need; in fact, no therapies have been completely successful in regenerating dental tissue complexes such as periodontium, which is also due to the lack of scaffolds that are able to guide and direct cell fate towards the reconstruction of different mineralized and non-mineralized dental tissues. In this respect, the present work develops a novel multifunctional hybrid scaffold recapitulating the different features of alveolar bone, periodontal ligament, and cementum by integrating the biomineralization process, and tape casting and electrospinning techniques. The scaffold is endowed with a superparamagnetic ability, thanks to the use of a biocompatible, bioactive superparamagnetic apatite phase, as a mineral component that is able to promote osteogenesis and to be activated by remote magnetic signals. The periodontal scaffold was obtained by engineering three different layers, recapitulating the relevant compositional and microstructural features of the target tissues, into a monolithic multifunctional graded device. Physico-chemical, morphological, and ultrastructural analyses, in association with preliminary in vitro investigations carried out with mesenchymal stem cells, confirm that the final scaffold exhibits a good mimicry of the periodontal tissue complex, with excellent cytocompatibility and cell viability, making it very promising for regenerative applications in dentistry.
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Affiliation(s)
- Simone Sprio
- Institute of Science and Technology for Ceramics-National Research Council (ISTEC-CNR), Via Granarolo 64, 48018 Faenza, Italy.
| | - Elisabetta Campodoni
- Institute of Science and Technology for Ceramics-National Research Council (ISTEC-CNR), Via Granarolo 64, 48018 Faenza, Italy.
| | - Monica Sandri
- Institute of Science and Technology for Ceramics-National Research Council (ISTEC-CNR), Via Granarolo 64, 48018 Faenza, Italy.
| | - Lorenzo Preti
- Institute of Science and Technology for Ceramics-National Research Council (ISTEC-CNR), Via Granarolo 64, 48018 Faenza, Italy.
- Laboratory of Bio-Inspired & Graphene Nanomechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, Via Mesiano 77, 38123 Trento, Italy.
| | - Tobias Keppler
- Otto Schott Institute of Materials Research, Friedrich Schiller University, Löbdergraben 32, 07743 Jena, Germany.
| | - Frank A Müller
- Otto Schott Institute of Materials Research, Friedrich Schiller University, Löbdergraben 32, 07743 Jena, Germany.
| | - Nicola M Pugno
- Laboratory of Bio-Inspired & Graphene Nanomechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, Via Mesiano 77, 38123 Trento, Italy.
- School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
- Ket-Lab, Edoardo Amaldi Foundation, Italian Space Agency, Via del Politecnico, 00133 Rome, Italy.
| | - Anna Tampieri
- Institute of Science and Technology for Ceramics-National Research Council (ISTEC-CNR), Via Granarolo 64, 48018 Faenza, Italy.
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Alyahya A, Alqareer A. Does the Removal of Cementum Facilitate Bacterial Penetration into Dentinal Tubules In Vitro? J Endod 2017; 43:1111-1115. [PMID: 28476468 DOI: 10.1016/j.joen.2017.02.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/19/2017] [Accepted: 02/20/2017] [Indexed: 11/17/2022]
Abstract
INTRODUCTION The importance of an intact layer of cementum on the root surface in preventing bacterial penetration into radicular dentin has not been sufficiently investigated. The aim of this in vitro study was to determine the effect of the absence of cementum from the root surface and the length of the infection period (2 or 4 weeks) on the maximum depth of bacterial penetration and the percentage of sectors lined with bacteria. METHODS Sound, single-rooted extracted teeth with closed apices were randomly assigned to either a control group (cementum present [CP]) or an experimental group (cementum removed [CR]). Each group was further divided randomly into 2 subgroups: 2-week infection (CP2 and CR2) and 4-week infection (CP4 and CR4). Teeth were then artificially infected with Enterococcus faecalis and prepared for histology. RESULTS A total of 107 teeth were available for histologic examination, 25 teeth in CP2, 31 teeth in CP4, 27 teeth in CR2, and 24 teeth in CR4. Pairwise comparisons revealed statistically significant differences in the maximum depth of bacterial penetration for the following combinations: CP2-CR2, CP2-CR4, CP4-CR2, and CP4-CR4 (P < .001). Pairwise comparisons also revealed a statistically significant difference in the percentage of sectors lined with bacteria for CP2-CR2, CP2-CP4, and CP2-CR4 (P < .001). CONCLUSIONS The results support the hypothesis that the absence of cementum facilitates bacterial penetration into dentinal tubules. Results also suggest that the process of radicular dentin infection is time dependent and highlight the importance of early treatment of infected teeth, especially in situations in which cementum discontinuity is suspected.
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Affiliation(s)
- Asma Alyahya
- Department of Developmental and Preventive Sciences, Faculty of Dentistry, Kuwait University, Kuwait.
| | - Athbi Alqareer
- Department of Developmental and Preventive Sciences, Faculty of Dentistry, Kuwait University, Kuwait
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Zhang YY, Huang YP, Zhao HX, Zhang T, Chen F, Liu Y. Cementogenesis is inhibited under a mechanical static compressive force via Piezo1. Angle Orthod 2017; 87:618-624. [PMID: 28418701 DOI: 10.2319/110616-799.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVE To investigate whether Piezo1, a mechanotransduction gene mediates the cementogenic activity of cementoblasts under a static mechanical compressive force. MATERIALS AND METHODS Murine cementoblasts (OCCM-30) were exposed to a 2.0 g/cm2 static compressive force for 3, 6, 12, and 24 hours. Then the expression profile of Piezo1 and the cementogenic activity markers osteoprotegerin (Opg), osteopontin (Opn), osteocalcin (Oc), and protein tyrosine phosphataselike member A (Ptpla) were analyzed. Opg, Opn, Oc, and Ptpla expression was further measured after using siRNA to knock down Piezo1. Real-time PCR, Western blot, and cell proliferation assays were performed according to standard procedures. RESULTS After mechanical stimulation, cell morphology and proliferation did not change significantly. The expression of Piezo1, Opg, Opn, Oc, and Ptpla was significantly decreased, with a high positive correlation between Opg and Piezo1 expression. After Piezo1 knockdown, the expression of Opg, Opn, Oc, and Ptpla was further decreased under mechanical stimulation. CONCLUSIONS Cementogenic activity was inhibited in OCCM-30 cells under static mechanical force, a process that was partially mediated by the decrease of Piezo1. This study provides a new viewpoint of the pathogenesis mechanism of orthodontically induced root resorption and repair.
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Abstract
Experimental studies have shown a great potential for periodontal regeneration. The limitations of periodontal regeneration largely depend on the regenerative potential at the root surface. Cellular intrinsic fiber cementum (CIFC), so-called bone-like tissue, may form instead of the desired acellular extrinsic fiber cementum (AEFC), and the interfacial tissue bonding may be weak. The periodontal ligament harbors progenitor cells that can differentiate into periodontal ligament fibroblasts, osteoblasts, and cementoblasts, but their precise location is unknown. It is also not known whether osteoblasts and cementoblasts arise from a common precursor cell line, or whether distinct precursor cell lines exist. Thus, there is limited knowledge about how cell diversity evolves in the space between the developing root and the alveolar bone. This review supports the hypothesis that AEFC is a unique tissue, while CIFC and bone share some similarities. Morphologically, functionally, and biochemically, however, CIFC is distinctly different from any bone type. There are several lines of evidence to propose that cementoblasts that produce both AEFC and CIFC are unique phenotypes that are unrelated to osteoblasts. Cementum attachment protein appears to be cementum-specific, and the expression of two proteoglycans, fibromodulin and lumican, appears to be stronger in CIFC than in bone. A theory is presented that may help explain how cell diversity evolves in the periodontal ligament. It proposes that Hertwig’s epithelial root sheath and cells derived from it play an essential role in the development and maintenance of the periodontium. The role of enamel matrix proteins in cementoblast and osteoblast differentiation and their potential use for tissue engineering are discussed.
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Affiliation(s)
- D D Bosshardt
- Department of Periodontology and Fixed Prosthodontics, School of Dental Medicine, University of Berne, Freiburgstrasse 7, CH-3010 Berne, Switzerland.
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10
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Jang AT, Merkle AP, Fahey KP, Gansky SA, Ho SP. Multiscale biomechanical responses of adapted bone-periodontal ligament-tooth fibrous joints. Bone 2015; 81:196-207. [PMID: 26151121 PMCID: PMC4663099 DOI: 10.1016/j.bone.2015.07.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 07/01/2015] [Accepted: 07/02/2015] [Indexed: 12/31/2022]
Abstract
Reduced functional loads cause adaptations in organs. In this study, temporal adaptations of bone-ligament-tooth fibrous joints to reduced functional loads were mapped using a holistic approach. Systematic studies were performed to evaluate organ-level and tissue-level adaptations in specimens harvested periodically from rats (N=60) given powder food for 6 months over 8,12,16,20, and 24 weeks. Bone-periodontal ligament (PDL)-tooth fibrous joint adaptation was evaluated by comparing changes in joint stiffness with changes in functional space between the tooth and alveolar bony socket. Adaptations in tissues included mapping changes in the PDL and bone architecture as observed from collagen birefringence, bone hardness and volume fraction in rats fed soft foods (soft diet, SD) compared to those fed hard pellets as a routine diet (hard diet, HD). In situ biomechanical testing on harvested fibrous joints revealed increased stiffness in SD groups (SD:239-605 N/mm) (p<0.05) at 8 and 12 weeks. Increased joint stiffness in early development phase was due to decreased functional space (at 8 weeks change in functional space was -33 μm, at 12 weeks change in functional space was -30 μm) and shifts in tissue quality as highlighted by birefringence, architecture and hardness. These physical changes were not observed in joints that were well into function, that is, in rodents older than 12 weeks of age. Significant adaptations in older groups were highlighted by shifts in bone growth (bone volume fraction 24 weeks: Δ-0.06) and bone hardness (8 weeks: Δ-0.04 GPa, 16 weeks: Δ-0.07 GPa, 24 weeks: Δ-0.06 GPa). The response rate (N/s) of joints to mechanical loads decreased in SD groups. Results from the study showed that joint adaptation depended on age. The initial form-related adaptation (observed change in functional space) can challenge strain-adaptive nature of tissues to meet functional demands with increasing age into adulthood. The coupled effect between functional space in the bone-PDL-tooth complex and strain-adaptive nature of tissues is necessary to accommodate functional demands, and is temporally sensitive despite joint malfunction. From an applied science perspective, we propose that adaptations are registered as functional history in tissues and joints.
