3D-printed Stents for Standardization of Composite-resin Sample Preparation

Objectives: Inconsistent dimensions and topographical features of composite-resin lead to huge standard deviations due to small thickness of the sample. Therefore, the present study aimed to overcome the limitations in standardizing composite-resin sample preparation by evaluating the effectiveness of custom 3D-printed stents.
Methods: A sample size of n=16, with a diameter of 10mm and a thickness of 1mm, was prepared using a stainless-steel mould. The composite resin-based material, Filtek Z350XT Shade Body A2, was used. The cured discs were divided into two groups: the test group (T) with a stent and the control group (C) without a stent. 3D printed stents were fabricated for (T) and eight discs were finished and polished under running water using grits ranging from 320-1200 on a grinder and polisher machine. The control discs (C) underwent the same procedure without a stent. Digital callipers were used to measure the thickness of both group discs. The mean roughness (Ra) was measured using a profilometer for all discs.
Results: Intrarater Reliability: The ICC result of both the test and control groups shows high correlation with the result at 0.99.
Dimensions: (T) shows a mean of 1.0mm which is near to ideal thickness with a lower SD 0.08mm when compared to (C) with mean of 1.09mm and a high SD of 0.26mm. Mann-Whitney Test shows that the result is statistically significant (p<0.05).
Surface Roughness: (T) shows a mean of 1.02µm which is near to acceptable range of (0.4 to 1.7µm) with a lower SD 0.33µm when compared to (C) with a mean of 3.37µm and a high SD of 1.89µm. Mann-Whitney Test shows that the result is statistically significant (p<0.05).
Conclusions: By standardizing the sample preparation protocol, variability can be minimized, ensuring consistent composite resin samples. This enhances study validity, enabling meaningful comparisons and conclusions.