title: In situ evaluation of the microbial adhesion on a hard acrylic resin and a soft liner used in removable prostheses.
abstract: OBJECTIVE
  The purpose of this study was to evaluate, in situ, the initial adhesion of microorganisms to as well as the surface roughness and chemical composition of ProBase Hot (Ivoclar Vivadent), a hard acrylic resin, and Vertex Soft (Vertex-Dental), an acrylic-based soft liner, used in removable dental prostheses.
  
  
  METHODS
  Equal sized disks of ProBase Hot and Vertex Soft were prepared and polished according to the recommended procedures for clinical use. Two disks of each material were mounted in individual oral splints and exposed for 4 hours to the oral cavities of 15 participants. The microbial adhesion to each material's surface was measured with the pour plate technique using rich and selective growth media. Statistical analysis was performed using the Student t test. Scanning electron microscopy and chemical composition analyses obtained through electron probe radiographic microanalysis of sample disks also were performed.
  
  
  RESULTS
  In comparison to ProBase Hot, Vertex Soft presented higher microbial adhesion, namely regarding total aerobes, anaerobes, streptococci, and mutans streptococci (P < .05). Also, Vertex Soft presented higher surface roughness. Differences in the chemical composition of the two materials also were found.
  
  
  CONCLUSIONS
  The Vertex Soft liner has been found to be more susceptible to microbial adhesion than the acrylic resin ProBase Hot, probably due to its greater surface roughness. The application of Vertex Soft liner to a hard denture base may lead to a higher risk of oral and systemic infections for patients, highlighting a greater need for plaque control, especially for more susceptible individuals.
authors.forename: Ana Sofia
authors.initials: AS
authors.lastname: Gomes
authors.forename: Benedita
authors.initials: B
authors.lastname: Sampaio-Maia
authors.forename: Mário
authors.initials: M
authors.lastname: Vasconcelos
authors.forename: Patrícia A
authors.initials: PA
authors.lastname: Fonesca
authors.forename: Helen
authors.initials: H
authors.lastname: Figueiral
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000328:Adult; D001420:Bacteria, Aerobic / Q000302:isolation & purification; D001421:Bacteria, Anaerobic / Q000302:isolation & purification; D001422:Bacterial Adhesion / Q000502:physiology*; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing / Q000379:methods; D003819:Denture Bases / Q000382:microbiology; D003822:Denture Liners / Q000382:microbiology*; D004577:Electron Probe Microanalysis; D005260:Female; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D009055:Mouth / Q000382:microbiology; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D013291:Streptococcus / Q000302:isolation & purification; D013295:Streptococcus mutans / Q000302:isolation & purification; D013499:Surface Properties; D055815:Young Adult
chemical_list: D000180:Acrylic Resins; D003764:Dental Materials; C110664:ProBase; C076426:Vertex Soft; D019904:Polymethyl Methacrylate