Conclusions

A fractured abutment screw of a crown supported by an endosseous implant is an unhappy complication. The fragment retained in the fixture can be retrieved with a festooned #557 latch slow-speed burr set in reverse torque. Once the fragment is loosened and advanced coronally, a clockwise-turning #33 1/3 burr is touched to the fragment side to completely remove it. Care is taken not to scar the fixture walls. The cemented abutment and crown can be salvaged by heating the crown/coronal screw fragment to 1000°C for 20 minutes. Upon cooling, the crown and abutment can then be separated. A new abutment screw can be used to secure the repolished abutment. The patient's diet, occlusal scheme, and maximal bite force should be assessed for overload. The new abutment/screw is torqued into the fixture and the crown occlusally adjusted and recemented for normal functioning. Fractured abutments of overdenture retainers can be treated in the same fashion. Assessment and correction of the occlusal scheme is important.