CLINICAL GUIDE
Scan Strategy (Dentsply Sirona)
Scan strategies for the Dentsply Sirona Omnicam and Primescan intra-oral scanners, why scan strategy matters for accuracy, the recommended sequences, and how to export to the lab.
Why scan strategy matters
Scan strategy directly affects the accuracy and dimensional stability of a full-arch scan, because it determines how individual images are “stitched” together in the scanning software. Think of drawing a 5-metre line using only a 15cm ruler: small errors accumulate over each segment, and over a longer distance the deviation grows. Full-arch scanning is similar, as the scanner head moves across a surface, images are stitched rapidly, and on longer spans errors add up and cause deformation. Sufficiently deformed upper- and lower-arch scans also make it hard for the software to superimpose the buccal bite scan and find the best fit, which is a common cause of unreliable bite registration. The guided scan strategies below (from the CEREC Ortho software and Dentsply Sirona scanner manuals) help avoid this.
OMNICAM
Omnicam scanning
Keep the scanner’s coated sapphire glass between 0 to 15mm from the surface (ideally 5mm), it does not rest on teeth or gums. The scanner emits a distinctive sound during successful registration; if a registration error occurs, return to a previously acquired point (an occlusal point is best) and continue. Divide each acquisition into four sequences.
Occlusal
From the distal tooth, scan in the mesial direction across the arch; for full-jaw acquisitions, begin the anterior transition with the lingual and labial areas before the incisors.
Buccal
Rotate the scanner 45° to a maximum 90° toward the buccal and guide it distally over the teeth; hold it “like a flute” (don’t tilt vertically to the direction of motion) and limit each buccal scan to one quadrant.
Lingual
Rotate from the buccal across to 45 to 90° lingual and guide mesially over the teeth.
Approximal
Use a wave motion in the occlusal, buccal and lingual directions, tilting 15° distally and mesially to capture the approximal contacts.
Buccal registration
Buccal registration establishes the relationship between the jaws: scan the occlusal, buccal and lingual views of the antagonist, then perform a close-up buccal scan of the bite block, capturing both arches plus ~5mm of gingiva. For long-span restorations across quadrants, take several buccal exposures. When scanning a full quadrant or jaw, move the scanner parallel along the arch and follow the guided tilt sequence; once complete, press “Next”, the model is calculated and beige-brown areas indicate missing data to re-scan.
PRIMESCAN
Primescan scanning
The same four-sequence approach applies, with a working distance of 0 to 20mm (ideally 2mm). For the buccal scan rotate ~20° toward the buccal; for the lingual scan rotate to a maximum 20° lingual. Two full-jaw procedures are supported.
Full-jaw, from the anterior
One starting from the oral surface of the anterior teeth and tracking each quadrant with a ~30° coronal-apical tilt.
Full-jaw, from the distal
One starting occlusally on the distal tooth with a ~60° oral tilt across the arch and back buccally.
Complete buccal scans on both sides for a full-jaw scan. Click “Next” to calculate the model and re-scan any missing (beige-brown) areas.
Note for both scanners
Remove soft tissue and cut away the moveable gingiva so only 2 to 5mm remains around the tooth, taking care not to cut required areas, this must be done during the ACQUISITION phase using the cutter.
File format, export and Connect
CEREC intra-oral scans can be exported as .stl files for any third-party software, or sent through the free Connect Case Centre, the central platform for digital impressions, where practices and labs register once to transmit digital orders securely within seconds. Take care to select the correct time zone when registering; if it’s wrong, local laboratories won’t be visible and you won’t be able to connect with them. Orthodontic procedures may require specialist partners, which you can reach via the Connect software.