A comparative study of two polishing systems on the surface roughness of acrylic resins for temporary restorations at Pedro Henríquez Ureña National University. In vitro study.

In dental practice, temporary restorations made with self-curing acrylic resins are commonly
used to protect prepared tooth structures, maintain function and aesthetics, and promote the
health of oral tissues until the final prosthesis is placed. The surface quality of these
restorations determines their clinical success because a smooth surface reduces biofilm
accumulation, pigmentation, and the risk of caries and periodontal disease. Additionally, a
smooth surface improves aesthetics and biocompatibility. According to the literature, a surface
roughness of less than 0.2 µm minimizes these risks.
This study compared the effectiveness of two polishing systems (Kit 1 and Kit 2) on the
surface roughness of acrylic resins for temporary restorations used at the Dr. René Puig Bentz
dental clinic at Pedro Henríquez Ureña National University from September to December
2025. The goal was to identify the system that provides the most suitable surface finish for
clinical application.
The methodology consisted of preparing self-curing acrylic resin samples that were
mechanically polished according to the protocols of each system. We evaluated surface
roughness using a roughness tester, which measures microscopic irregularities by scanning the
surface with a fine tip and converting the variations into quantifiable values for comparative
analysis.
The results revealed statistically significant differences between the two polishing systems. Kit
2 produced higher average surface roughness values than Kit 1 (mean: 1.416 µm vs. 1.109 µm;
median: 1.373 µm vs. 1.014 µm), suggesting that Kit 2 generates relatively rougher surfaces.
Likewise, measures of central tendency, including the mode, were consistently higher in Kit 2,
confirming a less smooth surface finish. In terms of data dispersion, Kit 2 showed slightly
higher standard deviations, suggesting greater variability in the results. This variability may be
related to differences in the abrasive design, cutting pattern, and stability during polishing. Kit
1 had a lower maximum value, indicating a more uniform finish without extreme values
affecting surface homogeneity.

However, neither system achieved values of 0.2 µm or less, with both falling above the
clinically acceptable threshold for optimal permanence in the oral cavity.
In conclusion, the polishing system in Kit 1 was more effective than Kit 2 at reducing the
surface roughness of acrylic resins for temporary restorations. However, neither system
achieved the recommended optimal level. These findings confirm the alternative hypothesis
(H1) and underscore the necessity of optimizing polishing protocols in academic training and
clinical practice due to surface roughness's direct influence on the aesthetics, biocompatibility,
and clinical success of temporary restorations.