1
|
Fadl A, Leask A. Hiding in Plain Sight: Human Gingival Fibroblasts as an Essential, Yet Overlooked, Tool in Regenerative Medicine. Cells 2023; 12:2021. [PMID: 37626831 PMCID: PMC10453328 DOI: 10.3390/cells12162021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/01/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
Adult human gingival fibroblasts (HGFs), the most abundant cells in the oral cavity, are essential for maintaining oral homeostasis. Compared with other tissues, adult oral mucosal wounds heal regeneratively, without scarring. Relative to fibroblasts from other locations, HGFs are relatively refractory to myofibroblast differentiation, immunomodulatory, highly regenerative, readily obtained via minimally invasive procedures, easily and rapidly expanded in vitro, and highly responsive to growth factors and cytokines. Consequently, HGFs might be a superior, yet perhaps underappreciated, source of adult mesenchymal progenitor cells to use in tissue engineering and regeneration applications, including the treatment of fibrotic auto-immune connective tissue diseases such as scleroderma. Herein, we highlight in vitro and translational studies that have investigated the regenerative and differentiation potential of HGFs, with the objective of outlining current limitations and inspiring future research that could facilitate translating the regenerative potential of HGFs into the clinic.
Collapse
Affiliation(s)
| | - Andrew Leask
- College of Dentistry, University of Saskatchewan, 105 Wiggins Road, Saskatoon, SK S7N 5A2, Canada;
| |
Collapse
|
2
|
Schaeske J, Fadeeva E, Schlie-Wolter S, Deiwick A, Chichkov BN, Ingendoh-Tsakmakidis A, Stiesch M, Winkel A. Cell Type-Specific Adhesion and Migration on Laser-Structured Opaque Surfaces. Int J Mol Sci 2020; 21:ijms21228442. [PMID: 33182746 PMCID: PMC7696563 DOI: 10.3390/ijms21228442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/02/2020] [Accepted: 11/03/2020] [Indexed: 11/16/2022] Open
Abstract
Cytocompatibility is essential for implant approval. However, initial in vitro screenings mainly include the quantity of adherent immortalized cells and cytotoxicity. Other vital parameters, such as cell migration and an in-depth understanding of the interaction between native tissue cells and implant surfaces, are rarely considered. We investigated different laser-fabricated spike structures using primary and immortalized cell lines of fibroblasts and osteoblasts and included quantification of the cell area, aspect ratio, and focal adhesions. Furthermore, we examined the three-dimensional cell interactions with spike topographies and developed a tailored migration assay for long-term monitoring on opaque materials. While fibroblasts and osteoblasts on small spikes retained their normal morphology, cells on medium and large spikes sank into the structures, affecting the composition of the cytoskeleton and thereby changing cell shape. Up to 14 days, migration appeared stronger on small spikes, probably as a consequence of adequate focal adhesion formation and an intact cytoskeleton, whereas human primary cells revealed differences in comparison to immortalized cell lines. The use of primary cells, analysis of the cell-implant structure interaction as well as cell migration might strengthen the evaluation of cytocompatibility and thereby improve the validity regarding the putative in vivo performance of implant material.
Collapse
Affiliation(s)
- Jörn Schaeske
- Department of Prosthetic Dentistry and Biomedical Materials Science, Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hannover, Germany; (J.S.); (A.I.-T.); (M.S.)
| | - Elena Fadeeva
- Institute of Quantum Optics, Leibniz University of Hannover, Welfengarten 1, 30167 Hannover, Germany; (E.F.); (S.S.-W.); (A.D.); (B.N.C.)
| | - Sabrina Schlie-Wolter
- Institute of Quantum Optics, Leibniz University of Hannover, Welfengarten 1, 30167 Hannover, Germany; (E.F.); (S.S.-W.); (A.D.); (B.N.C.)
| | - Andrea Deiwick
- Institute of Quantum Optics, Leibniz University of Hannover, Welfengarten 1, 30167 Hannover, Germany; (E.F.); (S.S.-W.); (A.D.); (B.N.C.)
| | - Boris N. Chichkov
- Institute of Quantum Optics, Leibniz University of Hannover, Welfengarten 1, 30167 Hannover, Germany; (E.F.); (S.S.-W.); (A.D.); (B.N.C.)
| | - Alexandra Ingendoh-Tsakmakidis
- Department of Prosthetic Dentistry and Biomedical Materials Science, Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hannover, Germany; (J.S.); (A.I.-T.); (M.S.)
| | - Meike Stiesch
- Department of Prosthetic Dentistry and Biomedical Materials Science, Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hannover, Germany; (J.S.); (A.I.-T.); (M.S.)
| | - Andreas Winkel
- Department of Prosthetic Dentistry and Biomedical Materials Science, Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hannover, Germany; (J.S.); (A.I.-T.); (M.S.)
