Three brands of dental ceramics for veneering to titanium: TitanBond (
O'Hara), Ti-Ceram (Ducera) and Titankeramik (Vita) were tested to comp
are their fracture properties in wet and in dry conditions. Eight poli
shed and precracked specimens of each material were stored in water at
37 degrees C for 28 d and then preloaded in a four-point bending jig
with a constant load of 50 N for 24 h under water. Five of the specime
ns were fractured by a four-point bending test also under water at 37
degrees C. Crack depths were measured in three different positions in
each of the remaining three specimens. Fracture load and crack depths
were used to calculate the fracture toughness. Another ten polished sp
ecimens were used to measure the flexural strength with a four-point P
ending test after storage in water at 37 degrees C for 28 d. Equal pro
cedures and numbers of specimens were used to measure fracture toughne
ss and flexural strength without preloading and storage in water.