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Webb CWB, D'Costa K, Tawagi E, Antonyshyn JA, Hofer OPS, Santerre JP. Electrospun methacrylated natural/synthetic composite membranes for gingival tissue engineering. Acta Biomater 2024; 173:336-350. [PMID: 37989435 DOI: 10.1016/j.actbio.2023.11.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 11/10/2023] [Accepted: 11/14/2023] [Indexed: 11/23/2023]
Abstract
New functional materials for engineering gingival tissue are still in the early stages of development. Materials for such applications must maintain volume and have advantageous mechanical and biological characteristics for tissue regeneration, to be an alternative to autografts, which are the current benchmark of care. In this work, methacrylated gelatin (GelMa) was photocrosslinked with synthetic immunomodulatory methacrylated divinyl urethanes and defined monomers to generate composite scaffolds. Using a factorial design, with the synthetic monomers of a degradable polar/hydrophobic/ionic polyurethane (D-PHI) and GelMa, composite materials were electrospun with polycarbonate urethane (PCNU) and light-cured in-flight. The materials had significantly different relative hydrophilicities, with unique biodegradation profiles associated with specific formulations, thereby providing good guidance to achieving desired mechanical characteristics and scaffold resorption for gingival tissue regeneration. In accelerated esterase/collagenase degradation models, the new materials exhibited an initial rapid weight loss followed by a more gradual rate of degradation. The degradation profile allowed for the early infiltration of human adipose-derived stromal/stem cells, while still enabling the graft's structural integrity to be maintained. In conclusion, the materials provide a promising candidate platform for the regeneration of oral soft tissues, addressing the requirement of viable tissue infiltration while maintaining volume and mechanical integrity. STATEMENT OF SIGNIFICANCE: There is a need for the development of more functional and efficacious materials for the treatment of gingival recession. To address significant limitations in current material formulations, we sought to investigate the development of methacrylated gelatin (GelMa) and oligo-urethane/methacrylate monomer composite materials. A factorial design was used to electrospin four new formulations containing four to five monomers. Synthetic immunomodulatory monomers were crosslinked with GelMa and electrospun with a polycarbonate urethane resulting in unique mechanical properties, and resorption rates which align with the original design criteria for gingival tissue engineering. The materials may have applications in tissue engineering and can be readily manufactured. The findings of this work may help better direct the efforts of tissue engineering and material manufacturing.
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Affiliation(s)
- C W Brian Webb
- Faculty of Dentistry, University of Toronto, 124 Edward St, M5G 1X3, Canada; Institute of Biomedical Engineering, University of Toronto, 164 College St Room 407, M5S 3G9, Canada
| | - Katya D'Costa
- Institute of Biomedical Engineering, University of Toronto, 164 College St Room 407, M5S 3G9, Canada
| | - Eric Tawagi
- Institute of Biomedical Engineering, University of Toronto, 164 College St Room 407, M5S 3G9, Canada
| | - Jeremy A Antonyshyn
- Institute of Biomedical Engineering, University of Toronto, 164 College St Room 407, M5S 3G9, Canada
| | - O P Stefan Hofer
- Division of Plastic and Reconstructive Surgery, University of Toronto, 149 College Street 5th Floor, M5T 1P5, Canada; Department of Surgery and Surgical Oncology, University Health Network, 190 Elizabeth St 1st Floor, M5G 2C4, Canada
| | - J Paul Santerre
- Faculty of Dentistry, University of Toronto, 124 Edward St, M5G 1X3, Canada; Institute of Biomedical Engineering, University of Toronto, 164 College St Room 407, M5S 3G9, Canada.
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Webb BCW, Glogauer M, Santerre JP. The Structure and Function of Next-Generation Gingival Graft Substitutes-A Perspective on Multilayer Electrospun Constructs with Consideration of Vascularization. Int J Mol Sci 2022; 23:5256. [PMID: 35563649 PMCID: PMC9099797 DOI: 10.3390/ijms23095256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 12/10/2022] Open
Abstract
There is a shortage of suitable tissue-engineered solutions for gingival recession, a soft tissue defect of the oral cavity. Autologous tissue grafts lead to an increase in morbidity due to complications at the donor site. Although material substitutes are available on the market, their development is early, and work to produce more functional material substitutes is underway. The latter materials along with newly conceived tissue-engineered substitutes must maintain volumetric form over time and have advantageous mechanical and biological characteristics facilitating the regeneration of functional gingival tissue. This review conveys a comprehensive and timely perspective to provide insight towards future work in the field, by linking the structure (specifically multilayered systems) and function of electrospun material-based approaches for gingival tissue engineering and regeneration. Electrospun material composites are reviewed alongside existing commercial material substitutes', looking at current advantages and disadvantages. The importance of implementing physiologically relevant degradation profiles and mechanical properties into the design of material substitutes is presented and discussed. Further, given that the broader tissue engineering field has moved towards the use of pre-seeded scaffolds, a review of promising cell options, for generating tissue-engineered autologous gingival grafts from electrospun scaffolds is presented and their potential utility and limitations are discussed.
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Affiliation(s)
- Brian C. W. Webb
- Faculty of Dentistry, University of Toronto, 124 Edward St, Toronto, ON M5G 1G6, Canada; (B.C.W.W.); (M.G.)
- Institute of Biomedical Engineering, University of Toronto, 164 Collage St Room 407, Toronto, ON M5S 3G9, Canada
| | - Michael Glogauer
- Faculty of Dentistry, University of Toronto, 124 Edward St, Toronto, ON M5G 1G6, Canada; (B.C.W.W.); (M.G.)
| | - J. Paul Santerre
- Faculty of Dentistry, University of Toronto, 124 Edward St, Toronto, ON M5G 1G6, Canada; (B.C.W.W.); (M.G.)
- Institute of Biomedical Engineering, University of Toronto, 164 Collage St Room 407, Toronto, ON M5S 3G9, Canada
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Xu X, Sun H, Wang Y, Cai H, Zhang D, Tan H, Li J. Fabrication of a multifunctional hydrogel with a robust interface bioinspired by the structure of the dentogingival junction. Chem Commun (Camb) 2020; 56:3633-3636. [DOI: 10.1039/d0cc00907e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A multifunctional hydrogel with a robust interface is fabricated with a “perforating fiber” structure bioinspired by the dentogingival junction.
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Affiliation(s)
- Xinyuan Xu
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Hui Sun
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Yaning Wang
- National Engineering Research Center for Biomaterials
- Sichuan University
- Chengdu
- People's Republic of China
| | - Huijuan Cai
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Dongyue Zhang
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Hong Tan
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Jianshu Li
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering
- Sichuan University
- Chengdu 610065
- P. R. China
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Manzolli Leite FR, Nascimento GG, Manzolli Leite ER, Leite AA, Cezar Sampaio JE. Effect of the association between citric acid and EDTA on root surface etching. J Contemp Dent Pract 2013; 14:796-800. [PMID: 24685777 DOI: 10.5005/jp-journals-10024-1405] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE This study aims to compare the clot stabilization on root surfaces conditioned with citric acid and ethylenediamine-tetraacetic acid (EDTA). MATERIALS AND METHODS Scaled root samples (n = 100) were set in fve groups: group I-control group (saline solution); group II (24% EDTA); group III (25% citric acid); group IV (EDTA + citric acid); group V (citric acid + EDTA). Fifty samples were assessed using the root surface modifcation index (RSMI). The other 50 received a blood drop after conditioning. Clot formation was assessed using blood elements adhesion index (BEAI). A blind examiner evaluated photomicrographs. Statistical analysis considered p < 0.05. RESULTS Groups-III and G-V attained the best results for RSMI and BEAI in comparison to control. The worst results for clot stabilization were seen in group-II. EDTA employment before citric acid (group-IV) reduced clot formation in comparison to citric acid use alone (group-III). CONCLUSION Root conditioning with citric acid alone and before EDTA had the best results for smear layer removal and clot stabilization. EDTA inhibited clot stabilization on root surface and must have a residual activity once it has diminished clot adhesion to root even after citric acid conditioning. Thus, EDTA can be used to neutralize citric acid effects on periodontal cells without affecting clot stabilization. Clinical signifcance: To demonstrate that citric acid use on root surfaces previously affected by periodontal disease may favor clot stabilization and may have a benefcial effect on surgical outcomes. Also, EDTA can be used to neutralize citric acid effects on periodontal cells.
