You can either repair the crown, or cut it off and replace it with a new one. Kinder Krowns® are backed by a 100% replacement guarantee on returned, fractured crowns.
D2934: Pre-fabricated esthetic coated stainless steel crown- primary tooth
Whatever you use to cement regular stainless steel crowns can be used to cement Kinder Krowns®. The cement of choice by the majority of dentists is a resin-modified glass ionomer or straight glass ionomer.