Caroliene Meijndert

144 Chapter 8 The general aim of the research described in this thesis was to assess the outcomes of treating a missing tooth in the aesthetic region with an implant, following short and long term outcome up to a decade of treatment. Patients treated in the various studies in this thesis had different grades of alveolar bone resorption, and requested implant therapy for one missing or failing tooth. A variety of dental implant designs within the portfolio of one implant brand were applied. In general it can be said that the implant survival rates in the studies described in this thesis were high, the peri-implant bone levels were stable, the peri-implant soft tissues were healthy and the aesthetic outcomes were satisfying, in both the healed and post-extraction sites. Peri-implant bone level change Tissue-level implants In the longest running study described in this thesis (10 years), a tissue level implant was used in augmented healed sites. Tissue level implants were initially designed to respect the biological width. The results in this study showed minor bone loss after 10 years (0.48 mm), which is comparable to the marginal bone loss reported by other 10-year studies of the aesthetic region (0.66 mm, Jemt, 2008; 0.75 mm Gotfredsen, 2012). These favorable outcomes confirm the efficiency of this concept ( Chapter 2 ). A disadvantage of a tissue level implant, especially when it is applied in the aesthetic region, is that it leaves little opportunity to design a personalised emergence profile for each abutment. The silver metal collar of the implant ‘may’ become visible around the gum line, which is a concern in the aesthetic region. Placing a tissue level implant deeper to overcome the risk of a visible metal collar was proven not to be a solution: the polished part in contact with the peri-implant bone led to crestal bone resorption and did not result in better coverage of the implant neck with mucosa (Hämmerle et al., 1996; Buser & Von Arx, 2000). In an attempt to overcome this limitation, there has been a shift from using tissue level implants to using bone level implants. Bone level implants The bone level implants used by the studies described in this thesis were placed in healed sites and showed negligible marginal bone loss after 5 years (0.13 mm) ( Chapter 3 ). The more recent bone level implants (with a tapered implant body) that were placed in healed sites were also accompanied by negligible marginal bone loss after 1 year in function (-0.07 mm) ( Chapters 4 and 5 ). Comparable results were reported in the