A follow-up study of screwpost-retained amalgam crowns

A follow-up study of amalgam crowns retained with brass screwposts (Dentatus) has been performed. The teeth had been restored by undergraduates at the Department of Cariology, School of Dentistry, Stockholm, during the years 1970-1976. Radiographs of the teeth made at the time of insertion of posts were available in all cases. The material comprised 56 teeth with altogether 69 screwposts. Average observation time was 7.8 years. Anamnestic data were collected and clinical and radiographic investigations of the restored teeth and surrounding tissues were carried out. Of the 56 teeth, 8 teeth containing altogether 11 screwposts had been lost by extraction. Annotations from the treating dentists were available in all cases and showed that five of the extractions had been necessary because of extensive caries, one because of parodontitis and two because of root fractures. No corrosion of screwposts had been observed in the fractured teeth. The anamnestic investigation revealed sporadic tenderness and metallic taste in only a few cases. The most frequent clinical findings were discoloration and pitting of amalgam surfaces and discoloration of tooth substance and gingiva. The discolorations of the gingiva were related to restorations extending below the gingival margin. No clinical or radiographic signs of corrosion of screwposts were found in the investigated teeth.