However, high localized compression may lead to ischemia and eventually bone necrosis in close vicinity to the implant. To increase primary stability, it has been suggested that tapered implants should be inserted into osteotomy sites prepared with a final drill that is slightly narrower than the implant diameter. Several studies have suggested that implants should be inserted using an increased torque to increase their primary stability, which may allow immediate loading. Void spaces between the implant and bone, which do not contribute to primary stability, are filled with a blood clot following implant placement later, these clots are replaced gradually by mature bone. Later, bone in direct contact with the implant will undergo remodeling, a process leading to increasing secondary stability. This mechanical compression provides primary stability up to a certain point in time. Initial primary stability stems from implant surface zones engaging in direct contact with the surrounding bone. It is also dependent on site-specific bone quality, surgical osteotomy preparation, and implant design. Secondary stability is sequential to new bone formation and remodeling at the bone-implant interface. Primary stability depends on several factors, including bone density site dimensions, drill speed, and drill feed-rate during osteotomy preparation, surgical technique, and macro-/microscopic implant morphology. Implant stability during the healing process is a result of primary and secondary stability. Micromovements exceeding 50–100 µm may result in fibrous tissue formation instead of osseous integration. Implant stability is a prerequisite for achieving osseointegration. Osseointegration has been defined as a direct and functional connection between a bone and an artificial implant. Multiple SMs were associated with greater c-BIC. Conclusions: BIC was not affected by the drilling protocol. c-BIC of implant type 4 with SMs was highest of all implant types after both healing periods. c-BIC of implant types with 6 CFs was similar and significantly lower than that of implant types 3 and 4.
Flutes on the coronal aspect impaired the BIC at 3 m. Results: At 1 month, t-BIC ranged from 85–91% without significant differences between implant types or drilling protocol. Animals were sacrificed after 1 and 3 months, total-BIC (t-BIC) and coronal-BIC (c-BIC) were evaluated by nondecalcified histomorphometry analysis. Two groups of forty-eight implants were inserted with a final drill diameter of 2.8 mm (DP1) or 3.2 mm (DP2). Implants neck designs evaluated were: type 1–6 coronal flutes (CFs), 8 shallow microthreads (SMs) type 2–6 CFs,4 deep microthreads (DMs) type 3–4 DMs type 4–2 CFs, 8 SMs. Methods: Ninety-six implants were inserted in 12 minipigs calvarium. The objective of this study was to evaluate four different implant neck designs using two different drilling protocols on the BIC. Background: Stress concentrated at an implant’s neck may affect bone-to-implant contact (BIC).
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