- Correspondence:
| |
Collapse
|
3
|
Kusakci-Seker B, Demirayak-Akdemir M. The effect of non-thermal atmospheric pressure plasma application on wound healing after gingivectomy. Int Wound J 2020; 17:1376-1383. [PMID: 32462820 DOI: 10.1111/iwj.13379] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/02/2020] [Accepted: 04/13/2020] [Indexed: 01/24/2023] Open
Abstract
Recent studies have indicated the potential benefits of Non-thermal atmospheric pressure plasma (NTAPP) as a novel therapeutic approach. The purpose of the current study was thus to assess the effect of NTAPP on gingival wound healing. Fifteen patients with bilaterally symmetrical gingival hyperplasia were included in the study. After gingivectomy and gingivoplasty, the left-hand side of the symmetrical surgical area was irradiated with NTAPP (plasma jet kINPen 11). Digital photographs of the gingival wounds were taken at baseline and days 3, 7, and 14. Wound epithelialisation was evaluated. Landry Wound Healing Index (WHI) scores and visual analogue scale (VAS) scores were also recorded. There were significant differences between the epithelialisation of the NTAPP-treated sites and the control sites after the surgical procedures. The NTAPP-treated sites had significantly smaller stained surface areas compared with the control sites on the 3rd, 7th , and 14th days (P < .05). The NTAPP-treated sites had better WHI scores than the control sites throughout the follow-up period (P < .05). It can be concluded that NTAPP enhances epithelialisation and stimulates wound healing after gingivectomy and gingivoplasty. However, further clinical studies with larger sample sizes are needed to determine the exact benefits of NTAPP for gingival wound healing.
Collapse
Affiliation(s)
- Basak Kusakci-Seker
- Department of Periodontology, Faculty of Dentistry, Eskişehir Osmangazi University, Eskişehir, Turkey
| | - Melike Demirayak-Akdemir
- Department of Periodontology, Faculty of Dentistry, Eskişehir Osmangazi University, Eskişehir, Turkey
| |
Collapse
|
4
|
Pillusky FM, Barcelos RCS, Vey LT, Barin LM, de Mello Palma V, Maciel RM, Kantorski KZ, Bürger ME, Danesi CC. Antimicrobial photodynamic therapy with photosensitizer in ethanol improves oxidative status and gingival collagen in a short-term in periodontitis. Photodiagnosis Photodyn Ther 2017; 19:119-127. [PMID: 28506773 DOI: 10.1016/j.pdpdt.2017.05.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/05/2017] [Accepted: 05/11/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND This study evaluated the antimicrobial photodynamic therapy (aPDT) effects using the methylene blue (MB) in ethanol 20% on systemic oxidative status and collagen content from gingiva of rats with periodontitis. METHODS Rats were divided into five experimental groups: NC (negative control; no periodontitis); PC (positive control; periodontitis without any treatment); SRP (periodontitis and scaling and root planing), aPDT I (periodontitis and SRP+aPDT+MB solubilized in water), and aPDT II (periodontitis and SRP+aPDT+MB solubilized in ethanol 20%). After 7days of removal of the ligature, the periodontal treatments were performed. At 7/15/30days, gingival tissue was removed for morphometric analysis. The erythrocytes were used to evaluate systemic oxidative status. RESULTS PC group showed higher lipoperoxidation levels at 7/15/30days. aPDT indicated a protective influence in erythrocytes at 15days observed by the elevation in levels of systemic antioxidant defense. aPDT II group was the only one that restored the total collagen area in 15days, and recovered the type I collagen area at the same time point. CONCLUSIONS aPDT as an adjunct to the SRP can induce the systemic protective response against oxidative stress periodontitis-induced and recover the gingival collagen, thus promoting the healing periodontal, particularly when the MB is dissolved in ethanol 20%.
Collapse
Affiliation(s)
- Fernanda Maia Pillusky
- Programa de Pós-Graduação em Ciências Odontológicas, Rua Marechal Floriano Peixoto, 1184, Centro, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
| | - Raquel Cristine Silva Barcelos
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria, Av. Roraima, 1000, Cidade Universitária, Camobi, Santa Maria, RS, Brazil.
| | - Luciana Taschetto Vey
- Programa de Pós-Graduação em Bioquímica Toxicológica, Universidade Federal de Santa Maria, Av. Roraima, 1000, Cidade Universitária, Camobi, RS, Brazil.
| | - Luisa Machado Barin
- Programa de Pós-Graduação em Ciências Odontológicas, Rua Marechal Floriano Peixoto, 1184, Centro, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
| | - Victor de Mello Palma
- Departamento de Patologia, Universidade Federal de Santa Maria, Av. Roraima, 1000, Cidade Universitária, Camobi, Santa Maria, RS, Brazil.
| | - Roberto Marinho Maciel
- Programa de Pós-Graduação em Ciências Odontológicas, Rua Marechal Floriano Peixoto, 1184, Centro, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
| | - Karla Zanini Kantorski
- Programa de Pós-Graduação em Ciências Odontológicas, Rua Marechal Floriano Peixoto, 1184, Centro, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil; Departamento de Estomatologia, Rua Marechal Floriano Peixoto, 1184, Centro, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
| | - Marilise Escobar Bürger
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria, Av. Roraima, 1000, Cidade Universitária, Camobi, Santa Maria, RS, Brazil; Programa de Pós-Graduação em Bioquímica Toxicológica, Universidade Federal de Santa Maria, Av. Roraima, 1000, Cidade Universitária, Camobi, RS, Brazil.
| | - Cristiane Cademartori Danesi
- Programa de Pós-Graduação em Ciências Odontológicas, Rua Marechal Floriano Peixoto, 1184, Centro, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil; Departamento de Patologia, Universidade Federal de Santa Maria, Av. Roraima, 1000, Cidade Universitária, Camobi, Santa Maria, RS, Brazil.
