Surgical Guides Make Implant Placement Predictable and Precise

This article describes a case in which the information obtained via a CBCT (CS 8100 3D, Carestream Dental, carestreamdental.com) and an intraoral scanner (CS 3600, Carestream Dental) was used to fabricate two single-unit maxillary implant restorations.

A female patient in her mid-30s presented with tooth No. 9 broken off at the gingiva and tooth No. 13 missing (Figure 1). Tooth No. 9 was determined to be non-restorable. The patient was offered several treatment options and ultimately chose single implants in both locations. In the diagnostic phase, the dentist obtained a CBCT image of the entire upper and lower arch, followed by upper and lower digital impressions, a bite record, and clinical photos.

The STL and DICOM files were sent to their laboratory of choice, WhiteCap Dental Lab and Milling, through a HIPAA-compliant portal, 360 Courier.

The laboratory used 360dps (360imaging, 360imaging.com) to virtually plan implants and design guides. At this stage, the team was able to evaluate implant positions relative to the positions of future restorations (Figure 2 through Figure 4). In the anterior esthetic zone, implants should be placed more apical and palatal than the natural tooth apex. This was taken into consideration for tooth No. 9. The implants were positioned away from the buccal plate and in an ideal restorative position. The proposed guides included "windows" or "slots" to be used by the clinician to confirm a proper seat of the guide intraoperatively (Figure 5). After the team approved the design, the laboratory 3D-printed the guides using an Eden260VS printer (Stratasys, stratasys.com).

The laboratory also 3D-printed an analog model representing the proposed position of the implants. Stock abutments were prepared, and PMMA crowns for both sites were fabricated in order to provide immediate temporaries during the surgical phase. Providing laboratory-made (milled) temporaries based on virtual implant planning data is remarkable and speaks to the accuracy of guided surgery.

The case healed wonderfully, and the implants landed in the precise locations where they were planned. After 3 months of healing, the patient returned for final digital impressions with optical scan bodies. Carestream Dental's CS 3600 scanner was used for the impression. The resulting STL file was sent through the HIPAA-compliant CS Connect portal (Carestream Dental) directly to the laboratory. Like email, the file went to the laboratory instantly. The STL contained a digital rendition of the scan bodies and thus implant positions. The laboratory could immediately begin fabrication of custom abutments and crowns (Figure 8 through Figure 10).

The laboratory designed the emergence profile of the titanium interface and placed the margin 0.5 mm subgingival, per the author's request. Hybrid abutments with milled titanium bases and zirconia copings were fabricated. A monolithic zirconia crown was fabricated for tooth No. 13. For tooth No. 9, the laboratory layered porcelain (IPS e.max Ceram, Ivoclar Vivadent, ivoclarvivadent.com) onto zirconia. The author prefers not to use full-contour zirconia in the esthetic area next to natural teeth, as he feels porcelain veneering offers a better match. The abutments and crowns were evaluated on the 3D-printed analog model (Figure 11 and Figure 12) and delivered to the clinician for seating.

Since the delivery of the crowns, the patient returned for a night guard delivery. She reported that everything looked and felt great.

The use of CBCT and intraoral scanning to produce surgical guides for implant placement can make a significant impact for the entire dental team on any case, but it was particularly important in esthetic areas. The trajectory and position of a natural tooth is often not the same as the ideal trajectory and position for an implant. Leveraging technology can produce more predictable clinical outcomes and reduce the intra-operative stress of implant surgery.

With guided surgery, implants can be placed predictably in ideal positions, which helps the laboratory fabricate better restorations and the restorative dentist seat them with minimal adjustments. The entire restorative process is easier with this technology, and it is rewarding for clinicians and laboratory technicians to be able to offer state-of-the-art treatment to their patients.

The author would like to thank the following WhiteCap Dental Lab & Milling team members for their work on this case: Laboratory manager/ceramist Jeff Anderson, CAD/CAM manager David Nowaskey, dental technician Josh Baker, and Surgical Guide Department head Jim Campbell.

Riley Clark, DMD, is a dentist at WhiteCap Institute in Heber City, Utah.   

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