title: Protective effect of the in situ pellicle on dentin erosion - an ex vivo pilot study.
abstract: OBJECTIVE
  The acquired pellicle is well known as an anti-erosive proteinaceous layer on enamel, but its protective properties on dentin have not been investigated in detail until now. The aim of the present ex vivo study was to evaluate the erosive effects on pellicle coated dentin.
  
  
  METHODS
  Bovine dentin slabs were exposed to the oral cavity of one subject for 120 min for in situ pellicle formation. Subsequently, the slabs were incubated with HCl (pH 2.3) in vitro for 5 min and erosive calcium-release was measured photometrically. In addition, the acid treated specimens were evaluated by transmission electron microscopy (TEM). Pellicle free samples served as controls.
  
  
  RESULTS
  Calcium erosion from the pellicle coated dentin slabs amounted to 23.5+/-2.9 microg Ca/min (pellicle free samples: 32.2+/-4.2 microg Ca/min). The difference was statistically significant (p < or = 0.05). In pellicle coated as well as in uncoated dentin samples, TEM-evaluation showed a demineralised dentinal surface layer which thickness ranged between 3 and 6 microm. The pellicle itself was partially dissolved but not removed by hydrochloric acid treatment.
  
  
  CONCLUSIONS
  The protective properties of the acquired pellicle against an erosive challenge of the dentinal surface are limited. The dentinal pellicle functions like an ion permeable network rather than a barrier.
authors.affiliation: Department of Operative Dentistry and Periodontology, University of Freiburg, Hugstetter Str. 55, D-79106 Freiburg, Germany. christian.hannig@uniklinik-freiburg.de
authors.forename: Christian
authors.initials: C
authors.lastname: Hannig
authors.forename: Klaus
authors.initials: K
authors.lastname: Becker
authors.forename: Nico
authors.initials: N
authors.lastname: Häusler
authors.forename: Wiebke
authors.initials: W
authors.lastname: Hoth-Hannig
authors.forename: Thomas
authors.initials: T
authors.lastname: Attin
authors.forename: Matthias
authors.initials: M
authors.lastname: Hannig
mesh_terms: D000328:Adult; D000818:Animals; D002118:Calcium / Q000032:analysis; D002417:Cattle; D044622:Dental Pellicle / Q000502:physiology* / Q000648:ultrastructure; D003804:Dentin / Q000473:pathology* / Q000648:ultrastructure; D006801:Humans; D006851:Hydrochloric Acid / Q000009:adverse effects; D008297:Male; D046529:Microscopy, Electron, Transmission; D010539:Permeability; D010783:Photometry; D010865:Pilot Projects; D020011:Protective Agents; D012995:Solubility; D013997:Time Factors; D014077:Tooth Erosion / Q000378:metabolism / Q000473:pathology*
chemical_list: D020011:Protective Agents; D006851:Hydrochloric Acid; D002118:Calcium