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ePaper created 2016-03-11, 23:13:06 | version 1.38.0
issue 2016 — 13 Advanced Implant Esthetics Article Figs. 1a & b Provisional abutment after modified roll flap (a). Temporary crown in place at the end of the surgical reopening (b). Figs. 2a–c Intraoperative placement of a 15° angled abutment (a). Precise rotational adjust- ment of the implant (b). Check of rotational adjust- ment in the axial plane (c). – In humans, several recent studies have concludedthatthere is a vertical advan- tage of 0.5 mm,4 horizontal advantage of 0.3 mm,5 vertical advantage of 0.2 mm6 and nonsignificant7 result for the OAOT protocol in different clinical situations. In their 2014 review of the literature on factors influencing apicalization of peri- implant tissue, Iglhaut et al.8 documented interest in the concept of the single abut- mentandproposedrecordingtheposition of the implant at the time of placement. Thus, there is some evidence suggesting that it is desirable to limit the number of manipulationsofthesubgingivalelements as much as possible, even though the lit- erature is not unanimous in this regard. The OAOT technique has a drawback pointed out by Piñeyro and Tucker:9 how- ever: the increased risk of cement over- flow where the abutment–crown limit is deeplyburied.Differentclinicalstrategies make it possible to apply the OAOT con- cept: – The fabrication, using 3-D imaging, of a surgicalguideandamachinedabutment prepared during the preoperative stage makes immediate placement possible, but it is also more risky, since any error in the guide or any lack of precision in the placement could makethe prepared abutment unusable. – Thesametechnique,startingwithanim- pression at time of implant placement, is less risky, since the position of the im- plant has already been finalized. Fig.1a Fig.1b Fig.2a Fig.2b Fig.2c Since these two techniques involve the collaboration of the laboratory, a simpli- fied protocol was used for the majority of the 120 NobelActive implants (Nobel Bio- care; 3 mm) placed over the past three years: – Preoperative cone beam computed to- mography imaging is used to determine whethera straight abutment ora 15° an- gulated abutment is the best choice for the specific clinical case. – Radiographic monitoring makes it pos- sible to check on the placement axis in the mesiodistal plane, and the use of a parallelism guide when the 2 mm drill is being used provides a check on the buccal–palatal plane. Once the implant is in place, an angulated prosthetic abutment is seated to optimize the ro- tational position of the implant, which is done to avoid, as far as possible, any adjustmenttothe abutment bygrinding (Figs. 2a–c). In order to assist with intraoperative fit- ting,thesurgicalkitscontainsterileangled Article_Russe_00-00.qxp_Layout 1 02.03.16 20:52 Seite 2 Article_Russe_00-00.qxp_Layout 102.03.1620:52 Seite 2