Retrospective clinical evaluation of tapered screw-vent implants: results after up to eight years of clinical function.

Uncertainty about the causes of peri-implant bone loss and difficulties in measuring it often have resulted in omission of bone loss data from published long-term implant studies. This nonrandomized, uncontrolled, retrospective study evaluated the clinical outcomes of treatment with tapered, multithreaded implants with a special emphasis on peri-implant crestal bone status. Chart reviews were conducted of 60 patients who had been treated with 267 implants for the placement of 1 or more missing and/or unsalvageable teeth, and who met general inclusion criteria for dental implant therapy. In all cases, marginal bone changes were calculated from the cementoenamel junction (CEJ) or the implant neck to the crestal bone level with standardized radiographs taken at implant placement (baseline) and during annual follow-up. After a mean followup of 7.5 years, implant survival was 98.5% (263/267) for all implants placed, and implant success was 96.2% (253/263) for all surviving implants. No discernible bone loss was evident in 88% of surviving implants. Crestal bone loss was observed in 25% (15/60) of total study subjects and in 12% (32/263) of all surviving implants: 29 implants exhibited 1 mm of bone loss and 3 implants lost 2 mm of bone. Low-density maxillary jawbone and more extensive bone remodeling, which were required around implants immediately placed into extraction sockets, were the probable causes of observed bone loss in this study. Implants exhibited excellent long-term outcomes with little or no bone loss.