| |
Collapse
|
5
|
Human gingival fibroblast response to enamel matrix derivative, porcine recombinant 21.3-kDa amelogenin and 5.3-kDa tyrosine-rich amelogenin peptide. Hum Cell 2017; 30:181-191. [PMID: 28470386 PMCID: PMC5486862 DOI: 10.1007/s13577-017-0164-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 02/07/2017] [Indexed: 01/05/2023]
Abstract
Enamel matrix derivative (EMD) containing a variety of protein fractions has been used for periodontal tissue regeneration. It is suggested that the proteins contained in EMD positively influence gingival fibroblasts migration and proliferation. Effects of EMD as well as of porcine recombinated 21.3-kDa amelogenin (prAMEL) and 5.3-kDa tyrosine-rich amelogenin peptide (prTRAP) on human gingival fibroblast (HGF-1, ATCC; USA) cell line were investigated. Real-time cell analysis (xCELLigence system; Roche Applied Science) was performed to determine the effects of EMD, prAMEL and prTRAP (12.5–50 μg/mL) on HGF-1 cell proliferation and migration. The effect of treatment on cell cycle was determined using flow cytometry. EMD significantly increased HGF-1 cell proliferation after 24- and 48-h incubation. Individually, prAMEL and prTRAP also increased HGF-1 cell proliferation; however, the difference was significant only for prAMEL 50 µg/mL. prAMEL and TRAP significantly increased HGF-1 cell migration after 60- and 72-h incubation. Cell cycle analysis showed significant decrease of the percentage of cells in the G0/G1 phase and a buildup of cells in the S and M phase observed after EMD and prAMEL stimulation. This process was ligand and concentration-dependent. The various molecular components in the enamel matrix derivative might contribute to the reported effects on gingival tissue regeneration; however, biologic effects of prAMEL and prTRAP individually were different from that of EMD.
Collapse
|
6
|
Torri F, Dell'Era P, Garrafa E. ELM: A New, Simple, and Economic Assay to Measure Motility of Lymphatic Endothelial Cells. Lymphat Res Biol 2017; 15:39-44. [PMID: 28135127 PMCID: PMC5369396 DOI: 10.1089/lrb.2016.0032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Relatively few attempts have been made to set up an assay that allows the measurement of lymphatic endothelial cells (LECs) motility. Nowadays, the most widely used methods involve adaptation of the Boyden chamber method or the wound scratch assay, both of them showing some limitations due to long and expensive setup and high variability. METHODS AND RESULTS We propose a new, economic, and easy to setup LEC Motility (ELM) assay that will contribute to the study of lymphangiogenesis. The experimental setup consists of extending the coating of the flask with extracellular matrix (ECM) proteins also at the area opposite to the cap, where the LECs will be initially seeded at various densities. The day after, the flasks will be inclined at an angle of about 20° to cover the entire coated surface. Twenty-four hours later, flasks will be moved to the standard position, and the motility of the cells will be easily observed. Using the ELM assay, we were able to compare the motility rate of LECs isolated from different origins, or seeded on different substrates. CONCLUSION We propose the use of a new method to evaluate the motility of LECs: the ELM assay. This cost-effective analysis has several advantages: It can be easily set up in any cell biology laboratory, can be carried out rapidly, and allows the monitoring of cellular motility for a long period.
Collapse
Affiliation(s)
- Fabio Torri
- 1 Department of Surgery, ASST-Spedali Civili Brescia , Brescia, Italy
| | - Patrizia Dell'Era
- 2 Cellular Fate Reprogramming Unit, Department of Molecular and Translational Medicine, University of Brescia , Brescia, Italy
| | - Emirena Garrafa
- 1 Department of Surgery, ASST-Spedali Civili Brescia , Brescia, Italy .,3 Department of Molecular and Translational Medicine, University of Brescia , Brescia, Italy
| |
Collapse
|
7
|
Chiquet M, Katsaros C, Kletsas D. Multiple functions of gingival and mucoperiosteal fibroblasts in oral wound healing and repair. Periodontol 2000 2017; 68:21-40. [PMID: 25867977 DOI: 10.1111/prd.12076] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2014] [Indexed: 12/22/2022]
Abstract
Fibroblasts are cells of mesenchymal origin. They are responsible for the production of most extracellular matrix in connective tissues and are essential for wound healing and repair. In recent years, it has become clear that fibroblasts from different tissues have various distinct traits. Moreover, wounds in the oral cavity heal under very special environmental conditions compared with skin wounds. Here, we reviewed the current literature on the various interconnected functions of gingival and mucoperiosteal fibroblasts during the repair of oral wounds. The MEDLINE database was searched with the following terms: (gingival OR mucoperiosteal) AND fibroblast AND (wound healing OR repair). The data gathered were used to compare oral fibroblasts with fibroblasts from other tissues in terms of their regulation and function during wound healing. Specifically, we sought answers to the following questions: (i) what is the role of oral fibroblasts in the inflammatory response in acute wounds; (ii) how do growth factors control the function of oral fibroblasts during wound healing; (iii) how do oral fibroblasts produce, remodel and interact with extracellular matrix in healing wounds; (iv) how do oral fibroblasts respond to mechanical stress; and (v) how does aging affect the fetal-like responses and functions of oral fibroblasts? The current state of research indicates that oral fibroblasts possess unique characteristics and tightly controlled specific functions in wound healing and repair. This information is essential for developing new strategies to control the intraoral wound-healing processes of the individual patient.
