Abstract:
Statement of problem: This study aims to compare the accuracy of three-dimensional changes in position and angulation between digital and conventional impression techniques in different angulated implants at the mandibular partial edentulous area with the use of a mandibular partial edentulous reference model with 4 dental implants in different angulations (15 degrees buccally,lingually, mesially, and distally). Conventional and digital impression techniques were used for master model and fabricated 15 conventional master casts and 15 three dimensional printing models. Each scan body was connected with implant or analog to transfer implant positions. All of the master model, master casts, and printing models were scanned with articulating arm computer coordinating measuring machine and evaluated with Polywork software program. Dimensional change of positions and angulations ware calculated and statistically analyzed. Reference Model with 4 angulated implants showed the distance to reference at 23.647, 31.984, 27.865, and 26.995 mm at 37, 36, 46, and 47 area respectively. Conventional method showed distance of 23.943, 32.137, 28.064, and 27.172 mm at 37, 36, 46 and 47area sequentially. Digital method presented with 23.592, 32.238, 27.798, and 26.899 mm at 37, 36, 46, 47 areas consecutively as shown 37, 36, 46, 47 areas of 23.637, 31.984 mm. Angulation measurement presented in reference model were 69.628 at 37 area, 78.455 at 36 area, 75.723 at 46 area, and 78.579 at 47 area. Conventional method displayed angulation of 71.076, 78.404, 75.968, and 77.944 at 37,36, 46, and 47 areas respectively. Digital method exhibited 69.298 and 78.351 at 37and 36 implants, 75.516, and 78.746 in angulation of 46 and 47 implants in digital technique Within the limitation of this vitro study, partially digital impression technique by the 3Shape intraoral scanner with 3D printing models presented significantly superior accuracy of 3- dimensional distance and angulation to conventional one. Conclusion : Angulated dental implants decreased the accuracy of the conventional approach. Both techniques were clinically acceptable to treat the patients. However, the digital technique is recommended to have more accuracy and decreased chair time. A digital impression of angulated implants was presented more accurate than conventional one in both of distance and angulation.