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Affiliation(s)
- Andrew T Jang
- Division of Biomaterials and Bioengineering, Department of Preventive and Restorative Dental Sciences, University of California San Francisco, CA 94143, United States
| | - Arno P Merkle
- Carl Zeiss X-ray Microscopy, Inc., 4385 Hopyard Road, Suite 100, Pleasanton, CA 94588, United States
| | - Kevin P Fahey
- Carl Zeiss X-ray Microscopy, Inc., 4385 Hopyard Road, Suite 100, Pleasanton, CA 94588, United States
| | - Stuart A Gansky
- Division of Oral Epidemiology & Dental Public Health, Department of Preventive and Restorative Dental Sciences, University of California San Francisco, CA 94143, United States
| | - Sunita P Ho
- Division of Biomaterials and Bioengineering, Department of Preventive and Restorative Dental Sciences, University of California San Francisco, CA 94143, United States.
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11
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Bartold PM, McCulloch CA. Information generation and processing systems that regulate periodontal structure and function. Periodontol 2000 2015; 63:7-13. [PMID: 23931050 DOI: 10.1111/prd.12037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2013] [Indexed: 01/16/2023]
Abstract
The periodontium is a very dynamic organ that responds rapidly to mechanical and chemical stimuli. It is very complex in that it is composed of two hard tissues (cementum and bone) and two soft connective tissues (periodontal ligament and gingiva). Together these tissues are defined by the molecules expressed by the resident periodontal cells in each compartment and this determines not only the structure and function of the periodontium but also how it responds to infection and inflammation. The biological activity of these molecules is tightly regulated in time and space to preserve tissue homeostasis, influence inflammatory responses and participate in tissue regeneration. In this issue of Periodontology 2000 we explore new experimental approaches and data sets which help to understand the molecules and cells that regulate tissue form and structure in health, disease and regeneration.
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Al-Daghreer S, Doschak M, Sloan AJ, Major PW, Heo G, Scurtescu C, Tsui YY, El-Bialy T. Effect of low-intensity pulsed ultrasound on orthodontically induced root resorption in beagle dogs. Ultrasound Med Biol 2014; 40:1187-1196. [PMID: 24613212 DOI: 10.1016/j.ultrasmedbio.2013.12.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Revised: 11/20/2013] [Accepted: 12/09/2013] [Indexed: 06/03/2023]
Abstract
We investigated the effect of low-intensity pulsed ultrasound (LIPUS) on orthodontically induced inflammatory root resorption in vivo. Ten beagle dogs were treated with an orthodontic appliance to move the mandibular fourth premolars bodily. The orthodontic movement was carried out for 4 wk with a continuous force of 1 N/side; using a split-mouth model, LIPUS was applied daily for 20 min. Fourth premolar and surrounding periodontal tissue were evaluated with micro-computed tomography and hematoxylin and eosin and tartrate-resistant acid phosphatase staining. We calculated the number, volume and distribution of root resorption lacunae and their percentage relative to total root volume, orthodontic tooth movement and periodontal ligament space. There was no significant difference in orthodontic tooth movement between the two sides. LIPUS significantly reduced the number of orthodontically induced inflammatory root resorption initiation areas by 71%, reduced their total volume by 68% and reduced their volume relative to the affected root total volume by 70%. LIPUS induced the formation of a precementum layer, thicker cementum and reparative cellular cementum.
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Affiliation(s)
- Saleh Al-Daghreer
- Department of Dentistry, Faculty of Medicine & Dentistry, Orthodontic Graduate Program, University of Alberta, Edmonton, Alberta, Canada; Division of Orthodontics, Department of Preventive Dental Sciences, Faculty of Dentistry, King Abdul Aziz University, Jeddah, Saudi Arabia.
| | - Michael Doschak
- Pharmaceutical Orthopaedic Research Lab, 2-020 J Katz Group Centre for Pharmacy & Health Research, University of Alberta, Edmonton, Alberta, Canada; Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Alastair J Sloan
- Tissue Engineering & Reparative Dentistry, School of Dentistry, Cardiff University, Heath Park, Cardiff, United Kingdom
| | - Paul W Major
- Department of Dentistry, Faculty of Medicine & Dentistry, Orthodontic Graduate Program, University of Alberta, Edmonton, Alberta, Canada
| | - Giseon Heo
- Department of Dentistry, Faculty of Medicine & Dentistry, Orthodontic Graduate Program, University of Alberta, Edmonton, Alberta, Canada
| | - Cristian Scurtescu
- Department of Electrical & Computer Engineering, W2-108 Electrical & Computer Engineering Research Facility, University of Alberta, Edmonton, Alberta, Canada
| | - Ying Y Tsui
- Department of Electrical & Computer Engineering, W2-108 Electrical & Computer Engineering Research Facility, University of Alberta, Edmonton, Alberta, Canada
| | - Tarek El-Bialy
- Department of Dentistry, Faculty of Medicine & Dentistry, Orthodontic Graduate Program, University of Alberta, Edmonton, Alberta, Canada; Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
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14
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Ho SP, Kurylo MP, Grandfield K, Hurng J, Herber RP, Ryder MI, Altoe V, Aloni S, Feng JQ, Webb S, Marshall GW, Curtis D, Andrews JC, Pianetta P. The plastic nature of the human bone-periodontal ligament-tooth fibrous joint. Bone 2013; 57:455-67. [PMID: 24063947 PMCID: PMC3938967 DOI: 10.1016/j.bone.2013.09.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 09/05/2013] [Accepted: 09/11/2013] [Indexed: 12/23/2022]
Abstract
This study investigates bony protrusions within a narrowed periodontal ligament space (PDL-space) of a human bone-PDL-tooth fibrous joint by mapping structural, biochemical, and mechanical heterogeneity. Higher resolution structural characterization was achieved via complementary atomic force microscopy (AFM), nano-transmission X-ray microscopy (nano-TXM), and microtomography (MicroXCT™). Structural heterogeneity was correlated to biochemical and elemental composition, illustrated via histochemistry and microprobe X-ray fluorescence analysis (μ-XRF), and mechanical heterogeneity evaluated by AFM-based nanoindentation. Results demonstrated that the narrowed PDL-space was due to invasion of bundle bone (BB) into PDL-space. Protruded BB had a wider range with higher elastic modulus values (2-8GPa) compared to lamellar bone (0.8-6GPa), and increased quantities of Ca, P and Zn as revealed by μ-XRF. Interestingly, the hygroscopic 10-30μm interface between protruded BB and lamellar bone exhibited higher X-ray attenuation similar to cement lines and lamellae within bone. Localization of the small leucine rich proteoglycan biglycan (BGN) responsible for mineralization was observed at the PDL-bone interface and around the osteocyte lacunae. Based on these results, it can be argued that the LB-BB interface was the original site of PDL attachment, and that the genesis of protruded BB identified as protrusions occurred as a result of shift in strain. We emphasize the importance of bony protrusions within the context of organ function and that additional study is warranted.
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Affiliation(s)
- Sunita P Ho
- Division of Biomaterials and Bioengineering, Department of Preventive and Restorative Dental Sciences, University of California San Francisco, San Francisco, CA, USA.
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15
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Bao X, Liu Y, Han G, Zuo Z, Hu M. The effect on proliferation and differentiation of cementoblast by using sclerostin as inhibitor. Int J Mol Sci 2013; 14:21140-52. [PMID: 24152444 PMCID: PMC3821662 DOI: 10.3390/ijms141021140] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 10/15/2013] [Accepted: 10/15/2013] [Indexed: 12/31/2022] Open
Abstract
Cementogenesis is of great importance for normal teeth root development and is involved in the repair process of root resorption caused by orthodontic treatment. As highly differentiated mesenchymal cells, cementoblasts are responsible for this process under the regulation of many endogenous agents. Among these molecules, sclerostin has been much investigated recently for its distinct antagonism effect on bone metabolism. Encoded by the sost gene, sclerostin is expressed in osteocytes and cementocytes of cellular cementum. it is still unclear. In the current study, we investigated the effects of sclerostin on the processes of proliferation and differentiation; a series of experiments including MTT, apoptosis examination, alkaline phosphatase (ALP) activity, gene analysis, and alizarin red staining were carried out to evaluate the proliferation and differentiation of cementoblasts. Protein expression including osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL) were also checked to analyze changes in osteoclastogenesis. Results show that sclerostin inhibits cementoblasts proliferation and differentiation, and promotes osteoclastogenesis. Interestingly, the monoclonal antibody for sclerostin has shown positive effects on osteoporosis, indicating that it may facilitate cementogenesis and benefit the treatment of cementum related diseases.
