An up to 15-year longitudinal study of 515 metal-ceramic FPDs: Part 2. Modes of failure and influence of various clinical characteristics.

PURPOSE

This study reported on the modes of failure and the influence of various clinical characteristics on the outcome of 515 metal-ceramic fixed partial dentures (FPD) involving 1,209 abutment and 885 pontics placed by one operator in a specialist prosthodontic practice between January 1984 and December 1997.

MATERIALS AND METHODS

Fifty-three percent of maxillary and 84% of mandibular FPDs involved one or more nonrigid abutment-pontic connections. Patients were recalled in 1993 (review 1) and 1998 (review 2) and clinically examined by the author. The modes of failure and influence of clinical characteristics, including abutment-pontic connection, post design in nonvital abutments, and regularity of professional maintenance, were evaluated.

RESULTS

At review 2, 80% of the FPDs were still in function, while 9% required retreatment. Tooth fracture accounted for 38%, caries for 11%, loss of retention for 13%, and periodontal breakdown for 27% of retreatments. Nonrigid abutment-pontic connection in posterior FPDs and regular professional maintenance were associated with significantly reduced failure rates. Except in posterior molars, there was no difference in failure rates between parallel-sided preformed stainless steel serrated posts and cast-gold alloy posts.

CONCLUSION

Tooth fracture was the most common reason for retreatment of the FPDs, although the rate of periodontal breakdown and caries increased significantly with time. Nonrigid abutment-pontic connection and regular professional maintenance were associated with significantly reduced failure rates. Post design and composition were not related to outcome.