Background: There is limited knowledge on the effect of scan body (SB) material type, torque value, and sterilization on linear displacements of implant SBs.Purpose: To evaluate the effect of material type, torque value, and sterilization on linear displacements of SBs during screw tightening by using digital image correlation (DIC) analysis.Materials and Methods: One polyetheretherketone (PEEK, Zfx Intraoral Scan Body) and one titanium SB (Ti, MPS Zimmer Scanbody R1410) were tightened with 5 Ncm torque on two implants (Zimmer TSV ⌀4.7 mm) by using a digital torque limiting device. SBs' initial spatial positions relative to the implants were recorded by using 3D DIC technique. Measurements were repeated after initially increasing torque value to 10 Ncm and then to 15 Ncm, and these steps were repeated for a total of 10 PEEK and 10 Ti SBs on both implants (n = 20). All SBs were then sterilized 25 times by using an autoclave (STATIM 5000 S G4) according to manufacturer's rec-
ObjectiveTo investigate the effect of cross‐polarization filters on the colors of shade tabs obtained with a digital single‐lens reflex (DSLR) camera, macrolens, and a ring flash.Materials and MethodsDigital images of four shade tables (1M1, 3L2.5, 3R2.5, and 5M3) from the VITA Toothguide 3D‐Master shade guide were taken using a DSLR camera, 100 mm macrolens, and ring flash with two different cross‐polarizing filters (Polar_eyes and Filtropolar), and without (Nonpolarizer; n = 7). The CIE L*a*b* color coordinates of digital images were calculated and remeasured with a spectroradiometer (SR). The color differences (ΔE00) between the SR and digital images were calculated and analyzed with the two‐way analysis of variance (ANOVA) and Tukey HSD test (α = 0.05).ResultsΔE00 values of all test groups were higher than the clinically acceptable threshold (∆E00 > 1.80). While the ∆E00 values of Filtropolar (6.19 ± 0.44) and Polar_eyes (7.82 ± 0.23) groups were significantly higher than the Nonpolarizer (4.69 ± 0.32) for the 1M1 shade tab, ∆E00 value of Polar_eyes (6.23 ± 0.34) was significantly lower than Nonpolarizer (10.71 ± 0.48) group for 5M3 shade tab (p < 0.05).ConclusionThe color‐matching results of tested digital photography techniques with and without cross‐polarization were unacceptable, compared to a spectroradiometer. While digital photography with Polar_eyes cross‐polarizing filter has closer results to the reference device for the low‐in‐value shade table (5M3), for the high‐in‐value shade table (1M1), improved results were obtained without a cross‐polarizing filter.Clinical SignificanceThe cross‐polarization filters are increasingly used in dentistry for tooth color communication with digital photography techniques. However, the digital photography techniques with‐without cross‐polarization filterers should be improved to obtain clinically acceptable color‐matching results.
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