dental implants

Key Steps

1. Take a CBCT and intraoral scan.

2. Merge the DICOM file with the STL file.

3. Do a digital wax-up of the tooth that needs to be replaced.

4. Plan the implant position in a restoratively driven manner.

5. Design the surgical guide.

6. 3D-print the surgical guide.

7. Place the implant using a guided implant surgical kit.

8. Take an implant-level intraoral scan with a scan body.

9. Deliver the implant restoration.

Digital workflows in implant dentistry improve practice efficiency, procedure predictability and clinical outcomes. Digital implant planning aims to ensure that the implant is placed in a restoratively driven manner, while guided implant placement aims to ensure that the implant is placed exactly where it is digitally planned. Guided implant placement achieves higher accuracy and lower failure rates than freehanded or half- guided surgery because it provides a defined implant drilling and insertion path.1–3 Implants placed in such a manner are also more apt to be restored with screw-retained restorations, which leads to easier maintenance. By digitizing data, the implant planning process is sped up, physical storage space is decreased and patient chair time is decreased.1,4,5

Cone Beam Computed Tomography

The foundational technology that makes a digital workflow possible in implant dentistry is cone beam computed tomography (CBCT). CBCT uses a single, inexpensive, flat-panel or image intensifier radiation detector. CBCT imaging is performed using a rotating platform to which the X-ray source and detector are fixed. The X-ray source and detector rotate around the object being scanned and multiple, sequential, planar projection images are acquired in an arc of 180 degrees or greater.6

X-ray attenuation measurements from each machine position are then used to reconstruct a 3D dataset of the implant site, which can then be used by CBCT viewing software to display either a 3D rendering or any cross-sectional view of the implant site.7,8 CBCT differs from computed tomography (CT) in that it uses a single X-ray source that produces a cone beam of radiation, rather than a fan beam as with CT. There is no accepted definition of when a fan beam (which is assumed to be planar) becomes a cone beam.9

The significantly lower cost and smaller computing power needed to analyze CBCT images compared to computed tomography made this technology accessible to the dental practice in 1999, when the first commercially available CBCT machine, the NewTom DVT 9000, was introduced in Europe.8

The American Academy of Oral and Maxillofacial Radiology (AAOMR) recommends that cross-sectional imaging be used for the assessment of all dental implant sites and that CBCT is the imaging method of choice for this information. 8 Once a CBCT image is taken, it is recommended that the image be interpreted by an oral and maxillofacial radiologist. The AAOMR noted that “dentists using CBCT should be held to the same standards as board certified oral and maxillofacial radiologists (OMFRs), just as dentists excising oral and maxillofacial lesions are held to the same standards as oral and maxillofacial surgeons. It is the responsibility of the practitioner obtaining the CBCT images to interpret the findings of the examination. Just as a pathology report accompanies a biopsy, an imaging report must accompany a CBCT scan.”10

A CBCT image can be obtained from a dental imaging center or by setting up a CBCT machine within the dental office. The choice for either depends on multiple factors including physical space, economic feasibility, practitioner comfort with the devices and the needs of the patient population. For those looking to purchase a machine for their office, contemporary CBCT devices have a smaller footprint than previous generations as well as higher resolution and faster image acquisition. Additionally, these CBCT machines possess scatter correction or scatter reduction methods that reduce X-ray artifacts from radiation being deflected by restorations using beam-blocking techniques 11 or mathematical corrections.12

Digital File Types

Digital implant planning requires two main pieces of data: a CBCT of the patient as a series of DICOM (.dcm) files and an intraoral scan of the arch as an STL (.stl) file. t