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Affiliation(s)
- Fabio Renato Manzolli Leite
- Adjunct Professor, Department of Semiology and Clinics, Federal University of Pelotas, Rio Grande do Sul, Brazil, Phone: 555332256741 e-mail:
| | | | | | - Amauri Antiquera Leite
- Adjunct Professor, Department of Clinical Analysis, State University of São Paulo, São Paulo, Brazil
| | - Josá Eduardo Cezar Sampaio
- Adjunct Professor, Department of Diagnosis and Surgery, State University of São Paulo, São Paulo, Brazil
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Zhang W, Song F, Windsor LJ. Cigarette smoke condensate affects the collagen-degrading ability of human gingival fibroblasts. J Periodontal Res 2009; 44:704-13. [PMID: 19453854 DOI: 10.1111/j.1600-0765.2008.01179.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND OBJECTIVE Cigarette smoke condensate, the particulate matter of cigarette smoke, is composed of thousands of chemicals, including nicotine. Cigarette smoking is a risk factor for periodontal disease. This study investigated the influence of cigarette smoke condensate on the collagen-degrading ability of human gingival fibroblasts and its mechanism. MATERIAL AND METHODS Human gingival fibroblasts were exposed for 72 h to various concentrations of total particulate matter cigarette smoke condensate. Cell proliferation and cytotoxicity were evaluated using water-soluble tetrazolium-1 and lactate dehydrogenase, respectively. The collagen-degrading ability of human gingival fibroblasts was evaluated in collagen-coated six-well plates. Conditioned media and membrane extracts were collected for zymography and western blot analyses of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). RESULTS Cell proliferation decreased and cytotoxicity increased in human gingival fibroblasts with increasing concentrations of cigarette smoke condensate. Cell proliferation decreased by more than 50% (p < 0.05) when the concentrations of total particulate matter cigarette smoke condensate were above 200 microg/mL, and cytotoxicity increased to more than 30% (p < 0.05) when the concentrations of total particulate matter cigarette smoke condensate were above 400 microg/mL. Cigarette smoke condensate increased the collagen-degrading ability of human gingival fibroblasts, especially at a concentration of 100 microg/mL (1.5-fold increase, p < 0.05) compared with the control. Cigarette smoke condensate increased the production of proMMP-1, proMMP-2, MMP-14 and TIMP-1, and decreased the production of TIMP-2, in conditioned media. Furthermore, compared with the control group, cigarette smoke condensate increased the production of MMP-2, MMP-14 and TIMP-2 in membrane extracts, especially at concentrations of 50-100 microg/mL. CONCLUSION Cigarette smoke condensate affects human gingival fibroblast proliferation and is toxic at total particulate matter cigarette smoke condensate concentrations of >or= 400 microg/mL. Cigarette smoke condensate can increase the collagen-degrading ability of human gingival fibroblasts by altering the production and localization of MMPs and TIMPs.
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Affiliation(s)
- W Zhang
- Department of Oral Biology, Indiana University School of Dentistry, Indianapolis, IN 46202, USA
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Binderman I, Bahar H, Yaffe A. Strain relaxation of fibroblasts in the marginal periodontium is the common trigger for alveolar bone resorption: a novel hypothesis. J Periodontol 2002; 73:1210-5. [PMID: 12416781 DOI: 10.1902/jop.2002.73.10.1210] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In summary, the present commentary proposes a hypothesis that alveolar bone remodeling and bone loss in periodontitis, periodontal surgery, and in orthodontic tooth movement is triggered by a common "strain relaxation" signaling pathway of gingival and periodontal fibroblasts. The abrupt splitting, degradation, or relaxation of collagen fibers in the marginal periodontium produces a "strain relaxation" signal in the local fibroblasts which reside on these fibers, activating an ECM-integrin-cytoskeleton pathway. A cascade of cellular reactions which lead to osteoclastic bone resorption starting on the inner aspect (periodontal) of the alveolar bone then persists. A novel therapeutic approach is suggested here by using locally delivered drugs intervening in the cell contractile apparatus.
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Affiliation(s)
- Itzhak Binderman
- Department of Oral Biology, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel
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BarKana I, Narayanan AS, Grosskop A, Savion N, Pitaru S. Cementum attachment protein enriches putative cementoblastic populations on root surfaces in vitro. J Dent Res 2000; 79:1482-8. [PMID: 11005732 DOI: 10.1177/00220345000790070901] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We tested the capacity of cementum attachment protein (CAP) to recruit putative cementoblastic populations to root surfaces in vitro by determining the phenotypic expression of periodontal ligament cloned cell populations. The clones were derived from cells that attached to either CAP-coated (experimental) or uncoated (control) root slices. Root slices were co-cultured with primary human periodontal ligament cells. Cloned and parent populations were analyzed for their capacity to express alkaline phosphatase (AP), osteopontin, bone sialoprotein (BSP), and CAP and to form mineralized tissue in vitro. The percentage of CAP- and BSP-positive clones was significantly higher in the experimental clones than in the controls. The percentage of cells positive for AP, BSP, and CAP was higher in the experimental clones than in their control counterparts. Mineralized tissue formation was observed only in the cell populations derived from the CAP-coated root slices. These results indicate that CAP is capable of recruiting putative cementoblastic populations on root slices in vitro and therefore might play an important role in cementogenesis during periodontal homeostasis and wound healing.
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Affiliation(s)
- I BarKana
- Department of Oral Biology, Goldschleger School of Dental Medicine, Tel Aviv University, Israel
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Zaman KU, Sugaya T, Hongo O, Kato H. A study of attached and oriented human periodontal ligament cells to periodontally diseased cementum and dentin after demineralizing with neutral and low pH etching solution. J Periodontol 2000; 71:1094-9. [PMID: 10960015 DOI: 10.1902/jop.2000.71.7.1094] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND This study aimed to evaluate quantitatively the migrated, attached, and oriented human periodontal ligament cells (HPLC) to periodontally diseased cementum and dentin after demineralization with low and neutral pH etching solution. METHODS Human teeth, extracted due to periodontal diseases, were scaled and root planed so that cementum remained on one longitudinal half of the root and dentin was exposed on the other half. Forty root slices of 200 microm thickness, obtained from the mid-third of these roots, were divided into four groups: group 1, demineralized with a saturated solution of citric acid (pH 1.20); group 2, with 24% EDTA (pH 7.04); group 3, with tetracycline HCl 100 mg/ml (pH 2.00); and group 4, only scaled and root planed (control). Root slices were placed over the confluent HPLC in 35 mm culture dishes and incubated. Phase contrast microscopic photographs of attached and oriented refractile HPLC to root surfaces were taken at days 1, 3, and 7. Quantitative analysis of attached and oriented HPLC from these photographs was done using special software. RESULTS The results showed no significant difference in the attachment and orientation index of HPLC to cementum compared to dentin in any method of demineralization at each time point (P >0.05), although there was a significantly higher cell attachment and orientation index to demineralized dentin with EDTA and citric acid than to non-etched dentin and to all 3 demineralized cementum surfaces compared to non-etched cementum (P<0.05). CONCLUSIONS EDTA and citric acid demineralization may enhance HPLC attachment and orientation to the root surface, and it is not always necessary to remove excessive cementum when the demineralizing procedure is used.
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Affiliation(s)
- K U Zaman
- Department of Periodontology and Endodontology, Hokkaido University, School of Dentistry, Sapporo, Japan
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9
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Abstract
AIM The aim of this study was to investigate the effect of surface morphology of root ends resected with various bur configurations on fibroblast attachment. METHODOLOGY Seventy-two human single-rooted teeth were collected and decoronated. The root canals were instrumented, and then obturated with thermoplasticized gutta-percha using AH-26 as the sealer. The roots were randomly divided into eight different groups, and apical root-end resections were performed using eight different instruments, which included high and low speed burs and a scalpel blade. After each root was resected, the surface area of the root end was measured. Cultured human periodontal ligament fibroblasts were radiolabelled and then allowed to attach, in vitro, to the root-ends. Cell attachment to the resected root-ends was determined by counting in a liquid scintillation system and expressed as the number of decays per min/mm2 (DPM/mm2) of root surface. RESULTS There was no significant difference in fibroblast attachment to the root-ends prepared with various instruments. CONCLUSIONS These findings indicate that the choice of instrument for root-end resection has little influence on the initial attachment of fibroblasts, and thus may have little effect on healing following root-end resection.