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Affiliation(s)
- Xingfu Bao
- Department of Orthodontics, School of Stomatology, Jilin University, Changchun 130021, China; E-Mail:
| | - Yuyan Liu
- Department of Endodontics, School of Stomatology, Jilin University, Changchun 130021, China; E-Mails: (Y.L.); (G.H.)
| | - Guanghong Han
- Department of Endodontics, School of Stomatology, Jilin University, Changchun 130021, China; E-Mails: (Y.L.); (G.H.)
| | - Zhigang Zuo
- Department of Orthodontics, School of Stomatology, Tianjin Medical University, Tianjin 300014, China; E-Mail:
| | - Min Hu
- Department of Orthodontics, School of Stomatology, Jilin University, Changchun 130021, China; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +86-431-88796023; Fax: +86-431-88955228
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Abstract
The periodontal ligament contains progenitor cells; however, their identity and differentiation potential in vivo remain poorly characterized. Previous results have suggested that periodontal tissue progenitors reside in perivascular areas. Therefore, we utilized a lineage-tracing approach to identify and track periodontal progenitor cells from the perivascular region in vivo. We used an alpha-smooth muscle actin (αSMA) promoter-driven and tamoxifen-inducible Cre system (αSMACreERT2) that, in combination with a reporter mouse line (Ai9), permanently labels a cell population, termed 'SMA9'. To trace the differentiation of SMA9-labeled cells into osteoblasts/cementoblasts, we utilized a Col2.3GFP transgene, while expression of Scleraxis-GFP was used to follow differentiation into periodontal ligament fibroblasts during normal tissue formation and remodeling following injury. In uninjured three-week-old SMA9 mice, tamoxifen labeled a small population of cells in the periodontal ligament that expanded over time, particularly in the apical region of the root. By 17 days and 7 weeks after labeling, some SMA9-labeled cells expressed markers indicating differentiation into mature lineages, including cementocytes. Following injury, SMA9 cells expanded, and differentiated into cementoblasts, osteoblasts, and periodontal ligament fibroblasts. SMA9-labeled cells represent a source of progenitors that can give rise to mature osteoblasts, cementoblasts, and fibroblasts within the periodontium.
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Affiliation(s)
- H Roguljic
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, CT, USA
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Bozić D, Grgurević L, Erjavec I, Razdorov G, Brkljacić J, Orlić I, Plancak D. Effect of bone morphogenetic protein-7 on gene expression of bone morphogenetic protein-4, dentin matrix protein-1, insulin-like growth factor-I and -II in cementoblasts in vitro. Coll Antropol 2012; 36:1265-1271. [PMID: 23390820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Formation of root cementum is a crucial moment in the development of the periodontium. Cells that produce the cementum are named cementoblasts and they posses some unique characteristics, which differentiates them from osteoblasts. Bone morphogenetic proteins (BMPs) are crucial regulators of both bone and tooth formation. In animal studies BMPs have shown to induce periodontal regeneration, however the molecular mechanism as how BMP-7 induces cementogenesis is largely unknown. We have investigated how BMP-7 regulates gene expression of BMP-4, Dentin matrix protein-1 (DMP-1), Insulin-like growth factor-I (IGF-I) and -II (IGF-II) in cementoblasts. BMP-7 induced proliferation, and mineralized nodule formation of cementoblasts. Our results show that gene expression was influenced by the BMP-7 concentration used, with 75 ng/mL generally down-regulating gene expression at 6 hours and then up-regulating after 24 hours. The 300 ng/mL concentration had an opposite effect while the 150 ng/mL concentration generally up-regulated gene expression after 6 hours and then after 24 hours maintained this up-regulation or had no effect compared to control, depending on the examined gene. The results show that BMP-7 down-regulated BMP-4 expression in cementoblasts but still up-regulated DMP-1 gene expression suggesting that BMP-7 can, in a paracrine manner, functionally substitute for BMP-4. Furthermore, it seems that BMP-7 exerts its effect more through the IGF-II than the IGF-I pathway as shown by an up-regulation of IGF-II and down-regulation of IGF-I. These results suggest that a combination of BMP-7/IGF-II could have a potential therapeutical significance in inducing cementogenesis and periodontal regeneration.
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Affiliation(s)
- Darko Bozić
- University of Zagreb, School of Dental Medicine, Department of Periodontology, Zagreb, Croatia.
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Silant'eva TA, Krasnov VV, Dobychina NA. [Reparative regeneration and adaptive remodeling of the mandible by transosseous osteosynthesis]. Stomatologiia (Mosk) 2012; 91:7-10. [PMID: 23011324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Mandibular injuries are the most common pathology of facial the skeleton. The aim of the study was to substantiate the effectiveness of treatment of this pathology using transosseous osteosynthesis method from the experimental and morphological point of view. The formation of bone union of mandibular fragments has been confirmed experimentally in 27 adult mongrel dogs after a month of fixation by the device and within a month after its demounting. The fibrous-and-connective union of full functional value has been formed in the zone of mandibular junction rupture in the same periods.
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Bai Y, Bai Y, Matsuzaka K, Hashimoto S, Fukuyama T, Wu L, Miwa T, Liu X, Wang X, Inoue T. Cementum- and periodontal ligament-like tissue formation by dental follicle cell sheets co-cultured with Hertwig's epithelial root sheath cells. Bone 2011; 48:1417-26. [PMID: 21376148 DOI: 10.1016/j.bone.2011.02.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 02/22/2011] [Accepted: 02/22/2011] [Indexed: 11/29/2022]
Abstract
Dental follicle cells (DFCs) are believed contain the precursor cells of the periodontium and can form cell sheets by secreting extracellular matrix (ECM) proteins. Cell sheet engineering has been recently developed and applied successfully in the field of tissue regeneration. However, research on the in vitro characteristics of DFC sheets is lacking and an assessment of whether DFC sheets can produce periodontal tissues in vivo has not been reported. To test the characteristics and applicability of DFC sheets in this field, we established a co-culture system of rat DFCs and Hertwig's epithelial root sheath (HERS) cells in vitro, and included the following controls: a co-culture of DFCs and alveolar mucosa epithelial cells, DFCs with no cells in the upper chamber, and DFCs cultured without an upper chamber. After 3 weeks of co-culturing the cells, the DFC sheets were transplanted into adult male rats' omenta. One week after co-culturing DFCs with HERS cells, mRNA levels of collagen type I (COL-1), alkaline phosphatase (ALP), runt related transcription factor 2 (Runx 2) and bone sialoprotein (BSP) were increased significantly. In addition, after 3 weeks of co-culturing the cells, the numbers of ALP-, osteocalcin (OCN)-, BSP- and osteoprotegerin (OPG)-positive DFCs increased. The DFCs also produced more calcified nodules and exhibited an increased number of subcellular organelles, which are important for protein synthesis and secretion. Moreover, gap junctions were found between the experimental DFCs within the sheet. Five weeks of in vivo growth of DFC sheets pre-exposed to HERS cells led to the formation of cementum-like tissues, which were positive for OCN, BSP and OPG, as well as the formation of periodontal ligament-like tissues, which were positive for COL-1. In contrast, control cells only produced fibrous tissues. These results indicate that the DFC sheets induced by HERS cells are able to produce periodontal tissues through epithelial-mesenchymal interactions. Therefore, DFC sheets may be useful in the field of periodontium regeneration.
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Affiliation(s)
- Yudi Bai
- Department of Pediatric Dentistry, School of Stomatology, Fourth Military Medical University, Xi'an, China
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Nam H, Kim J, Park J, Park JC, Kim JW, Seo BM, Lee JC, Lee G. Expression profile of the stem cell markers in human Hertwig's epithelial root sheath/Epithelial rests of Malassez cells. Mol Cells 2011; 31:355-60. [PMID: 21359676 PMCID: PMC3933961 DOI: 10.1007/s10059-011-0045-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 01/14/2011] [Accepted: 01/14/2011] [Indexed: 12/12/2022] Open
Abstract
Hertwig's epithelial root sheath/Epithelial rests of Malassez (HERS/ERM) cells are unique epithelial cells in the periodontal ligament. They remain in periodontal tissues through-out the adult life, and it is expected that their functional role is to maintain the homeostasis of the periodontium through reciprocal interactions with other periodontal cells. In this study, we investigated whether HERS/ERM cells have primitive stem cell characteristics: those of embryonic stem cells as well as of epithelial stem cells. Primary HERS/ERM cells had typical epithelial cell morphology and characteristics and they maintained for more than five passages. They expressed epithelial stem cell-related genes: ABCG2, ANp63, p75, EpCAM, and Bmi-1. Moreover, the expression of embryonic stem cell markers such as Oct-4, Nanog, and SSEA-4 were detected. Next, we investigated whether the expression of these stem cell markers was maintained during the sub-culture process. HERS/ERM cells showed different expression levels of these stemness genes at each passage, but their expression was maintained throughout the passages. Taken together, our data suggest that a primary culture of HERS/ERM cells contains a population of primitive stem cells that express epithelial stem cell markers and embryonic stem cell markers. Furthermore, these cell populations were maintained during the sub-culturing process in our culture conditions. Therefore, our findings suggest that there is a strong possibility of accomplishing cementum tissue engineering with HERS/ERM cells.
