Effects Of Disinfecting On Contaminated Alginate Impressions And Dimensional Stability Of Resultant Gypsum Casts

Objective:This study evaluated the effects of disinfecting on contaminated hydrocolloid impressions in vitro and dimensional stability of resultant gypsum casts by immersing them in different disinfectants.The purpose of this study is to investigate an appropriate disinfecting method and provide theoretical bases to clinical procedure.Materials and methods :This study includes two parts .Part Ⅰ Bactericidal effects of different disinfectants on contaminated alginate impression. 1 Experimental preparation .The powder of alginate materials was disinfected in ozonizer for 2 hours .Standard maxillary dental arch gypsum model, trays ,distilled water were disinfected in autoclave at 121℃ for 15 min. 3 to 14 generation of Staphylococcus aureus ,Streptococcus sanguis and Candida albicans were selected .The cultures were flushed by 5ml PBS buffer liquid ,and then the liquid was transferred to cuvette and adjusted to 10~8 bacteria per milliliter. 105 alginate impression samples were set from gypsum model without bacteria.2 grouping and disinfecting .The total number of specimens in treatment groups including Staphylococcus...