Effects of two Postprocessing Methods onto Surface Dimension of in-Office Fabricated Stereolithographic Implant Surgical Guides

Purpose To evaluate the effects of two postprocessing methods in terms of the overall, intaglio, and cameo surface dimensions of in-office stereolithographic fabricated implant surgical guides. Materials and methods Twenty identical implant surgical guides were fabricated using a stereolithographic printer. Ten guides were postprocessed using an automated method. The other ten guides were postprocessed using a series of hand washing in combination with ultrasonics. Each guide was then scanned using cone-beam computed tomography to produce a set of digital imaging and communications in medicine (DICOM) files which were converted into standard tessellation language (STL) files. The STL file was then superimposed onto the original STL design file using the best fit alignment. The average positive and negative surface discrepancy differences in terms of means and variances were analyzed using t-test (alpha = 0.05). Results For the alternative group, the average positive and negative overall, intaglio, and cameo surface discrepancies were 77.38 +/- 10.68 mu m and -67.74 +/- 6.55 mu m; 78.83 +/- 8.65 mu m and -68.16 +/- 5.26 mu m; and 70.5 +/- 8.48 mu m -64.84 +/- 5.55 mu m, respectively. For the automated group, the average positive and negative overall, intaglio, and cameo surface discrepancies were 51.88 +/- 4.38 mu m and -170.7 +/- 11.49 mu m; 64.3 +/- 4.44 mu m and -89.45 +/- 6.25 mu m; and 83.59 +/- 4.81 mu m and -144.26 +/- 13.19 mu m, respectively. There was a statistical difference between the means of the two methods for the overall, intaglio, and cameo positive and negative discrepancies (p< 0.001). Conclusions For a single implant tooth-supported implant guide, using hand washing with ultrasonics appeared to be consistently better than the automated method. The manual method presented with more positive discrepancies, while the automated method presented with more negative discrepancies.