title: Effect of hyaluronic acid on morphological changes to dentin surfaces and subsequent effect on periodontal ligament cell survival, attachment, and spreading.
abstract: OBJECTIVE
  Hyaluronic acid (HA) is a natural constituent of connective tissues and plays an important role in their development, maintenance, and regeneration. Recently, HA has been shown to improve wound healing. However, no basic in vitro study to date has investigated its mode of action. Therefore, the purpose of this study was to examine morphological changes of dentin surfaces following HA coating and thereafter investigate the influence of periodontal ligament (PDL) cell survival, attachment, and spreading to dentin discs.
  
  
  METHODS
  HA was coated onto dentin discs utilizing either non-cross-linked (HA) or cross-linked (HA cl) delivery systems. Morphological changes to dentin discs were then assessed using scanning electron microscopy (SEM). Thereafter, human PDL cells were seeded under three in vitro conditions including (1) dilution of HA (1:100), (2) dilution of HA (1:10), and (3) HA coated directly to dentin discs. Samples were then investigated for PDL cell survival, attachment, and spreading using a live/dead assay, cell adhesion assay, and SEM imaging, respectively.
  
  
  RESULTS
  While control dentin discs demonstrated smooth surfaces both at low and high magnification, the coating of HA altered surface texture of dentin discs by increasing surface roughness. HA cl further revealed greater surface texture/roughness likely due to the cross-linking carrier system. Thereafter, PDL cells were seeded on control and HA coated dentin discs and demonstrated a near 100 % survival rate for all samples demonstrating high biocompatibility of HA at dilutions of both 1:100 and 1:10. Interestingly, non-cross-linked HA significantly increased cell numbers at 8 h, whereas cross-linked HA improved cell spreading as qualitatively assessed by SEM.
  
  
  CONCLUSIONS
  The results from the present study demonstrate that both carrier systems for HA were extremely biocompatible and demonstrated either improved cell numbers or cell spreading onto dentin discs. Future in vitro and animal research is necessary to further characterize the optimal delivery system of HA for improved clinical use.
  
  
  CONCLUSIONS
  HA is a highly biocompatible material that may improve PDL cell attachment or spreading on dentin.
authors.affiliation: Clinic of Preventive Dentistry, Periodontology and Cariology, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Andrea
authors.initials: A
authors.lastname: Mueller
authors.affiliation: Department of Cranio-Maxillofacial Surgery, Bern University Hospital, Inselspital, Bern, Switzerland.|Department of Oral Surgery, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Fujioka-Kobayashi
authors.affiliation: Department of Preventive, Restorative and Pediatric Dentistry, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Heinz-Dieter
authors.initials: HD
authors.lastname: Mueller
authors.affiliation: Department of Preventive, Restorative and Pediatric Dentistry, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Adrian
authors.initials: A
authors.lastname: Lussi
authors.affiliation: Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Anton
authors.initials: A
authors.lastname: Sculean
authors.affiliation: Clinic of Preventive Dentistry, Periodontology and Cariology, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.|Department of Preventive, Restorative and Pediatric Dentistry, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Schmidlin
authors.affiliation: Department of Preventive, Restorative and Pediatric Dentistry, School of Dental Medicine, University of Bern, Bern, Switzerland. rmiron@nova.edu.|Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland. rmiron@nova.edu.|Department of Periodontology, College of Dental Medicine, Nova Souhteastern University, Fort Lauderdale, FL, USA. rmiron@nova.edu.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Miron
mesh_terms: D000818:Animals; D002417:Cattle; D002448:Cell Adhesion / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects*; D003804:Dentin / Q000187:drug effects*; D006801:Humans; D006820:Hyaluronic Acid / Q000494:pharmacology*; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D010513:Periodontal Ligament / Q000166:cytology / Q000187:drug effects*; D013499:Surface Properties
chemical_list: D006820:Hyaluronic Acid
keywords: Connective tissue regeneration; Growth factors; Hyaluronan; Periodontal regeneration; Soft tissue regeneration; Wound healing