Page 84 - Peri-implant health: the effect of implant design and surgical procedure on bone and soft tissue stability

CHAPTER 4
Quality of the Papers
The paper search revealed in total 87 included studies (summarized in Table 3) that reported a mean bone loss on implant level over a 5 to 20 year follow-up time; 48 were prospective and 39 were retrospective. Some papers compared different treatment protocols, which were considered as separate study groups for the statistical analysis of implant survival or bone loss calculation because some pertained to different surface or implant types as well as different treatment protocols. In the 123 treatment groups in total 15,695 implants were inserted in 6,755 patients and information about mean bone loss at the last examination visit was available from 13,970 implants after at least 5 years of implant function. The total drop-out of implants from baseline to the evaluation time point was 11% for the 87 selected papers.
Fifty-three out of 87 studies pertained to 10,533 originally placed implants from the portfolio of the three world leading companies Dentsply, Nobel Biocare and Straumann representing proportionally 67.1% from the total material. With 9,136/10,533 initially placed implants remaining at follow-up, the dropout rate was 13.3%.
Information on probing depth and bleeding on probing was available in only 40 and 49 of the included studies, respectively. Twenty-seven out of 87 papers reported peri-implantitis prevalence on implant level (Table 4) ranging between 0% and 39.7%. This large range can be explained by the arbitrarily chosen thresholds and diagnostic parameters for disease. The cut-off bone loss for peri- implantitis ranged from 1 to 3 mm and the cut-off probing pocket depth ranged from 4 to 6 mm. However, only 19/27 papers reported bleeding on probing, 16/27 reported probing depth, and only 11/27 actually defined peri-implantitis.
Implant Survival
From the 87 included papers and 123 study groups, the survival was reported in 79 papers and 107 study groups and ranged between 73.4% and 100%. Figure 1, A–C summarizes the implant survival rate and corresponding function time for the three surface roughness groups. In 44% of the studies the implant survival rate was between 95% and 100%, in half of the studies the survival ranged between 90% and 94.9%. Only in 6% of the studies the survival was below 90% with 73.4% survival after 20 years being the lowest one with a porous titanium alloy implant having a rough
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