CAMLOG and Science

CAMLOG&Science – Chapter 4 ABUTMENT EXCHANGES IN PLATFORM SWITCHING IMPLANTS AND DIFFERENT ABUTMENT MATERIALS In order to condition the implant-supporting soft tissues, repeated abutment exchanges are often performed during the healing phase. In a dog study, the effect of two exchanges of titanium (Ti6Al4V) and zirkonum dioxide (ZrO 2 ) abutments was evaluated using CONELOG ® implants (Becker et al. 2012). The abutments were dis- and reconnected four and six weeks after implant insertion or left undisturbed. Histological evaluation at eight weeks REMOVAL OF CEMENT-RETAINED IMPLANT RESTORATIONS Periimplantitis therapy or technical complications such as screw loosening or ceramic fractures may result in the need of removing prosthetics. When removing cement-retained restorations, vertical mechanical loading is applied on the bone and on the implant-bone interface. Mehl et al. (2013) evaluated the impact of such loads in a study inminipigs with CAMLOG ® implants. They imitated crown removal with 20 or 100 dynamic impulses of 18 Ns. After 13 demonstrated that abutment exchanges resulted in a disruption of themucosal seal as well as in an increased formation of a junctional epithelium and bone resorption compared to undisturbed healing. There was no significant dif- ference between both abutment materials although the undisturbed ZrO 2 abutments tended to show slightly better soft-tissue and bone values than Ti6Al4V abutments (Tab. 5). The authors concluded that repeated abutment manipulation may increase soft and hard-tissue changes in implants with plat- form-switching design regardless of the abutment material (Ti6Al4V or ZrO 2 ). to 18 weeks, they histologically did not find any differences regarding bone- implant contact area between loaded and non-loaded implants. The authors concluded that the removal of cement-retained restorations did not impair the mechanical implant stability, but increased bone remodeling activity. However, care should be taken when limited osseointegration due to peri-im- plantitis is evident since then vertical loading may result in implant loss. Tab. 5: Mean (± standard deviation in mm) of histomorphometrical measurements of periimplant tissues at eight weeks after implant placement in the jaw of three dogs and after repeated dis- and reconnection of the Ti6Al4V and ZrO 2 abutments (Test Group). PM = mucosal margin, IS = implant shoulder, aJE = the apical extension of the long junctional epithelium, CBI = the most coronal bone in contact with the implant. (Adapted from Becker et al. (2012)). Group Modification PM-aJE aJE-CBI IS-aJE IS-CBI Vestibular aspects Test Ti6Al4V 2.08 ± 0.67 2.19 ± 1.41 1.05 ± 0.61 1.14 ± 0.86 Test ZrO 2 2.15 ± 0.21 0.21 ± 2.26 0.60 ± 0.84 1.50 ± 1.41 Control Ti6Al4V 2.19 ± 019 1.24 ± 0.70 0.28 ± 0.33 0.95 ± 0.62 Control ZrO 2 2.00 ± 0.14 0.95 ± 0.21 0.75 ± 0.07 0.20 ± 0.28 Oral aspects Test Ti6Al4V 1.91 ± 0.25 1.30 ± 0.20 0.19 ± 0.24 1.11 ± 0.34 Test ZrO 2 3.20 ± 1.55 3.80 ± 1.55 1.00 ± 1.41 2.80 ± 0.14 Control Ti6Al4V 1.45 ± 0.59 0.92 ± 0.15 0.42 ± 0.29 0.50 ± 0.39 Control ZrO 2 1.80 ± 0.42 0.65 ± 0.49 0.40 ± 0.56 0.25 ± 0.07 Vestibular and Oral aspects Test Ti6Al4V 1.99 ± 0.40 1.74 ± 0.75 0.62 ± 0.18 1.12 ± 0.06 Test ZrO 2 2.67 ± 0.67 2.95 ± 1.90 0.80 ± 1.13 2.15 ± 0.77 Control Ti6Al4V 1.82 ± 0.37 1.08 ± 0.30 0.35 ± 0.29 0.72 ± 0.18 Control ZrO 2 1.90 ± 0.28 0.80 ± 0.35 0.57 ± 0.24 0.22 ± 0.10