ABSTRACT
In this experimental study the surface-hardness changes of three phosphate-bonded investments were observed in relation to: a) the ratio of liquid-powder, b) the way of the mixing, in 3 hours and 24 hours after mixing. The Vickers hardness test was used for testing the surface hardness of the specimens (ISOMA SA, Bienne, Swiss, hardness testing apparatus). This study indicated that the surface hardness of the specimens increased after mechanical mixing, and also that it was higher in 24 hours than in 3 hours. Also, as more water was included in the mixing liquid, as lower became the surface hardness of the materials. Finally, it was observed that one material appeared to have the greatest fluctuations of surface hardness: Maruvest MI.
Subject(s)
Dental Casting Investment/chemistry , Hardness , Humans , Humidity , Magnesium/chemistry , Materials Testing , Phosphates/chemistry , Powders , Quaternary Ammonium Compounds/chemistry , Solutions , Stress, Mechanical , Temperature , Time Factors , Vibration , Water/chemistryABSTRACT
The aim of this study is to investigate the dimensional changes of hydrocolloid impression materials agar type and alginates, when they are placed in fluids for AIDS virus sterilization as Sterile pack, alcohol 75%, sodium chloride 10% and Cidex for 40 min. It was found out that when the hydrocolloids were placed in alcoholic and Sterile pack fluids a great deal of changes happened (contraction and shrinkage) that made the sterilization in them impossible. The percentage of linear extention and imbibition noticed in hydrocolloids when they were placed in sodium chlorides and Cidex solutions showed that sterilization in them is usually possible. The best way of sterilization is to make a gypsum model from the hydrocolloid impression and place it in the furnace for 30 min in 60 degrees C.
Subject(s)
Colloids/chemistry , Dental Impression Materials/chemistry , Disinfectants , Acquired Immunodeficiency Syndrome/prevention & control , Agar/chemistry , Alginates/chemistry , Ethanol , Glutaral/chemistry , HIV , Sodium ChlorideABSTRACT
The influence of four antiseptic solutions on some dental materials was examined in this study. The antiseptic solutions were sodium chloride 10%, alcohol 75%, Cidex and Sterile pack fluid, whereas the dental materials were dental modelling wax, impression compound, shellac base plate and zinc-oxide eugenol paste. The change of weight and the change of length which were observed in 40 minutes were measured. According to our results the modelling waxes, as well as the impression paste are not influenced by the antiseptic solutions. The impression compound must not be sterilised in Sterile pack fluid, which dissolves it, but it can be floated in the rest of the solutions. The shellac base plates are influenced by all the antiseptic solutions studied, especially by alcohol 75% and Sterile pack fluid.
Subject(s)
Dental Impression Materials , Disinfectants , Resins, Plant , Waxes , Zinc Oxide-Eugenol Cement , Acquired Immunodeficiency Syndrome/prevention & controlABSTRACT
In achieving infection control in the dental office and the dental laboratory it has been suggested that impressions made in the dental office should be disinfected before they are send to the dental laboratory. In this study we examined the solubility and the linear changes of some elastomer impression materials after their immersion in disinfection agents after ten, twenty and forty minute time intervals. The disinfection agents used were: 75% alcohol, domestic chlorine 10%, the agent sterile pack (isopropyl alcohol) and 2% activated glutaraldehyde (SIDEX). Water was used as control. Our findings show that all types of elastomer impression materials appear to suffer insignificant changes both linear and weight-wise but polyether impression materials show significant changes in almost all the disinfection agents that were used and the time intervals that were studied.
