Access opening guide produced using a 3D printer (AOG-3DP) as an effective tool in difficult cases for dental students.

Objectives: The aim of this study was to determine the effectiveness of using an access opening guide in teaching ideal access opening shape and preventing excessive tooth loss, with a focus on predoctoral dental students.

Methods: Ninety teeth that were mounted in a box just below the level of the cementoenamel junction using tray resin were randomly divided into two study groups. An access opening guide produced using a 3D printer (AOG-3DP) was designed using cone-beam computed tomography (CBCT). The AOG-3DP was applied in the test groups, while no aid was used in the control group. Access preparations in both groups performed by predoctoral dental students were scanned using CBCT to detect overpreparation. The preparation time and access cavity volume were evaluated.

Results: The mean times required for achieving access opening were 327.2 and 97.4 s in the control and AOG-3DP groups, respectively, for premolars, and 547.4 and 104.5 s for molars. The mean volumes for premolars and molars differed from the ideal cavities by 38.1 and 72.2 mm , respectively, in the control group, and by -2.0 and -8.7 mm the AOG-3DP group.

Conclusions: Using the AOG-3DP significantly reduced the access opening time for premolars and molars. However, there is a limitation in that CBCT DICOM images must be converted to stereolithographic .stl files in order to be printed via 3D technology. This requires additional preclinical treatment time for imaging and subsequent printing. It could be considered that this can be a useful method in difficult cases.