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Affiliation(s)
- G D Weston
- Department of Dentistry, University of Queensland, Brisbane, Australia
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10
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Abstract
BACKGROUND There is limited clinical evidence that pathologically migrated teeth may reposition themselves after conventional periodontal treatment. The current research was carried out to determine the frequency of spontaneous repositioning of pathologically migrated teeth after routine periodontal therapy, and to study the relation between the severity of migration and the degree of repositioning following treatment. METHODS Sixteen patients with moderate to severe periodontal disease and presenting 33 diastema sites secondary to pathologic migration participated in this study. After conventional periodontal treatment had been performed, reactive repositioning was assessed by measuring the space between pathologically migrated teeth and adjacent teeth on study models obtained at baseline, re-evaluation at 6 weeks after scaling and root planing, and 4 months after surgery. RESULTS After scaling and root planing only, 48.5% of all sites exhibited some degree of repositioning with 36.4% of all sites closing completely. After surgery (6 months after baseline observations), 69.7% of all sites exhibited some degree of repositioning with 51.5% of all sites closing completely. When only small to moderate diastemata were considered (<1 mm), 77.8% of sites closed completely. CONCLUSIONS The findings of this study support the hypothesis that spontaneous repositioning after conventional periodontal treatment is likely, particularly when only light to moderate degrees of pathologic migration are considered. We hypothesize that this spontaneous movement is due to wound contraction during healing.
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Affiliation(s)
- P E Gaumet
- University of Texas Health Science Center at San Antonio, Department of Periodontics, 78284-7894, USA
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Abstract
The impact of Tony Melcher's scientific work on periodontal regeneration is discussed in light of his interests in cellular domains and bone healing, the physiology of the periodontal ligament, and his development of organ and cell culture methods. Collectively, his scientific accomplishments have pointed us in new directions for approaching periodontal regeneration and have helped to create new research opportunities, many of which were previously unrecognized. Tony's scientific ideas are insightful, numerous, and compelling; his ability to make these ideas come alive and relevant to clinical problems has been a major influence in shaping our current thinking on the biology of the periodontium and on periodontal regeneration.
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Affiliation(s)
- C A McCulloch
- MRC Group in Periodontal Physiology, Faculty of Dentistry, University of Toronto, ON, Canada
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Affiliation(s)
- U M Wikesjö
- Department of Periodontology, Temple University School of Dentistry, Philadelphia, Pennsylvania, USA
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Tenorio D, Foyle DM, Hughes FJ. The modulatory role of cementum matrix on osteoblastic cells in vitro. J Periodontal Res 1997; 32:362-74. [PMID: 9210090 DOI: 10.1111/j.1600-0765.1997.tb00546.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The formation of new cementum is an important issue in clinical periodontology, as cementum is required to provide attachment for newly formed periodontal tissues to the root surface. In this study a model of cementogenesis in vitro was used in order to test the effects of root surface demineralization on the migration, attachment and formation of a cementum-like tissue by osteoblastic cells cultured on cementum and to test the specificity of cementum matrix in modulating those effects by comparison of root co-cultures with bone co-cultures. It was demonstrated that root surface demineralization did not significantly alter the orientation, number and attachment of cells to the root co-cultures. The results also demonstrated that cementum and bone matrix appear to behave differently in culture, as seen by their distinct action on the morphological profile of the attached cells and the extracellular matrix deposited by these cells. These results demonstrate that although cementum matrix appears to stimulate the production of cementum-like tissue, this action is not confined to cementum matrix alone, since a similar material was also deposited on dentine and bone surfaces. Thus, these results do not support a specific action of cementum matrix on the modulation of the cementoblast phenotype. The use of co-cultures of neonatal rat calvaria cells with root slices represents a promising model of cementogenesis in vitro; however, studies should be undertaken towards the identification of markers to distinguish between cementoblast and osteoblast phenotypes in order to further validate this model.
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Affiliation(s)
- D Tenorio
- Department of Periodontology, St Bartholomews & The Royal London School of Medicine & Dentistry, UK
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Beertsen W, McCulloch CA, Sodek J. The periodontal ligament: a unique, multifunctional connective tissue. Periodontol 2000 1997; 13:20-40. [PMID: 9567922 DOI: 10.1111/j.1600-0757.1997.tb00094.x] [Citation(s) in RCA: 360] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- W Beertsen
- Department of Periodontology, Academic Center for Dentistry Amsterdam (ACTA) University of Amsterdam, The Netherlands
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15
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D'Errico JA, MacNeil RL, Takata T, Berry J, Strayhorn C, Somerman MJ. Expression of bone associated markers by tooth root lining cells, in situ and in vitro. Bone 1997; 20:117-26. [PMID: 9028535 DOI: 10.1016/s8756-3282(96)00348-1] [Citation(s) in RCA: 147] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Periodontal disease is marked by inflammation and subsequent loss and/or damage to tooth-supporting tissues including bone, cementum, and periodontal ligament. A key tissue in the initial process of periodontal development as well as regeneration following periodontal disease is cementum. Research efforts aimed toward understanding mechanisms involved in periodontal development and regeneration, and in particular the formation of root cementum, have been hampered by an inability to isolate and culture cells involved in cementum production (i.e., cementoblasts). Much has been learned regarding the processes and mechanisms involved in bone formation and function from experiments using bone cell cultures. Therefore, the purpose of this study was to develop a strategy whereby cementoblasts could be isolated, cultured, and characterized. As a first step, using in situ hybridization, we determined the timed and spatial expression of mineral-associated proteins during first molar root development in CD-1 mice. These proteins included dentin sialoprotein (DSP), osteopontin (OPN), bone sialoprotein (BSP), osteocalcin (OCN), and type I collagen. During root development in mice BSP, OPN, and OCN mRNAs were expressed selectively by cells lining the tooth root surface--cementoblasts--with high levels of expression at day 41. Importantly, at this time point BSP, OPN, and OCN mRNAs were not expressed throughout the periodontal ligament. These findings provided us with markers selective to root-lining cells, or cementoblasts, in situ, and established the time (day 41) for isolating cells for in vitro studies. To isolate cells from tissues adherent to the root surface, enzymatic digestion was used, similar to what are now considered classical techniques for isolation of osteoblasts. To determine whether cells in vitro contained root-lining cells and cementoblasts, cultured cells were analyzed for expression of mineral-associated proteins. Cells within this heterogeneous primary population expressed type I collagen, BSP, OPN, and OCN as determined by in situ hybridization. In contrast, cells within this population did not express dentin sialoprotein, an odontoblast-specific protein. These procedures have provided a means to obtain root-lining cells in vitro that can now be cloned and used for studies directed at determining the properties of root-lining cells, or cementoblasts, in vitro.
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Affiliation(s)
- J A D'Errico
- Department of Periodontics/Prevention/Geriatrics and Pharmacology, University of Michigan, Ann Arbor, USA.
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Blomlöf JP, Blomlöf LB, Lindskog SF. Smear removal and collagen exposure after non-surgical root planing followed by etching with an EDTA gel preparation. J Periodontol 1996; 67:841-5. [PMID: 8884639 DOI: 10.1902/jop.1996.67.9.841] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Low pH aqueous solutions of citric acid have been used in surgical periodontal therapy mainly for two reasons. It dissolves smear after a relatively short exposure time and it has been claimed to selectively remove root surface-associated mineral exposing collagen to varying degrees. The use of low pH etching agents has recently been challenged in both experimental in vitro and in vivo studies based on their necrotizing effect on the surrounding periodontal tissues. The purpose of the present study was to assess the efficacy of subgingival application of an EDTA gel preparation in removing smear and exposing collagen fibers in root surfaces following non-surgical periodontal therapy. Root surfaces which were root planed did not reveal any patent dentinal tubuli or collagen fibers. This was in contrast to the findings seen after root planing followed by etching, where intertubular surfaces were covered by a dense fibrillar network extending into patent dentinal tubuli. In high magnification these intertubular fibers displayed the cross-striated texture typical for collagen fibers. Etching of root planed surfaces with EDTA may thus enhance the effect of non-surgical root debridement in the same way as has been shown during experimental surgical procedures.
