Clinical and Radiological Outcomes of Two Implants with Different Prosthetic Interfaces and Neck Configurations: Randomized, Controlled, Split‐Mouth Clinical Trial

Abstract

Peri-implant bone loss seems to occur following implant placement/loading regardless of all the efforts to eliminate it. Several factors, including surgical trauma, biologic width establishment, lack of passive fit of the superstructures, implant-abutment microgap, and occlusal overloading, may increase peri-implant bone loss. Over the years, new interface designs were introduced and clinical studies suggest that internal conical connection and platform shifting may be advantageous for marginal bone preservation. To compare clinical and radiological outcomes of two implant designs with different prosthetic interfaces and neck configurations in a randomized, controlled, split-mouth clinical trial. Thirty-four partially edentate patients randomly received at least one internal conical connection with back-tapered collar and platform shifting design or external-hexagon implants with flat-to-flat implant-abutment interface. Primary end point was peri-implant bone level changes at different time points, failures of implants and/or prosthesis, any complications, implant stability quotient (ISQ) values, and periodontal parameters. No dropout occurred. Marginal bone changes were statistically significantly different with better results for the internal conical connection. No implants and prosthesis failures have been observed, yielding a cumulative survival rate of 100%. A high ISQ value was found for both implants, and no statistically significant difference was found for ISQ mean values between interventions at each time point (p > .05). All implants showed no bleeding on probing and a very slight amount of plaque at the 1-year-in-function visit. Both implant designs investigated performed similarly in terms of failure rates, providing successful results up to 1 year after loading. The back-tapered neck configuration with conical connection and built-in platform shifting showed statistically lower marginal bone loss than straight neck configuration with flat-to-flat implant-abutment interface and external-hexagonal connection.