title: Effects of autoclave sterilization on properties of dental rubber dam as related to its use as barrier membrane in guided tissue regeneration.
abstract: OBJECTIVE
  Dental rubber dams (RDs) were used as barrier membranes in guided tissue regeneration for the treatment of periodontal intraosseous defects with acceptable clinical results. The aim of the present study was to investigate the effects of autoclave sterilization on properties of RD as related to its use as a barrier membrane in guided tissue regeneration.
  
  
  METHODS
  RDs were sterilized by either an autoclave, gamma irradiation, or chemical agents and then co-cultured with human gingival fibroblasts. The cell responses to sterilized RDs were investigated by inverted phase contrast microscopy, scanning electron microscopy (SEM) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) technique. The surface alterations of the autoclaved RDs were observed under SEM. The tensile strength, tear strength and elongation at break of the autoclaved RDs were tested by a universal testing machine.
  
  
  RESULTS
  The results from cell culture, microscopic and MTT studies showed that RDs sterilized by autoclave and gamma irradiation did not deteriorate gingival fibroblasts and provided surfaces suitable for cell attachment, whereas chemical-sterilized RDs were toxic to these cells. Ultrastructurally, surface changes from the non-autoclaved RDs, including some melted areas, small pores and folds were observed on the autoclaved RD surface. The tensile strength and tear strength of the autoclaved RDs were significantly lower than those of the non-autoclaved RDs (p = 0.042, p < 0.001, respectively). In contrast, the elongation at break of the autoclaved RDs was higher than that of the non-autoclaved RDs (p < 0.001).
  
  
  CONCLUSIONS
  These results suggest that the autoclave sterilization deteriorated the physical properties of RDs even though they seemed to be compatible to the cultured human cells. Therefore, the sterilization method should be taken into consideration when RDs are utilized as barrier membranes.
authors.affiliation: Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand. awandee@chula.ac.th
authors.forename: Wandee
authors.initials: W
authors.lastname: Apinhasmit
authors.forename: Somchai
authors.initials: S
authors.lastname: Limsombutanon
authors.forename: Somporn
authors.initials: S
authors.lastname: Swasdison
authors.forename: Nophadol
authors.initials: N
authors.lastname: Suppipat
mesh_terms: D000704:Analysis of Variance; D002478:Cells, Cultured; D019551:Dental Disinfectants / Q000633:toxicity*; D005347:Fibroblasts / Q000187:drug effects*; D005720:Gamma Rays; D016557:Guided Tissue Regeneration, Periodontal; D006801:Humans; D008422:Materials Testing; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning; D016733:Rubber Dams; D018709:Statistics, Nonparametric; D013227:Steam; D013242:Sterilization / Q000379:methods; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D019551:Dental Disinfectants; D008567:Membranes, Artificial; D013227:Steam