Influence of Manufacturing Method on the Guided Implant Position

Objectives: The study aims to evaluate the effect of three different 3D Printers (one SLA and two DLP printers) and subtractive technique on the accuracy of dental implants placed in-vitro in a lower jaw free end situation.
Methods: Using resin clones of a patient case providing a free end situation in the region 37 in total 60 implants have been placed by surgical guides (n=12) manufactured by SLA (Form 2, Formlabs) and DLP Printers (D20II, Rapidshape (RS); Solflex 320, Voco (SF)) and control group was manufactured subtractive in a 5-axis CNC machine (MCX5) with a sleeve height of 2mm. The difference between the virtually designed preoperative and the real postoperative implant position (accuracy) was analysed considering the horizontal crestal and apical displacement, the angular displacement of the long implant axis and the vertical displacement at implant apex.
Results: Displacements of the different parameters are displayed in Table 1. Significant differences have been found comparing the SLA and the DLP printers. While showing that SLA in comparison to DLP had a significant lower accuracy in angular (p=0.049) and displacement at crest (p=0.032). When comparing the two DLP printers with V-Print SG resin, RP printer showed lower accuracy and highly significant differences in all parameters compared to SF. Control showed significant lower values to all other groups at displacement at crest and apex. The results were within an acceptable clinical range.
Conclusions: Within the limitations of this study DLP and SLA printers showed both acceptable in-vitro accuracy when it comes to surgical guides in free end situations. DLP with printing thickness around 50 µm though seems to be superior to conventional SLA printing technology. If more accuracy is needed it is recommended to use milled guides.