The purpose of this study is to evaluate the effect of printing layer thickness on accuracy of computer aided surgical guide

Computer aided surgical guide has many variables that affect its accuracy , in this study one variable is considered that may affect the accuracy of surgical guide which is printing of layer thickness of surgical guide whether 50 micron or 100 micron.

computer aided surgical guide is constructed by imaging the patient pre-operative cone beam CT wearing scan appliance , then virtual implant placement on special soft ware ( Blue sky Bio ) and optical scanning of patient casts , afterword superimposition of the virtual implants on the scanned casts to design the surgical guide and printing on 3D printer ( Zenith 3D printer , Dentis , Korea ) with printing layer thickness 50 micron in first group and 100 micron in second group . Fixation of surgical guide in patient mouth and drilling of implant osteotomy through the guiding sleeves , post-operative Cone Beam CT with the same apparatus and setting as pre-operative scan .

Finally, the pre-operative and post operative scans were then overlapped to measure linear and angular deviation of the virtually planned and actual implants position.

Inclusion Criteria:

• patients partially or totally edentulous arches .
• patients with Bucco-lingual bone thickness >6 mm allowing flapless implant placement
• patients free from any systemic diseases that may affect bone quality e.g diabetes .

Exclusion Criteria:

• patients with thin ridges.
• patients with systemic disease that may affect bone quality.
• Patients with poor oral hygiene and active periodontal diseases.
• Anatomical situations requiring regenerative procedure.