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Affiliation(s)
- J P Blomlöf
- Department of Oral Histology and Cell Biology, School of Dentistry, Karolinska Institutet, Stockholm, Sweden
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Qian JJ, Bhatnagar RS. Enhanced cell attachment to anorganic bone mineral in the presence of a synthetic peptide related to collagen. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1996; 31:545-54. [PMID: 8836852 DOI: 10.1002/(sici)1097-4636(199608)31:4<545::aid-jbm15>3.0.co;2-f] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We have examined the ability of a synthetic 15-residue peptide, P-15, related to a biologically active domain of type I collagen, to promote attachment of human dermal fibroblasts to anorganic bovine bone mineral (ABM) phase. The attachment of cells increased with increasing content of P-15 on the surface of ABM particles, as seen by the increased binding of radiolabeled cells, and by light microscopy and scanning electron microscopy. Incorporation of radioactive precursors of DNA and protein synthesis showed that cells on P-15-coated ABM synthesized over twofold the amount of DNA and protein than did cells on uncoated ABM. Fibroblasts attached to ABM in the presence of P-15 formed three-dimensional colonies. Cellular bridges formed between adjacent particles which aggregated in clusters with tissue-like structure. Cultures on ABM.P-15 stained for alkaline phosphatase. These observations suggest that P-15-coated ABM may be a useful matrix for bone repair.
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Affiliation(s)
- J J Qian
- Laboratory of Connective Tissue Biochemistry, University of California, San Francisco 94143-0424, USA
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Abstract
BACKGROUND Fibroblasts are the predominant cells of the periodontal ligament (PL) and have important roles in the development, function, and regeneration of the tooth support apparatus. Biological processes initiated during the formation of the PL contribute to the long-lasting homeostasic properties exhibited by PL fibroblast populations. DEVELOPMENT The formation of the PL is likely controlled by epithelial-mesenchymal and epithelial hard tissue interactions, but the actual mechanisms that contribute to the development of cellular lineages in the PL are unknown. Fibroblasts in the normally functioning PL migrate through the tissue along collagen fibres to cementum and bone and in an apico-coronal direction during tooth eruption. ADULT TISSUE: Cell kinetic experiments have shown that PL fibroblasts comprise a renewal cell system in steady-state and the progenitors can generate multiple types of more differentiated, specialized cells. Progenitor cell populations of the PL are enriched in locations adjacent to blood vessels and in contiguous endosteal spaces. In normally functioning periodontal tissues, there is a relatively modest turnover of cells in which apoptotic cell death balances proliferation. Large increases of cell formation and cell differentiation occur after application of orthodontic forces or wounding. As PL cells comprise multiple cellular phenotypes, it has been postulated that after wounding, the separate phenotypes repopulating the site will ultimately dictate the tissue form and type. CONCLUSIONS PL fibroblasts play an essential role in responses to mechanical force loading of the tooth by remodelling and repairing effete or damaged matrix components. In consideration of the important roles played by fibroblasts in PL homeostasis, they could be described as "the architect, builder, and caretaker" of the periodontal ligament.
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Affiliation(s)
- P Lekic
- MRC Group in Periodontal Physiology, Faculty of Dentistry, University of Toronto, Ontario, Canada
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Pitaru S, McCulloch CA, Narayanan SA. Cellular origins and differentiation control mechanisms during periodontal development and wound healing. J Periodontal Res 1994; 29:81-94. [PMID: 8158503 DOI: 10.1111/j.1600-0765.1994.tb01095.x] [Citation(s) in RCA: 166] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In the context of cellular origins, odontogenic epithelium and oral epithelium are the sources for junctional epithelium during development and during wound healing respectively. In contrast, both odontogenic and non-odontogenic mesenchyme contain the progenitors for gingival fibroblasts in developing tissues while in wounded tissues, gingival fibroblasts are derived from gingival connective tissues and comprise a heterogeneous population of cells with diverse properties and functions. Periodontal ligament, bone and cementum cell populations apparently originate from dental follicle progenitor cells during development, but during wound healing derive from ancestral cells in periodontal ligament and bone. Cellular differentiation in developing periodontium is governed in part by epithelial-mesenchymal interactions that generate specific signals which regulate selective cell populations in time and space. On the other hand, differentiation during wound healing and regeneration is regulated by a vast array of extracellular matrix informational molecules and by cytokines that induce both selective and non-selective responses in the different cell lineages and their precursors. Further, several important signalling systems are irretrievably lost after development is complete. Thus, in the context of cellular origins and differentiation, developing and wounded periodontal tissues exhibit fundamental differences. Future prospects for improved healing and regeneration of periodontal tissues may derive from identification and isolation of informational molecules that are stored in connective tissue matrices. These molecules and elucidation of their functions may open new perspectives in our understanding of the biology of periodontal wound healing and may provide novel approaches to periodontal regeneration.
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Affiliation(s)
- S Pitaru
- Department of Oral Biology, Maurice and Gabriela Goldschleger School of Medicine, Tel Aviv University, Israel
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20
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Massas R, Pitaru S, Weinreb MM. The effects of titanium and hydroxyapatite on osteoblastic expression and proliferation in rat parietal bone cultures. J Dent Res 1993; 72:1005-8. [PMID: 8388412 DOI: 10.1177/00220345930720060201] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Titanium and hydroxyapatite are used for the fabrication of dental and orthopedic implants. The longevity of these implants depends on the amount and rate of bone formation that occurs around their surfaces. In the present study, the effects of titanium, hydroxyapatite, and polystyrene (control) on the proliferation of rat calvarial cells, and on their capacity to express alkaline phosphatase and respond to parathyroid hormone (PTH) stimulation, were studied. The nature of the substrate did not affect the DNA and protein contents of experimental and control cultures throughout the experimental period. Alkaline phosphatase expression and PTH response, as assessed by DNA synthesis and adenylate cyclase activity, were higher in cultures grown on hydroxyapatite and polystyrene than in those grown on titanium. These results indicate that hydroxyapatite was a more favorable substrate than titanium for the growth and differentiation of osteoblast-like cells in vitro.
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Affiliation(s)
- R Massas
- Department of Oral Biology, Goldschleger School of Dental Medicine, Tel Aviv University, Israel
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21
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Hou LT, Kollar EJ, Yaeger JA. Epithelial cell-fibroblast interactions: modulation of extracellular matrix proteins in cultured oral cells. J Periodontal Res 1993; 28:102-14. [PMID: 8478784 DOI: 10.1111/j.1600-0765.1993.tb01057.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A model system involving co-cultures of human gingival or periodontal ligament fibroblasts with mouse epithelial root sheath cells or human gingival epithelial cells was used to study epithelial cell-fibroblast interactions. Double-labeled immunofluorescence and microfluorometry were used to investigate the expression of extracellular matrix molecules of collagen type I (collagen I), type III (collagen III) and fibronectin in fibroblasts. When fibroblasts from either source were cultured alone, the fluorescence for collagen I and fibronectin ranged from strongly positive to almost negative. Collagen III staining was relatively weak compared with that of collagen I. After 2-3 days of co-culture, gingival fibroblasts and ligament fibroblasts adjacent to the mouse sheath cells exhibited enhanced intracellular fluorescence for collagen I and fibronectin. Very little change was observed for collagen III. Gingival fibroblasts cultured with gingival epithelial cells showed increased fluorescence for collagen I but decreased fluorescence for fibronectin. In contrast, the fluorescence intensity for both collagen I and fibronectin in ligament fibroblasts were reduced after 3 days of co-culture with gingival epithelial cells. Ultrastructural changes in fibroblasts co-cultured with mouse root sheath cells included increased Golgi cisternae and vesicles and an increased abundance of rough endoplasmic reticulum, polyribosomes, secretory vesicles and pinocytotic vesicles. Thus, the expression of extracellular matrix proteins and the metabolic activity of fibroblasts can be modulated by oral epithelial cells.
