The effect of layer thıckness on the accuracy of the dıfferent ın-house clear alıgner attachments

Topsakal K. G., Gökmen Ş., Yurdakurban E., Duran G. S., Görgülü S.

Clinical Oral Investigations, vol.27, no.9, pp.5331-5341, 2023 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 27 Issue: 9
  • Publication Date: 2023
  • Doi Number: 10.1007/s00784-023-05153-5
  • Journal Name: Clinical Oral Investigations
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, EMBASE, MEDLINE
  • Page Numbers: pp.5331-5341
  • Keywords: 3-dimensional printing, Clear aligner therapy, Attachment, Layer thickness
  • Çanakkale Onsekiz Mart University Affiliated: No


Objective: The accuracy of the attachments, one of the key components of clear aligner therapy, is important for obtaining more precise tooth movement. The aim of this study was to evaluate the accuracy of the ovoid, hemi-ellipsoid, and vertical rectangular attachments produced by the digital light-processing(DLP) 3-dimensional printing technologies with 25 µm, 75 µm, and 125 µm layer thickness. Materials and methods: The ovoid, hemi-ellipsoid, and vertical rectangular attachments were positioned onto the convex surface of the central incisor by the software. The printing process was carried out by a DLP printer using a commercially printed resin with 25 µm, 75 µm, and 125 µm layer thickness (n = 30, for each group). All test models’ digital data was exported into the reverse engineering software for the superimposition. After selecting the 5 comparison points for the ovoid and vertical rectangular attachments, and 6 comparison points for the hemi-ellipsoid attachment, the Root Mean Square (RMS) was evaluated for each group. Results: There is a statistically significant difference between the 25 µm and 125 µm layer thickness of total RMS values in the ovoid, hemi-ellipsoid, and vertical rectangular attachment groups (p = 0.001, p = 0.03, and p = 0.00 respectively). The printing time with the 25 µm layer thickness was 4 times longer than with the 125 µm layer thickness. Conclusions: This study revealed that the accuracy of the attachments used for in-house clear aligner therapy is affected by the layer thickness of the 3D printer. Clinical relevance: The layer thickness of the 3D printer is a crucial factor in determining attachment accuracy, but its clinical significance is minimal. Clinicians should make informed decisions about the appropriate layer thickness, taking into account their workflow preferences, time constraints, and other practical considerations specific to their clinical practice.