| Background and Aim: Fiber reinforced composite(FRC) is a new oral prosthetic material composed of fiber and resin, which possesses features of high density, high strength, high modulus, and corrosion resistance. The common fibers are carbon fiber, aramid Kevlar fiber, glass fiber, and polyethylene fiber. At present, the use of carbon fiber and aramid Kevlar fiber is limited because of the unsatisfactory color. Glass fiber is widely used while the application of polyethylene fiber, as an organic fiber is only used recently. There are few researches refer to the biocompatibility of FRC as oral prosthetic material. We investigate its biocompatibility through short-term acute toxic reaction, cytotoxic test, hemolysis test, and oral mucosa irritation test, aiming to provide theoretical basis for clinical application.Materials and methods: a) short-term acute toxic reaction: a total of 20 inbred NIH mice were randomly allocated into experimental group and control group, and the extract of Ribbond fiber and distilled water were respectively administrated at a dose of 20 ml/kg, once a day for 7 days. The general condition, toxic symptom and weight of mice were recorded. On the 14th day, all the animals were executed and the organswere removed for histological examination, b) cytotoxic test: Ribbond fiber was sheared into two pieces of 12.5 mm × 4.0 mm × 0.5mm to make extract, which was later diluted to be 50%, 25%, and 12.5% by culture solution. Polyvinyl chloride(PVC) was used as positive control and RPMI 1640 culture solution, negative control. The fibroblast suspension of mouse connective tissue was prepared and cultured. The culture solution was replaced by the fiber extract 24 hours later. On the 1st, 3 rd, 5 th, and 7th day, the optical density was determined, and the relative growth rate was calculated which was then used to evaluate the cytotoxicity of the material, c) hemolysis test: the anticoagulant rabbit serum was added to the mixture(5 gram Ribbond fiber in 10 ml normal saline, experimental group), normal saline (negative group), and distilled water(positive group) and then placed on the centrifuge. The serum was absorbed and the optical density was determined by a spectrophotometer at 490nm. The hemolysis rate was calculated, d) oral mucosa irritation test: the Ribbond fiber, PVC(positive control), and gutta percha(negative control) were made into round patches with a diameter of 4 mm and thickness of 0.5 mm, and then respectively fixed on the check pouch mucosa of the hamster by using woundless suture. After 14 days, animals were executed and the mucosa was taken for histological examination. Results: a) short-term acute toxic reaction: no animal died during the experiment. The mice were active, quick in action with shiny hair, and increased weight. There was no significant difference between experimental group and control group. The organs in experimental group were normal. No denaturation, atrophy, or necrosis was observed, b) cytotoxic test: the absorbance of the extracts with different concentrations increased with culture time, and positive control group increased more slowly compared with negative group and experimental group. The absorbance of the extract with lower concentration was higher. The cytotoxicity of Ribbond fiber was at grade 0-1. c) hemolysis test: the means for negative control group, positive control group, and experimental group were 0.0677, 0.9613, and 0.0723, respectively. The hemolysis rate was 0.52%. d) oral mucosa irritation test: only the mucosa exposed to PVC was rough. No roughness, congestion, ulcer, or hemorrhage was found in mucosa exposed to the Ribbon fiber or the gutta percha. It was showed that theepithelia tissue was intact with no hyperkeratosis or hyperplasia. And no congestion, hemorrhage, or infiltration of inflammatory cells was observed in connective tissue. Conclusion: Ribbond fiber has favorable biocompatibility. It does not induce acutehemolysis or irritate oral mucosa and has no cytotoxicity or short-term toxicity. |
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