Page 57 - Peri-implant health: the effect of implant design and surgical procedure on bone and soft tissue stability

HOW DO PERI-IMPLANT BIOLOGIC PARAMETERS CORRESPOND WITH IMPLANT SURVIVAL AND PERI-IMPLANTITIS? A CRITICAL REVIEW
This review contains four papers that reported the Kaplan–Meier survival analysis. Chappuis reported a sudden increase after 12 years, the latter related to a combination of biologic and technical failures.14 Jensen analyzed the implants retrospectively with a start of the measurement after 3 years and reported all losses before 5 years.96 Also, the other two papers by Meyle and Shi showed a downhill Kaplan–Meier survival rate in relation to follow‐up time.94,98 It seems therefore appropriate to conclude that implants do fail over time, although in small numbers.
The mean PD reported in 25 of the 41 papers varied between 2.2 mm and 4.3 mm, with only one study reporting a mean PD above 4 mm. It is obvious from the results presented in this review that a relationship between mean PD and mean bone loss or peri‐implantitis prevalence is absent. From a clinical perspective, one should realize that probing is technique sensitive and may be affected by probing force, probing direction, design of the restorations, design of implant, and type of prosthetic components. Obviously, the prosthetic reconstruction may jeopardize probing due to incorrect probing direction or restorations’ overhangs. This may potentially also provoke iatrogenic bleeding. Serino and colleagues examined the PD before and after removal of the prosthetic reconstruction.58 While the PD before removal had a poor correlation with bone loss, it correlated well with the PD after removal as assessed during surgery. Christiaens concluded in a recent published paper that probing depth around peri‐implantitis affected implants significantly underestimated the true bone level by 1 mm.99 Garcia‐ Garcia and colleagues showed a significant underestimation of the interproximal bone level by intra‐oral radiography of 1.3 mm on average.100 Merli concluded that assessment of bone loss by three clinicians showed the highest intraclass correlation coefficient while the intraclass correlation coefficient for PD and BoP was low.101 The paper of Coli and colleagues concluded, based on evidence from animal as well as human studies, that it is unreliable to simply diagnose an implant as having peri‐implantitis because of a pre‐established PD.18 It is well known that values of 6–9 mm PD have been described in association with long‐ term successful dental implants. Human studies have shown that in healthy peri‐ implant mucosa, the probing depths are in most of the cases (60%–63%) above 4 mm and even up to 6 mm.7,55 One should also keep in mind that the interproximal probing depth measurement is affected by a significant papilla regrowth after crown installation. These findings support the importance of a combination of diagnostic parameters when diagnosing peri‐implantitis.
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