No abstract

The aim of the present study was to evaluate single tooth replacements by non-submerged implants. In the time period from 1990 to 1998, 72 patients were consecutively admitted for treatment with a total of 109 solid screw ITI-implants supporting single crowns. All crowns were ceramic to metal fused with a ceramic occlusal surface and mounted to the octa-abutment. The mean observation time was 4.3 years, ranging from >1 to 9 years. The implants were monitored regularly by periimplant parameters. Periapical radiographs using the parallel technique were taken after the healing period and in 1999 for comparative measurements. No implant was lost during the healing phase, while 3 failures occurred after a loaded period of 2.5 and >5 years, respectively. The 5-year cumulative survival rate was 99.1%. In the course of the study, only 2 implants exhibited marginal inflammation that required treatment. The radiographically measured distance (DIB) from the implant shoulder to the first implant-bone contact was significantly increased in 1999 and different between the two readings. However, this difference in DIB was not significant between implants with a short (1 year) and long (>5 years) observation period. It was concluded that changes in the crestal bone level occur mostly in the first postsurgical year. Prosthetic complications were rare, mostly encountered in the first year after loading and often limited to re-tightening of the occlusal screw.

The surgical procedure appears to be a safe method with rare complications. Radiographic assessment of the augmentation procedure proved to be difficult, and measurements are not fully reliable.

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The Periotest values of mandibular implants, registered before and after loading by overdentures, were compared. Thirty edentulous patients with 60 Bonefit ITI implants were selected with an average age of 69 years. The Periotest values were measured 1) after a healing period of 3 months and 2) after the overdentures had been worn for a period of 12 months. Periodontal parameters were recorded at both examinations. Furthermore, 17 biopsies of mandibular bone taken from the implant sites during implant surgery were analyzed to assess the bone density. The histomorphometric evaluation was done using a point count method. At the end of the healing period, all registered Periotest values were negative, ranging from -1 to -8 with an average of 4.08. One year later, all measurements showed negative values again, ranging from -2 to -8 with an average of 4.97. The difference was statistically significant. Seventeen biopsies of mandibular bone were evaluated to determine the density. The range of bone density was from 22.4% and 90.9%. There was no correlation found between bone density and Periotest values. However, a significant correlation could be observed between mandibular atrophy and bone density.