If you instantiate a basic viewer with the
Autodesk.Viewing.Private.GuiViewer3D class, you'll get an array of buttons like this:
This is the toolbar at Viewer version 2.10.
However, if there are unwanted functionalities on the bar, you can disable it using the following lines of code.
var control = toolbar.getControl('modelTools');
This will get rid of the explode button in the default Viewer toolbar.