Abstract
The prognosis of the prosthetic rehabilitation is linked to the proper transfer of the clinical data to the dental laboratory, in the digital or conventional workflow. The aim of the present study was to compare the dimensional accuracy of analog and digitalized models, focusing on the influence of impression polymeric materials on the final digital model. Methods: The master model with standard reference points and the three groups of test models, obtained by alginic acid polymer impression (group A) and condensation-cured poly(dimethyl siloxane) in two impression techniques (1-step putty/light-body-group 1T, 2-steps putty/ light-body-group 2T), were measured in four standardized points before and after digitization. The differences from the master model and between the pair analog and digital models was calculated and statistically analysed using Mann-Whitney tests (2 groups), and one-way Anova (3 groups) with post-hoc Tukey s Test was applied for pairwise analysis (a;=0.05). Results: All analog and digitalized model tests showed altered dimensions from the master model. A general reduction of the digitalized models, in sagittal and transversal dimensions, was observed, comparing to the reference model. The impression material was a significant factor influencing dimensional accuracy. Conclusions: a statistically significant difference was found between most of the models and the master model. However, through digitalization, some of the errors were compensated. The digital models from alginic acid polymer group (group A) registered the highest trueness, with no statistically significant difference (P]0.05) from the reference model.
Highlights
Due to their excellent biocompatibility, satisfactory mechanical properties, and processability, polymers are used in different areas in dentistry, and have fundamental importance as dental impression materials, restorative materials, bone substitutes, or as accessory materials [1,2].The prosthetic rehabilitation’s success relies on the adequate data transfer from the clinical settings to the dental laboratory [3]
To be used for impressions, the polymeric materials needs to have a certain viscosity to prevent displacement of soft tissues, hydrophilicity, a low degree of polymerization shrinkage, slight thermal contraction, to be non-toxic, to be mixed, with short setting time, to be sufficiently flexible to allow removal from the undercut regions without causing distortion and to have storage stability, to overcome the delay between the taking of an impression and its arrival in the dental laboratory where the model is poured [7]
The reproducibility of each type of model obtained from different types of polymeric impression materials were evaluated
Summary
Due to their excellent biocompatibility, satisfactory mechanical properties, and processability, polymers are used in different areas in dentistry, and have fundamental importance as dental impression materials, restorative materials, bone substitutes, or as accessory materials [1,2].The prosthetic rehabilitation’s success relies on the adequate data transfer from the clinical settings to the dental laboratory [3]. To be used for impressions, the polymeric materials needs to have a certain viscosity to prevent displacement of soft tissues, hydrophilicity (a hydrophobic material will lead to holes in the impression surface due to trapped air), a low degree of polymerization shrinkage (to prevent obtaining larger crowns), slight thermal contraction (as it cools from mouth to room temperature), to be non-toxic, to be mixed, with short setting time, to be sufficiently flexible to allow removal from the undercut regions without causing distortion and to have storage stability, to overcome the delay between the taking of an impression and its arrival in the dental laboratory where the model is poured [7]
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