Cytotoxicity and bonding property of dental ceramics.
OBJECTIVE
Yttria partially stabilized zirconia (YPSZ) ceramic is suitable for dental and medical use because of its high fracture toughness and chemical durability. The purpose of this study was to estimate the cytotoxicity and bonding property of zirconia ceramic compared to other dental ceramics.


METHODS
Eight commercial dental ceramics including Denzir (YPSZ) are used in this cytotoxicity test. The human gingival fibroblast (GF) cells were cultured using extraction solutions of ceramics. The cytotoxicity was estimated by two different methods. The bonding strength of Denzir was compared to Empress2 using zinc phosphate, glass ionomer, and adhesive resin cements. A brass plate was prepared with drilled tapered holes and ceramic specimens were prepared to fit the holes and bonded. The bonding strength was estimated by the punching test.


RESULTS
No significant (p>0.05) cytotoxicity was observed in all ceramic extractions. The two evaluation methods showed no significant differences. Denzir and Empress2 showed similar bonding strength with zinc phosphate or glass ionomer cement bonding. For both Empress2 and Denzir the glass ionomer cement showed significantly (p<0.001) higher bonding strength compared to the zinc phosphate cement. Empress2 showed significantly higher bonding strength with adhesive resin cement. However, the Denzir showed lower bonding strength with adhesive resin cement.


CONCLUSIONS
No ceramic extractions showed any evidence of cytotoxicity. Therefore, the low in vitro cytotoxicity of ceramic extractions including Denzir was confirmed. Denzir showed a similar bonding strength to Empress2 with zinc phosphate or glass ionomer cement bonding with this testing method and lower bonding strength with adhesive resin cement than with Empress2.
Uo
Motohiro
M
Department of Dental Materials and Engineering, Graduate School of Dentistry, Hokkaido University, North 13 West 7, Kita-ku, 060-8586 Sapporo, Japan. uo@den.hokudai.ac.jp
Sjögren
Göran
G
Sundh
Anders
A
Watari
Fumio
F
Bergman
Maud
M
Lerner
Ulf
U
D002478:Cells, Cultured; D004396:Coloring Agents / Q000378:metabolism; D004247:DNA / Q000187:drug effects; D001840:Dental Bonding; D003776:Dental Porcelain / Q000633:toxicity; D005347:Fibroblasts / Q000187:drug effects; D005899:Glass Ionomer Cements; D006801:Humans; D008422:Materials Testing; D010078:Oxazines; D019279:Resin Cements; D033081:Shear Strength; D014966:Xanthenes; D015019:Yttrium / Q000633:toxicity; D015036:Zinc Phosphate Cement; D015040:Zirconium / Q000633:toxicity
D004396:Coloring Agents; C453860:Denzir; D005899:Glass Ionomer Cements; D010078:Oxazines; D019279:Resin Cements; D014966:Xanthenes; D003776:Dental Porcelain; C005843:resazurin; D015019:Yttrium; D015036:Zinc Phosphate Cement; D004247:DNA; D015040:Zirconium; C028541:zirconium oxide; C091417:yttria