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ePaper created 2018-03-14, 10:36:46 | version 1.38.0
I case study_ pink biomimetic implant system ‘Recent systematic reviews consistently confirm that implants with platform- switched abutments are associated with better crestal bone preservation than implants with platform- matched abutments.’ provisionalization.28 The implant system used in the current multi- center study incorporates a platform-switch rang- ing between 0.5 mm and 1.38 mm, depending on implant fixture diameter (IFD): Taken together, these findings offer evidence that the functionality of this implant system in vari- ous placement protocols may complement bone- and soft-tissue-preserving effects, with immediate placement in combination with platform switching. IFD = Ø3.8 mm: 0.5 mm PS IFD = Ø4.5 mm: 0.57 mm PS IFD = Ø5.5 mm: 0.7 mm PS IFD = Ø6.5 mm: 1.38 mm PS Platform switching has become a standard feature in implant component design and has expanded the clinician’s control over crestal bone preservation. Numerous studies29-33 and systematic reviews24,34-37 have reported reduced alveolar crestal bone resorption for platform-switched implants compared with platform-matched implants. Considerable clinical evidence suggests platform switching has a bone-protective effect. Cappiello, et al, reported a significant preservation effect (vertical bone loss was 0.72 mm less with platform-switched healing abutments versus controls) in a controlled clinical trial of 131 implants (all placed at the crest) in 45 patients.32 Clinical studies by Prosper, et al,38 and Canullo et al39 have also demonstrated advan- tages of platform-switched implants over regular implants with respect to crestal bone stability, with a minimum of 24 months follow-up. Recent system- atic reviews consistently confirm that implants with platform-switched abutments are associated with better crestal bone preservation than implants with platform-matched abutments.35-37 While platform-switched implant configura- tions also appear to preserve soft tissue and provide increased control over gingival esthetics according to some reports,40,41 several recent studies tend toward reporting similar tissue-esthetics preserva- tion with platform-switched and other abutment– implant interface designs,9,10,42 which suggests that platform switching favors stable tissue dynamics. However, a study by Zuiderveld, et al, found platform switching to have no effect on midbuccal mucosal (MBM) measurements one year after crown place- ment; rather, the buccopalatal positioning of the implant itself (i.e., more toward the buccal) resulted in a more apically positioned MBM.43 Findings of a systematic review by Prasad, et al, emphasize the importance of considering a synthe- sis of factors comprising implant design, occlusal forces and bone and soft-tissue volumes in opti- mally preserving crestal bone.44 As a further caveat, even the authors of some recent systematic reviews raise notes of caution about remaining unknowns as to functional specifics of platform switching and stress the need for further and more specific data from clinical studies to evaluate them.34,35 _Five-year prospective clinical study An ongoing five-year study continues to evaluate the use of this implant system (168 implants placed in 120 partially edentulous patients). Its objectives include assessment of the five-year survival rate of this implant system, implant success, incidence of excessive bone loss, peri-implant infection and other complications, incidence of adverse device effects, change in marginal bone level, visual soft- tissue esthetic outcomes, and the number and nature of prosthetic revisions. Alignment, orientation and magnification of the periapical radiographic images of all subjects’ implants and alveolar bone levels were standardized by rotating and translating each image such that all were uniformly aligned, oriented and scaled using a semi-automated program (MATLAB®, MathWorks, www.mathworks.com/products/matlab/). For an- gles, imaging differences in both elevation (above or below correct plane) and azimuth (mesial–distal) between images in the same series were computed. All of the images in this data set have a percentage error of less than 3.5 percent. Clinical analyses of the investigator-reported 18-month interim survival rates, marginal bone and soft-tissue level changes, and esthetics estimate an overall success rate among all sites of 95.8 percent. Consistent with other implant designs, most os- seointegration failures in the study occurred during the healing period following placement or shortly after prosthetic loading. However, unlike other designs, the location (mandible versus maxilla)45-48 and length of the implant46-49 had no apparent ef- fect on the survival rate. After loading, this implant system has demonstrated a survival rate of more than 99 percent, based on available data from this ongoing study. This is primarily a clinical implant survival and efficacy study with hard- and soft-tissue metric endpoints. The study protocol defines implant suc- cess as peri-implant bone loss ≤3 mm. Its descriptive endpoints require radiographic and photographic documentation only, and the esthetic results are presented as clinical photographs. • Note: Please see Implants C.E. magazine’s next edition, 02/2018, for Part 2 of this article. References available upon request from the pub- lisher. 12 I implants 1_2018