In-vitro-Untersuchung zur Zytotoxizität kieferorthopädischer Kunststoffe
In vitro investigation of the cytotoxicity of orthodontic resins
by Daniela Witt
Date of Examination:2017-08-01
Date of issue:2017-07-20
Advisor:Prof. Dr. Ralf Bürgers
Referee:Prof. Dr. Ralf Bürgers
Referee:PD Dr. Astrid Heutelbeck
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Abstract
English
The aim of this study was to evaluate and to compare cytotoxicity and roughness of the autopolymerized orthodontic acrylic resin Weitur® and the photopolymerized Orthocryl® LC. Also possible relationships between cytotoxicity and roughness have been investigated. The autopolymerized resin Weitur® contains, in contrast to Orthocryl® LC, methyl methacrylate and dibenzoyl peroxide. Orthocryl® LC is based on the monomer urethandimethacrylate. In total 120 specimens have been prepared and polished as specified by the manufacturers. Half of the specimies of each material were subjected to thermocycling for artificial aging before cytotoxicity-testing. L929 mouse fibroblasts (L929) and human gingival fibroblasts (GF1) were used for cytotoxicity-testing. The specimens were paste into 48-well-plates by appling an addition cross linked silicone and 10000 cells were seeded in each well of the 48-well-plates. Cell viability was examined by 2- (2-methoxy- 4 -nitrophenyl) -3- (4-nitrophenyl) - 5- (2,4 -disulfophenyl) - 2H –tetrazolium-test (WST-8-test). Non polymerized Orthocryl® LC, which main component is UDMA, was used as positive control, as negative control glas specimens and pure cell-controlls were chosen. Also cytotoxicity of the silicone was tested. Cell viability testing by WST-8-test and light microscopic controls were performed after six, 24 and 48 hours. Neither polymerized Orthocryl® LC nor polymerized Weitur ® showed significant cytotoxicity on L929 or GF1 at any time. There were no signifcant differences in cytotoxicity between both materials and between aged and non-aged specimens. In contrast to the polymerized specimens, unpolymerized Orthocryl® LC showed a high cytotoxic potential. The addition cross linked silicone and the negative controls had no significant effect on cell viability. In total L929 showed a significant decreased cell viability after six hours in the pilot-testig and after six, 24 and 48 hours in main testing. Weitur® aged and non aged showed significant higher roughness than Orthocryl® LC. Artificial aging led to a significant decreased rougness of Weitur®. Roughness of Orthocryl® LC was not affected by artificial aging. Cytotoxicity was not influenced by R(A).
Keywords: Orthodontic resin; methylmethacrylate; cytotoxicity