Collapse
|
8
|
Pansani TN, Basso FG, Turrioni APS, Soares DG, Hebling J, de Souza Costa CA. Effects of low-level laser therapy and epidermal growth factor on the activities of gingival fibroblasts obtained from young or elderly individuals. Lasers Med Sci 2016; 32:45-52. [PMID: 27677475 DOI: 10.1007/s10103-016-2081-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 09/19/2016] [Indexed: 11/28/2022]
Abstract
This study evaluated the effects of low-level laser therapy (LLLT) and epidermal growth factor (EGF) on fibroblasts obtained from young and elderly individuals. Gingival fibroblasts from young (Y) and elderly (E) individuals were seeded in wells of 24-well plates with Dulbecco's modified Eagle's medium (DMEM) containing 10 % of fetal bovine serum (FBS). After 24 h, the cells were irradiated (LASERTable-InGaAsP-780 ± 3 nm, 25 mW, 3 J/cm2) or exposed to EGF (100 μM). After 72 h, cells were evaluated for viability, migration, collagen and vascular endothelial growth factor (VEGF) synthesis, and gene expression of growth factors. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests (α = 5 %). Y and E fibroblasts irradiated with laser or exposed to EGF showed increased viability and collagen synthesis. Enhanced cell migration was observed for Y fibroblasts after both treatments, whereas only the LLLT stimulated migration of E cells. VEGF synthesis was higher for Y and E cells exposed to EGF, while this synthesis was reduced when E fibroblasts were irradiated. Increased gene expression of VEGF was observed only for Y and E fibroblasts treated with LLLT. Regardless of a patient's age, the LLLT and EGF applications can biostimulate gingival fibroblast functions involved in tissue repair.
Collapse
Affiliation(s)
- Taisa Nogueira Pansani
- Department of Dental Materials and Prosthodontics, Araraquara School of Dentistry, University Estadual Paulista (UNESP), Araraquara, Brazil
| | - Fernanda Gonçalves Basso
- Department of Orthodontics and Pediatric Dentistry, Araraquara School of Dentistry, University Estadual Paulista (UNESP), Araraquara, Brazil
| | - Ana Paula Silveira Turrioni
- Department of Pediatric Dentistry, School of Dentistry, University Federal Uberlândia (UFU), Uberlândia, Brazil
| | - Diana Gabriela Soares
- Department of Dental Materials and Prosthodontics, Araraquara School of Dentistry, University Estadual Paulista (UNESP), Araraquara, Brazil
| | - Josimeri Hebling
- Department of Orthodontics and Pediatric Dentistry, Araraquara School of Dentistry, University Estadual Paulista (UNESP), Araraquara, Brazil
| | - Carlos Alberto de Souza Costa
- Department of Physiology and Pathology, Araraquara School of Dentistry, University Estadual Paulista (UNESP), Humaita, 1680. Centro, 14801903, Araraquara, SP, Brazil.
| |
Collapse
|
9
|
Kato A, Miyaji H, Ishizuka R, Tokunaga K, Inoue K, Kosen Y, Yokoyama H, Sugaya T, Tanaka S, Sakagami R, Kawanami M. Combination of Root Surface Modification with BMP-2 and Collagen Hydrogel Scaffold Implantation for Periodontal Healing in Beagle Dogs. Open Dent J 2015; 9:52-9. [PMID: 25674172 PMCID: PMC4319209 DOI: 10.2174/1874210601509010052] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 12/10/2014] [Accepted: 12/14/2014] [Indexed: 11/23/2022] Open
Abstract
Objective : Biomodification of the root surface plays a major role in periodontal wound healing. Root surface modification with bone morphogenetic protein (BMP) stimulates bone and cementum-like tissue formation; however, severe ankylosis is simultaneously observed. Bio-safe collagen hydrogel scaffolds may therefore be useful for supplying periodontal ligament cells and preventing ankylosis. We examined the effects of BMP modification in conjunction with collagen hydrogel scaffold implantation on periodontal wound healing in dogs. Material and Methods: The collagen hydrogel scaffold was composed of type I collagen sponge and collagen hydrogel. One-wall infrabony defects (5 mm in depth, 3 mm in width) were surgically created in six beagle dogs. In the BMP/Col group, BMP-2 was applied to the root surface (loading dose; 1 µg/µl), and the defects were filled with collagen hydrogel scaffold. In the BMP or Col group, BMP-2 coating or scaffold implantation was performed. Histometric parameters were evaluated at 4 weeks after surgery. Results: Single use of BMP stimulated formation of alveolar bone and ankylosis. In contrast, the BMP/Col group frequently enhanced reconstruction of periodontal attachment including cementum-like tissue, periodontal ligament and alveolar bone. The amount of new periodontal ligament in the BMP/Col group was significantly greater when compared to all other groups. In addition, ankylosis was rarely observed in the BMP/Col group. Conclusion: The combination method using root surface modification with BMP and collagen hydrogel scaffold implantation facilitated the reestablishment of periodontal attachment. BMP-related ankylosis was suppressed by implantation of collagen hydrogel.
