Purpose: Success and safety of dental implants requires accurate treatment planning and
precise implant placement. There should be no deviation between the virtually planned implant
position and the actual implant position after the implant installation regardless the technique of
construction of the surgical-guide. So this study was to evaluate and compare the accuracy of two
different CAD/CAM surgical guides in placement of all-on-4 implants. Materials and methods:
A prospective randomized controlled double blind clinical study was carried out, in which twenty
four implants were placed in 6 edentulous patients. Patients were randomly allocated into one of the
two groups: control group where surgeries were done using digital light processing (DLP) surgicalguides
and study group where implants were placed using selective laser sintering (SLS) surgicalguides.
Each patient received 4 implants in the anterior part of the mandible, 2 axial implants in the
center and 2 tilted implants at the distal ends. CBCT were taken to the implants after the surgery and
the actual implant positions were compared to the planned implant position. The deviation between
the planned and actual implant positions were compared between the 2 techniques of surgical guide
constructions. Results: The results of comparison between the two groups showed a statistically
significant difference for all comparisons, with the SLS fabricated guides showing higher deviation
from control than those fabricated by the DLP printer.
Conclusion: Although the computer manufactured surgical guides simplifies surgery and help
in optimal implant placement, there is still evidence of degree of deviation from the planned implants
positions in both of the surgical guides, particularly the SLS fabricated guides so a safety zone so a
safety zone is recommended during planning to avoid to avoid critical anatomical structures.