Evaluation of tissue response to dental alloys by subcutaneous implantation

The tissue response of two low-gold alloys (Midas and Rajah), two silver-palladium alloys (Albacast and Alba V), and one type III gold alloy (JSC) was studied after subcutaneous implantation of cylindrical implants in 24 guinea pigs. Casting of each alloy were inserted into polyethylene tubes and implanted by means of a standardized technique. Each animal received five implants representing the five alloys. The implants were left in place for 30 and 90 days. Microscopic evaluation of the implant sites showed that after 30 days the tissue reactions were slight to moderate, with only small differences between the alloys. After 90 days the reactions were slight to extreme. One of the silver-palladium alloys (Alba V) demonstrated several severe and extreme reactions after 90 days. The other silver-palladium alloy (Albacast) demonstrated the least tissue response of the five alloys in the 90-day group.