ABSTRACT
Four commercial tissue conditioners have been assessed in terms of their dimensional stability and ability to reproduce surface detail according to ADA specification #19 for impression materials. Results have been compared with those of a number of elastomeric impression materials. The tissue conditioners performed adequately and as such could be used as impression materials within 24 hours of their application. While they did not compare well with the elastomeric impression materials they comply with the limitations of the ADA specifications. It is suggested that standards specific to these materials should be developed.
Subject(s)
Dental Impression Materials/chemistry , Tissue Conditioning, Dental , Acrylic Resins/chemistry , American Dental Association , Analysis of Variance , Dental Impression Materials/standards , Materials Testing , Methylmethacrylates/chemistry , Phthalic Acids/chemistry , Polymethacrylic Acids/chemistry , Reproducibility of Results , Resins, Synthetic/chemistry , Silicone Elastomers/chemistry , Sulfides/chemistry , Time Factors , United StatesABSTRACT
The surface hardness of dental stone and improved dental stone was investigated when crystallised in contact with tissue conditioners and compared with that observed when the two types of gypsum are crystallised in contact with impression materials used clinically. Vickers hardness tests were performed 45 minutes, 2 hours and 24 hours after the beginning of stone mixing. The tissue conditioners did not have adverse effects on the surface hardness of gypsum products. On the contrary, they gave casts with excellent surface hardness, as did the elastomeric impression materials.
Subject(s)
Calcium Sulfate/chemistry , Dental Impression Materials/chemistry , Models, Dental , Tissue Conditioning, Dental , Acrylic Resins/chemistry , Denture Liners , Hardness , Humans , Materials Testing , Methylmethacrylates/chemistry , Phthalic Acids/chemistry , Surface PropertiesABSTRACT
Changes in dental stone and improved dental stone surface hardness observed when prepared with aqueous solutions of potassium salts (K2SO4, KCl, KF, KBr, KNO4, KMnO4, K2Cr2O7) in concentrations of 0.5-5.0% were investigated. Parallel studies were carried out on dental stone and improved dental stone prepared with distilled water and crystallised in contact with alginate impression material, previously immersed in the above solutions for 2 minutes. Vicker's hardness tests were performed 3 hours and 24 hours after the initial set. The surface hardness of dental stone and improved dental stone is increased significantly by either method. The most effective hardening solution is potassium sulphate in concentrations of 0.5-5.0%. The degree of increase in surface hardness is directly proportional to the concentration of the solutions and proportionately greater at a shorter time (3 hours after the initial set).
