Page 30 - Peri-implant health: the effect of implant design and surgical procedure on bone and soft tissue stability

CHAPTER 3
of prosthesis insertion but increased to 5.6%, 10.8%, 15.2%, 17.2%, and 23.5% after 1, 5, 10, 15, and 20 years, respectively. Vervaeke and colleagues performed a prospective study, whereby 50 full‐arch rehabilitations were immediately loaded the day of surgery on 5-8 implants in the maxilla and mandible and followed for 9 years.38 Implant survival was 99.2%, and the total mean bone loss, including initial remodeling, was calculated on patient level being limited to 1.7 mm. However, on implant level, 30% of the individual implants had lost more than 2 mm, figures largely affected by the inclusion of smokers and patients with a periodontal history. Hence, in the context of peri‐implantitis, the mean crestal bone values calculated on patient level are not appropriate to detect disease around individual implants. The same holds true for cross‐sectional evaluation at a given time point when the baseline radiograph is lacking and bone levels are used as surrogate for peri‐implantitis detection. A recent report of Pettersson and Sennerby revealed that 15% of the implants showed more than 2 mm bone loss after 5 years.39 Applying the criteria published in a paper written for the European Workshop on Periodontology in 2012 by Sanz and colleagues, these implants could be diagnosed with peri‐implantitis.35 However, in this particular study, 25% of the implants had already bone loss up to 2 mm due to the specific implant design and over time there was stability or even improvement of the bone level.
Probing depth
Periodontal probing is a common basic diagnostic tool in periodontal diagnosis around teeth. Ericsson and Lindhe had described distinct differences between teeth and implants in soft tissue composition, organization, and attachment between the gingiva and the root surface on one hand and between the peri‐ implant mucosa and the implant surface on the other.40 Therefore, this affects the interpretation of probing depth measurements. In healthy tissue, the probe penetration is more advanced around implants, although this is depending on the probing force.41-44 Soft tissue around implants has also been found thicker than around teeth. This was first described in animals and confirmed by human biopsies.45,46 Parpaiola and colleagues assessed the dimensions of the soft tissue cuff present at various aspects around teeth and implants using human biopsies.47 The soft tissue cuff that surrounded a tooth varied between 2 mm at flat surfaces and 4 mm at proximal surfaces, while at implant sites, the mucosa at proximal as well as flat surfaces was 1–1.5 mm greater. The probing depth (PD) was greater at proximal than at facial or palatal/lingual surfaces at tooth sites
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