Περίληψη:
Background The replica technique with its modifications (negative
replica) has been used for the assessment of marginal fit (MF). However,
identification of the boundaries between prosthesis, cement, and
abutment is challenging. The recently developed Digital Image Analysis
Sequence (DIAS) addresses this limitation. Although DIAS is applicable,
its reliability has not yet been proven. The purpose of this study was
to verify the DIAS as an acceptable method for the quantitative
assessment of MF at cemented crowns, by conducting statistical tests of
agreement between different examiners. Methods One hundred fifty-one
implant-supported experimental crowns were cemented. Equal negative
replicas were produced from the assemblies. Each replica was sectioned
in six parts, which were photographed under an optical microscope. From
the 906 standardized digital photomicrographs (0.65 mu m/pixel), 130
were randomly selected for analysis. DIAS included tracing the profile
of the crown and the abutment and marking the margin definition points
before cementation. Next, the traced and marked outlines were
superimposed on each digital image, highlighting the components’
boundaries and enabling MF measurements. One researcher ran the analysis
twice and three others once, independently. Five groups of 130
measurements were formed. Intra- and interobserver reliability was
evaluated with intraclass correlation coefficient (ICC). Agreement was
estimated with the standard error of measurement (SEM), the smallest
detectable change at the 95% confidence level (SDC95%), and the Bland
and Altman method of limits of agreement (LoA). Results Measured MF
ranged between 22.83 and 286.58 pixels. Both the intra- and
interobserver reliability were excellent, ICC = 1 at 95% confidence
level. The intra- and interobserver SEM and SDC95% were less than 1 and
3 pixels, respectively. The Bland-Altman analysis presented graphically
high level of agreement between the mean measurement of the first
observer and each of the three other observers’ measurements.
Differences between observers were normally distributed. In all three
cases, the mean difference was less than 1 pixel and within +/- 3 pixels
LoA laid at least 95% of differences. T tests of the differences did
not reveal any fixed bias (P > .05, not significant). Conclusion The
DIAS is an objective and reliable method able to detect and quantify MF
at ranges observed in clinical practice.
Συγγραφείς:
Villias, Aristeidis A.
Kourtis, Stefanos G.
Karkazis, Hercules
C.
Polyzois, Gregory L.
