a kit containing the components essential for repairing , in situ , damaged or fractured porcelain dental prostheses . such repair includes cleaning , shaping , and priming the damaged area , applying a bonding agent preferably containing two silanes and a water - displacing solvent , then applying a filling agent comprising vitreous powder and a resin binder , allowing the agent to set and harden , and finishing . a filler composition or agent and an advantageous bonding composition are also provided .