Page 98 - Peri-implant health: the effect of implant design and surgical procedure on bone and soft tissue stability

CHAPTER 4
there is still no consensus on the criteria to define peri-implantitis.
By and large, the mean weighted bone loss ranged between 0 and 2 mm in 90% of the study groups (Figure 3, A–C). Only in 9/123 study groups (7.3%) was the mean bone loss above 2 mm as reported in 3 studies. However, since mean values may hide the real problematic cases, the statistical analysis using mean value and standard deviation allowed calculation of number of implants with an arbitrarily chosen bone loss threshold of above 1, 2, or 3 mm. We adopted the 2 mm bone loss threshold as proposed by Klinge and colleagues211 since this could be suggestive of “risk-zone” cases.
The overall results demonstrate that 49% and 18% of all implants in the 87 studies lost more than 1 mm and 2 mm bone, respectively, during function above 5 years. It seems logical to conclude that setting a threshold for disease below this value is unrealistic and probably leads to false positive diagnosis of dis- ease. Only 5% of the implants lost more than 3 mm bone. The proportion of implants losing above 2 mm bone is 14%, 18%, and 20% for minimally rough, moderately rough, and rough surfaces, respectively. Of course, the prevalence of 2 or 3 mm bone loss does not necessarily equals peri-implantitis. The approach applied in our paper may even overestimate the prevalence of peri-implantitis because bone loss should be accompanied by inflammation of the surrounding tissues as demonstrated by the presence of bleeding or pus. This explains why self-reported peri- implantitis prevalence (Table 4) does not always correspond with the prevalence of bone loss above 2 to 3 mm as reported in Table 3. The paper of Roc- cuzzo198 demonstrates nicely that implants placed in patients with aggressive periodontal disease history have 15.1% peri-implantitis but only 1% of bone loss above 2 or 3. Meyle and colleagues140 has no implants with bone loss above 2 mm yet finds 24% of peri- implantitis due to 27% bleeding. This seems suggestive of mucositis diagnosis instead of peri-implantitis. The parameters bleeding or the bone loss threshold taken for disease seem to have a very decisive effect in rocketing peri-implantitis upwards in many studies. Interestingly, in an 18-year follow-up study, Dierens and colleagues212 demonstrated that bleeding on probing is a bad predictor for bone loss or peri-implantitis.
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