Primary stability and osseointegration comparing a novel tapered design tissue-level implant with a parallel design tissue-level implant. An experimental in vivo study

Objectives: The aim of the present study was to compare a novel tapered, double-threaded self-tapping tissue-Level design implant (TLC) to a well-established parallel walled tissue-level (TL) implant in terms of primary and secondary stability over time. Materials and Methods: Test TLC (n = 10/per timepoint) and control TL (n = 10/per timepoint) implants were placed in the mandible of minipigs and left for submerged healing for 3, 6, and 12 weeks. Maximum insertion torque and implant stability quotient (ISQ) were measured for each implant at placement. Osseointegration and cortical bone maintenance were histologically evaluated by measuring total bone-to-implant contact (BIC) and first bone-to-implant contact (fBIC). Results: A significantly higher maximum insertion torque was measured for the test implant TLC compared to the control TL implant (57.83 +/- 24.73 Ncm and 22.62 +/- 23.16 Ncm, respectively; p < .001). The mean ISQ values were comparable between the two implant types (75.00 +/- 6.70 for TL compared to 75.40 +/- 3.20 for TLC, p = .988). BIC was comparable between both implant types at each of the evaluated time points. The fBIC was found to be significantly more coronal at 12 weeks for the TLC implant compared to the TL implant (0.31 +/- 0.83 mm for TLC compared to -0.22 +/- 0.85 for TL, p = .027). Conclusion: The novel tapered tissue level design implant showed improved primary stability and an overall improved crestal bone height maintenance compared to the parallel walled design at 12 weeks.