Abstract
PURPOSE:
To
compare the effectiveness of 6.0 to 8.0 mm-wide diameter implants,
placed immediately after tooth extraction, with conventional 4.0 or 5.0
mm diameter implants placed in a preserved socket after a 4-month period
of healing in the molar region.
MATERIALS AND METHODS:
Just
after extraction of one or two molar teeth, and with no vertical loss
of the buccal bone in relation to the palatal wall, 100 patients
requiring immediate post-extractive implants were randomly allocated to
immediate placement of one or two 6.0 to 8.0 mm-wide diameter implants
(immediate group; 50 patients) or for socket preservation using a
porcine bone substitute covered by a resorbable collagen barrier
(delayed group; 50 patients), according to a parallel group design in
one centre. Bone-to-implant gaps were filled with autogenous bone
retrieved with a trephine drill used to prepare the implant sites for
the immediate wide diameter post-extractive implants. Four months after
socket preservation, one to two 4.0 or 5.0 mm-wide delayed implants were
placed. Implants were loaded 4 months after placement with fixed
provisional restorations in acrylic, and replaced after 4 months by
fixed, definitive, metal-ceramic restorations. Patients were followed to
1 year after loading. Outcome measures were: implant failures,
complications, aesthetics assessed using the pink esthetic score (PES),
peri-implant marginal bone level changes, patient satisfaction, number
of appointments and surgical interventions recorded, when possible, by
blinded assessors.
RESULTS:
Three
patients dropped out 1 year after loading from the immediate group vs
six from the delayed group. Five implants out of 47 failed in the
immediate group (10.6%) vs two out 44 (4.6%) in the delayed group, the
difference being not statistically significant (difference in proportion
= 6.0%, 95% CI: -8.8% to 20.8%, P = 0.436). In the immediate group 10
patients were affected by 10 complications, while in the delayed group
four patients were affected by four complications. The difference was
not statistically significant (difference in proportion = 12%, 95% CI:
-2% to 26%, P = 0.084). At delivery of the definitive prostheses, 4
months after loading, the mean total PES score was 9.65 ± 1.62 and 10.44
± 1.47 in the immediate and delayed groups, respectively. At 1 year
after loading, the mean total PES score was 9.71 ± 2.71 and 10.86 ± 1.37
in the immediate and delayed groups, respectively. The Total PES score
was statistically significantly better at delayed implants both at 4
months (mean difference = 0.79; 95% CI: 0.05 to 1.53; P = 0.03) and at 1
year (mean difference = 1.15; 95% CI: 0.13 to 2.17; P = 0.02). Marginal
bone levels at implant insertion (after bone grafting) were 0.04 mm for
immediate and 0.11 mm for delayed implants, which was statistically
significantly different (mean difference = 0.07; 95% CI: 0.02 to 0.12; P
< 0.0001). One year after loading, patients in the immediate group
lost on average 1.06 mm and those from the delayed group 0.63 mm, the
difference being statistically significant (mean difference = 0.43 mm;
95% CI: 0.15 to 0.61; P < 0.0001). All patients were fully or
partially satisfied both for function and aesthetics, and would undergo
the same procedure again both at 4 months and 1 year after loading.
Patients from the immediate group required on average 7.48 ± 1.45 visits
to the clinician and 2.14 ± 0.49 surgical interventions and to have
their definitive prostheses delivered vs 10.30 ± 0.99 visits and 3.08 ±
0.40 surgical interventions for the delayed group, the difference being
statistically significant (P < 0.001 for visits, and P < 0.001 for
surgical interventions).
CONCLUSIONS:
Preliminary
1 year follow-up data suggest that immediate placement of 6.0 to 8.0 mm
wide diameter implants in molar extraction sockets yielded inferior
aesthetic outcomes than ridge preservation and delayed placement of
conventional 4.0 to 5.0 mm diameter implants. Conflict of interest
statement: This trial was partially funded by the manufacturer of the
implants evaluated in this investigation (MegaGen Implant Co, Gyeongbuk,
South Korea). However, data belonged to the authors and in no way did
the manufacturer interfere with the conduct of the trial or the
publication of its results.
Comments