title: Color stability and flexural strength of poly (methyl methacrylate) and bis-acrylic composite based provisional crown and bridge auto-polymerizing resins exposed to beverages and food dye: an in vitro study.
abstract: OBJECTIVE
  To evaluate the color stability and flexural strength of poly (methyl methacrylate) (PMMA) and bis-acrylic composite based provisional crown and bridge auto-polymerizing resins exposed to tea, coffee, cola, and food dye.
  
  
  METHODS
  Two provisional crown and bridge resins, one DPI self-cure tooth molding powder (PMMA) (Group A), and one Protemp 4 Temporization Material (bis-acrylic composite) (Group B) were used. Disk-shaped specimens for color stability testing (n = 30 for each material) and bar-shaped specimens for flexural strength testing (n = 30 for each material) were fabricated using a metal mold. The specimens were immersed in artificial saliva, artificial saliva + tea, artificial saliva + coffee, artificial saliva + cola, and artificial saliva + food dye solutions and stored in an incubator at 37°C. Color measurements were taken before immersion, and then after 3 and 7 days of immersion. Flexural strength was evaluated after 7 days of immersion.
  
  
  RESULTS
  Group A showed significantly higher color stability as compared to Group B, and artificial saliva + coffee solution had the most staining capacity for the resins. Test solutions had no effect on the flexural strength of Group A, but Group B specimens immersed in artificial saliva + cola showed significantly lower flexural strength values as compared to the control group.
  
  
  CONCLUSIONS
  The findings of the study showed that for materials used in the study, PMMA was more color stable than bis-acrylic composite based resin. Also, material based on PMMA was more resistant to damage from dietary beverages as compared to bis-acrylic composite based provisional crown and bridge resin.
authors: Department of Prosthodontics and Crown and Bridge, JSS Dental College and Hospital, Mysore, Karnataka, India.
authors: Anil K
authors: AK
authors: Gujjari
authors: Vishrut M
authors: VM
authors: Bhatnagar
authors: Ravi M
authors: RM
authors: Basavaraju
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D001628:Beverages; D002253:Carbonated Beverages; D003069:Coffee / Q000737:chemistry; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D003442:Crowns; D003764:Dental Materials / Q000737:chemistry*; D003794:Dental Restoration, Temporary; D003833:Denture, Partial, Temporary; D005505:Food Coloring Agents / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D018583:Pliability; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D012464:Saliva, Artificial / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013662:Tea / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; D003069:Coffee; D003188:Composite Resins; D003764:Dental Materials; D005505:Food Coloring Agents; D012464:Saliva, Artificial; D013662:Tea; D019904:Polymethyl Methacrylate; C069714:Protemp