In vitro colonisation of acrylic resin denture base materials by Streptococcus oralis and Actinomyces viscosus

Aim: The aim of the study was to compare the attachment of two typical stra ins of oral bacteria to four denture base materials. Design: In vitro study . Method: Discs of acrylic resin denture base materials (Paladon 65, polish ed and unpolished; Palapress; Microbase, polished and unpolished, and Triad VLC) were placed into Petri dishes with Schaedler's medium, inoculated wit h Streptococcus oralis 34 or Actinomyces viscosus T14V. Main outcome measur es: After 24h or 48h the numbers of adhering bacteria were measured. Result s: The bacteria adhered to all discs in similar numbers: 3-9 x 10(6)/ml (vi able cell count) and 9-22 x 10(8)/ml (total cell count) for T14V, and 2-6 x 10(6)/ml (viable cell count) and 1.5-3 x 10(8)/ml (total cell count) for 3 4. Conclusions: Polishing had little effect on adherence. Denture base mate rials are not resistant against adherence and possible surface damage by or al bacteria. Therefore, thorough oral hygiene is important for denture wear ers.