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Affiliation(s)
| | | | | | - Joo-Cheol Park
- Department of Oral Histology-Developmental Biology, School of Dentistry, Seoul National University, Seoul 110-749, Korea
| | - Jung-Wook Kim
- Department of Pediatric Dentistry, School of Dentistry, Seoul National University, Seoul 110-749, Korea
| | - Byoung-Moo Seo
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Seoul 110-749, Korea
| | - Jae Cheoun Lee
- Children’s Dental Center and CDC Baby Tooth Stem Cell Bank, Seoul 135-953, Korea
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Chen XY, Chen SL, Zhang MC. [Influence of bone quality on the stress distribution for three-posterior immediately loaded implants: a three-dimensional finite element analysis]. Zhonghua Kou Qiang Yi Xue Za Zhi 2011; 46:233-236. [PMID: 21612714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
OBJECTIVE To assess and compare the peri-implant stress distribution of three posterior implants under immediate loading with 4 different bone qualities using three dimensional (3D) finite element (FE) analysis. METHODS A 3D finite element model representing three implants in a portion of mandible at the 654 region was developed, and three implants received a crown each. Four types of bone qualities (B1, B2, B3 and B4) were designed for the model. Load of 100 N was applied on the occlusal surfaces of the crowns at a 45° angle to the vertical axis of the implants. RESULTS Von Mises stresses in the peri-implant bone of 4 in bone quality from B1 to B4 were (13.17 ± 9.32), (12.95 ± 9.14), (15.00 ± 9.44), and (16.81 ± 10.74) MPa, and those of 5 were (15.51 ± 10.32), (14.73 ± 8.96), (16.79 ± 8.40), and (18.34 ± 8.45) MPa. Stress in bone quality B4 showed the highest value, followed by B3 bone, the lowest stress were found in B1 and B2 bone. It was significantly different (P < 0.05). However, von Mises stresses in different quality of bone around 6 [(42.45 ± 25.71), (41.66 ± 25.29), (42.70 ± 23.24), (42.06 ± 23.66) MPa] were close to each other, and were as twice or three times as those of 4 and 5, irrespective of different bone qualities. CONCLUSIONS The stress distribution around implant under immediate loading was not only affected by different bone qualities, but also by the direction of loading, and the latter may have a greater impact when a severe load delivered.
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Affiliation(s)
- Xia-yun Chen
- Department of Stomatology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China
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22
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Mendoza AM, Reina ES, García-Godoy F. Evolution of apical formation on immature necrotic permanent teeth. Am J Dent 2010; 23:269-274. [PMID: 21207794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
PURPOSE To evaluate the evolution of apical formation on 28 necrotic immature permanent teeth treated with calcium hydroxide at different stages of root development. METHODS Apical formation in 28 necrotic incisors was carried out (27 upper and one lower incisors), in children between the ages of 6 and 13 years old (11 males, 10 females). Following anesthesia and rubber dam isolation, the chamber was opened and the coronal and root pulp tissue was removed. Next, after measuring the canal, the root canal was irrigated with 5% sodium hypochlorite. Once the canal was dried, it was filled with the CaOH2 powder mixed with physiologic saline solution to a dense consistency but malleable. This paste was compressed into the canal using a cotton pellet. The canal was completely filled up to the apex. Finally, the cavity opening was sealed with zinc oxide-eugenol (IRM) and glass-ionomer (Vitrebond). Follow-up appointments were made every 3 months in order to evaluate the evolution of the periapical radiolucency and the formation of the apical barrier. RESULTS The duration of the apical induction was 8.6 +/- 5.36 months. Increase or lack of growth in the length of the root canal and the type of root end closing was as follows: cementoid tissue (85.72%); osseous tissue (14.28%), with a 100% overall success rate. The evolution of these teeth was monitored over a 2-year period with re-infections occurring in 7.1 percent of the cases.
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Paula-Silva FWG, Ghosh A, Arzate H, Kapila S, da Silva LAB, Kapila YL. Calcium hydroxide promotes cementogenesis and induces cementoblastic differentiation of mesenchymal periodontal ligament cells in a CEMP1- and ERK-dependent manner. Calcif Tissue Int 2010; 87:144-57. [PMID: 20440482 DOI: 10.1007/s00223-010-9368-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 04/12/2010] [Indexed: 12/13/2022]
Abstract
Periodontal tissue engineering is a complex process requiring the regeneration of bone, cementum, and periodontal ligament (PDL). Since cementum regeneration is poorly understood, we used a dog model of dental pulpal necrosis and in vitro cellular wounding and mineralization assays to determine the mechanism of action of calcium hydroxide, Ca(OH)(2), in cementogenesis. Laser capture microdissection (LCM) followed by qRT-PCR were used to assay responses of periapical tissues to Ca(OH)(2) treatment. Additionally, viability, proliferation, migration, and mineralization responses of human mesenchymal PDL cells to Ca(OH)(2) were assayed. Finally, biochemical inhibitors and siRNA were used to investigate Ca(OH)(2)-mediated signaling in PDL cell differentiation. In vivo, Ca(OH)(2)-treated teeth formed a neocementum in a STRO-1- and cementum protein-1 (CEMP1)-positive cellular environment. LCM-harvested tissues adjacent to the neocementum exhibited higher mRNA levels for CEMP1, integrin-binding sialoprotein, and Runx2 than central PDL cells. In vitro, Ca(OH)(2) and CEMP1 promoted STRO-1-positive cell proliferation, migration, and wound closure. Ca(OH)(2) stimulated expression of the cementum-specific proteins CEMP1 and PTPLA/CAP in an ERK-dependent manner. Lastly, Ca(OH)(2) stimulated mineralization by CEMP1-positive cells. Blocking CEMP1 and ERK function abolished Ca(OH)(2)-induced mineralization, confirming a role for CEMP1 and ERK in the process. Ca(OH)(2) promotes cementogenesis and recruits STRO-1-positive mesenchymal PDL cells to undergo cementoblastic differentiation and mineralization via a CEMP1- and ERK-dependent pathway.
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Kim SH, Tramontina VA, Ramos CM, Prado AMBD, Passanezi E, Greghi SLA. Experimental surgical and orthodontic extrusion of teeth in dogs. INT J PERIODONT REST 2009; 29:435-443. [PMID: 19639064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The purpose of this study was to evaluate histologically the root surfaces of teeth submitted to orthodontic and surgical extrusion procedures in a dog model. Eighteen adult male dogs, divided into six groups of three dogs each, were used in the study. Each animal underwent two procedures: rapid orthodontic extrusion and surgical extrusion of the maxillary lateral incisors. The animals were sacrificed to produce samples at 7, 14, 45, 90, 120, and 180 days after surgery for assessment of cross sections of the coronal, medial, and apical thirds of the treated teeth. At early time points, some active surface and inflammatory resorption was observed exclusively in the surgical extrusion group; however, samples collected at later times demonstrated functional repair of the resorption gaps in both groups. Ankylosis was observed as a minor event and was apparently of a transient nature in samples of the surgical extrusion group. The results demonstrate the importance of maintaining the periodontal ligament and cementum surface; both are vital for the prevention of root resorption. It may be postulated that orthodontic extrusion is more conservative and physiologic than surgical extrusion; however, the results showed that function was restored in both groups.
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Affiliation(s)
- Sung Hyun Kim
- Department of Periodontology, Pontifical Catholic University of Parana, School of Dentistry, Curitiba, Brazil.
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Alhezaimi K, Al-Shalan T, O'Neill R, Shapurian T, Naghshbandi J, Levi P, Griffin T. Connective tissue-cementum regeneration: a new histologic regeneration following the use of enamel matrix derivative in dehiscence-type defects. A dog model. INT J PERIODONT REST 2009; 29:425-433. [PMID: 19639063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The goal of this investigation was to evaluate histologically and histometrically the healing process in dehiscence-type defects treated by enamel matrix derivative (EMD). Five adult female beagle dogs were used. Buccal osseous dehiscences were surgically created on the maxillary canines and the second and fourth premolars. Thirty defect sites were randomly assigned to treatment and control groups (15 defect sites for each group). The treatment group received EMD application, while the control groups received no EMD. After 4 months of healing, the dogs were sacrificed and tissue blocks were prepared. Histometric parameters were employed to evaluate the type of periodontal tissues that formed in the defects. All created dehiscence defects in the test sites treated by EMD had formed functional connective tissue fibers inserted into regenerated cellular cementum. The mean amount of apicocoronal regenerated cementum was 3.74 +/- 0.43 mm in EMD- treated sites, whereas the control sites had not formed cementum in the created dehiscence defects (P < .000). Statistically significant differences were found between treatment and control sites. Within the limits of this study, it can be concluded that EMD alone effectively promoted new cementum and functionally oriented connective tissue formation.
