title: A Biofilm Pocket Model to Evaluate Different Non-Surgical Periodontal Treatment Modalities in Terms of Biofilm Removal and Reformation, Surface Alterations and Attachment of Periodontal Ligament Fibroblasts.
abstract: OBJECTIVE
  There is a lack of suitable in vitro models to evaluate various treatment modalities intending to remove subgingival bacterial biofilm. Consequently, the aims of this in vitro-study were: a) to establish a pocket model enabling mechanical removal of biofilm and b) to evaluate repeated non-surgical periodontal treatment with respect to biofilm removal and reformation, surface alterations, tooth hard-substance-loss, and attachment of periodontal ligament (PDL) fibroblasts.
  
  
  METHODS
  Standardized human dentin specimens were colonized by multi-species biofilms for 3.5 days and subsequently placed into artificially created pockets. Non-surgical periodontal treatment was performed as follows: a) hand-instrumentation with curettes (CUR), b) ultrasonication (US), c) subgingival air-polishing using erythritol (EAP) and d) subgingival air-polishing using erythritol combined with chlorhexidine digluconate (EAP-CHX). The reduction and recolonization of bacterial counts, surface roughness (Ra and Rz), the caused tooth substance-loss (thickness) as well as the attachment of PDL fibroblasts were evaluated and statistically analyzed by means of ANOVA with Post-Hoc LSD.
  
  
  RESULTS
  After 5 treatments, bacterial reduction in biofilms was highest when applying EAP-CHX (4 log10). The lowest reduction was found after CUR (2 log10). Additionally, substance-loss was the highest when using CUR (128±40 µm) in comparison with US (14±12 µm), EAP (6±7 µm) and EAP-CHX (11±10) µm). Surface was roughened when using CUR and US. Surfaces exposed to US and to EAP attracted the highest numbers of PDL fibroblasts.
  
  
  CONCLUSIONS
  The established biofilm model simulating a periodontal pocket combined with interchangeable placements of test specimens with multi-species biofilms enables the evaluation of different non-surgical treatment modalities on biofilm removal and surface alterations. Compared to hand instrumentation the application of ultrasonication and of air-polishing with erythritol prevents from substance-loss and results in a smooth surface with nearly no residual biofilm that promotes the reattachment of PDL fibroblasts.
authors.affiliation: Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Tobias T
authors.initials: TT
authors.lastname: Hägi
authors.affiliation: Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Klemensberger
authors.affiliation: Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Riccarda
authors.initials: R
authors.lastname: Bereiter
authors.affiliation: Centre of Electron Microscopy, University Hospital of Jena, Jena, Germany.
authors.forename: Sandor
authors.initials: S
authors.lastname: Nietzsche
authors.affiliation: Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland; Department of Prosthetic Dentistry, University of Cluj-Napoca, Cluj-Napoca, Romania; Department of Periodontology, Philips University, Marburg, Germany.
authors.forename: Raluca
authors.initials: R
authors.lastname: Cosgarea
authors.affiliation: Department of Preventive, Restorative and Pediatric Dentistry, University of Bern, Bern, Switzerland.
authors.forename: Simon
authors.initials: S
authors.lastname: Flury
authors.affiliation: Department of Preventive, Restorative and Pediatric Dentistry, University of Bern, Bern, Switzerland.
authors.forename: Adrian
authors.initials: A
authors.lastname: Lussi
authors.affiliation: Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Anton
authors.initials: A
authors.lastname: Sculean
authors.affiliation: Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Sigrun
authors.initials: S
authors.lastname: Eick
mesh_terms: D001419:Bacteria / Q000254:growth & development; D018441:Biofilms; D002448:Cell Adhesion; D015169:Colony Count, Microbial; D003804:Dentin / Q000473:pathology; D005347:Fibroblasts / Q000473:pathology*; D006801:Humans; D008954:Models, Biological; D010513:Periodontal Ligament / Q000382:microbiology* / Q000473:pathology* / Q000601:surgery; D010514:Periodontal Pocket / Q000382:microbiology* / Q000473:pathology / Q000601:surgery; D013499:Surface Properties; D014070:Tooth / Q000473:pathology