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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