Silver/mercury fillings are bad for teeth. They leak bacteria into the tooth and they expand and contract because they are metal. This can cause teeth to crack.
And that is just what happened to this tooth. In 2015, leakage and cracks were diagnosed in this tooth and a direct bonded composite restoration was suggested. These restorations bond to the tooth, sealing and strengthening it. For a variety of reasons, the patient was not able to get the recommended treatment done.
Fast forward 2 years to 2017. The patient said that something just did not feel right with this tooth. Upon examination, it was seen that this tooth split in half...right along the cracks that were diagnosed 2 years earlier.
Unfortunately, when this happens the tooth cannot be saved. The tooth was extracted and will be replaced with an implant supported crown.