Comparison of dimensional accuracy of digital models by intraoral scanning method in comparison with molding with alginate

Abstract

Background: Intraoral scanners (IOS) have been developed to address the drawbacks of traditional
impression systems, such as improving patient comfort and expediting the restoration process.
The objective of this study was to compare the dimensional accuracy of IOSs with traditional
impression systems.
Materials and Methods: In this experimental study, a maxillary reference model was utilized for
the study. The mesiodistal, occlusogingival, and buccolingual distances between points were measured
on the model using a digital caliper and recorded as the control group. The reference model was
then scanned once using an IOS device (CEREC AC) to generate a digital model. Reference points
were measured and recorded using EXOCAD V.2019 software. Sixteen alginate impressions
were cast in separate trays from the reference model, and dental stone IV was poured into them.
Reference points were also measured on the casts using a caliper. Finally, the measurements of IOS
models, alginate templates, and reference models were compared in terms of size and dimensional
differences. Data analysis was performed using the analysis of variance with independent t‑tests,
with a significance level of <0.05. The study utilized a maxillary reference model.
Results: The mean differences in mesiodistal dimensions of only the right second premolars (P = 0.017),
buccolingual dimensions of central incisors (P = 0.037), lateral incisors (P = 0.050), and right first
molar (P = 0.028) showed significant differences between IOS and alginate methods compared to
the reference model. The dimensions reported in the IOS method were higher (0.71–1.26 mm)
than those in the alginate method compared to the reference model.
Conclusion: Based on the results of this study and acknowledging its limitations, it can be
concluded that the IOS method yielded a greater number of measurements than the reference
model when evaluated on a limited number of teeth within the complete maxillary arch. However,
the measurements obtained using the alginate method were more closely aligned with those of
the reference model. The minimal differences observed between digital impressions and traditional
measurement techniques, the IOS method may be regarded as a viable alternative to conventional
methods, owing to its numerous advantages.
Key Words: Alginate impressions, dental stone, dimensional accuracy, intraoral scanners,measurement techniques, patient comfort

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 Mehrdad Kazemian: Pubmed,Google Scholar