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Affiliation(s)
- Khalid Alhezaimi
- College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
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Ho SP, Senkyrikova P, Marshall GW, Yun W, Wang Y, Karan K, Li C, Marshall SJ. Structure, chemical composition and mechanical properties of coronal cementum in human deciduous molars. Dent Mater 2009; 25:1195-204. [PMID: 19464049 DOI: 10.1016/j.dental.2009.04.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 04/12/2009] [Accepted: 04/20/2009] [Indexed: 11/18/2022]
Abstract
OBJECTIVES It was hypothesized that the coronal cementum containing collagen forms a weak junction with enamel unlike the well integrated DEJ and CDJ. METHODS The hypothesis was investigated in two parts: (1) evaluate the structure, chemical composition and mechanical properties of coronal cementum and its junction with enamel using scanning electron microscopy, micro-X-ray computed tomography, and atomic force microscopy. The chemical composition and mechanical properties were determined by evaluating the spatial variations of inorganic (PO(4)(3-)nu(1) mode at 960 cm(-1)) and organic (C-H deformation at 1452 cm(-1); C-H stretch at 2940 cm(-1)) contents using Raman microspectroscopy and elastic modulus and hardness values using nanoindentation. (2) Estimate the strength and evaluate the microstructure of coronal cementum interface with enamel using SEM and MicroXCT. RESULTS AND CONCLUSIONS Coronal cementum is heterogeneous because it is a combination of laminar acellular afibrillar cementum and acellular extrinsic fiber cementum with relatively higher organic content. It integrates micromechanically via a scallop-like weak interface with enamel unlike the biomechanically efficient DEJ and CDJ and is continuous with primary root cementum. A single tooth could exhibit all three types of cementum enamel junctions; an overlap, butt and a gap depending on the sectioning plane. The elastic modulus of coronal cementum (11.0+/-5.8 GPa) is significantly lower (p<0.05; Student's t-test with 95% confidence interval) than primary cementum (15.8+/-5.3 GPa).
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Affiliation(s)
- Sunita P Ho
- Division of Biomaterials and Bioengineering, Department of Preventive and Restorative Dental Sciences, UCSF, San Francisco, CA 94143-0758, USA.
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McGuire MK, Scheyer T, Nevins M, Schupbach P. Evaluation of human recession defects treated with coronally advanced flaps and either purified recombinant human platelet-derived growth factor-BB with beta tricalcium phosphate or connective tissue: a histologic and microcomputed tomographic examination. INT J PERIODONT REST 2009; 29:7-21. [PMID: 19244878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The current study examined the histologic and microcomputed tomographic (micro CT) outcomes of the treatment of gingival recession defects with either a subepithelial connective tissue graft (CTG) or 0.3 mg/mL recombinant human platelet-derived growth factor (rhPDGF-BB) on a beta tricalcium phosphate (beta-TCP) matrix. Gingival recession defects were surgically created in six premolar teeth with no more than 3 mm of keratinized marginal tissue, an osseous crest 2 to 3 mm apical to the newly created gingival margin, and recession depth of at least 3 mm. The defects were left untouched for 2 months; then, four defects were grafted with rhPDGF-BB + beta-TCP + a wound healing dressing, and two defects received CTGs. A coronally advanced flap covered each grafted site. Nine months later, sections were obtained for examination. All four sites treated with rhPDGF-BB + beta-TCP showed connective tissue fibers (Sharpey fibers) perpendicularly inserting into newly formed cementum and alveolar bone. In the two sites treated with CTGs, a long junctional epithelium was seen coronal to the osseous crest and connective tissue fibers ran parallel to the adjacent root surfaces, with no evidence of insertion into cementum or bone. There was no evidence of regeneration of cementum, inserting connective tissue fibers, or supporting alveolar bone. Regeneration of the periodontium in gingival recession defects is possible through growth factor-mediated therapy.
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Yukna RA, Carr RL, Evans GH. Histologic evaluation of an Nd:YAG laser-assisted new attachment procedure in humans. INT J PERIODONT REST 2007; 27:577-587. [PMID: 18092452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This report presents histologic results in humans following a laser-assisted new attachment procedure (LANAP) for the treatment of periodontal pockets. Six pairs of single-rooted teeth with moderate to advanced chronic periodontitis associated with subgingival calculus deposits were treated. A bur notch was placed within the pocket at the clinically and radiographically measured apical extent of calculus. All teeth were scaled and root planed with ultrasonic and hand scalers. One of each pair of teeth received treatment of the inner pocket wall with a free-running pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG) laser to remove the pocket epithelium, and the test pockets were lased a second time to seal the pocket. After 3 months, all treated teeth were removed en bloc for histologic processing. LANAP-treated teeth exhibited greater probing depth reductions and clinical probing attachment level gains than the control teeth. All LANAP-treated specimens showed new cementum and new connective tissue attachment in and occasionally coronal to the notch, whereas five of the six control teeth had a long junctional epithelium with no evidence of new attachment or regeneration. There was no evidence of any adverse histologic changes around the LANAP specimens. These cases support the concept that LANAP can be associated with cementum-mediated new connective tissue attachment and apparent periodontal regeneration of diseased root surfaces in humans.
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Affiliation(s)
- Raymond A Yukna
- Department of Periodontics, Louisiana State University School of Dentistry, New Orleans, Louisiana, USA.
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Ho SP, Marshall SJ, Ryder MI, Marshall GW. The tooth attachment mechanism defined by structure, chemical composition and mechanical properties of collagen fibers in the periodontium. Biomaterials 2007; 28:5238-45. [PMID: 17870156 PMCID: PMC2423002 DOI: 10.1016/j.biomaterials.2007.08.031] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Accepted: 08/17/2007] [Indexed: 11/27/2022]
Abstract
In this study, a comparison between structure, chemical composition and mechanical properties of collagen fibers at three regions within a human periodontium, has enabled us to define a novel tooth attachment mechanism. The three regions include, (1) the enthesis region: insertion site of periodontal ligament (PDL) fibers (collagen fibers) into cementum at the root surface, (2) bulk cementum, and (3) the cementum-dentin junction (CDJ). Structurally, continuity in collagen fibers was observed from the enthesis, through bulk cementum and CDJ. At the CDJ the collagen fibers split into individual collagen fibrils and intermingled with the extracellular matrix of mantle dentin. Under wet conditions, the collagen fibers at the three regions exhibited significant swelling suggesting a composition rich in polyanionic molecules such as glycosaminoglycans. Additionally, site-specific indentation illustrated a comparable elastic modulus between collagen fibers at the enthesis (1-3 GPa) and the CDJ (2-4 GPa). However, the elastic modulus of collagen fibers within bulk cementum was higher (4-7 GPa) suggesting presence of extrafibrillar mineral. It is known that the tooth forms a fibrous joint with the alveolar bone, which is termed a gomphosis. Although narrower in width than the PDL space, the hygroscopic CDJ can also be termed as a gomphosis; a fibrous joint between cementum and root dentin capable of accommodating functional loads similar to that between cementum and alveolar bone. From an engineering perspective, it is proposed that a tooth contains two fibrous joints that accommodate the masticatory cyclic loads. These joints are defined by the attachment of dissimilar materials via graded stiffness interfaces, such as: (1) alveolar bone attached to cementum with the PDL; and (2) cementum to root dentin with the CDJ. Thus, through variations in concentrations of basic constituents, distinct regions with characteristic structures and graded properties allow for attachment and the load bearing characteristics of a tooth.
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Affiliation(s)
- Sunita P Ho
- Department of Preventive and Restorative Dental Sciences, Division of Biomaterials and Bioengineering, University of California, San Francisco, CA 94143-0758, USA.
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Kémoun P, Laurencin-Dalicieux S, Rue J, Farges JC, Gennero I, Conte-Auriol F, Briand-Mesange F, Gadelorge M, Arzate H, Narayanan AS, Brunel G, Salles JP. Human dental follicle cells acquire cementoblast features under stimulation by BMP-2/-7 and enamel matrix derivatives (EMD) in vitro. Cell Tissue Res 2007; 329:283-94. [PMID: 17443352 DOI: 10.1007/s00441-007-0397-3] [Citation(s) in RCA: 192] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2006] [Accepted: 02/09/2007] [Indexed: 12/14/2022]
Abstract
The dental follicle (DF) surrounding the developing tooth germ is an ectomesenchymal tissue composed of various cell populations derived from the cranial neural crest. Human dental follicle cells (HDFC) are believed to contain precursor cells for cementoblasts, periodontal ligament cells, and osteoblasts. Bone morphogenetic proteins (BMPs) produced by Hertwig's epithelial root sheath or present in enamel matrix derivatives (EMD) seem to be involved in the control of DF cell differentiation, but their precise function remains largely unknown. We report the immunolocalization of STRO-1 (a marker of multipotential mesenchymal progenitor cells) and BMP receptors (BMPR) in DF in vivo. In culture, HDFC co-express STRO-1/BMPR and exhibit multilineage properties. Incubation with rhBMP-2 and rhBMP-7 or EMD for 24 h increases the expression of BMP-2 and BMP-7 by HDFC. Long-term stimulation of these cells by rhBMP-2 and/or rhBMP-7 or EMD significantly increases alkaline phosphatase activity (AP) and mineralization. Expression of cementum attachment protein (CAP) and cementum protein-23 (CP-23), two putative cementoblast markers, has been detected in EMD-stimulated whole DF and in cultured HDFC stimulated with EMD or BMP-2 and BMP-7. RhNoggin, a BMP antagonist, abolishes AP activity, mineralization, and CAP/CP-23 expression in HDFC cultures and the expression of BMP-2 and BMP-7 induced by EMD. Phosphorylation of Smad-1 and MAPK is stimulated by EMD or rhBMP-2. However, rhNoggin blocks only Smad-1 phosphorylation under these conditions. Thus, EMD may activate HDFC toward the cementoblastic phenotype, an effect mainly (but not exclusively) involving both exogenous and endogenous BMP-dependent pathways.
