Deformation of stereolithographically produced surgical guides: an observational case series report.
BACKGROUND
Template-based computer-guided implant placement holds the promise of more precise and less traumatic placement of dental implants. Errors in the fabrication process of the surgical guide may lead to unfavorable clinical outcomes.


OBJECTIVE
This report discusses the potential of unintentional volumetric deformation of stereolithographically (SLA) produced surgical guides (NobelGuide, Nobel Biocare AB, Göteborg, Sweden) compared with the original scan denture.


METHODS
Three-dimensional radiographic data acquired by medical computerized tomography (CT) or cone beam CT (Newtom 3G, AFP Imaging Corporation, Elmsford, NY, USA) can be utilized in specialized software to develop treatment planning for dental implant placement. This information can then be transferred to the patient via a surgical guide. Stereolithography is a rapid prototyping process that can be used to create such a guide stent. Three cases are shown describing different levels of deformation of SLA-produced surgical guides.


RESULTS
Unintentional deformation of SLA-produced surgical guides is possible. Deformation of surgical guides can create dissimilarity between the virtually planned position and the actual position of the implants.


CONCLUSIONS
Incorrect setting of the ISO values for the segmentation of the scan denture has been found to be a factor in the deformation of SLA-produced surgical guides, although more, at this time known but also less understood, issues appear to be involved. Only one manufacturer's product is discussed; further research is warranted to determine if the discrepancies are process or product based. It might be prudent to closely evaluate the volumetric congruence of SLA-produced surgical stents before their clinical use to prevent undesired clinical outcomes.
Stumpel
Lambert J
LJ
Private practice, 450 Sutter Street, Suite 2530, San Francisco, CA 94108, USA. lambertstumpel@pacbell.net
D054893:Cone-Beam Computed Tomography; D003758:Dental Implantation, Endosseous / Q000379:methods*; D061827:Dimensional Measurement Accuracy; D004868:Equipment Failure; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D057893:Immediate Dental Implant Loading; D007575:Jaw, Edentulous / Q000000981:diagnostic imaging* / Q000534:rehabilitation; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D003765:Models, Dental; D023861:Photography, Dental; D011873:Radiology Information Systems; D012984:Software; D015607:Stents; D025321:Surgery, Computer-Assisted; D014057:Tomography, X-Ray Computed