Page 212 - Peri-implant health: the effect of implant design and surgical procedure on bone and soft tissue stability
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                                CHAPTER 9
Based on 8,182 implants, the overall weighted mean bone loss was 1.1 mm after a loading time ranging from 5 to 20 years. The mean bone loss did not correlate with the reported prevalence of peri-implantitis, and the diagnostic parameters mean probing pocket depth and mean bleeding on probing. Moreover, the reported peri-implantitis prevalence did not correlate with mean probing pocket depth. However, a strong correlation was found between the reported prevalence of peri-implantitis and bleeding on probing. The survival rate showed a substantial correlation with function time, showing minor implant loss over time. We concluded that the case definition for peri-implantitis varied significantly between studies, indicating that an unambiguous definition based on a specified threshold for bone loss is not agreed upon in the literature.
Chapter 4 (Study II) scrutinized the literature on long-term peri-implant bone loss and the relation with implant surface roughness and patient-related factors such as smoking and history of periodontitis. Implant systems are categorised based on the surface roughness expressed in Sa-value; minimally rough (Sa value: 0.5 – 1 μm), moderately rough (Sa value: 1 – 2 μm), and rough (Sa value: > 2 μm). In implant dentistry’s early days, only minimally rough and microporous titanium plasma-sprayed rough implant systems were available.
However, over time several implant modifications were done by sandblasting, acid-etching, anodic oxidation, or hydroxyapatite coating resulting in a moderately rough implant system. These modifications improved the osteoconductive and osteoinductive properties of the implant. The surface of the moderately rough implant system showed better blot cloth stabilisation, enhanced production of biological mediators, stimulate osteogenic maturation leading to higher bone-to- implant contact, and increased bonding strength of the bone to the implant. On the other hand, rougher implant systems are linked to increased bacterial adhesion with a higher risk of being affected by peri-implantitis.
The search yielded 2,566 studies and 156 were selected for further reading. Only 87 reported information about surface roughness of the implants and mean bone loss after at least five years of function. In these papers in total 15,695 implants were inserted in 6,755 patients. The average weighted survival rate for these implants was 97.3% after at least 5 years of function. If 3 mm bone loss was used as a threshold to quantify peri-implantitis, less than 5% of the implants were affected.
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