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Affiliation(s)
- Philippe Kémoun
- Laboratory of Oral Biology, Faculty of Odontology, University Paul-Sabatier, 3 Chemin des Maraîchers, 31062, Toulouse Cedex, France
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Gonçalves PF, Gurgel BCV, Pimentel SP, Sallum EA, Sallum AW, Casati MZ, Nociti FH. Effect of two different approaches for root decontamination on new cementum formation following guided tissue regeneration: a histomorphometric study in dogs. J Periodontal Res 2007; 41:535-40. [PMID: 17076778 DOI: 10.1111/j.1600-0765.2006.00902.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND OBJECTIVE The aim of the present study was to evaluate comparatively the effect of two different approaches for root decontamination on new cementum formation following guided tissue regeneration (GTR). MATERIAL AND METHODS Nine mongrel dogs were used to obtain bilateral chronic class III furcation defects by placing cotton ligatures around both third mandibular premolars. The teeth were randomly assigned to receive one of the following treatments: scaling and root planing, by means of hand and rotatory instruments, in order to remove soft and hard deposits as well as all root cementum (group A); or removal of only soft microbial deposits, by polishing the root surface with rubber cups and polishing paste, aiming for maximum root cementum preservation (group B). Both groups were treated with GTR, with the use of resorbable polyglycolic-lactic acid membranes (RESOLUT XT). RESULTS Four months later, data analysis showed that a superior length (mm) (3.59 +/- 1.67 and 6.20 +/- 2.26 for groups A and B, respectively; p = 0.004) and a thicker layer (microm) (18.89 +/- 9.47 and 52.29 +/- 22.48 for groups A and B, respectively; p = 0.001) of new cementum was achieved by keeping the root cementum in place during root decontamination (group B). Regardless of the treatment modality, the new cementum was predominantly of a reparative, cellular extrinsic and intrinsic fiber type. CONCLUSION Within the limits of the present study, it may be concluded that root cementum preservation may affect the new cementum formation following GTR in class III furcation defects, and the treatment modality did not influence the type of newly formed cementum.
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Affiliation(s)
- P F Gonçalves
- Division of Periodontics, School of Dentistry at Piracicaba, UNICAMP, São Paulo, Brazil
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32
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Abstract
Substantial advancements have been made in defining the cells and molecular signals that guide tooth crown morphogenesis and development. As a result, very encouraging progress has been made in regenerating crown tissues by using dental stem cells and recombining epithelial and mesenchymal tissues of specific developmental ages. To date, attempts to regenerate a complete tooth, including the critical periodontal tissues of the tooth root, have not been successful. This may be in part due to a lesser degree of understanding of the events leading to the initiation and development of root and periodontal tissues. Controversies still exist regarding the formation of periodontal tissues, including the origins and contributions of cells, the cues that direct root development, and the potential of these factors to direct regeneration of periodontal tissues when they are lost to disease. In recent years, great strides have been made in beginning to identify and characterize factors contributing to formation of the root and surrounding tissues, that is, cementum, periodontal ligament, and alveolar bone. This review focuses on the most exciting and important developments over the last 5 years toward defining the regulators of tooth root and periodontal tissue development, with special focus on cementogenesis and the potential for applying this knowledge toward developing regenerative therapies. Cells, genes, and proteins regulating root development are reviewed in a question-answer format in order to highlight areas of progress as well as areas of remaining uncertainty that warrant further study.
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Affiliation(s)
- Brian L Foster
- Department of Periodontics, School of Dentistry, University of Washington, Seattle, Washington 98195, USA
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Luan X, Ito Y, Holliday S, Walker C, Daniel J, Galang TM, Fukui T, Yamane A, Begole E, Evans C, Diekwisch TGH. Extracellular matrix-mediated tissue remodeling following axial movement of teeth. J Histochem Cytochem 2006; 55:127-40. [PMID: 17015623 PMCID: PMC1941842 DOI: 10.1369/jhc.6a7018.2006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tooth eruption is a multifactorial process involving movement of existing tissues and formation of new tissues coordinated by a complex set of genetic events. We have used the model of the unopposed rodent molar to study morphological and genetic mechanisms involved in axial movement of teeth. Following extraction of opposing upper molars, lower molars supererupted by 0.13 mm. Labeled tissue sections revealed significant amounts of new bone and cementum apposition at the root apex of the unopposed side following supereruption for 12 days. Newly apposited cementum and alveolar bone layers were approximately 3-fold thicker in the experimental vs the control group, whereas periodontal ligament width was maintained. Tartrate-resistant acid phosphatase staining indicated bone resorption at the mesial alveolar walls of unopposed molars and provided in tandem with new bone formation at the distal alveolar walls an explanation for the distal drift of molars in this model. Microarray analysis and semiquantitative RT-PCR demonstrated a significant increase in collagen I, integrin beta5, and SPARC gene expression as revealed by comparison between the unopposed molar group and the control group. Immunohistochemical verification revealed increased levels of integrin beta5 and SPARC labeling in the periodontal ligament of the unopposed molar. Together our findings suggest that posteruptive axial movement of teeth was accomplished by significant formation of new root cementum and alveolar bone at the root apex in tandem with upregulation of collagen I, integrin beta5, and SPARC gene expression.
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Affiliation(s)
- Xianghong Luan
- Department of Oral Biology, University of Illinois at Chicago College of Dentistry, Chicago, IL 60612, USA
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Hatakeyama J, Philp D, Hatakeyama Y, Haruyama N, Shum L, Aragon MA, Yuan Z, Gibson CW, Sreenath T, Kleinman HK, Kulkarni AB. Amelogenin-mediated regulation of osteoclastogenesis, and periodontal cell proliferation and migration. J Dent Res 2006; 85:144-9. [PMID: 16434732 DOI: 10.1177/154405910608500206] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We previously reported that amelogenin isoforms M180 and leucine-rich amelogenin peptide (LRAP) are expressed in the periodontal region, and that their absence is associated with increased cementum defects in amelogenin-knockout (KO) mice. The aim of the present study was to characterize the functions of these isoforms in osteoclastogenesis and in the proliferation and migration of cementoblast/periodontal ligament cells. The co-cultures of wild-type (WT) osteoclast progenitor and KO cementoblast/periodontal ligament cells displayed more tartrate-resistant acid phosphatase (TRAP)-positive cells than the co-cultures of WT cells. The addition of LRAP to both co-cultures significantly reduced RANKL expression and the TRAP-positive cells. Proliferation and migration rates of the KO cementoblast/periodontal ligament cells were lower than those of WT cells and increased with the addition of either LRAP or P172 (a porcine homolog of mouse M180). Thus, we demonstrate the regulation of osteoclastogenesis by LRAP, and the proliferation and migration of cementoblast/periodontal ligament cells by LRAP and P172.
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Affiliation(s)
- J Hatakeyama
- Functional Genomics Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD 20892, USA
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Larson TD. Part one: The restoration of non-vital teeth: structural, biological, and micromechanical issues in maintaining tooth longevity. Northwest Dent 2006; 85:29, 31, 33-5 passim. [PMID: 17112116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
This manuscript will review research from 1967 to the present to find the best evidence for the reconstruction of non-vital teeth. The paper will review the contention that non-vital teeth are "more brittle" by analyzing the relevant physical properties of vital versus non-vital teeth; describe the structures of the tooth used to manage stress and strain; describe the formation of dentinal cracks and propagation of fracture planes through dentin; and analyze forces placed on human teeth and their effects on the tooth in Part One. In Part Two, the paper will describe the strength of various dowel and core designs relative to strength, retention, and durability and describe the results of testing various dentin bonding materials in strength and retention of dowels in non-vital teeth. The review will conclude with recommendations as to the materials and techniques in specific clinical situations best capable of single tooth reconstruction to ensure tooth longevity together with the scientific basis for their adoption.
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Affiliation(s)
- Thomas D Larson
- Department of Restorative Sciences, Division of Operative Dentistry, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA.
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Arambawatta AKS, Yamamoto T, Wakita M. An immunohistochemical study of the attachment mechanisms in different kinds of adhesive interfaces in teeth and alveolar bone of the rat. J Periodontal Res 2006; 41:259-65. [PMID: 16827718 DOI: 10.1111/j.1600-0765.2006.00866.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND OBJECTIVE This study was designed to examine the histological and immunohistochemical nature of different kinds of adhesive interfaces in the rat molar region under identical experimental conditions and to discuss the structural and functional similarities between these adhesive interfaces. MATERIAL AND METHODS Four kinds of adhesive interfaces - an initial attachment layer for principal fibers on the developing alveolar bone surface, a reattachment layer for principal fibers on resorbed alveolar bone surface, cement lines on the alveolar bone surface unrelated to the principal fibers, and the cemento-dentinal junction - were examined in 25-d-old male Wistar rats. Routine histological staining, immunohistochemical staining for bone sialoprotein and osteopontin, and digestion tests with trypsin were conducted. RESULTS The adhesive interfaces showed very similar histological and immunohistochemical features: they were intensely hematoxylin-stainable, deficient in collagen fibrils, and rich in bone sialoprotein and osteopontin. After trypsin treatment the four adhesive interfaces had lost immunoreactivity to bone sialoprotein and osteopontin, and the two adjacent tissue parts held together finally separated at the adhesive interfaces. CONCLUSION The above findings suggest that (i) the different types of adhesive interfaces in the rat molar region have a common structure in that they are filled with highly accumulated bone sialoprotein and osteopontin and deficient in collagen fibrils; (ii) accumulated bone sialoprotein and osteopontin are closely associated with the adhesion at the interfaces; and (iii) the adhesive interfaces have a similar developmental process.