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Affiliation(s)
- L T Hou
- Department of Biostructure and Function School of Dental Medicine, University of Connecticut, Farmington
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22
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23
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24
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Pitaru S, Noff M. The development of a novel implant: induction of a non-rigid and self-renewing anchorage of artificial implants to bone. CLINICAL MATERIALS 1992; 13:29-34. [PMID: 10171970 DOI: 10.1016/0267-6605(93)90086-m] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Artificial implants currently used in orthopaedic surgery and dentistry are anchored to the surrounding bone by rigid mechanical fixation. Long-term studies indicate that the rate of implant failure due to loosening increases steeply after 10 years of function. The loosening is attributed to the micro-movements occurring at the bone implant interface. Non-rigid, self-renewing ligamentous anchorage is nature's solution to the problem of micro-movements. An excellent example of this type of anchorage is the tooth-bone system, where the tooth is anchored to the bone by a fibrous connective tissue. A novel artificial implant, bearing on its surface a unique biological substrate (BS), was designed to induce a ligamentous anchorage of implant to bone. The implant consists of a metallic core to which the BS is bound. The BS is a composite of plastic material and a collagen mesh which is partly incorporated into the plastic material and partly freely extended from its outer surface as artificial Sharpey's fibers. BS fabrication did not affect the capacity of the collagen to withstand non-specific degradation in vitro. Non-weight-bearing implants implanted into the femoral bone of rats induced and maintained a ligament-like tissue up to 4 months. The collagen fibers of the ligament-like tissue were spliced with the artificial BS Sharpey's fibers and were also anchored as Sharpey's fibers into the surrounding bone. Examination of control plastic implants (without the BS) revealed bone formation in close approximation to the implant surface.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S Pitaru
- Department of Oral Biology, Goldschleger School of Dental Medicine, Tel Aviv University, Israel
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25
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Yonemura K, Narayanan AS, Miki Y, Page RC, Okada H. Isolation and partial characterization of a growth factor from human cementum. BONE AND MINERAL 1992; 18:187-98. [PMID: 1392693 DOI: 10.1016/0169-6009(92)90806-o] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cementum is the mineralized interface through which collagen fibers of periodontal connective tissues are anchored onto the tooth surface. We have isolated and partially characterized a mitogenic factor from human cementum which has properties different from other growth factors. Cementum was harvested from healthy human teeth, extracted in 1.0 M CH3COOH and mitogenic activities were fractionated by heparin-affinity chromatography. Proteins eluted by 0.4-0.6 M NaCl, which contained most of the cementum mitogenic activity, were precipitated by trichloroacetic acid and resolved by HPLC through ion-exchange and reverse-phase columns. NaDodSO4-polyacrylamide gel electrophoresis revealed that the purified preparation contained a M(r) 23,000 protein and this protein was associated with mitogenic activity. The purified cementum-derived growth factor (CGF) was active alone, but at suboptimal concentrations its activity was potentiated by small quantities of plasma-derived serum and epidermal growth factor (EGF). The activity was resistant to heat, but it was destroyed by trypsin digestion. Reduction and alkylation destroyed the mitogenic activity, however electrophoretic mobility was not affected. Binding of EGF to fibroblast membranes was not affected by the CGF and assays to detect platelet-derived growth factor were negative. These characteristics indicated that CGF is a distinct molecular species. Our data show that cementum contains several mitogenic factors and that CGF is the major cementum mitogen.
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Affiliation(s)
- K Yonemura
- Department of Pathology, School of Medicine, University of Washington, Seattle
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26
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Schroeder HE. Biological problems of regenerative cementogenesis: synthesis and attachment of collagenous matrices on growing and established root surfaces. INTERNATIONAL REVIEW OF CYTOLOGY 1992; 142:1-59. [PMID: 1487394 DOI: 10.1016/s0074-7696(08)62074-4] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- H E Schroeder
- Department of Oral Structural Biology, University of Zurich, Switzerland
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27
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Holtgrave EA. Attachment of cementum on different hydroxylapatite ceramic (HAC) substrata in vivo. A light and electron microscopic study. J Periodontal Res 1991; 26:511-8. [PMID: 1662267 DOI: 10.1111/j.1600-0765.1991.tb01803.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The role of substrate surface characteristics for periodontal regeneration was studied in rats. Cementogenesis was initiated by dental follicle cells retained after dissecting out a molar tooth germ in 5-day-old rats. The tooth germ was substituted by a bone replacement material, namely HAC granules of porous consistency. Tissue blocks were removed after 24 weeks and processed for light and electron microscopic examination. On all HAC surfaces a new cementum-like tissue developed, similar to that of natural root surfaces. The results strongly indicate that the exposure of collagen fibers is not essential in order to achieve new periodontal attachment.
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Affiliation(s)
- E A Holtgrave
- Department of orthodontics, Free University of Berlin, FRG
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28
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Pitaru S, Hekmati M, Metzger Z, Savion N. Epithelial-connective tissue interaction on the tooth surface: an in vitro model. J Periodontal Res 1991; 26:461-7. [PMID: 1837052 DOI: 10.1111/j.1600-0765.1991.tb01796.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In the present study, and in vitro system was developed and designed to examine the interaction between gingival fibroblasts (GF) and epithelial cells (EC) on the tooth surface. Porcine roots were cut transversely into 300 microns-thick root slices (RS). Gingival explants were placed on the upper RS surface and cultured in a defined medium permissive for the growth of EC. After 4 or 6 days, RS yielding EC were transferred onto confluent cultures of GF and further co-cultured for either 4 or 8 d. Cultures were then fixed and examined by SEM. The upper RS surfaces and the upper half of their peripheral aspect were covered by EC. The lower half of the peripheral RS surfaces were populated by GF originating from the confluent culture of GF. EC and GF made contact at approximately the middle of the side of the root slice. In cultures of epithelial components grown in defined medium for either 4 or 6 d and harvested 4 d after assembling the system, the EC-GF junction was located 117 +/- 45 and 271 +/- 82 microns, respectively from the upper RS aspect. Extending the co-culture period did not affect the EC-GF junction location. These results indicate that GF-EC contact stops the migration of these cells on root surfaces in vitro. The described system should be valuable for studying cellular events that may affect the formation of a new dentogingival junction following surgical periodontal therapy.
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Affiliation(s)
- S Pitaru
- Section of Oral Biology, Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel
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29
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Olson S, Arzate H, Narayanan AS, Page RC. Cell attachment activity of cementum proteins and mechanism of endotoxin inhibition. J Dent Res 1991; 70:1272-7. [PMID: 1833426 DOI: 10.1177/00220345910700090801] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Cementum occupies a unique anatomical location where soft connective tissues of the periodontium are attached to root surfaces. Cell attachment properties of proteins present in cementum were studied. Human and bovine cementum were extracted with 0.5 mol/L CH3COOH followed by 4 mol/L guanidine, and proteins were separated by ion-exchange chromatography and SDS-polyacrylamide gel electrophoresis. Cells were labeled with radioactive amino acids and added to tissue-culture plastic plates incubated with cementum proteins, and attachment was measured. Results showed that cementum proteins promoted the attachment of smooth muscle cells, endothelial cells, and fibroblasts, but not epithelial cells. Fibroblasts attached more efficiently than other cell types, and they manifested spreading with re-organization of actin filaments. No attachment occurred to plates incubated with endotoxin from A. actinomycetemcomitans. Fewer fibroblasts attached to plates treated with cementum proteins in the presence of endotoxin, but cells pre-treated with endotoxin attached normally. Attachment was not inhibited when plates were incubated first with attachment proteins and then with endotoxin; however, it was decreased when endotoxin or bovine serum albumin preceded cementum proteins. Cementum proteins with Mr 68,000, 61,000, 55,000, and 36,000 (p68, p61, p55, and p36, respectively) manifested attachment activity, while protein(s) with Mr 23,000-24,000 did not. Western blots revealed that guanidine extracts contained three bands cross-reacting with anti-bovine sialoprotein-II antibody, but the p61, p55, and p36 were negative. We conclude that cementum contains bovine sialoprotein-II and at least four other fibroblast attachment proteins, and that they do not support epithelial cell attachment.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S Olson
- Department of Pathology, University of Washington, Seattle 98195
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30
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Grevstad HJ. Collagen fiber reunion in wound repair: transmission electron microscopic study of rat gingiva. SCANDINAVIAN JOURNAL OF DENTAL RESEARCH 1990; 98:537-43. [PMID: 2091250 DOI: 10.1111/j.1600-0722.1990.tb01009.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The purpose of this study was to characterize connective tissue at the site of reunion following surgical injury of the transseptal fiber system in rat molars. Eight conventional albino rats aged 50 days were incised interdentally and the lesions allowed to heal for 14 days followed by specimen preparation for transmission electron microscopy. Four specimens with identifiable areas of fiber attachment at the light microscopic level of magnification were selected for a detailed ultrastructural examination. Transitional connective tissue consisted of thin (250-375 A) and thick (greater than or equal to 450 A) collagen fibrils at a ratio of 41/59 mainly arranged as aggregates of uniformly sized fibrils. Fibril thickness in the vicinity of fibroblasts (n = 40) varied at a ratio of 65 (thin)/35 (thick). Distribution and spatial arrangement of fibrillar components indicate that the site of reunion is characterized by separate aggregates of fibrils rather than alignment of individual collagen fibrils of varying thickness suggestive of covalent linkage.
