Hydrolysis of level glass up to DIN ISO 719 (98 c) hydrolysis of 5 patient-level first-class. This means the particle size is 300-500 μ m glass exposed to the 98 c water 1 hour less than 31 u g Na2O/g glass water soluble. In addition, the glass has reached the level hydrolysis DIN ISO 720 (121 c) hydrolysis of 3 levels of the first level. This means exposure to 121 c 1 hour in water, less than 62ug Na2O/grams of glass to be hydrolyzed.