What is the best way to repair a chipped porcelain restoration intraorally?

To repair porcelain, first use a diamond bur to roughen the margins of the surface to repair. If there is metal present, place a metal primer directly onto the metal portion of the surface to repair. Next, if you need to opaque the metal, use a bonding agent on the metal surface and place opaque composite on that surface only and light cure. Next, use a ceramic primer, or silane, to wet the surface of the porcelain to be repaired. After letting the ceramic primer set for 30 seconds, air dry and then place the bonding agent of your choice onto the prepared surface. Next, use a flowable composite, important because it wets the surface to be repaired well. Flowable composite is  slightly less brittle than restorative composite, making it flex with the restoration better.

Many dental companies have all of these products available for purchase separately. You might already have them if you do a lot of bonding of ceramic veneers to tooth structure.

The success rate of porcelain repair is variable. It may not be a good long-term solution and you should make your patients aware of this before performing the procedure.