الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The 5-axis milling machine unit enabled milling small
angles, steep walls, and undercuts from different directions.
44 Lithium disilicate (IPS e.max CAD Blocks; Ivoclar
AG) was used in the milling of the inlay restorations to
ensure standardization and avoid variations during fabrication
that could influence the accuracy of the produced
restoration.43 The cementation process can be techniquesensitive;
therefore, a dual-polymerizing self-adhesive
resin cement was used to avoid undesirable outcomes
such as voids, excessive cement thickness, and marginal
gaps.55 The cross-sectional method has been used to
evaluate fit precision and has been reported to be better
than alternative techniques, allowing direct measurement
of the internal fit under the stereomicroscope and decreasing
repositioning errors.62,64
According to Lee et al,56 IOSs significantly affect the
marginal and internal fit of fixed restorations. A significant
marginal discrepancy increases the plaque index
at restoration margins and is associated with periodontal
disease, secondary caries, and pulpal irritation.61 Most
studies have found that the clinically acceptable range of
marginal gap value has been reported to be <120 μm.24
Accordingly, decreasing the cement gap will improve the
marginal fit.61 Inadequate support for ceramic restoration
and high polymerization shrinkage in luting cement
has been associated with excessive internal gaps,53 and
internal gap values of 50 to 100 μm have been reported
to produce optimal resin cement performance.24 Consistent
with the findings of Homsy et al,41 the results of
the present study showed that the marginal gap was
lower than the internal gap. A possible explanation for
this difference is the preparation geometry with complex
and multiple angles of the inlay preparation, which reduced
the scanning accuracy.6,41,44
The scanning path of the 30 inlay preparations began
with the occlusal, then the palatal or lingual, and ended
with the buccal surfaces, while the difference among the 3
groups was only in the scanner head movement.11,34 This
path was consistent with that reported by Muller et al20
and Stefanelli et al,33 who recommended using the suggested
scan path as it led to improved accuracy compared
with scan paths that begin from the buccal surface.
Conversely, Oh et al3 reported that the accuracy of the 3D
model was not affected by where the scan was initiated.
Scanning accuracy was determined by using both distinct
IOS and scanning strategies from the present study.