Fig. 4

3D printing of the models and the surgical guides. a, b The models were printed in the laboratory with a 3D printer (Form2®, Formlabs Inc., Somerville, MA, USA) and the implant analogues were positioned. These models not only included the correct position of the planned implants, but also the mucosa and the residual teeth, that have not been removed in the planning, in order to facilitate the superimposition in the guided surgery software, and to stabilize the surgical guide during the intervention. The compromised teeth had to be subsequently removed during surgery. c, d 3D printing of the models and the surgical guides. Based on the virtual planning, surgical guides were printed too. The sleeves were then inserted in the guides. In the lower jaw, since the sleeves of the incisors touched each other, two different guides were 3D printed