Effect Of Recasting On Hemolysis And Oral Mucosal Irritation Of The Non-Nickel-Based Ceramic Alloys

Objective: To study the effect of recasting on hemolysis and oral mucosal irritation ofthe non-nickel-based ceramic alloys.Methods: Four kinds of non-nickel-based ceramic alloys provided by themanufacturer were recast for1~3times respectively to gain samples of3generations.Before being recast again, all ceramic alloys should be handled with the processresearched before.(1) According to ISO/TR7405-1984standards, samples wereavailable after four kinds of non-nickel-based ceramic alloys being recast1to3timesand polished. The extraction was performed, then physiological saline and fresh rabbitwhole blood was added into it. After centrifuged, the optical density of the supernatantwas read by a spectrophotometer. The data was analyzed by SPSS17.0software withANOVA.（2）According to YY-T0127.1-1993Standard, samples were available afterfour kinds of non-nickel-based ceramic alloys being recast1~3times and polished.Polypropylene and industrial polyvinyl chloride (PVC) were made to be negative andpositive control samples. The sterile samples were fixed into the cheek pouch of goldSyrian hamsters. After14days, the pouch fixed with samples were observed andrecorded. The tissue samples from representative areas of the pouches were removedfor histological evaluation.Results:(1) Four kinds of non-nickel-based ceramic alloys being recast1to3times,all the hemolysis rates were below5%. No statistically difference of optical densitywas found among3generations of the same ceramic alloy (p＞0.05).(2) The appetiteand activity of the golden Syrian hamsters were normal during the14days. Just asnegative control group, no apparently abnormalities of oral mucosa were found in testgroups, such as congestion, bleeding, erosion or ulcer, while congestion and swellingwere found in positive group. Microscopically, epithelium was intact, cellular levelwas clear and arranged orderly, few leucocytes were found in test groups. There areno obvious differences between test groups and negative group. Besides the cobalt-chromium ceramic alloy cast for3rd time show mild irritation to the oralmucosa, other ceramic alloys cast for1~3times show minimal irritation or noneirritation.Conclusion: It is preliminarily estimated that the biocompatibility of the four kindsnon-nickel-based ceramic alloys in hemolytic test and oral mucosal irritation test isacceptable.