Page 14 - Peri-implant health: the effect of implant design and surgical procedure on bone and soft tissue stability

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been shown to affect implant failure irrespective of the implant surface, increase the risk of postoperative infection and yield more marginal bone loss especially in the maxilla.17 Moreover, the history of periodontal disease was suggested as a second important patient-related factor. Increased susceptibility for periodontitis may translate into an increased susceptibility for implant loss, loss of supporting bone and/or postoperative infection.18 Interestingly, no significant relation was found between diabetes and implant failure.19
■ IMPLANT-RELATEDFACTORS
In addition to patient-related factors, implant-related factors could influence peri- implant bone stability. Several modifications in implant macro-design and micro- design have been introduced to optimize peri-implant bone stability. One of the most investigated and debated implant-related micro-design factors over the last decades is surface topography and composition. Both factors have their influence on implant surface roughness, which is expressed in a Sa value. This three- dimensional value expresses an absolute difference in the height of each point compared to the arithmetical mean of the surface.20 In the early years of implant dentistry two types of implant surfaces were used, namely the minimally rough surface (Sa = 0.5–1 μm) and the microporous titanium plasma-sprayed surface (Sa > 2 μm). The former was coined as smooth, while the latter was denoted as a rough implant surface.
Manufactures performed modification of the implant surface by sandblasting, acid-etching, anodic oxidation, or hydroxyapatite coating. These techniques resulted in a moderately rough implant surface (Sa = 1–2 μm), which is nowadays the most used roughness in dental implants. These modifications were necessary to improve the osteoconductive and osteoinductive properties of the implant. Studies showed that the moderately rough implant surface had better blot cloth stabilisation, enhanced production of biological mediators, stimulated osteogenic maturation leading to higher bone-to-implant contact, and increased bonding strength of the bone to the implant.21,22 Additionally, the modifications also led to a lower clinical failure rate,23 and researchers observed a higher removal torque compared to the smooth implant surfaces.24 Hence, this surface modification made it possible to load the implant earlier or even immediately
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