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Affiliation(s)
- H J Grevstad
- Department of Periodontology, School of Dentistry, University of Bergen, Norway
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31
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Fardal O, Lowenberg BF. A quantitative analysis of the migration, attachment, and orientation of human gingival fibroblasts to human dental root surfaces in vitro. J Periodontol 1990; 61:529-35. [PMID: 2167966 DOI: 10.1902/jop.1990.61.8.529] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The purpose of this study was to assess the migration, attachment, and orientation of human gingival fibroblasts to human dental roots over a period of 21 days in vitro. The fibroblasts were incubated with a total of 120 periodontally diseased and non-diseased root slices (200 microns thickness) which had been treated in the following manner: 1) Root planed diseased root (DT); 2) Root planed and citric acid demineralized diseased root (DTD); 3) Non-treated diseased root (DNT); 4) Citric acid demineralized diseased root (DNTD); 5) Non-diseased control (ND); 6) Citric acid demineralized non-diseased root (CA); 7) Citric acid and collagenase digested non-diseased root (CAC); 8) EDTA demineralized non-diseased root (E); and 9) EDTA-demineralized and collagenase-digested non-diseased root (EC). The results showed that that most active phase of cell attachment and orientation occurred during the first 10 days of the experiment. Statistical differences were observed between the variables, and, in terms of cell attachment and orientation to the root slices, it was concluded that: 1) Root planing improves diseased roots; 2) Acid demineralization subsequent to root planing improved diseased roots to such an extent as to render them comparable to non-diseased roots; 3) Citric acid demineralization alone improved diseased roots to the same extent as root planed diseased roots; 4) The exposure of collagen fibrils resulting from acid demineralization of the tools is not the sole reason for the improvement of the root surface, but rather a combination of the exposed collagen fibrils with the creation of a more hospitable environment was found to be responsible.
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Affiliation(s)
- O Fardal
- University of Toronto, Faculty of Dentistry
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32
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Aukhil I, Nishimura K, Fernyhough W. Experimental regeneration of the periodontium. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 1990; 1:101-15. [PMID: 2129620 DOI: 10.1177/10454411900010020101] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- I Aukhil
- Department of Periodontics, University of North Carolina School of Dentistry, Chapel Hill
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33
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McAllister B, Narayanan AS, Miki Y, Page RC. Isolation of a fibroblast attachment protein from cementum. J Periodontal Res 1990; 25:99-105. [PMID: 2139124 DOI: 10.1111/j.1600-0765.1990.tb00899.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cementum forms the interface through which soft connective tissue of the periodontium is attached to the root surface. The interactions between cementum and connective tissue are not completely understood and whether cementum influences periodontal connective tissue formation and regeneration is not clear. We have examined the effect of cementum components on the attachment of gingival fibroblasts. Cementum was harvested from healthy human and bovine teeth and extracted sequentially in 0.5 M CH3COOH, 4 M guanidine and bacterial collagenase. Fibroblast attachment was measured using 51Cr-labelled human gingival fibroblasts on tissue culture plates previously incubated with cementum components. Results showed that all three extracts mediated fibroblast attachment and attachment was dependent on concentration and incubation time. The attachment activity was not destroyed by digestion with bacterial collagenase or by antibodies to fibronectin and laminin. However, it was inhibited by a peptide containing the amino acid sequence RGD. By gel filtration or HPLC using a DEAE-cellulose column several proteins with attachment activity were fractionated. SDS-polyacrylamide gel electrophoresis revealed that HPLC fraction eluted by 0.2-0.3 M NaCl contained a protein with molecular weight 55 kDa as a major component. This protein was isolated and shown to promote fibroblast attachment, and optimal attachment occurred at a concentration of 2 micrograms/ml. We conclude that cementum contains substances capable of mediating fibroblast attachment and that these substances play an important role in periodontal connective tissue formation and regeneration by facilitating fibroblast attachment to root surfaces.
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Affiliation(s)
- B McAllister
- Department of Periodontics, University of Texas Health Sciences Center, San Antonio
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34
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Al-Ali W, Bissada NF, Greenwell H. The effect of local doxycycline with and without tricalcium phosphate on the regenerative healing potential of periodontal osseous defects in dogs. J Periodontol 1989; 60:582-90. [PMID: 2810011 DOI: 10.1902/jop.1989.60.10.582] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The purpose of this study was to evaluate the clinical and histological effects of high concentration doxycycline on osseous regeneration in adult beagle dogs. Four 5 mm two-wall periodontal osseous defects were created in the premolar and molar area of each quadrant yielding a total of 48 defects in the three dogs. Ligature-induced periodontitis was maintained for 6 weeks. Two weeks following ligature removal, one of the following graft procedures was randomly assigned to each defect: 1) doxycycline alone (DOX); 2) tricalcium phosphate alone (TCP); 3) a combined graft of DOX plus TCP, or 4), surgically debrided control. All areas received thorough scaling and root planing at the time of surgery. Clinical parameters evaluated at 4, 12, and 20 weeks after the surgical treatment included the gingival index and probing depths. Crevicular fluid was examined at 3, 10, and 28 days postoperatively for tetracycline fluorescence. Direct clinical measurements from the CEJ to a notch placed at the base of the defect and from the CEJ to the alveolar crest were made at the time of surgical treatment and reentry. The reentry procedures were performed at 4, 12, and 20 weeks postoperatively. Immediately following reentry block sections were obtained from each quadrant and prepared for examination with the light microscope. The gingival index and probing depth measurements showed greater improvement in the DOX and DOX + TCP groups. Increased regeneration (new bone, cementum, and periodontal ligament) and reduced alveolar crest resorption were observed more frequently in DOX and DOX + TCP defects, while healing by long junctional epithelium was more common in defects not treated with doxycycline.(ABSTRACT TRUNCATED AT 250 WORDS)
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35
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Qwarnström EE, MacFarlane SA, Page RC. Effects of interleukin-1 on fibroblast extracellular matrix, using a 3-dimensional culture system. J Cell Physiol 1989; 139:501-8. [PMID: 2786880 DOI: 10.1002/jcp.1041390308] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This study describes the alterations induced by Interleukin-1 alpha and -beta (IL-1 alpha and IL-1 beta) on fibroblast-synthesized extracellular matrix. Fibroblasts were grown between pieces of dentin or in collagen-coated Terasaki wells for 3 or 6-9 weeks to create 3-dimensional cell-containing matrices constituted primarily of proteoglycans and collagens, respectively. Following incubation with IL-1 alpha or IL-1 beta (10(-9) M) at 37 degrees C for 24 or 72 hr, samples were prepared for light and electron microscopy. Both IL-1 alpha and IL-1 beta induced collapse of the extracellular matrix by 72 hr, as manifested by a decrease of the cross-sectional area and an increased density of the matrices. Three-week matrices were reduced 26% and 45% by using IL-1 alpha and IL-1 beta, respectively. Comparable values obtained by using 6-week matrices were 14% and 30%. Cells within the matrix, normally stellate in shape with numerous extended processes, attained a more rounded or spindle shape with few and reduced processes and showed apparent alterations at cell matrix attachment sites and rearrangement of the cytoskeleton. Elongated cells at the top of the matrix appeared more compressed. The alterations were more pronounced in cultures incubated with IL-beta than with IL-1 alpha. Immunocytochemistry of extracellular matrix components revealed a decrease in staining intensity of chondroitin and dermatan sulfate in the 3-week matrix following IL-1 beta incubation. There was also a decrease in collagen type 1 staining of 9-week matrices treated with IL-1 alpha or IL-1 beta. These studies show that IL-1 has an effect on fibroblast-synthesized extracellular matrix and indicate that the effects of IL-1 alpha and IL-1 beta may differ. The resulting collapse of the matrix appears at least in part to be due to changes in proteoglycans and collagens.