Collapse
Affiliation(s)
- Akihito Kato
- Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | - Hirofumi Miyaji
- Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | - Ryosuke Ishizuka
- Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | - Keisuke Tokunaga
- Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | - Kana Inoue
- Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | - Yuta Kosen
- Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | - Hiroyuki Yokoyama
- Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | - Tsutomu Sugaya
- Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | - Saori Tanaka
- Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | - Ryuji Sakagami
- Section of Periodontology, Department of Odontology, Fukuoka Dental College, Fukuoka, Japan
| | - Masamitsu Kawanami
- Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| |
Collapse
|
10
|
Lin FY, Hsiao FP, Huang CY, Shih CM, Tsao NW, Tsai CS, Yang SF, Chang NC, Hung SL, Lin YW. Porphyromonas gingivalis GroEL induces osteoclastogenesis of periodontal ligament cells and enhances alveolar bone resorption in rats. PLoS One 2014; 9:e102450. [PMID: 25058444 PMCID: PMC4109931 DOI: 10.1371/journal.pone.0102450] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 06/17/2014] [Indexed: 02/03/2023] Open
Abstract
Porphyromonas gingivalis is a major periodontal pathogen that contains a variety of virulence factors. The antibody titer to P. gingivalis GroEL, a homologue of HSP60, is significantly higher in periodontitis patients than in healthy control subjects, suggesting that P. gingivalis GroEL is a potential stimulator of periodontal disease. However, the specific role of GroEL in periodontal disease remains unclear. Here, we investigated the effect of P. gingivalis GroEL on human periodontal ligament (PDL) cells in vitro, as well as its effect on alveolar bone resorption in rats in vivo. First, we found that stimulation of PDL cells with recombinant GroEL increased the secretion of the bone resorption-associated cytokines interleukin (IL)-6 and IL-8, potentially via NF-κB activation. Furthermore, GroEL could effectively stimulate PDL cell migration, possibly through activation of integrin α1 and α2 mRNA expression as well as cytoskeletal reorganization. Additionally, GroEL may be involved in osteoclastogenesis via receptor activator of nuclear factor κ-B ligand (RANKL) activation and alkaline phosphatase (ALP) mRNA inhibition in PDL cells. Finally, we inoculated GroEL into rat gingiva, and the results of microcomputed tomography (micro-CT) and histomorphometric assays indicated that the administration of GroEL significantly increased inflammation and bone loss. In conclusion, P. gingivalis GroEL may act as a potent virulence factor, contributing to osteoclastogenesis of PDL cells and resulting in periodontal disease with alveolar bone resorption.
Collapse
Affiliation(s)
- Feng-Yen Lin
- Division of Cardiology, Taipei Medical University Hospital, Taipei, Taiwan
- Cardiovascular Research Center, Taipei Medical University Hospital, Taipei, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Fung-Ping Hsiao
- Institute of Oral Biology, National Yang-Ming University, Taipei, Taiwan
| | - Chun-Yao Huang
- Division of Cardiology, Taipei Medical University Hospital, Taipei, Taiwan
- Cardiovascular Research Center, Taipei Medical University Hospital, Taipei, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chun-Ming Shih
- Division of Cardiology, Taipei Medical University Hospital, Taipei, Taiwan
- Cardiovascular Research Center, Taipei Medical University Hospital, Taipei, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Nai-Wen Tsao
- Division of Cardiovascular Surgery, Taipei Medical University Hospital, Taipei, Taiwan
| | - Chien-Sung Tsai
- Division of Cardiovascular Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Shue-Fen Yang
- Department of Dentistry, National Yang-Ming University, Taipei, Taiwan
- Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Nen-Chung Chang
- Division of Cardiology, Taipei Medical University Hospital, Taipei, Taiwan
- Cardiovascular Research Center, Taipei Medical University Hospital, Taipei, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Shan-Ling Hung
- Institute of Oral Biology, National Yang-Ming University, Taipei, Taiwan
- Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Yi-Wen Lin
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Institute of Oral Biology, National Yang-Ming University, Taipei, Taiwan
| |
Collapse
|
11
|
Accardo C, Himel VT, Lallier TE. A Novel GuttaFlow Sealer Supports Cell Survival and Attachment. J Endod 2014; 40:231-4. [DOI: 10.1016/j.joen.2013.08.029] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 08/24/2013] [Accepted: 08/27/2013] [Indexed: 10/26/2022]
|
12
|
Anitua E, Troya M, Orive G. An autologous platelet-rich plasma stimulates periodontal ligament regeneration. J Periodontol 2013; 84:1556-66. [PMID: 23289869 DOI: 10.1902/jop.2013.120556] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Regeneration of periodontal tissues is one of the most important goals for the treatment of periodontal disease. The technology of plasma rich in growth factors provides a biologic approach for the stimulation and acceleration of tissue healing. The purpose of this study is to evaluate the biologic effects of this technology on primary human periodontal ligament fibroblasts. METHODS The authors studied the response of periodontal ligament cells to this pool of growth factors on cell proliferation, cell migration, secretion of several biomolecules, cell adhesion, and expression of α2 integrin. Cell proliferation and adhesion were evaluated by means of a fluorescence-based method. Cell migration was performed on culture inserts. The release of different biomolecules by periodontal ligament fibroblasts was quantified through enzyme-linked immunosorbent assay. The α2 integrin expression was assessed through Western blot. RESULTS This autologous technology significantly stimulated cell proliferation, migration, adhesion, and synthesis of many growth factors from cells including vascular endothelial growth factor, thrombospondin 1, connective tissue growth factor, hepatocyte growth factor, and procollagen type I. The α2 integrin expression was lower in plasma rich in growth factor-treated cells compared to non-stimulated cells, although no statistically significant differences were observed. CONCLUSION This plasma rich in growth factors exerts positive effects on periodontal ligament fibroblasts, which could be positive for periodontal regeneration.
