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Wednesday, July 27, 2016
Randomized controlled within-subject evaluation of digital and conventional workflows for the fabrication of lithium disilicate single crowns. Part I: digital versus conventional unilateral impressions
Trials comparing the overall performance of fully digital and conventional workflows in reconstructive dentistry are needed.
purpose of the first part of this randomized controlled clinical trial
was to determine whether optical impressions produce different results
from conventional impressions with respect to time efficiency and
patient and operator perceptions of the clinical workflow.
Material and methods
digital impressions and 1 conventional impression were made in each of
10 participants according to a randomly generated sequence. The digital
systems were Lava COS, iTero, and Cerec Bluecam. The conventional
impression was made with the closed-mouth technique and polyvinyl
siloxane material. The time needed for powdering, impressions, and
interocclusal record was recorded. Patient and clinician perceptions of
the procedures were rated by means of visual analog scales. The paired t test with Bonferroni correction was applied to detect differences (α=.05/6=.0083).
mean total working time ±standard deviation amounted to 260 ±66 seconds
for the conventional impression, 493 ±193 seconds for Lava, 372 ±126
seconds for iTero, and 357 ±55 seconds for Cerec. The total working time
for the conventional impression was significantly lower than that for
Lava and Cerec. With regard to the working time without powdering, the
differences between the methods were not statistically significant. The
patient rating (very uncomfortable=0; comfortable=100) measured 61 ±34
for conventional impression, 71 ±18 for Lava, 66 ±20 for iTero, and 48
±18 for Cerec. The differences were not statistically significant. The
clinician rating (simple=0; very difficult=100) was 13 ±13 for the
conventional impression, 54 ±27 for Lava, 22 ±11 for iTero, and 36 ±23
for Cerec. The differences between the conventional impression and Lava
and between iTero and Lava were statistically significant.
conventional impression was more time-effective than the digital
impressions. In terms of patient comfort, no differences were found
between the conventional and the digital techniques. With respect to the
clinician perception of difficulty, the conventional impression and the
digital impression with iTero revealed more favorable outcomes than the
digital impression with Lava.