Küsimus nr 6340

Silver küsis (14. mai 2013)
Kas ütriumoksiidiga stabiliseeritud tsirkooniumoksiid on tõepoolest ohutu ilma süsteemsete toimeteta materjal, mida kroonina kasutada hammastel?
Juhtusin kohtama sellist uuringut:
http://tinyurl.com/b3ebwuq

Seal seisab selline kahtlusi tekitav rida:
"In acid solution (lactic acid 0.02 M at 37¡C) yttrium and zirconium ions increased (to 3 lg cm2), leading to the conclusion that zirconia ceramics cannot be used in an acid environment as the oral cavity"
Kristo Ivanov vastas (2013-05-22 10:27)
Tere Silver!

Tänud küsimuse eest!

Antud artikli puhul on tegemist referatiivse ülevaatega, kuhu on koondatud andmed 166 teaduslikust artiklist (algallikast).

Lause "In acid solution (lactic acid 0.02 M at 37¡C) yttrium and zirconium ions increased (to 3 lg cm2), leading to the conclusion that zirconia ceramics cannot be used in an acid environment as the oral cavity." ei pärine antud artikli kokkuvõtte osast, vaid hoopis arutelu osast, kus on toodud välja ja arutletud erinevate teaduslike uuringute tulemuste üle.

Antud juhul pärineb tulemus 1993. a teostatud uuringust ( "Evaluation of biocompatability of various ceramic poweders with human fibroblasts in vitro"; Li J, Liu Y, Hermansson L, Söremark R.; Clin Mater. 1993;12(4):197-201.) ning esindab vaid ühe uurimisrühma 20 aasta vanust seisukohta, et ütrium-tetragonaalne tsirkooniumoksiid ei ole biosobiv.

Kui uurite tähelepanelikumalt Teie poolt esitatud artikli kokkuvõtet, milles on arvestatud kõigi algallikate seisukohtadega, siis näete, et tsirkooniumoksiidi peetakse igati biosobivaks materjaliks:

"The following conclusions concerning the use of zirco-
nia as a ceramic biomaterial, can be drawn:

(1) No local or systemic adverse reactions correlatable to the material were detected, neither were cytotoxic efects directly correlatable to the presence of zirconia ceramics or precursors observed in spite of the variety of the materials tested and test methods used (di§erent cell lines, animal models and implant sites).
(2) Mechanical properties of TZP allows the manufacture of 22.22 mm ball heads suitable for clinical applications. TZP properties allow a high safety factor in terms of low sensitivity to the stress risers in the bore, allowing more flexibility in modular design.
(3) Mechanichal properties are dependent on the precursors and on the process selected for the manufacture of components.
(4) The production of TZP ceramic biomaterials demands the use of high chemical and radiochemical purity precursors, as high purity materials can only comply with the levels of hydrothermal stability demanded to TZP in the specific application.
(5) Wear tests show that the tribological behaviour of the UHMWPE/TZP couple are better than the ones of the UHMWPE/metal couple. Moreover, the tribological behaviour of the UHMWPE/TZP are at least similar to the UHMWPE/alumina couples. The feasibility of TZP ball heads in small diameters (down to 22.22 mm) may contribute to the reduction of volumetric wear of UHMWPE sockets"

Tervitades,
Kristo Ivanov
Kristo Ivanov Kristo Ivanov, hambaarst

Kristo Ivanov töötab Nordic Hambakliinik peaarstina ning SA TÜ Kliinikumi arst-õppejõuna hambaravi erialal. Lõpetanud TÜ arstiteaduskonna, spetsialiseerunud restauratiivse hambaravi eriarstiks ning hetkel PhD kraad omandamisel

Seotud asutustega:
· Nordic Hambakliinik Laeva 2 (Navigatori Ärimaja, V korrus), Tallinn
· Tartu Ülikooli Kliinikumi Stomatoloogiakliinik L.Puusepa 1A (4.korrus), Tartu, Tartumaa