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Affiliation(s)
- A K S Arambawatta
- Department of Oral Health Science, Hokkaido University, Graduate School of Dental Medicine, Sapporo, Japan.
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Affiliation(s)
- Margarita Zeichner-David
- Centre for Craniofacial Molecular Biology, School of Dentistry, Division of Surgical, Therapeutics and Bioengineering Sciences, University of Southern California, Los Angeles, California, USA
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Gonçalves PF, Gurgel BCV, Pimentel SP, Sallum EA, Sallum AW, Casati MZ, Nociti FH. Root Cementum Modulates Periodontal Regeneration in Class III Furcation Defects Treated by the Guided Tissue Regeneration Technique: A Histometric Study in Dogs. J Periodontol 2006; 77:976-82. [PMID: 16734571 DOI: 10.1902/jop.2006.050243] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Because the possibility of root cementum preservation as an alternative approach for the treatment of periodontal disease has been demonstrated, this study aimed to histometrically evaluate the effect of root cementum on periodontal regeneration. METHODS Bilateral Class III furcation defects were created in dogs, and each dog was randomly assigned to receive one of the following treatments: control (group A): scaling and root planing with the removal of root cementum; or test (group B): removal of soft microbial deposits by polishing the root surface with rubber cups and polishing paste, aiming at maximum cementum preservation. Guided tissue regeneration (GTR) was applied to both groups. RESULTS Four months after treatment, a superior length of new cementum (3.59 +/- 1.67 mm versus 6.20 +/- 2.26 mm; P = 0.008) and new bone (1.86 +/- 1.76 mm versus 4.62 +/- 3.01 mm; P = 0.002) and less soft tissue along the root surface (2.77 +/- 0.79 mm versus 1.10 +/- 1.48 mm; P = 0.020) was observed for group B. Additionally, group B presented a larger area of new bone (P = 0.004) and a smaller area of soft tissue (P = 0.008). CONCLUSION Within the limits of this study, root cementum may modulate the healing pattern obtained by guided tissue regeneration in Class III furcation defects.
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Affiliation(s)
- Patricia F Gonçalves
- Division of Periodontics, School of Dentistry at Piracicaba, State University of Campinas, São Paulo, Brazil
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Affiliation(s)
- Antonio Nanci
- Department of Stomatology, University of Montreal, Quebec, Canada
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40
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Miranda LA, Gomes SC, Soares IJ, Oppermann RV. A resin-modified glass ionomer cement barrier for treating degree II furcation defects: a pilot study in dogs. Acta Odontol Scand 2006; 64:37-41. [PMID: 16428181 DOI: 10.1080/00016350500367520] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate in an animal model the healing of degree II furcation defects treated with: an experimental barrier of resin-modified glass-ionomer cement (GIC), a polylactic acid barrier (GUI), and flap surgery (CTR). MATERIAL AND METHODS In 3 beagles, 18 class II furcation defects were surgically produced in mandibular and maxillary premolars and exposed to plaque accumulation for 21 days. Following a full flap, notches were made at the base to the bone defect. GIC barriers were prepared immediately before use from a commercial product and fit to place with the same product. The GIC barriers were removed after 30 days and the dogs euthanized after 120 days. Histologic sections were analyzed in a computer-assisted microscope. Epithelium, new cementum with inserting fibers, and connective tissue lining the root surface in-between notches were measured and medians of percentage values calculated. RESULTS In the GIC, epithelium constituted 3.5% (median values) of the notch-to-notch root area; new cementum was 83.6% and connective tissue 12.9%. These values were 0%, 73.6%, and 26.4% for the GUI group and 35.6%, 43.2%, and 0% for the CTR group. Bone fill median values were 54.3% for GIC, 20.6% for GUI, and 24.6% for CTR. CONCLUSION GIC and GUI prevented epithelial migration and promoted the formation of new periodontal tissues in experimentally induced class II furcation defects in dogs.
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Affiliation(s)
- Letícia Algarves Miranda
- Graduate Programme in Periodontology, Dental School, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
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41
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Jia HM, Ouyang XY, Cao CF. [Effects of enamel matrix protein on the growth of human periodontal ligament cells on root cementum surfaces]. Zhonghua Kou Qiang Yi Xue Za Zhi 2006; 41:74-6. [PMID: 16640927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
OBJECTIVE To evaluate the effect of enamel matrix protein (EMP) on the attachment and proliferation of periodontal ligament cells (PDLC) on diseased cementum surfaces in vitro. METHODS Cementum chips were obtained from diseased roots exposed to periodontal pocket. Thirteen diseased root cementum chips were conditioned with EMP. Meanwhile, 13 diseased and 13 healthy cementum chips were treated with physiological saline as control. The growth and morphology of PDLC on the root surface were observed after 24 hours incubation by scanning electron microscope (SEM). PDLC attachment and proliferation were quantified using MTT assay at 16 or 72 hours. RESULTS The cells on EMP treated roots under SEM were growing robust like the cells on healthy roots. By contrast, the diseased cementum surface without conditioned with EMP was only partly covered with spindle-shaped cells, with filopodia appearing short and thin. MTT assay indicated that the number of adhered and proliferated cells on diseased cementum chips treated with EMP was significantly greater than that on diseased chips treated with saline (adhesion: 0.45 +/- 0.03 vs. 0.37 +/- 0.05, P < 0.05; proliferation: 0.71 +/- 0.02 vs. 0.55 +/- 0.08, P < 0.01), but less than that on healthy chips (adhesion: 0.45 +/- 0.03 vs. 0.67 +/- 0.08, P < 0.05; proliferation: 0.71 +/- 0.02 vs. 1.05 +/- 0.09, P < 0.05). CONCLUSIONS It was suggested that EMP could promote the growth of PDLC on the diseased root cementum surface.
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Affiliation(s)
- Hui-mei Jia
- Department of Periodontology, The First Outpatient Dental Clinic of Peking University School and Hospital of Stomatology, Beijing 100034, China
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Foster BL, Nociti FH, Swanson EC, Matsa-Dunn D, Berry JE, Cupp CJ, Zhang P, Somerman MJ. Regulation of cementoblast gene expression by inorganic phosphate in vitro. Calcif Tissue Int 2006; 78:103-12. [PMID: 16467974 DOI: 10.1007/s00223-005-0184-7] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Accepted: 10/18/2005] [Indexed: 10/25/2022]
Abstract
Examination of mutant and knockout phenotypes with altered phosphate/pyrophosphate distribution has demonstrated that cementum, the mineralized tissue that sheathes the tooth root, is very sensitive to local levels of phosphate and pyrophosphate. The aim of this study was to examine the potential regulation of cementoblast cell behavior by inorganic phosphate (P(i)). Immortalized murine cementoblasts were treated with P(i) in vitro, and effects on gene expression (by quantitative real-time reverse-transcriptase polymerase chain reaction [RT-PCR]) and cell proliferation (by hemacytometer count) were observed. Dose-response (0.1-10 mM) and time-course (1-48 hours) assays were performed, as well as studies including the Na-P(i) uptake inhibitor phosphonoformic acid. Real-time RT-PCR indicated regulation by phosphate of several genes associated with differentiation/mineralization. A dose of 5 mM P(i) upregulated genes including the SIBLING family genes osteopontin (Opn, >300% of control) and dentin matrix protein-1 (Dmp-1, >3,000% of control). Another SIBLING family member, bone sialoprotein (Bsp), was downregulated, as were osteocalcin (Ocn) and type I collagen (Col1). Time-course experiments indicated that these genes responded within 6-24 hours. Time-course experiments also indicated rapid regulation (by 6 hours) of genes concerned with phosphate/pyrophosphate homeostasis, including the mouse progressive ankylosis gene (Ank), plasma cell membrane glycoprotein-1 (Pc-1), tissue nonspecific alkaline phosphatase (Tnap), and the Pit1 Na-P(i) cotransporter. Phosphate effects on cementoblasts were further shown to be uptake-dependent and proliferation-independent. These data suggest regulation by phosphate of multiple genes in cementoblasts in vitro. During formation, phosphate and pyrophosphate may be important regulators of cementoblast functions including maturation and regulation of matrix mineralization.
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Affiliation(s)
- B L Foster
- Department of Periodontics, School of Dentistry, University of Washington, Seattle, WA, USA.
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Abstract
The purpose of this study was to histomorphologically evaluate (in dog's teeth) the influence of tooth movement in the healing of chronic periapical lesions. Thirty roots of incisors and premolars of two dogs (1-year-old) were used in this research. After pulpectomy, the root canals remained exposed to the oral environment for 6 months for achievement of periapical lesions. Twenty root canals were biomechanically prepared and received a calcium hydroxide dressing for 14 days before being filled with gutta-percha points and Sealapex sealer. After root canal treatment, some incisors were submitted to orthodontic movement, whereas the other roots remained without orthodontic movement. The orthodontic appliance was removed at 5 months and 15 days after treatment, the dogs were killed 15 days later and the specimens were prepared for histomorphological analysis. The results showed that the orthodontic movement delayed, but did not hinder, the periapical healing process.
