Dialog buttons get the btn-class; default unicode icons are replaced with Materialize' icons (Google Material Icons) medium material-icons-name (cannot say if this according to the material-concept are the right icons / colors to use) :

Dlg.DEFAULTS.buttons.classes = {
  ok: 'btn',
  cancel: 'btn',
  yes: 'btn',
  no: 'btn'
}
Dlg.DEFAULTS.icons = {
  alert: '<i class="medium material-icons blue-text">report_problem</i>',
  information: '<i class="medium material-icons blue-text">info</i>',
  confirm: '<i class="medium material-icons blue-text">question_answer</i>',
  bell: '<i class="medium material-icons orange-text">notifications</i>',
  error: '<i class="medium material-icons red-text">block</i>',
  wait: '<i class="small material-icons blue-text">build</i>',
  input: '', 
}
Dlg.DEFAULTS.input.classes.label = 'hide'