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Affiliation(s)
- E E Qwarnström
- Department of Pathology, University of Washington, Seattle 98195
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36
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Selvig KA, Bogle G, Claffey NM. Collagen linkage in periodontal connective tissue reattachment. An ultrastructural study in beagle dogs. J Periodontol 1988; 59:758-68. [PMID: 3204483 DOI: 10.1902/jop.1988.59.11.758] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Early stages of connective tissue reattachment to surgically denuded cementum and root dentin following citric acid application were studied in fenestration wounds. Block specimens were obtained after seven, 14, and 21 days. Continuity between newly deposited collagen fibrils in the granulation tissue and unmasked dental matrix collagen had been established within seven days by interdigitation of fibrils in an up to 0.5 micron-wide zone at the cementum or dentin surface. Splicing of collagen at the fibrillar level by direct attachment to the severed end of matrix fibrils or by juxtapositioning of new and old fibrils was seen in rare instances only. At 14 and 21 days, distinct bundles of collagen fibrils inserted deeply into the orifice of dentinal tubules. Arrested and reversed surface resorption was encountered at all time points. At these sites as well, new collagen fibrils interdigitated with denuded matrix collagen, while some resorbed surfaces were characterized by absence of collagen continuity. The results lend continued support to the concept of reattachment based on interdigitation of collagen fibrils. However, since attachment is established even in the absence of this feature, a significant role for specific attachment substances not shown can also be postulated.
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Affiliation(s)
- K A Selvig
- University of Bergen, School of Dentistry, Department of Dental Research, Norway
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37
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Pitaru S, Hekmati M, Geiger S, Savion N. The effects of partial demineralization and fibronectin on migration and growth of gingival epithelial cells on cementum in vitro. J Dent Res 1988; 67:1386-91. [PMID: 3183155 DOI: 10.1177/00220345880670110501] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The capacity of mineralized cementum to support epithelial cell migration and growth and the effect that fibronectin and partial demineralization of cementum have on these processes were assessed in vitro. Dog gingival explants, 1 X 2 mm, were cultured on the cementum surfaces of pig root pieces in a defined medium consisting of DMEM and F12 (1V/1V), transferrin, insulin, epidermal growth factor, cortisone, selenium, and high-density lipoprotein. Sixty root pieces were divided into four equal groups according to the treatment: (1) untreated mineralized cementum; (2) treated with 5 micrograms of fibronectin; (3) partially demineralized in 18% EDTA for 30 min; and (4) both partially demineralized and fibronectin-treated as above. Epithelial cell migration and growth on each of the four differently treated cementum surfaces were assessed histomorphometrically by means of scanning electron microscopy. The defined culture medium supported the selective migration and growth of epithelial cells from the gingival explants onto the mineralized cementum. This was confirmed by the positive immunostaining of these cells with antikeratin antibodies. Partial demineralization of cementum inhibited epithelial migration and growth by 83% and 91%, respectively. Fibronectin treatment did not affect epithelial cell migration and growth on mineralized cementum, but it decreased the degree of epithelial cell migration and growth inhibition on partially demineralized cementum to 57% and 43%, respectively. The results indicate that: (i) mineralized cementum may consist of components that are recognized by gingival epithelial cells and support their migration and growth in vitro; (ii) these components can be removed by demineralization; and (iii) fibronectin partially restores epithelial cell migration and growth on partial demineralized cementum in vitro.
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Affiliation(s)
- S Pitaru
- Department of Oral Biology, Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel
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Pitaru S, Hekmati M, Soldinger M, Savion N. Growth and migration of gingival epithelial cells on mineralized and partially demineralized root surfaces in an in vitro system. J Periodontol 1988; 59:531-4. [PMID: 3050020 DOI: 10.1902/jop.1988.59.8.531] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The capacity of epithelial cells to migrate and grow from gingival explants cultured on mineralized and partially demineralized root surfaces in an in vitro system was assessed. Explants of attached gingiva were obtained from mongrel dogs, cut into rectangular pieces (1 x 2 mm) and cultured either on mineralized or partially demineralized cementum in a defined culture medium containing transferrin, insulin, epidermal growth factor, cortisone, high density lipoprotein and selenium. After seven days of culture, the specimens were prepared for scanning electron microscopic examination. The amount of epithelial outgrowth from each explant was assessed by measuring the distances between the four aspects of the rectangular explant and the furthest epithelial cell located opposite to each of these aspects. The mean value obtained for epithelial outgrowth of explants grown on mineralized cementum was six times higher than that for explants cultured on partially demineralized cementum. These results indicate that partially demineralized cementum does not support epithelial growth and migration in vitro.
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Affiliation(s)
- S Pitaru
- Department of Oral Biology, Maurice and Gabriela Goldschleger School of Dental Medicine and Research Department, Tel Aviv University, Israel
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Lowenberg BF, Pilliar RM, Aubin JE, Sodek J, Melcher AH. Cell attachment of human gingival fibroblasts in vitro to porous-surfaced titanium alloy discs coated with collagen and platelet-derived growth factor. Biomaterials 1988; 9:302-9. [PMID: 3214654 DOI: 10.1016/0142-9612(88)90023-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The influence of biological coating, with or without the incorporation of growth factor, on the migration, attachment and orientation of human gingival fibroblasts in relation to porous-surfaced titanium alloy (Ti6AI4V) discs, was measured. Comparison was made between coating the discs with collagen and with collagen incorporating platelet-derived growth factor (PDGF); controls comprised porous-surfaced discs coated with agar or collagen containing bovine serum albumin (used as a carrier for the PDGF), uncoated porous-surfaced Ti6AI4V discs (with or without additional protein additives) exhibited significantly higher attachment indices (AI) and orientation indices (OI) compared with naked control discs (p less than 0.01); OI was also significantly higher than that of surface-demineralized root slices (p less than 0.001) on days 1, 2 and 3. Addition of PDGF to the collagen resulted in a further enhancement in OI on days 1 and 2 (p less than 0.01) over that shown by discs coated with collagen incorporating the bovine serum albumin vehicle. There was no cell attachment and consequently, no cell orientation, in relation to Ti alloy discs that had been coated with agar. These data suggest that attachment and orientation of cells following migration in relation to porous-surfaced Ti6AI4V discs can be modified by the application of biological molecules to the surface of the disc. This may have a useful application in clinical implantology.
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Affiliation(s)
- B F Lowenberg
- MRC Programme in Dental Implantology, Faculty of Dentistry, University of Toronto, Ontario, Canada
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Preisig E, Schroeder HE. Long-term culture of human periodontal ligament cells with autologous root discs. J Periodontal Res 1988; 23:211-21. [PMID: 2969973 DOI: 10.1111/j.1600-0765.1988.tb01360.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Biagini G, Checchi L, Miccoli MC, Vasi V, Castaldini C. Root curettage and gingival repair in periodontitis. J Periodontol 1988; 59:124-9. [PMID: 3279178 DOI: 10.1902/jop.1988.59.2.124] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Twelve patients, aged 35 to 60, having adult periodontitis were treated with scaling and root planning performed with ultrasonic and hand scalers. Biopsies were taken, gingival crevicular fluid and clinical parameters were analyzed at different times, and the healing process was monitored. Findings showed a clear correlation between the amount of crevicular fluid and the histological inflammatory pattern, whereas no relationship between crevicular fluid and gingival pocket depth was apparent. In this study, no differences were found in the histological features of the repair process triggered by either type of scaler.
