title: Effects of tooth-brushing force with a desensitising dentifrice on dentine tubule patency and surface roughness.
abstract: OBJECTIVE
  To investigate the effects of a 5% NovaMin containing dentifrice on dentine tubule patency and surface roughness at 100g and 400g tooth brush abrasion forces.
  
  
  METHODS
  75 polished human dentine samples were prepared and randomly allocated into one of five groups; control (1), Na2PFO3100g abrasion force (2), NovaMin 100g (3), Na2PFO3400g (4) and NovaMin 400g (5). The control group underwent two 2-min cycles of artificial saliva (AS), one 2-min erosion cycle; the rest underwent two toothbrush abrasion cycles in an AS/dentifrice slurry and one 2-min erosion cycle. All samples were imaged at baseline and post intervention using Tandem Scanning Microscopy and Profilometry to analyse tubule patency and roughness.
  
  
  RESULTS
  Mean tubule patency increased significantly between baseline and post intervention in groups 1,2 and 4 and decreased significantly post intervention in groups 3 and 5 (p<0.01). Post intervention, there were statistically significant differences in mean patent tubules between NovaMin and the Na2PFO3and control groups (p<0.001). Surface roughness increased for all groups between baseline and post interventions (P<0.001); mean (SD) roughness increases for groups 1, 2, 3, 4 and 5 were 0.14 (0.05) μm, 0.18 (0.04) μm, 0.16 (0.06) μm, 0.19 (0.07) μm and 0.21 (0.02) μm respectively. Differences between group 1 and 5 were significant (p<0.01).
  
  
  CONCLUSIONS
  Brushing with NovaMin resulted in significant dentine tubule occlusion at 100g and 400g, but brushing with Na2PFO3resulted in increased tubule patency. Surface roughness increased significantly at 400g brushing with NovaMin. There was no correlation between tubule patency and surface roughness.
  
  
  CONCLUSIONS
  A NovaMin desensitising dentifrice resulted in tubule occlusion even at high brushing forces. There was minimal increase in surface roughness at the lower (100g) brushing force.
authors.affiliation: Department of Prosthodontics, King's College London Dental Institute, Guy's, King's and St. Thomas' Hospitals, London, SE1 9RT, UK. Electronic address: francesca.mullan@kcl.ac.uk.
authors.forename: F
authors.initials: F
authors.lastname: Mullan
authors.affiliation: Department of Prosthodontics, King's College London Dental Institute, Guy's, King's and St. Thomas' Hospitals, London, SE1 9RT, UK.
authors.forename: S
authors.initials: S
authors.lastname: Paraskar
authors.affiliation: Department of Prosthodontics, King's College London Dental Institute, Guy's, King's and St. Thomas' Hospitals, London, SE1 9RT, UK.
authors.forename: D W
authors.initials: DW
authors.lastname: Bartlett
authors.affiliation: Department of Prosthodontics, University of Dundee, School of Dentistry, Dundee, DD1 4HR, UK.
authors.forename: R C
authors.initials: RC
authors.lastname: Olley
mesh_terms: D003764:Dental Materials / Q000737:chemistry; D003802:Dentifrices / Q000494:pharmacology*; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D057133:Dentin Desensitizing Agents / Q000494:pharmacology*; D003807:Dentin Sensitivity / Q000209:etiology; D004338:Drug Combinations; D005459:Fluorides / Q000494:pharmacology; D005898:Glass; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010710:Phosphates / Q000494:pharmacology; D011897:Random Allocation; D012464:Saliva, Artificial / Q000737:chemistry; D013499:Surface Properties; D014072:Tooth Abrasion / Q000209:etiology*; D014077:Tooth Erosion / Q000209:etiology; D014099:Toothbrushing / Q000009:adverse effects* / Q000379:methods
chemical_list: D003764:Dental Materials; D003802:Dentifrices; D057133:Dentin Desensitizing Agents; D004338:Drug Combinations; C510984:NovaMin; D010710:Phosphates; D012464:Saliva, Artificial; C012980:fluorophosphate; D005459:Fluorides
keywords: Dentine hypersensitivity; NovaMin; Surface roughness; TSM; Tubule patency