title: Effects of toothbrush hardness on in vitro wear and roughness of composite resins.
abstract: OBJECTIVE
  To investigate and compare the effects of toothbrushes with different hardness on abrasion and surface roughness of composite resins.
  
  
  METHODS
  Toothbrushes (DENT. EX Slimhead II 33, Lion Dental Products Co. Ltd., Tokyo, Japan) marked as soft, medium and hard, were used to brush 10 beam-shaped specimens of each of three composites resins (Venus [VEN], Venus Diamond [VED] and Venus Pearl [VEP]; HeraeusKulzer) with standardized calcium carbonate slurry in a multistation testing machine (2N load, 60 Hz). After each of five cycles with 10k brushing strokes the wear depth and surface roughness of the specimens were determined. After completion of 50k strokes representative samples were inspected by SEM. Data were treated with ANOVA and regression analyses (p < 0.05).
  
  
  RESULTS
  Abrasion of the composite resins increased linearly with increasing number of brushing cycles (r² > 0.9). Highest wear was recorded for VEN, lowest for VED. Hard brushes produced significantly higher wear on VEN and VEP, whereas no difference in wear by toothbrush type was detected for VED. Significantly highest surface roughness was found on VED specimens (Ra > 1.5 µm), the lowest one on VEN (Ra < 0.3 µm). VEN specimens showed increased numbers of pinhole defects when brushed with hard toothbrushes, surfaces of VEP were uniformly abraded without level differences between the prepolymerized fillers and the glass filler-loaded matrix, VED showed large glass fillers protruding over the main filler-loaded matrix portion under each condition.
  
  
  CONCLUSIONS
  Abrasion and surface roughness of composite resins produced by toothbrushing with dentifrice depend mainly on the type of restorative resin. Hardness grades of toothbrushes have minor effects only on abrasion and surface roughness of composite resins. No relationship was found between abrasion and surface roughness.
  
  
  CONCLUSIONS
  The grade of the toothbrush used has minor effect on wear, texture and roughness of the composite resin.
authors.affiliation: Assistant Lecturer, Department of Conservative Dentistry, Division of Esthetic Dentistry and Clinical Cariology, Showa University School of Dentistry, Tokyo, Japan, Phone: +81-3-3787-1151, e-mail: kyoizumi@dent.showa-u.ac.jp.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kyoizumi
authors.affiliation: Visiting Lecturer, Department of Conservative Dentistry, Division of Esthetic Dentistry and Clinical Cariology, Showa University School of Dentistry, Tokyo, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Yamada
authors.affiliation: Associate Professor (Retired), Department of Conservative Dentistry Division of Esthetic Dentistry and Clinical Cariology, Showa University School of Dentistry, Tokyo, Japan.
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Assistant Professor, Department of Restorative Dentistry, Division of Operative Dentistry, Tohoku University Graduate School of Dentistry Sendai, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kanehira
authors.affiliation: Professor, Guest Researcher, Liaison Center for Innovative Dentistry Tohoku University Graduate School of Dentistry, Sendai, Japan.
authors.forename: Werner J
authors.initials: WJ
authors.lastname: Finger
authors.affiliation: Professor, Department of Oral Function and Morphology, Liaison Center for Innovative Dentistry and Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, Sendai, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Sasaki
mesh_terms: D017609:Barium Compounds / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002119:Calcium Carbonate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D004867:Equipment Design; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013499:Surface Properties; D014099:Toothbrushing / Q000295:instrumentation*; D014100:Toothpastes / Q000737:chemistry
chemical_list: D017609:Barium Compounds; D003188:Composite Resins; D003764:Dental Materials; D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; D014100:Toothpastes; C488393:Venus (composite resin); C102738:barium glass filler; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; D002119:Calcium Carbonate