From Ars Technica:
The most visible of these changes is some new icons. Earlier Windows 10 builds included some icons that were, frankly, monumentally ugly. The new icons look somewhat better,
From top to bottom: Windows 8.1 icons, old Windows 10 icons, new build Windows 10 icons
Microsoft is expected to release Windows 10 sometime in July. As usual do not be in a rush to upgrade your dental office. New releases are notoriously buggy and most dental software vendors lag way behind Windows upgrades. It is likely to be close to a year or so before dental software is upgraded to work with Windows 10.