Collapse
|
13
|
Bulmanski Z, Brady M, Stoute D, Lallier TE. Cigarette smoke extract induces select matrix metalloproteinases and integrin expression in periodontal ligament fibroblasts. J Periodontol 2012; 83:787-96. [PMID: 22122519 DOI: 10.1902/jop.2011.110395] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND The periodontal ligament (PDL) is the connective tissue that anchors the cementum of the teeth to the alveolar bone. PDL fibroblasts are responsible for the production of collagen and remodeling of the PDL. Periodontal disease is increased among smokers in both incidence and severity. This study examines the direct effect of smoking on PDL fibroblasts and their production of various matrix components and remodeling enzymes. METHODS PDL cells were plated for 1 day and then treated with various concentrations of cigarette smoke extract (CSE). Survival of PDL cells was quantified after exposure to CSE, and their ability to contract three-dimensional collagen gels was examined. Changes in transcript expression after CSE treatment was compared using reverse transcription-polymerase chain reaction analysis for matrix metalloproteinases (MMPs), collagens, and integrins. RESULTS Treatment with CSE-induced cell death at concentrations of ≥5%. PDL-cell-induced collagen gel contraction was reduced at concentrations of 1.5% CSE. Treatment with CSE selectively increased the expression of collagen Vα3 and decreased collagen XIα1. CSE increased the expression of MMP1 and MMP3 and, to a lesser extent, MMP2 and MMP8. CSE also increased the expression of integrins α1, α2, and α10 (collagen receptors) and α9 (a tenascin receptor). CONCLUSIONS This study shows that cigarette smoking has local effects on the cells of the PDL. CSE reduced survival of PDL cells and their ability to contract collagen matrices. CSE also altered the expression of molecules known to provide the structural integrity of the ligament by altering collagen synthesis and remodeling as well as cell adhesion.
Collapse
Affiliation(s)
- Zachary Bulmanski
- Department of Oral Biology, Center of Excellence in Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, School of Dentistry, 1100 Florida Ave., New Orleans, LA 70119, USA
| | | | | | | |
Collapse
|
14
|
Kosen Y, Miyaji H, Kato A, Sugaya T, Kawanami M. Application of collagen hydrogel/sponge scaffold facilitates periodontal wound healing in class II furcation defects in beagle dogs. J Periodontal Res 2012; 47:626-34. [PMID: 22443229 DOI: 10.1111/j.1600-0765.2012.01475.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND OBJECTIVE A three-dimensional scaffold may play an important role in periodontal tissue engineering. We prepared bio-safe collagen hydrogel, which exhibits properties similar to those of native extracellular matrix. The aim of this study was to examine the effect of implantation of collagen hydrogel/sponge scaffold on periodontal wound healing in class II furcation defects in dogs. MATERIAL AND METHODS The collagen hydrogel/sponge scaffold was prepared by injecting collagen hydrogel, cross-linked to the ascorbate-copper ion system, into a collagen sponge. Class II furcation defects (of 5 mm depth and 3 mm width) were surgically created in beagle dogs. The exposed root surface was planed and demineralized with EDTA. In the experimental group, the defect was filled with collagen hydrogel/sponge scaffold. In the control group, no implantation was performed. Histometric parameters were evaluated 2 and 4 wk after surgery. RESULTS At 2 wk, the collagen hydrogel/sponge scaffold displayed high biocompatibility and biodegradability with numerous cells infiltrating the scaffold. In the experimental group, reconstruction of alveolar bone and cementum was frequently observed 4 wk after surgery. Periodontal ligament tissue was also re-established between alveolar bone and cementum. Volumes of new bone, new cementum and new periodontal ligament were significantly greater in the experimental group than in the control group. In addition, epithelial down-growth was suppressed by application of collagen hydrogel. CONCLUSION The collagen hydrogel/sponge scaffold possessed high tissue compatibility and degradability. Implantation of the scaffold facilitated periodontal wound healing in class II furcation defects in beagle dogs.
Collapse
Affiliation(s)
- Y Kosen
- Department of Periodontology and Endodontology, Division of Oral Health Science, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | | | | | | | | |
Collapse
|
15
|
Wu R, Zhang JF, Fan Y, Stoute D, Lallier T, Xu X. Reactive electrospinning and biodegradation of cross-linked methacrylated polycarbonate nanofibers. Biomed Mater 2011; 6:035004. [DOI: 10.1088/1748-6041/6/3/035004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
16
|
Palaiologou A, Stoute D, Fan Y, Lallier TE. Altered cell motility and attachment with titanium surface modifications. J Periodontol 2011; 83:90-100. [PMID: 21486180 DOI: 10.1902/jop.2011.100733] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Titanium implants are widely used in dentistry to replace lost teeth. Various surface modifications have been used to improve implant retention and osseointegration. This study is designed to compare the ability of three titanium surfaces to promote cell attachment and cell motility of cells relevant to periodontal tissues. METHODS Three clinically relevant surfaces were tested: 1) machined titanium; 2) a titanium surface roughened through acid etching (dual thermal-etched titanium [DTET]); and 3) a titanium surface roughened with nanometer-scale calcium phosphate deposition (nanoscale calcium phosphate-impregnated titanium [NCPIT]). Cell attachment and migration were examined for four cell types: rat osteosarcoma cells, human osteoblasts, and gingival and periodontal ligament (PDL) fibroblasts. RESULTS All four cell types attached to each of the three titanium surfaces equally by 2 hours, and the PDL and gingival fibroblasts generally displayed less attachment than the osteosarcoma cells and osteoblasts. The cells displayed differential motility and long-term attachment to each of the titanium surfaces. Osteosarcoma cells displayed preferential motility on NCPIT, whereas PDL fibroblasts were more motile on machined titanium, and gingival fibroblasts moved more rapidly on both DTET and NCPIT. Osteoblasts displayed little motility on any of the titanium surfaces and lost viability on NCPIT after 24 hours. Gingival fibroblasts lost attachment to machined titanium. CONCLUSIONS Periodontal cells displayed differential motility and long-term attachment to titanium surfaces. Selective modification of titanium surface properties in various regions of an implant may be useful in guiding specific cell populations to specific locations where they might best aid in osseointegration and soft tissue remodeling.
