Abstract
AIM:
The
use of intraoral scanners (IOS) for making digital implant impressions
is increasing. However, there is a lack of evidence on the accuracy of
IOS compared with conventional techniques. Therefore, the aim of this
systematic review was to collect evidence on the accuracy of digital
implant impression techniques, as well as to identify the main factors
influencing the accuracy outcomes.
MATERIALS AND METHODS:
Two
reviewers searched electronic databases in November, 2016. Controlled
vocabulary, free-text terms, and defined inclusion and exclusion
criteria were used. Publications in English language evaluating the
accuracy outcomes of digital implant impressions were identified. Pooled
data were analysed qualitatively and pertinent data extracted.
RESULTS:
In
total, 16 studies fulfilled the inclusion criteria: one in vivo and 15
in vitro studies. The clinical study concluded that angular and distance
errors were too large to be acceptable clinically. Less accurate
findings were reported by several in vitro studies as well. However, all
in vitro studies investigating the accuracy of newer generation IOS
indicated equal or even better results compared with the conventional
techniques. Data related to the influence of distance and angulation
between implants, depth of placement, type of scanner, scanning
strategy, characteristics of scanbody and reference scanner, operator
experience, etc were analysed and summarised. Linear deviations (means)
of IOS used in in vitro studies ranged from 6 to 337 µm. Recent studies
indicated small angle deviations (0.07-0.3°) with digital impressions.
Some studies reported that digital implant impression accuracy was
influenced by implant angulation, distance between the implants, implant
placement depth and operator experience.
CONCLUSIONS:
According
to the results of this systematic review and based on mainly in vitro
studies, digital implant impressions offer a valid alternative to
conventional impressions for single- and multi-unit implant-supported
restorations. Further in vivo studies are needed to substantiate the use
of currently available IOS, identify factors potentially affecting
accuracy and define clinical indications for specific type of IOS. Data
on Data on accuracy OF digital records, as well as accuracy of printed
or milled models for implant-supported restorations, are of high
relevance and are still lacking. Conflict-of-interest and funding
statement: The authors state there is no conflict of interest.
Comments