Implant design and intraosseous stability of immediately placed implants: a human cadaver study

Objective: The objective of this study was to explore effects of implant macrodesign and diameter on initial intraosseous stability and interface mechanical properties of immediately placed implants. Material and method: Mandibular premolars of four fresh-frozen human cadavers were extracted. 04.1/4.8 mm ITI(R) TE(R), 04.1 and 4.8 mm solid screw synOcta(R) ITI(R) implants were placed into freshly prepared extraction sockets. Resonance frequency analysis was conducted to quantify primary implant stability quotient (ISQ). Installation torque value (ITV) and removal torque value (RTV) of the implants were measured using a custom-made strain-gauged torque wrench connected to a data acquisition system at a sample rate of 10,000 Hz. The vertical defect depth around the collar of each implant was measured directly by an endodontic spreader. The bone-implant contact was determined in digitalized images of periapical radiographs and expressed as percentage bone contact. Results: The ISQ values of the TE(R) implant was higher than the 04.1 mm implant (P < 0.01), and comparable with the 04.8 mm implants (P > 0.05). ITVs and RTVs of TE(R) and 04.8 mm implants were higher than the 04.1 mm implant, although the differences between groups were statistically insignificant (P > 0.05). The vertical defect depths around all types of implants were similar. In the radiographic analyses, percentage bone-implant contact of the TE(R) and 04.8 mm implants were comparable at the marginal bone region and both were higher than that of the 04.1 mm ITI9(R) implant. Nonparametric correlations between groups revealed a significant correlation between ITV and RTV (r=0.838; P < 0.001), but not between ISQ values and ITVs and RTVs (P > 0.05). Conclusion: Immediately placed ITI(R) TE(R) implant leads to initial intraosseous stability and interface mechanical properties comparable with a wide diameter implant.