Abstract
Objectives:
This randomised, controlled multicentre trial aimed at comparing two
versions of a variable-thread dental implant design to a standard
tapered dental implant design in cases of immediate functional loading
for 36 months after loading. Materials and methods: 177 patients (325
implants) were included at 12 study centres and randomly allocated into
one of three treatment groups: NAI (variable-thread design, NobelActive
internal connection), NAE (variable-thread design, NobelActive external
connection) and, as control, NR (standard tapered design, NobelReplace
tapered groovy). Inclusion criteria concerned healed bony implant sites
and feasibility for immediate loading. Clinical and radiographic
examinations were performed at implant placement and after 3, 6, 12, 24
and 36 months. The outcome measures were marginal bone remodelling
(primary outcome), implant survival and success, papilla score, plaque
accumulation, and bleeding on probing. Results: 127 patients (NAI: 45,
NAE: 41, NR: 41) were followed-up and evaluated after 36 months. No
significant differences in cumulative survival rates were seen for the
groups (NAI: 95.7%; NAE: 96.3%; NR: 96.6%). In all groups, bone
remodelling occurred during the first 3 months, with stable or even
increasing bone levels after the initial remodelling period. The bone
remodelling from insertion to 36 months for the NAI group (-0.89 ± 1.65
mm) was comparable (P = 0.98) to that of the NR group (-0.85 ± 1.32 mm).
The NAE group showed comparable bone remodelling during the first year,
with an increase in following years resulting in significantly less
overall bone loss (-0.16 ± 1.06 mm) (P = 0.041). Overall improvement in
papilla size was observed in all treatment groups. Conclusions: Over 36
months, the results show stable or improving bone levels for all
treatment groups after the initial bone remodelling seen during the
first 3 months after placement. The variable- thread implants showed
results comparable to those of standard tapered implants in cases of
immediate function, and therefore can be considered as a treatment
option for immediate loading.
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