No Need to reinstall the programs if the presets have been deleted. Go to iZotopes website and in their support section there will be a FAQ that links you to all of the presets that can be downloaded in zip files. You just either extract them back into the Documents folder or manually drap and drop them into the folder to restore your presets.
It was with Ozone 5 standard and its happened a couple of times. And the fact that the presets are available to download separately indicates to me that the fact they dematerialise is probably a known issue. 2b1af7f3a8