Caroliene Meijndert

148 Chapter 8 of a present papilla). It must be acknowledged that the papilla fill in the interdental spaces in single-tooth implant treatment does not seem to be depended on peri-implant bone height changes (Rocuzzo et al., 2018). This is in contrast to statements we made previously for the mid-buccal mucosa level, but it emphasizes the complex biology around an implant restoration. Peri-implant soft tissue health The gingiva index, pocket probing depth and bleeding upon probing around dental implants are outcomes when evaluating the health of the soft tissue around dental implants. In general, it can be said that all the studies described in this thesis recorded healthy soft tissues at all evaluation periods. Apparently, high patient compliance to the prescribed post-treatment oral hygiene instructions, as is part of a university-based study with a strict protocol, could have played an important role in the observed health of the peri-implant soft tissues. Nonetheless, as reported by Visser et al. (2011), and noted in Chapter 2, despite careful instructions on the necessary aftercare after crown placement, 63% of the patients needed supplemental oral hygiene support after 5 years. We realize that the strict protocol followed in the university setting might not be always feasible in general practice. But knowing that, despite the strict protocol, more than half of the patients needed additional instructions stretches even more the importance of the instructions and the aftercare for a long-term stable implant restoration. Another possible explanation for the good peri-implant health outcome in the studies reported in this thesis, might be, as mentioned before, at least in part due to the implant-abutment connections used. All the bone level implants were equipped with a platform switched conical connection, which has the smallest microgap between the components, thus resulting in the least amount of micromovement and bacterial leakage (Zipprich et al.,2018; Ivanovki et al., 2018). Implant-abutment connection Over time, there has been a shift in the use of tissue level implants to bone level implants in the aesthetic region. A microgap at the connection between the implant and abutment is inherent in a bone level design, thus affecting the benefit of an uncompromised biological width, possibly leading to more peri-implant bone loss. This can potentially reflect poorly on the aesthetic outcome due to insufficient soft tissue support. A systematic review of the literature was performed to gain insight