Maintenace of Biologic Width of Immediately Loaded Implants in Humans

Objectives: Characteristics and dynamics of biologic width of immediately loaded implants is very important for biological form and function. Information is usually from histological investigations in animals, and confirmatory evidence from humans is lacking because of difficulty obtaining histological materials. However, clinical and radiographic parameters around immediately loaded implants correspond to the individual histological components of the biologic width. Our earlier 2 year study reported initial formation of a biologic width, and this present study reports 4 year outcomes. Methods: Study population comprised 14 adults with edentulous mandibles each of whom had 5 intraforaminal mandibular implants, and these 70 implants had been immediately loaded. Clinical parameters comprising Plaque Index, Bleeding Index, Mucosal Margin Location, Pocket Depth, and Attachment Level were measured by a standardized, calibrated examiner every six months. Standardized periapical radiographs had been taken of the implants using customized stents at loading, 6 mo, and 1,2, 3 and 4 years, and crestal alveolar bone level was measured by a trained examiner. These clinical and radiographic data were combined and correlated to calculate biologic width around these immediately loaded implants, and comparisons across time were made using paired-statistical analyses. Results: Biologic Width at 6 mo, and Years 1,2,3 and 4 was 3.22 (0.15) [Mean (SE), mm], 3.17 (0.13), 2.87 (0.11), 2.74 (0.10), and 3.10 (0.12), with no statistically significant differences in overall dimension. However, individual differences of the component pocket depths and connective tissue contact did vary significantly across time. Inflammation indices were negligible indicating this remodeling was in a physiologic environment. Crestal alveolar bone levels had initially remodeled in relation to immediate loading but were subsequently unchanged. Conclusions: Biologic Width of these immediately loaded implants in humans seemed constant over time, but there were component changes representing dynamic physiologic remodeling.  Supported by ITI, Penn Periodontal Fund, and Alpha Omega.