In vitro comparison of guided versus freehand implant placement: use of a new combined TRIOS surface scanning, Implant Studio, CBCT, and stereolithographic virtually planned and guided technique

Implant placement requires precise planning and execution to avoid collision with critical anatomical structures. Technology advances may improve placement outcomes. The purpose of this study was to trial and measure in an in vitro environment the accuracy of placing a single dental implant in the planned position using a specific guided surgery technique compared with a freehand surgery technique. The dental model of a patient missing tooth 16 was printed 30 times (EnvisionTEC 3Dent). Each print was scanned (TRIOS color scanner) to create a 3D surface model, and radiographed (Gendex CB-500) to create cone beam computed tomography (CBCT) data. The surface data and CBCT data were merged (Implant Studio software), and a Straumann RC bone level Ø 4.1 × 8 mm implant placement was planned. A surgical guide was printed (Stratasys OrthoDesk) for each case (n = 30). Simulated cases were assigned to Group A (guided) or Group B (freehand, where the fabricated guide was discarded). Implants were placed, and the models rescanned (TRIOS). The new data was superimposed on the original data, and the surgical implant location compared with the planned position for each model (Convince software) by a researcher blinded to group allocation. Differences in angulation (degrees); shoulder, apex, and depth displacements (mm); and direction of displacement were assessed with Mann-Whitney U and Fisher exact tests. Data was expressed as medians bounded by interquartile ranges (IQRs). Implant angulation and apical displacement were significantly closer to the planned position in the guided group compared with the freehand group (3.91 degrees: IQR 2.45 to 5.38 degrees vs 8.82 degrees: IQR 4.84 to 9.84 degrees, P = 0.005; and 0.87 mm: IQR 0.53 to 1.11 mm vs 1.48 mm: IQR 1.14 to 1.72 mm, P 0.001, respectively). Implant shoulder displacement, depth displacements, and direction of displacement did not differ between the groups. Within the in vitro environment, merged 3D surface scan data and 3D CBCT scan data can be used to plan and guide implant placement with greater accuracy than with the freehand technique. Keywords: cone beam computed tomography, computer-aided design (CAD), dental implants, three-dimensional imaging, three-dimensional surface scanning, patient care planning