title: A profilometry-based dentifrice abrasion Method for V8 brushing machines. Part I: Introduction to RDA-PE.
abstract: OBJECTIVE
  This paper describes the development and standardization of a profilometry-based method for assessment of dentifrice abrasivity called Radioactive Dentin Abrasivity - Profilometry Equivalent (RDA-PE).
  
  
  METHODS
  Human dentine substrates are mounted in acrylic blocks of precise standardized dimensions, permitting mounting and brushing in V8 brushing machines. Dentin blocks are masked to create an area of "contact brushing." Brushing is carried out in V8 brushing machines and dentifrices are tested as slurries. An abrasive standard is prepared by diluting the ISO 11609 abrasivity reference calcium pyrophosphate abrasive into carboxymethyl cellulose/glycerin, just as in the RDA method. Following brushing, masked areas are removed and profilometric analysis is carried out on treated specimens. Assessments of average abrasion depth (contact or optical profilometry) are made.
  
  
  RESULTS
  Inclusion of standard calcium pyrophosphate abrasive permits a direct RDA equivalent assessment of abrasion, which is characterized with profilometry as Depth test/Depth control x 100. Within the test, the maximum abrasivity standard of 250 can be created in situ simply by including a treatment group of standard abrasive with 2.5x number of brushing strokes. RDA-PE is enabled in large part by the availability of easy-to-use and well-standardized modern profilometers, but its use in V8 brushing machines is enabled by the unique specific conditions described herein.
  
  
  CONCLUSIONS
  RDA-PE permits the evaluation of dentifrice abrasivity to dentin without the requirement of irradiated teeth and infrastructure for handling them. In direct comparisons, the RDA-PE method provides dentifrice abrasivity assessments comparable to the gold industry standard RDA technique.
authors.forename: Donald J
authors.initials: DJ
authors.lastname: White
authors.forename: Eva
authors.initials: E
authors.lastname: Schneiderman
authors.forename: Ellen
authors.initials: E
authors.lastname: Colón
authors.forename: Samuel
authors.initials: S
authors.lastname: St John
mesh_terms: D002131:Calcium Pyrophosphate / Q000737:chemistry; D003743:Dental Enamel / Q000187:drug effects* / Q000528:radiation effects; D003802:Dentifrices / Q000009:adverse effects* / Q000737:chemistry; D003804:Dentin / Q000187:drug effects* / Q000528:radiation effects; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D014072:Tooth Abrasion / Q000209:etiology* / Q000517:prevention & control; D057085:Tooth Wear / Q000209:etiology* / Q000517:prevention & control; D014099:Toothbrushing; D014100:Toothpastes / Q000009:adverse effects* / Q000737:chemistry
chemical_list: D003802:Dentifrices; D014100:Toothpastes; D002131:Calcium Pyrophosphate