title: Effect of chitosan/riboflavin modification on resin/dentin interface: spectroscopic and microscopic investigations.
abstract: The aim of this study is to investigate the morphological and chemical changes of demineralized dentin collagen-matrix and resin/dentin interface associated with chitosan/riboflavin modification. Dentin disc specimens were prepared from sound molars, acid-etched with 35% phosphoric acid and modified with either 0.1% riboflavin or chitosan/riboflavin (Ch/RF ratios 1:4 or 1:1) and photo-activated by UVA. Morphological and chemical changes associated with surface modification were characterized by SEM and micro-Raman spectroscopy. Dentin surfaces of sound molars were exposed, acid-etched, and modified as described before. Etch-and-rinse dentin adhesive was applied, light-cured, and layered with resin-restorative composite. The resin infiltration and resin/dentin interface were characterized by micro-Raman spectroscopy and SEM. An open-intact collagen network-structure, formation of uniform hybrid-layer and higher resin infiltration were found with 0.1%RF and Ch/RF 1:4 modifications. Raman analysis revealed chemical changes and shifts in Amide bands with the modification of dentin collagen-matrix. The use of riboflavin and chitosan/riboflavin formulations to modify dentin-collagen matrix, with the defined ratios, stabilizes the collagen fibrillar network and enhances resin infiltration and hybrid layer formation. These preliminary results are encouraging for subsequent consideration of chitosan/riboflavin modification in adhesive dentistry.
authors.affiliation: Discipline of Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore 119083, Republic of Singapore.
authors.forename: Umer
authors.initials: U
authors.lastname: Daood
authors.forename: Kulsum
authors.initials: K
authors.lastname: Iqbal
authors.forename: Lorraine I
authors.initials: LI
authors.lastname: Nitisusanta
authors.forename: Amr S
authors.initials: AS
authors.lastname: Fawzy
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry; D003432:Cross-Linking Reagents; D058250:Dental Restoration Repair; D003804:Dentin / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D012117:Resins, Synthetic / Q000737:chemistry*; D012256:Riboflavin / Q000737:chemistry*; D012996:Solutions; D013059:Spectrum Analysis, Raman; D013499:Surface Properties
chemical_list: D003432:Cross-Linking Reagents; D012117:Resins, Synthetic; D012996:Solutions; D003094:Collagen; D048271:Chitosan; D012256:Riboflavin