Page 213 - Peri-implant health: the effect of implant design and surgical procedure on bone and soft tissue stability

Regarding implant surface roughness, the systematic review suggests that peri-implant bone loss around minimally rough implant systems was statistically significantly less than the moderately rough and rough implant systems. No statistically significant difference was observed between moderately rough and rough implant systems. The meta-analyses showed less average peri-implant bone loss around smoother surfaces. However, due to the heterogeneity of the papers and the multifactorial cause for bone loss, the impact of surface roughness alone seems somewhat limited and of minimal clinical importance. In addition, the meta-analysis showed that smoking and history of periodontitis increased the risk for bone loss.
Chapter 5 (Study III) includes two prospective split-mouth studies. Both studies included edentulous patients in need of a two-implant-supported overdenture in the mandible. The first part of Study III described the effect of the site-specific factor ‘soft-tissue thickness’ on crestal bone remodeling and peri-implant health. Twenty-six patients received two moderately rough implants. According to the manufacturer’s guidelines, the control implant was installed equicrestally. The test implant was placed below crestal level to ensure at least 3 mm space for biologic width establishment on the abutment part. Initially, 26 patients were treated with one equicrestally and one subcrestally placed implant. After 36 months, 24 patients were available for follow-up.
The second part of Study III determined the effect of implant surface roughness on crestal bone remodeling. As concluded in Study II, crestal bone loss might be related to the implant surface roughness. The existing literature suggests higher survival rates for moderately rough implants compared to minimally rough implants. On the other hand, recent literature and the findings of Study II suggest that implants with a minimally rough surface yield less long-term crestal bone loss.
An implant with a hybrid surface combines the benefit of a moderately rough implant body and a minimally rough implant neck. To determine the effect of implant surface roughness on crestal bone loss, 23 patients received two implants: an implant with a moderately rough surface (Sa value: 1.3 μm) and a hybrid implant with a minimally rough coronal neck of 3 mm (Sa value: 0.9 μm) combined with a moderately rough body (Sa value: 1.3 μm). Apart from the difference in implant
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