RELIABILITY OF 3-D-PRINTED MANDIBLES CONSTRUCTED FROM CONE BEAM CT VOLUMES OF DIFFERENT VOXEL SIZES

Background 3-D printing, also known as additive manufacturing or rapid prototyping, is a manufacturing process in which layers are sequentially added to create an object. 3-D printing is used in a wide variety of fields, ranging from dentistry and medicine to food manufacturing, toy manufacturing, house manufacturing, and automobile manufacturing and in the fashion industry. 3-D printed models can have a wide variety of uses in dentistry, ranging from anatomic models to surgical implants. Objective(s) The aim of the present study was to establish the reliability of linear cephalometric measurements made on mandibles and their respective 3-D printed models created from different voxel sizes in cone beam computed tomography (CBCT) scans. Study Design Ten dry mandibles were used for this study. All mandibles were scanned using the i-CAT FLX cone beam CT unit (Imaging Sciences International, LLC, Hatfield, PA) using voxel sizes of 0.30 mm, 0.25 mm, and 0.20 mm at 16 × 8 cm field of view and 360° rotation arc. The 3-D models were reconstructed and saved as STL files using 3-D Slicer software and sent to a 3-D printer for printing. Two observers measured the 10 mandibles and 30 3-D printed models. The measurements were repeated on 50% of the samples after at least 1 week. Cronbach's alpha and intraclass correlation coefficient were calculated to measure reliability. Results Good to excellent interobserver and intraobserver reliability were achieved across most of the measurements. There was no difference in reliability across models made from different voxel sizes. Discussion/Conclusions The present study successfully showed that the reliability of measurements made on 3-D printed models of dry skull mandibles created using the fused deposition modeling technique with images of different voxel sizes from an iCAT FLX CBCT machine are valid, reproducible, and reliable and can be used for diagnostic and clinical purposes. 3-D printing, also known as additive manufacturing or rapid prototyping, is a manufacturing process in which layers are sequentially added to create an object. 3-D printing is used in a wide variety of fields, ranging from dentistry and medicine to food manufacturing, toy manufacturing, house manufacturing, and automobile manufacturing and in the fashion industry. 3-D printed models can have a wide variety of uses in dentistry, ranging from anatomic models to surgical implants. The aim of the present study was to establish the reliability of linear cephalometric measurements made on mandibles and their respective 3-D printed models created from different voxel sizes in cone beam computed tomography (CBCT) scans. Ten dry mandibles were used for this study. All mandibles were scanned using the i-CAT FLX cone beam CT unit (Imaging Sciences International, LLC, Hatfield, PA) using voxel sizes of 0.30 mm, 0.25 mm, and 0.20 mm at 16 × 8 cm field of view and 360° rotation arc. The 3-D models were reconstructed and saved as STL files using 3-D Slicer software and sent to a 3-D printer for printing. Two observers measured the 10 mandibles and 30 3-D printed models. The measurements were repeated on 50% of the samples after at least 1 week. Cronbach's alpha and intraclass correlation coefficient were calculated to measure reliability. Good to excellent interobserver and intraobserver reliability were achieved across most of the measurements. There was no difference in reliability across models made from different voxel sizes. The present study successfully showed that the reliability of measurements made on 3-D printed models of dry skull mandibles created using the fused deposition modeling technique with images of different voxel sizes from an iCAT FLX CBCT machine are valid, reproducible, and reliable and can be used for diagnostic and clinical purposes.