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Affiliation(s)
- G Biagini
- Institute of Human Morphology, University of Ancona, Italy
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Abbas DK, Albandar JM, Helgeland K, Johansen JR. Attachment of human gingival fibroblasts to planed root surfaces exposed to human plasma in vitro. Acta Odontol Scand 1987; 45:353-60. [PMID: 3314316 DOI: 10.3109/00016358709096358] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We studied the effect of exposing planed dentin surfaces (DS) to human plasma on the attachment of human gingival fibroblasts (HGF) in vitro as compared with their attachment to citric-acid-demineralized DS. Sixty-six DS were prepared from root-planed roots of surgically extracted human third molars. In a pilot experiment 30 DS were demineralized in citric acid (pH 1.0 for 3 min), and each of 3 DS were placed in a culture dish and incubated with fresh plasma for 0, 10, or 30 sec, 1, 10, or 30 min, or 1, 1.5, 2, or 4h. In a second experiment, three culture dishes containing three DS each were assigned to each of four groups. These were untreated (control), incubated with plasma for 2h, acid-demineralized only, or acid-demineralized and then incubated with plasma for 2h. To each dish was added 0.2 X 10(6) HGF, and these were incubated for 2, 6, or 24 h. The unattached cells were then removed, and the DS fixed and processed for SEM. The results showed that exposing demineralized dentin surfaces to plasma causes the absorption of a coating layer, presumably of organic nature, as early as 30 sec after exposure. Acid-demineralized DS alone or together with plasma treatment enhanced both the attachment and the growth of HGF. However, treatment with plasma alone seemed to enhance the HGF attachment less than did acid demineralization alone.
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Affiliation(s)
- D K Abbas
- Department of Periodontology, Dental Faculty, University of Oslo, Norway
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Pitaru S, Soldinger M, Madgar D, Metzger Z. Bacterial endotoxin inhibits migration, attachment, and orientation of human gingival fibroblasts in vitro and delays collagen gel contraction. J Dent Res 1987; 66:1449-55. [PMID: 3476617 DOI: 10.1177/00220345870660090801] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The purpose of this study was to assess the effect of endotoxin adsorbed to dental surfaces and to collagen type I on the migration, attachment, and orientation of human gingival fibroblasts (HGF). Transversely cut porcine tooth root slices (RS), 200 micron thick, were prepared. Half of the RS obtained were partially demineralized in EDTA. Half of the demineralized and non-demineralized RS were incubated with 400 micrograms/mL of endotoxin for 24 hr, whereas the other half were maintained in PBS and served as controls. Experimental and control RS were placed on confluent layers of HFG and cultured for six days. Cell migration toward and cell attachment to the periphery of the RS and the formation of oriented cell sheets were assessed by means of photographic techniques. Additionally, six-day-old cultures were fixed and processed for SEM observation. In separate experiments, the effect of endotoxin on cell attachment to collagen type I and on contraction of three-dimensional collagen gels was assessed. It was found that: (i) bacterial endotoxin inhibited migration and attachment of HGF to both demineralized and non-demineralized cementum and interfered with the development of oriented cellular structure: (ii) the inhibitory effect was significantly more pronounced for non-demineralized than for demineralized cementum: (iii) the morphology of HGF attached to endotoxin-treated dental surfaces was altered compared with that of their controls: and (iv) bacterial endotoxin inhibited cell attachment to collagen type I and delayed the contraction of collagen gel.
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Ripamonti U, Petit JC, Lemmer J, Austin JC. Regeneration of the connective tissue attachment on surgically exposed roots using a fibrin-fibronectin adhesive system. An experimental on the baboon (Papio ursinus). J Periodontal Res 1987; 22:320-6. [PMID: 2442345 DOI: 10.1111/j.1600-0765.1987.tb01592.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Melcher AH, McCulloch CA, Cheong T, Nemeth E, Shiga A. Cells from bone synthesize cementum-like and bone-like tissue in vitro and may migrate into periodontal ligament in vivo. J Periodontal Res 1987; 22:246-7. [PMID: 2955109 DOI: 10.1111/j.1600-0765.1987.tb01579.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Lowenberg BF, Pilliar RM, Aubin JE, Fernie GR, Melcher AH. Migration, attachment, and orientation of human gingival fibroblasts to root slices, naked and porous-surfaced titanium alloy discs, and Zircalloy 2 discs in vitro. J Dent Res 1987; 66:1000-5. [PMID: 3475314 DOI: 10.1177/00220345870660050101] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cell migration, attachment, and orientation of cultured human gingival fibroblasts (HGF) were measured in relation to four types of specimens: Ti-6Al-4V alloy discs with either ground surfaces or porous structured surfaces, and Zr alloy discs (Zircalloy 2) with either ground surfaces or surfaces modified by being heated to form a thicker oxide cover. Surface-demineralized and non-demineralized root slices were used as controls. Initial cell attachment was measured by means of a 51Cr assay, and cell attachment and orientation following migration by an assay that measures development of the resulting refractile material in relation to the specimen. No significant difference between initial cell attachment to Ti alloy and control demineralized root slices could be detected after one hr using the 51Cr assay. However, with the second assay, cell attachment and orientation at three, seven, 10, and 14 days were significantly higher in relation to surface-demineralized root slices than to all of the metal discs and the non-demineralized root slices. While cell attachment to the surface-ground Ti alloy discs appeared to be higher than that to the porous-surfaced Ti alloy discs at three days and seven days, cell orientation to the porous-surfaced Ti alloy discs and the non-demineralized root slices at days 7, 10, and 14 was greater than that to all of the other metal discs. These data suggest that surface geometry could affect attachment and orientation of cells in vitro.
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Pitaru S, Melcher AH. Organization of an oriented fiber system in vitro by human gingival fibroblasts attached to dental tissue: relationship between cells and mineralized and demineralized tissue. J Periodontal Res 1987; 22:6-13. [PMID: 2950228 DOI: 10.1111/j.1600-0765.1987.tb01533.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Inoue T, Cox JE, Pilliar RM, Melcher AH. Effect of the surface geometry of smooth and porous-coated titanium alloy on the orientation of fibroblasts in vitro. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1987; 21:107-26. [PMID: 3549736 DOI: 10.1002/jbm.820210114] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The migration and orientation of human gingival fibroblasts in relation to the rim of smooth-surfaced and porous-coated titanium discs placed on multilayers in vitro was investigated. Samples were examined after 6 h, 24 h, 3 days, and 7 days of culture using phase-contrast and scanning electron microscopy. The cells migrated from the multilayer onto the smooth-surfaced discs forming bridges between them, and orientated along parallel circumferential grooves in the rim of the discs. This resulted in the cellular bridges orientating at an acute angle to the rim of the disc, and adjacent cells in the multilayer orientating parallel to the rim. Cellular bridges were also formed between the porous-coated discs and the multilayer but, because the cells that migrated onto, and between, the spheres of the porous-coat showed no preferred orientation, the bridges retained their orientation at right angles to the surface of the rim. This in turn resulted in the cells of the adjacent multilayer becoming similarly orientated. These observations suggest that the geometrical configuration of the surface of implants could influence whether a capsule or an orientated fibrous attachment is developed in relation to implants in vivo.
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Abstract
Reattachment is at present an ephemeral goal. There is, therefore, much interest in clarifying the events which determine patterns of cellular repopulation of denuded cementum during periodontal healing, and thus determine the outcome of reattachment surgery. It has previously been reported that human saliva inhibits the initial attachment or subsequent locomotion of human gingival fibroblast-like cells on plastic substrata in vitro, and that this property is a function of a high molecular weight sulphated glycoprotein in saliva. Recent work reported here shows that saliva in vitro also inhibits attachment to human cementum in serum-free medium. This effect can be reversed by superficial citric acid (pH 1.0) demineralisation of saliva-treated cementum. However, demineralisation itself does not augment cell attachment to either saliva-coated or normal cementum compared with controls. It is postulated that adsorption of saliva on cementum in vivo may lead to periodontal wound healing by repair (long junctional epithelium) rather than by regeneration of ligament and cementum; a novel explanation for the previously reported efficacy of citric acid in wound healing might be related to its ability to remove adsorbed saliva from the root surface and thus permit early root colonisation by connective tissue cells.
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