Collapse
Affiliation(s)
- Archontia Palaiologou
- Department of Periodontics, Louisiana State University Health Science Center, School of Dentistry, New Orleans, LA 70119, USA.
| | | | | | | |
Collapse
|
17
|
Enoch S, Peake M, Wall I, Davies L, Farrier J, Giles P, Kipling D, Price P, Moseley R, Thomas D, Stephens P. ‘Young’ Oral Fibroblasts Are Geno/Phenotypically Distinct. J Dent Res 2010; 89:1407-13. [DOI: 10.1177/0022034510377796] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Wound healing within the oral mucosa results in minimal scar formation compared with wounds within the skin. We have recently demonstrated distinct differences in the aging profiles of cells (oral mucosal and patient-matched skin fibroblasts) isolated from these tissues. We hypothesized that the increased replicative potential of oral mucosal fibroblasts may confer upon them preferential wound-healing capacities. Passage-matched early cultures of oral mucosal fibroblasts and skin fibroblasts demonstrated distinct gene expression profiles, with several genes linked to wound healing/tissue repair. This was related to an increased ability of the ‘replicatively younger’ oral mucosal fibroblasts to repopulate a wound space and reorganize their surrounding extracellular matrix environment, key activities during the wound-healing process. We conclude that oral mucosal fibroblasts exhibit a preferential healing response in vivo, due to their ‘replicatively younger’ phenotype when compared with that of patient-matched skin fibroblasts.
Collapse
Affiliation(s)
- S. Enoch
- Wound Biology Group, Cardiff Institute of Tissue Engineering and Repair, Tissue Engineering and Reparative Dentistry, School of Dentistry
- Department of Burns and Plastic Surgery, University Hospital of South Manchester, Southmoor Road, Wythenshawe, Manchester M23 7LT, UK
| | - M.A. Peake
- Wound Biology Group, Cardiff Institute of Tissue Engineering and Repair, Tissue Engineering and Reparative Dentistry, School of Dentistry
| | - I. Wall
- Wound Biology Group, Cardiff Institute of Tissue Engineering and Repair, Tissue Engineering and Reparative Dentistry, School of Dentistry
- Advanced Centre for Biochemical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
| | - L. Davies
- Wound Biology Group, Cardiff Institute of Tissue Engineering and Repair, Tissue Engineering and Reparative Dentistry, School of Dentistry
| | - J. Farrier
- Wound Biology Group, Cardiff Institute of Tissue Engineering and Repair, Tissue Engineering and Reparative Dentistry, School of Dentistry
| | - P. Giles
- Department of Pathology, School of Medicine
| | - D. Kipling
- Department of Pathology, School of Medicine
| | - P. Price
- Wound Healing Research Unit, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XY, Wales, UK
| | - R. Moseley
- Wound Biology Group, Cardiff Institute of Tissue Engineering and Repair, Tissue Engineering and Reparative Dentistry, School of Dentistry
| | - D. Thomas
- Wound Biology Group, Cardiff Institute of Tissue Engineering and Repair, Tissue Engineering and Reparative Dentistry, School of Dentistry
| | - P. Stephens
- Wound Biology Group, Cardiff Institute of Tissue Engineering and Repair, Tissue Engineering and Reparative Dentistry, School of Dentistry
| |
Collapse
|
18
|
Spencer AY, Lallier TE. Mechanical tension alters semaphorin expression in the periodontium. J Periodontol 2010; 80:1665-73. [PMID: 19792857 DOI: 10.1902/jop.2009.090212] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Periodontal remodeling requires coordinated cell movement. Semaphorins are cell-surface signals that regulate cell migration and may be differentially regulated by periodontal cells. Mechanical tension can regulate periodontal ligament (PDL) remodeling. We predicted that mechanical tension alters the expression of the subset of semaphorins in the periodontium likely to be most involved with regulating the remodeling of this tissue. METHODS PDL and gingival cells were exposed to mechanical tension, and their attachment and movement on collagen matrices were evaluated. Alterations in extracellular matrix and semaphorin transcript expression were monitored by semiquantitative reverse transcription-polymerase chain reaction. RESULTS Mechanical tension induced osteoclast regulatory transcripts in the PDL cells to a greater extent than gingival fibroblasts, increasing the expression of osteoprotegerin and decreasing receptor activator of nuclear factor-kappa B ligand. These mechanical forces reduced PDL cell mingling, without altering cell attachment or motility. Concurrently, these forces induced dynamic changes in several semaphorin molecules in PDL cells, increasing semaphorin 3D and 5B and decreasing semaphorin 7A. In addition, plexin transcript expression was altered, decreasing plexin A1 and increasing plexin C1. These changes were different than those observed in gingival fibroblasts. CONCLUSIONS These data suggest that a subset of semaphorins and plexins are dynamically regulated in the PDL. Because these molecules may be involved in cell guidance, changes in semaphorins may play a pivotal role in periodontal remodeling, affecting angiogenesis or PDL cell invasion into sites of injury.
Collapse
Affiliation(s)
- Amber Y Spencer
- Department of Cell Biology and Anatomy, Center of Excellence in Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Science Center, New Orleans, LA 70119, USA
| | | |
Collapse
|
19
|
U94 of human herpesvirus 6 inhibits in vitro angiogenesis and lymphangiogenesis. Proc Natl Acad Sci U S A 2009; 106:20446-51. [PMID: 19918067 DOI: 10.1073/pnas.0905535106] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human herpesvirus 6 (HHV-6) is a lymphotropic virus, but recent observations showed that also vascular endothelial cells (ECs) are susceptible to infection, both in vivo and in vitro. The observation that lymph nodes are a site of viral persistence suggests that lymphatic ECs (LECs) might be even more relevant for HHV-6 biology than vascular ECs. Here, we provide evidence that HHV-6 can infect LECs in vitro and establish a latent infection. Thus HHV-6 infection induces the loss of angiogenic properties both in LECs and in vascular ECs, as shown by the inability to form capillary-like structures and to seal wound scratches. The antiangiogenic effects observed in infected cells are associated to the expression of HHV-6 U94/rep, a latency-associated gene. In fact, transfection of U94/rep or addition of recombinant U94/REP protein to ECs inhibits the formation of in vitro capillary-like structures, reduces migration of ECs, and blocks angiogenesis, rendering rat aortic rings insensitive to VEGF-induced vasculogenetic activity. The ability of U94/rep to block different angiogenetic steps may lead to approaches in the potential control of the proliferation of blood and lymphatic vessels.
