title: The role of the toothbrush in the abrasion process.
abstract: OBJECTIVE
  To evaluate the relative abrasivity of different toothbrushes both qualitatively and quantitatively.
  
  
  METHODS
  Acrylic plates were exposed to brushing in a brushing machine with ten different toothbrushes with water alone and with a toothpaste. The results were evaluated using a profilometer after one and 6 h of brushing (corresponding to 2000 and 12,000 double strokes, respectively). A surface roughness value (Ra-value) and also a volume loss value were calculated from the profilometer measurements. These values were then compared to each other.
  
  
  RESULTS
  The results showed that brushing with water alone caused less abrasion than when a toothpaste was added. Six-hour brushing with water caused less abrasion than 1 h with a toothpaste. The number of filaments or filament diameter influenced the results in various ways. When brushing with water, the harder toothbrush (Jordan Medium) caused more abrasion (higher Ra-value), but when adding the toothpaste, the softer toothbrush (Jordan soft) caused more abrasion after 12,000 double strokes.
  
  
  CONCLUSIONS
  Besides supporting the fact that a toothpaste is needed to create a significant abrasion, this study also showed that a softer toothbrush can cause as much and in some cases more abrasion than harder ones. When conducting abrasivity studies, it is important to look at both the quantitative and qualitative aspect of abrasivity.
authors.affiliation: Department of Dental Medicine, Division of Periodontology, Karolinska Institute, Huddinge, Sweden. georg.tellefsen@ki.se
authors.forename: G
authors.initials: G
authors.lastname: Tellefsen
authors.forename: A
authors.initials: A
authors.lastname: Liljeborg
authors.forename: A
authors.initials: A
authors.lastname: Johannsen
authors.forename: G
authors.initials: G
authors.lastname: Johannsen
mesh_terms: D000180:Acrylic Resins; D003742:Dental Devices, Home Care / Q000009:adverse effects*; D004867:Equipment Design; D006801:Humans; D018709:Statistics, Nonparametric; D013499:Surface Properties; D014072:Tooth Abrasion / Q000209:etiology*; D014099:Toothbrushing / Q000009:adverse effects* / Q000295:instrumentation*; D014100:Toothpastes / Q000009:adverse effects*
chemical_list: D000180:Acrylic Resins; D014100:Toothpastes