title: Influence of surface roughness on streptococcal adhesion forces to composite resins.
abstract: OBJECTIVE
  To determine streptococcal adhesion forces with composite resins with different surface roughness.
  
  
  METHODS
  Polishing and grinding were applied to obtain smooth (roughness 20 nm), moderately rough (150 nm) and rough (350 nm) surfaces of two orthodontic, light-cured composites. Adhesion forces between Streptococcus sanguinis and Streptococcus mutans and the composite surfaces were measured using atomic force microscopy in absence or presence of a salivary conditioning film. Initial adhesion forces were measured as well adhesion after 120 s of contact, as longer contact times are known to result in stronger adhesion forces ("bond-strengthening"). Surface roughness in absence and presence of salivary conditioning films were compared using ANOVA, while adhesion forces were subjected to a Weibull analysis.
  
  
  RESULTS
  Initial adhesion forces in absence of a salivary conditioning film amounted between -0.7 and -0.9 nN for smooth composite resins and increased between -1.0 and -2.0 nN for the roughest surfaces. Streptococcal adhesion forces after bond-strengthening were significantly stronger than upon initial contact, irrespective of the composite type. Salivary conditioning films significantly decreased the surface roughness of the composites, as well as the streptococcal adhesion forces. Yet, also in the presence of a conditioning film, rougher composite surfaces exerted stronger adhesion forces, irrespective of composite type or bacterial strain.
  
  
  CONCLUSIONS
  Streptococcal adhesion forces to orthodontic composite resins increase with increasing roughness of the composite surfaces. Composite surface roughness less affects adhesion forces with S. mutans than with S. sanguinis.
authors.affiliation: Department of Biomedical Engineering, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
authors.forename: Li
authors.initials: L
authors.lastname: Mei
authors.forename: Henk J
authors.initials: HJ
authors.lastname: Busscher
authors.forename: Henny C
authors.initials: HC
authors.lastname: van der Mei
authors.forename: Yijin
authors.initials: Y
authors.lastname: Ren
mesh_terms: D000465:Algorithms; D000537:Aluminum Oxide / Q000737:chemistry; D001422:Bacterial Adhesion / Q000502:physiology*; D018441:Biofilms; D001696:Biomechanical Phenomena; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002327:Cariostatic Agents / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D044622:Dental Pellicle / Q000502:physiology; D003775:Dental Polishing / Q000379:methods; D005260:Female; D005898:Glass / Q000737:chemistry; D006801:Humans; D008297:Male; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D056951:Photoelectron Spectroscopy; D019279:Resin Cements / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D012969:Sodium Fluoride / Q000737:chemistry; D013291:Streptococcus / Q000145:classification / Q000502:physiology*; D013295:Streptococcus mutans / Q000502:physiology; D013499:Surface Properties; D013997:Time Factors; D017155:Wettability
chemical_list: D002327:Cariostatic Agents; D003188:Composite Resins; D003764:Dental Materials; D019279:Resin Cements; C477790:Transbond XT; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; D012969:Sodium Fluoride; D000537:Aluminum Oxide