Page 187 - Peri-implant health: the effect of implant design and surgical procedure on bone and soft tissue stability

into the case definitions, thresholds applied for diagnosis of peri-implantitis, and whether commonly used biologic diagnostic parameters, such as mean bone loss, probing pocket depth, and bleeding on probing correspond to implant survival and peri-implantitis prevalence.
Study I showed that the included papers used 15 different peri-implantitis definitions. The case definitions varied considerably between studies, primarily due to heterogeneous thresholds for bone loss, ranging from any detectable bone loss to 3.5 mm. Low thresholds for bone loss lead to a higher prevalence of peri- implantitis on implant level than when higher thresholds are used. In addition to bone loss, other commonly used parameters to define peri-implantitis were arbitrarily selected thresholds for probing pocket depth, and bleeding on probing and/or suppuration. Moreover, 15 out of the 41 papers reported peri-implantitis prevalence on implant level without giving a specific case definition. These differences in thresholds make comparisons between studies difficult and lead to an over- or underestimation of peri-implantitis. Therefore, Study I concluded that many authors report extremely high ‘self-quoted’ prevalence of peri-implantitis despite extremely low mean bone loss values.7-9
This considerable variation in scientific reporting induces unreliable figures of the prevalence of peri-implantitis and may contribute to inadequate clinical actions. To illustrate, we applied the different definitions on our clinical data of Study IV. Nine definitions for peri-implantitis were applicable on our data (TABLE 1) and six were non-applicable (Table 2). Given the applicable definitions, the prevalence of peri-implantitis on implant level in the study population of Study IV has a range of 0% and 29.2%. Clinically this means that over a fourth of the implant the implant tissues diagnosed as diseased are healthy.
Table 3 summarizes the proportion of implants examined in Study IV concerning bone level, probing pockets depth, and bleeding on probing. The single implant variables were calculated as the mean of site measurements, respectively two radiographical bone values or four clinical peri-implant sites. A cross-table presents bone loss around each individual implant in relation to the probing depth or bleeding. Thirty-six implants presented with less than 0.5 mm bone loss after 5 years. In fact, 22 implants had no bone loss at all and only 9 out of these 22 showed bleeding on probing. All implants yielded less than 4 mm probing depth
GENERAL DISCUSSION
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