Caroliene Meijndert

163 Summary satisfaction had improved from 55.7 (pre-treatment) to 90.0 (1-year follow-up) on a 0-100 VAS scale. We can conclude that immediate implant placement and restoration with the new tapered bone level implant system is accompanied by good initial clinical and radiographic results as well as high patient satisfaction. A common denominator amongst all the studies was the stability and health of the peri-implant tissues. The implant abutment connection became of interest as it is located in the critical zone that guards the ‘inside’ from the ‘outside’ environment. In vitro studies have suggested that there is a microgap in each connection type (internal, external, platform switched, platform matched, parallel and conical configurations), but that the conical connection shows the smallest microgap. The microgap can harbour peri-implant pathogens with the potential of inducing inflammation in the peri-implant tissues. Clinical trials have suggested that dental implants with a conical implant-abutment configuration are accompanied by less peri-implant bone loss than non-conical configurations. Therefore, a systematic review of the literature was performed to assess the effect of different implant-abutment interface designs on peri- implant bone level changes, implant loss and mid-buccal mucosa changes around single implants placed in the anterior maxilla ( chapter 7 ). Eligible prospective studies were divided according to the internal implant-abutment configuration: i) platform switched conical (PS-conical), ii) platform switched parallel (PS-parallel) and iii) platformmatched parallel (PM-parallel). A detailed search was carried out in Pubmed, EMBASE, Cochrane, Scopus, Open Grey and African journals Online (until December 1, 2020). Risk of bias was assessed with RoB 2.0 and ROBINS-I. A meta regression analysis was carried out primarily on the pooled peri-implant bone level changes followed by implant loss and mid-buccal mucosa level change. The manuscript complied with the PRISMA guidelines and was registered in the PROSPERO database (ID: 225092). A total of 5,513 hits gave 44 eligible articles for the analyses. The bone level change and implant loss did not differ significantly between the PS-conical and PS-parallel connections, and their bone losses were significantly lower than with PM connections, but only the PS-conical had significantly lower implant losses than the PM connections. The mid-buccal mucosa level changes were comparable between the three connection configurations. Moderate to high risk of bias was detected in the included studies. The conclusion is that the performance of PS-conical and PS-parallel connection configurations are comparable, with significantly less bone loss compared to PM-parallel connection configurations, but all 3 lead to small mid-buccal mucosa changes which did not differ significantly between the groups. A