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Bergenholtz G, Wikesjö UME, Sorensen RG, Xiropaidis AV, Wozney JM. Observations on healing following endodontic surgery in nonhuman primates (Macaca fascicularis): Effects of rhBMP-2. ACTA ACUST UNITED AC 2006; 101:116-25. [PMID: 16360616 DOI: 10.1016/j.tripleo.2005.02.085] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2004] [Revised: 01/03/2005] [Accepted: 02/25/2005] [Indexed: 11/19/2022]
Abstract
OBJECTIVES The potential of recombinant human bone morphogenetic protein-2 (rhBMP-2) to enhance bone healing following endodontic surgery was tested. The pattern and timing of de novo bone formation and cementum regeneration, and the potential for root resorption and ankylosis to accompany bone formation were evaluated. STUDY DESIGN Pulpal infections were induced in maxillary and mandibular incisor teeth in young adult Cynomolgus monkeys. The teeth received conventional endodontic treatment immediately followed by surgical root resection. In a randomized split-mouth design, contralateral apical bone defects received rhBMP-2 in absorbable collagen sponge (ACS) carrier or served as sham-surgery controls to provide histological and radiographic evaluations following 1 (mandibular incisors) and 4.5 (maxillary incisors) month(s) postsurgery. RESULTS At 1 month postsurgery trabecular bone filled the apical bone defects. The newly formed bone appeared considerably more mature and had assumed characteristics of the contiguous resident bone at 4.5 months postsurgery. The resected root tips were almost completely covered by new cementum with a maturing functionally oriented periodontal ligament. Localized inflammatory infiltrates were associated with the filled root canals and extruded root-filling material. Root resorption and ankylosis were not observed. There were no apparent differences in healing patterns between sites implanted with rhBMP-2/ACS and those serving as sham-surgery controls. CONCLUSIONS Under conditions where the influence of infectious elements and irritation caused by root filling material are minimized, bone formation and cementum regeneration appears rapid following endodontic surgery. rhBMP-2/ACS did not offer an obvious benefit above and beyond that of the native osteogenic potential in this animal model.
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Chutimanutskul W, Darendeliler MA, Swain MV, Shen G, Petocz P. Physical properties of human premolar cementum: hardness and elasticity. Aust Orthod J 2005; 21:117-21. [PMID: 16429867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
AIMS To determine if the cementum on the maxillary right and left first premolars has identical physical properties. METHODS Ten normal maxillary first premolar teeth, extracted from five orthodontic patients with a mean age of 14.0 years, were used. The teeth had not been subjected to an orthodontic force. The hardness and elastic modulus of the cementum were measured on the buccal and lingual surfaces of the roots at three locations: cervical third, middle third and apical third. RESULTS There were no significant side-to-side differences in cementum hardness (Mean side-to-side difference: 0.0063 GPa; SD: 0.0279; p = 0.525) or elastic modulus (Mean side-to-side difference: -0.027 GPa; SD: 0.111; p = 0.814). The hardness and elastic modulus of the cementum decreased from cervical to apical regions on both root surfaces. CONCLUSIONS Similar physical properties of the cementum on the maxillary right and left first premolars suggest that intra-arch comparisons can be used to investigate root resorption caused by orthodontic forces.
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Harkness M. Forces that shape our profession. Aust Orthod J 2005; 21:149-50. [PMID: 16429871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
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Fernandes JMA, Rego ROCC, Spolidorio LC, Marcantonio RAC, Marcantonio Júnior E, Cirelli JA. Enamel matrix proteins associated with GTR and bioactive glass in the treatment of class III furcation in dogs. Braz Oral Res 2005; 19:169-75. [PMID: 16308603 DOI: 10.1590/s1806-83242005000300003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study investigated, both histologically and histometrically, the efficacy of enamel matrix derived proteins (EMD) associated with bioactive glass (BG) and an absorbable membrane in the treatment of class III furcation defects in mongrel dogs. After surgical defect creation and chronification, the lesions were randomly divided into three groups according to the treatment employed: Test Group 1 - EMD + BG + membrane, Test Group 2 - EMD + membrane and Control Group - BG + membrane. After a 90-day healing period, the dogs were sacrificed. The descriptive analysis and the histometric data showed similar results for the experimental groups in all studied parameters (MANOVA, p > 0.05). The association of Emdogain® with bioglass and GTR, or with GTR only, showed similar results when compared with the ones obtained with bioglass associated with membrane in the treatment of class III furcation defects in dogs. The three modalities of treatment showed partial filling of the furcations, with bone and cementum regeneration limited to the apical portion of the defects.
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Graziani F, Laurell L, Tonetti M, Gottlow J, Berglundh T. Periodontal wound healing following GTR therapy of dehiscence-type defects in the monkey: short-, medium- and long-term healing. J Clin Periodontol 2005; 32:905-14. [PMID: 15998277 DOI: 10.1111/j.1600-051x.2005.00789.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To describe periodontal wound healing in dehiscence-type defects following guided tissue re-generation (GTR) therapy. METHODS Ten adult Macaca fascicularis monkeys were used. Buccal dehiscence-type defects were created at the maxillary second pre-molars and second molars. After 3 months, GTR surgery was performed. The animals were euthanized at 6 weeks, 6 months and 2 years after surgery. Block biopsies were harvested, and prepared for histological analysis. RESULTS A new attachment apparatus was structured already after 6 weeks of healing. A 10-20 microm thin layer of acellular extrinsic fibre cementum (AEFC) had formed along the instrumented root surface. At 6 months, the thickness of the supracrestal cementum was comparable with that at 6 weeks, while the thickness of the subcrestal cementum had increased to 40-60 microm. In this zone, the cementum consisted of an inner layer of AEFC attached to the circum-pulpal dentin and an outer layer of cellular mixed fibre cementum (CMFC). The numerical extrinsic fibre density was twice that at 6 weeks. At 2 years, the periodontal tissues resembled the pristine periodontium. CONCLUSION Periodontal healing following GTR therapy of recession-type defects will result in a restitutio ad integrum, i.e. healing by re-generation. A continuous maturation process occurs over at least 2 years.
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Affiliation(s)
- Filippo Graziani
- Department of Periodontology, Eastman Dental Institute, University College London, London, UK
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Villaça JH, Novaes AB, Souza SLSD, Taba M, Molina GO, Carvalho TLL. Bioactive glass efficacy in the periodontal healing of intrabony defects in monkeys. Braz Dent J 2005; 16:67-74. [PMID: 16113937 DOI: 10.1590/s0103-64402005000100012] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The purpose of this study was the histomorphologic analysis of the efficacy of bioactive glass particles with a narrow size range (Biogran) in the periodontal healing of 2-wall intrabony defects in monkeys. The 2-wall defects were made in the mesial area of the left and right second premolars of four monkeys, filled with gutta-percha and, after 15 days, they were debrided and either naturally filled with coagulum (control) or implanted with bioactive glass (test). In the control sites, the junctional epithelium migrated up to the base of the defect. The presence of newly formed cementum was more significant in the test defects. Both control and test sites showed newly formed bone at the base of the defect. The test defects presented foci of newly formed bone around and within the glass particles localized in the middle third, distant from the defect walls. Histologic analysis showed that the 300- to 355-microm bioactive glass particles aided new periodontal insertion. In conclusion, the tested bioactive glass had better healing potential than debridement only. The graft material showed a promising inhibition of apical migration of the junctional epithelium and greater cementum deposition on the radicular surface of the intrabony defects. The replacement of bioactive glass particles by new bone occurred due not only to an osteoconductive property, but also to an osteostimulatory capacity. Future investigations should evaluate this potential comparatively or together with other grafting materials, regenerative techniques and biological modifiers, as well as assess the longitudinal stability of the new attachment.
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Affiliation(s)
- José Henrique Villaça
- Department of Bucco-Maxillo-Facial Surgery and Traumatology and Periodontology, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
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Takahashi D, Odajima T, Morita M, Kawanami M, Kato H. Formation and resolution of ankylosis under application of recombinant human bone morphogenetic protein-2 (rhBMP-2) to class III furcation defects in cats. J Periodontal Res 2005; 40:299-305. [PMID: 15966907 DOI: 10.1111/j.1600-0765.2005.00794.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVES Periodontal regeneration under application of bone morphogenetic protein (BMP) is compromised by ankylosis. Ankylosis disappearance following application of BMP has been observed in the case of a small defect, which might be beneficial change for periodontal regeneration. However, the histological observation of ankylosis disappearance has not been demonstrated in a large defect. The purpose of this present study was to confirm resolution of ankylosis during periodontal regeneration by recombinant human BMP-2 (rhBMP-2) applied to class III furcation defects. MATERIAL AND METHODS Class III furcation defects were created in the premolars of six adult cats. The rhBMP-2 material, prepared by applying rhBMP-2 to a combination of polylactic acid-polygricolic copolymer and gelatin sponge (PGS; 0.33 microg rhBMP-2/mm(3) PGS) or control material containing only PGS, was implanted into each defect. The cats were killed at 3, 6 or 12 weeks after surgery and serial sections were prepared for histological and histometrical observation. RESULTS Ankylosis was observed in some of the rhBMP-2/PGS group at 3 and 6 weeks, but not at 12 weeks. At 6 weeks, osteoclast-like cells were visible in the rhBMP-2/PGS group with ankylosis. Residual PGS was evident between the bone and root surface in the rhBMP-2/PGS group without ankylosis at 3 weeks. CONCLUSIONS Resolution of ankylosis by osteoclast-like cells possibly occurred under application of rhBMP-2. Residual PGS might play an important role in preventing ankylosis formation.
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Affiliation(s)
- D Takahashi
- Department of Oral Functional Science, Hokkaido University Graduate School of Dental Medicine, Hokkaido, Japan.
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