A new implant designed to maximize contact with trabecular bone: survival to 18 months.

ABSTRACT

PROBLEM: A roughened, commercially pure titanium (CP-Ti) implant design has been developed that features a different length and pitch for each screw thread to direct functional stresses away from cortical bone and to the more resilient trabecular bone. Abutment-implant connection is made using a conical taper to provide a seal against invasion by microorganisms. PURPOSE: To assess short-term (18 months) clinical performance of this innovative implant design. METHODS: A total of 1,419 implants were placed in 313 patients to support 419 prostheses in a multidisciplinary, multicentered, prospective clinical study conducted by the Ankylos Implant Clinical Research Group (AICRG). More than 100 dentists at 32 centers in the United States, 1 in Korea, and 1 in Taiwan are involved in the study. Failure was defined as implant removal for any reason. The influence of mobility at placement, implant length and diameter, incision type, augmentation, crestal bone reduction, bone density, and the use of the operating room or dental clinic on survival were evaluated over 18 months. Crestal bone loss between placement and uncovering was also determined. RESULTS: Crestal bone loss ranged from 0.2 to 0.5 mm. The overall success rate from placement to 18 months was 96.6%. Implants mobile at placement failed more frequently (16.9%) compared with stable implants (3.1%). Wide-diameter implants and longer implants exhibited higher survival rates. Incision design and surgery location did not influence survival. Bone density was important to clinical survival.