4.3 Intraoral Imaging for CAD Restorations
Key Takeaways
- CAD-related intraoral imaging depends on clean surfaces, dry field control, retraction, accurate capture of margins, contacts, occlusion, and adjacent teeth.
- The RDA may assist by preparing the scanner, patient, and field as directed, but does not design or approve the final restoration independently.
- Common scan problems include saliva, blood, fogging, missing margin detail, soft-tissue obstruction, and bite registration errors.
- A useful digital record is tied to the correct patient, tooth, arch, and restoration plan.
Intraoral imaging records for CAD restorations
Computer-aided design workflows depend on accurate digital information. An intraoral scanner or camera does not magically fix a poorly prepared field. If saliva covers the margin, tissue blocks the preparation, the scanner misses the distal contact, or the bite record is wrong, the final restoration may not fit. Domain 1B can test these practical record-quality ideas even when the question does not use advanced software vocabulary.
The RDA may help prepare the patient, scanner, isolation, retraction, suction, and field as directed by the dentist. The RDA may also help capture images or scans when trained and authorized by office procedure and applicable duties. The dentist remains responsible for diagnosis, preparation evaluation, design approval, and treatment decisions.
A good CAD record includes more than the prepared tooth. It often needs adjacent teeth for contacts, opposing arch information for occlusion, and a bite relationship. The record must also be attached to the correct patient and tooth. A beautifully captured scan under the wrong patient is a serious record error.
| CAD imaging need | What can go wrong | RDA support step |
|---|---|---|
| Clear margin | Saliva, blood, tissue, or shadow hides finish line | Suction, dry, retract, or alert dentist as directed |
| Adjacent contacts | Scanner misses mesial or distal neighbor | Capture complete neighboring surfaces |
| Opposing arch | Occlusal design lacks opposing tooth data | Follow scan sequence for opposing surfaces |
| Bite registration | Patient bites incorrectly or moves | Give clear instructions and recapture if directed |
| File labeling | Scan stored under wrong tooth or patient | Verify patient, tooth, arch, and record name |
Patient management is part of imaging quality. Explain that the scanner will move around the teeth and that the patient may need to remain still or bite gently when asked. Use saliva control and breaks when needed. If the patient gags, has limited opening, or becomes fatigued, communicate with the dentist rather than forcing a rushed scan that misses critical data.
The exam may ask what causes a poor digital impression. Common causes include moisture, insufficient retraction, powder or reflective surface issues depending on scanner type, fast wand movement, missed areas, fogged mirror or lens, and patient motion. The best answer is often to correct the field or recapture the missing area, not to proceed to design with incomplete data.
Intraoral imaging also supports patient education, but do not confuse education with diagnosis. Showing a patient a cracked cusp or open margin image can help the dentist explain findings. The RDA should avoid telling the patient that a specific treatment is required unless the dentist has directed the communication.
Use this scan-readiness list:
- Confirm the tooth, arch, patient, and planned restoration record.
- Prepare the scanner tip and infection control barrier according to manufacturer and office procedure.
- Dry and retract the field as directed so margins and contacts are visible.
- Capture preparation, adjacent teeth, opposing arch, and bite records in the required sequence.
- Review the scan for missing data and route it to the dentist for evaluation.
The RDA exam usually rewards the answer that protects fit, function, and record accuracy. Digital speed is helpful only when the record is complete enough for the dentist and laboratory or milling workflow to use.
Which scan problem most directly threatens the fit of a CAD restoration?
What information is commonly needed beyond the prepared tooth in a CAD scan?
Who is responsible for approving diagnosis and final restoration decisions in the CAD workflow?