Long-Term Maintenance of Biologic Width of Implants in Humans

Objectives: Objectives: Characteristics and dynamics of biologic width of 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 in obtaining histological materials. However, there are clinical and radiographic parameters around implants which correspond to the individual histological components of the biologic width. Our earlier studies at 2 and 4 years (Polson 2010,2014), reported initial formation and maintenance of a biologic width, and this present study reports outcomes over a 5 year period.
Methods: Methods: Study population comprised 8 adults with edentulous mandibles each of whom had 5 intraforaminal mandibular implants, and these 40 implants had been loaded after conventional osseointegration. 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, 1, 2, 3, 4 and 5 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 implants, and comparisons across time were made using paired-statistical analyses.
Results: Results: The Biologic Width at 6 mo, and Years 1,2,3, 4 and 5 was 3.20 (0.19) [Mean (SE), mm], 3.22 (0.17), 3.30 (0.21), 3.24 (0.16), 3.34 (0.20), 3.24 (0.25), with no statistically significant differences. However, individual differences of the component pocket depths and connective tissue contact did vary significantly across time. Inflammation indices were negligible indicating that this remodeling was in a physiologic environment, and crestal alveolar bone levels were unchanged due to lack of microgap.
Conclusions: Conclusions: Implant biologic width in humans was remarkably constant over time, but there were component changes representing dynamic physiologic remodeling. Supported by ITI, Penn Periodontal Fund ,and Alpha Omega.