Collapse
|
20
|
Galli C, Passeri G, Cacchioli A, Gualini G, Ravanetti F, Elezi E, Macaluso GM. Effect of Laser-Induced Dentin Modifications on Periodontal Fibroblasts and Osteoblasts: A New In Vitro Model. J Periodontol 2009; 80:1648-54. [DOI: 10.1902/jop.2009.090152] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
21
|
Barczyk M, Olsen LHB, da Franca P, Loos B, Mustafa K, Gullberg D, Bolstad A. A Role for α11β1 Integrin in the Human Periodontal Ligament. J Dent Res 2009; 88:621-6. [DOI: 10.1177/0022034509339291] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We previously demonstrated a role for α11β1 integrin in periodontal ligament (PDL)-driven tooth eruption in the mouse. To explore a possible role for α11β1 in the human periodontium, we have characterized the expression and function of α11 in human PDL tissue, in human PDL fibroblasts (hPDLF), and in human gingival fibroblasts (hGF). α11 expression was detected in PDL tissue, in hPDLF, and in hGF cells. Platelet-derived growth factor-BB and insulin-like growth factor II stimulated contraction of collagen lattices by both types of fibroblasts. α2 integrin blocking antibodies and the use of α11 siRNA demonstrated a role for both α2β1 and α11β1 in collagen lattice remodeling. Analysis of the proximal ITGA11 promoter from persons with chronic periodontal disease failed to reveal any polymorphism. Analysis of our data shows that α11β1 is a major collagen receptor on cultured human PDL cells and implies that it is also functionally important in the PDL in vivo.
Collapse
Affiliation(s)
- M.M. Barczyk
- Department of Clinical Dentistry - Periodontics, University of Bergen, Aarstadveien 17, N-5009 Bergen, Norway
- Department of Biomedicine - Physiology, University of Bergen, Norway
- Department of Periodontology, Academic Center for Dentistry Amsterdam -ACTA-, University of Amsterdam and Vrije University, The Netherlands; and
- Department of Clinical Dentistry—Center for Clinical Dental Research, University of Bergen, Norway
| | - L.-H. Borge Olsen
- Department of Clinical Dentistry - Periodontics, University of Bergen, Aarstadveien 17, N-5009 Bergen, Norway
- Department of Biomedicine - Physiology, University of Bergen, Norway
- Department of Periodontology, Academic Center for Dentistry Amsterdam -ACTA-, University of Amsterdam and Vrije University, The Netherlands; and
- Department of Clinical Dentistry—Center for Clinical Dental Research, University of Bergen, Norway
| | - P. da Franca
- Department of Clinical Dentistry - Periodontics, University of Bergen, Aarstadveien 17, N-5009 Bergen, Norway
- Department of Biomedicine - Physiology, University of Bergen, Norway
- Department of Periodontology, Academic Center for Dentistry Amsterdam -ACTA-, University of Amsterdam and Vrije University, The Netherlands; and
- Department of Clinical Dentistry—Center for Clinical Dental Research, University of Bergen, Norway
| | - B.G. Loos
- Department of Clinical Dentistry - Periodontics, University of Bergen, Aarstadveien 17, N-5009 Bergen, Norway
- Department of Biomedicine - Physiology, University of Bergen, Norway
- Department of Periodontology, Academic Center for Dentistry Amsterdam -ACTA-, University of Amsterdam and Vrije University, The Netherlands; and
- Department of Clinical Dentistry—Center for Clinical Dental Research, University of Bergen, Norway
| | - K. Mustafa
- Department of Clinical Dentistry - Periodontics, University of Bergen, Aarstadveien 17, N-5009 Bergen, Norway
- Department of Biomedicine - Physiology, University of Bergen, Norway
- Department of Periodontology, Academic Center for Dentistry Amsterdam -ACTA-, University of Amsterdam and Vrije University, The Netherlands; and
- Department of Clinical Dentistry—Center for Clinical Dental Research, University of Bergen, Norway
| | - D. Gullberg
- Department of Clinical Dentistry - Periodontics, University of Bergen, Aarstadveien 17, N-5009 Bergen, Norway
- Department of Biomedicine - Physiology, University of Bergen, Norway
- Department of Periodontology, Academic Center for Dentistry Amsterdam -ACTA-, University of Amsterdam and Vrije University, The Netherlands; and
- Department of Clinical Dentistry—Center for Clinical Dental Research, University of Bergen, Norway
| | - A.I. Bolstad
- Department of Clinical Dentistry - Periodontics, University of Bergen, Aarstadveien 17, N-5009 Bergen, Norway
- Department of Biomedicine - Physiology, University of Bergen, Norway
- Department of Periodontology, Academic Center for Dentistry Amsterdam -ACTA-, University of Amsterdam and Vrije University, The Netherlands; and
- Department of Clinical Dentistry—Center for Clinical Dental Research, University of Bergen, Norway
| |
Collapse
|