Submergence of roots for alveolar ridge preservation. A failure (4-year follow-up study).

A 4-year clinical and radiographic follow-up study of 20 cases of crown-resected root-filled roots, covered by mucosal flaps, distributed among 15 patients, has been carried out. Only cases of uneventful submergence of the root with intact healthy mucosa were regarded as successful. This study shows that: (1) The number of failures increases with the years; from 3 cases at the 1-year to 11 cases at the 4-year follow-up, corresponding to 53% (8/15) of the patients. In the failures, an exposure of the root-surface was seen, but without inflammation in the surrounding tissue. These roots could be extracted without bone loss. (2) Alveolar ridge atrophy is not prevented by retained roots, and is probably the primary reason for failure of coverage. The 11 failures showed alveolar ridge atrophy, which was observed before failure in 6 cases. None of the successful cases showed alveolar ridge atrophy. The present method cannot be recommended as a routine procedure.