Introduction:
Two factors set up this lithium disilicate crown for fracture:
1) Endo asscess weakened it.
2) Occlusal thickness not adequate.
Crown has fractured
Distal half of lithium disilicate crown has fractured. It was difficult for the dentist to achieve, needing occlusal clearance and still preserving a ferrule.
Buccal View
Rebuilding the crown
On a stone model, I rebuilt the crown in composite and made an occlusal stamp with Triad Gel. I had the model because the patient desired bleaching trays. I could have temporarily rebuilt the tooth and made the stamp directly in the normal fashion on the day of the appointment.
Occlusal view of the Triad Gel stamp
Stamping the composite will give me a head start on the occlusal adjustment.
Greater Curve Standard Band in place
Greater Curve Standard with a mesial contact opening surrounds the tooth. I reduced the occlusal further and was able to reduce the opposing tooth as well. I failed to take a prep photo to show the ferrule was now nearly non existent.
Seating the stamp
After some minor adjustments, the occlusal stamp fully seats inside the Greater Curve matrix.
Placing teflon tape over the stamp
This prevents the composite from sticking to the Triad Gel stamp.
Appearance of the restoration after the stamp has been removed
Sequence of of the buildup: Clean and Boost (Apex Dental), Futurabond U (Voco), Activa A2 (Pulpdent) provided the bottom 1/2 of the restoration. The base Activa was light cured. Filtek A2 was snowplowed into a thin layer of uncured Activa to finish out the top 1/2 of the restoration. The Triad Stamp was then pushed into the uncured Filtek. Stamp removed. Some excess composite smoothed away and the Filtek was cured. For isolation, I used a Saliva Ejector Holder which secured buccal and lingual NeoDrys.
Final direct composite crown
Most of the shaping was done after the matrix was removed.
Buccal view
Photo of tooth 8 months later
Conclusion:
Before attempting a similar case, make sure the crown margins are just supraginival in order to hold a tofflemire band.
Because there was no ferrule and lack of occlusal clearance, I felt another crown would succumb to the same fate as the previous crown. Also, maintaining isolation while bonding a new crown would be difficult.
I have had very good luck with full direct composite crowns has long as the composite does not extend across a wide interproximal space. Composite will chip if it is not supported.
I realize this treatment may be controversial to some, however, I want to show what is possible.