In general, the edentulous case can be quite challenging, but there's an easy way to acquire the required scan data.
Before scanning the case, change the iScan settings as follows:
Filtering Level: Level 3 Model Display Mode: Reliability Map — it shows the reliability by highlighting the scan data in green and orange. The areas highlighted in green indicate that the scan data is reliable while the areas in orange indicate unreliable data.
While scanning, make sure you don't miss any of the following:
Maxillar: vestibule, frenum, maxillary tuberosity, hamular notch Mandible: vestibule, frenum, retromolar pad, alveololingual sulcus
Scanning the maxillar
Start scanning from the rugae area, which is the distinguishing mark in the maxillar.
Build up the main data structure by scanning the alveolar ridge on both the left and right sides.
Scan the buccal side including the vestibule and frenum.
Scan the palate area. Like before, start scanning from the rugae area, and acquire the scan data by moving the scanner tip in a way shuttling between the left and right alveolar ridges and heading towards the posterior palate till you cover the whole posterior palate.
When the alignment is lost, move back to the rugae area, and continue to rescan from that area to where the scan was lost. If there is recurring loss of alignment around the same area, perform the scan data optimization before continuing to rescan.
Scanning the mandible
Start scanning from the one side fo the retromolar pad.
Build up the main data structure by scanning the alveolar ridge until you reach the opposite side of the retromolar pad.
Scan the rest, including the vestibule and frenum.
💡 Useful tips
Maintain the optimal distance between the scanner tip and the gingiva; it is recommended to check this via the live view screen on iScan while scanning. It is likely that the alignment would be lost multiple times while scanning an edentulous case. By and large, the principle which should be applied to edentulous cases for better alignment is to use distinguishing shapes: incisive papilla, rugae area, retromolar pad, and alveolar ridge. Especially for cases where distinguishing shapes are not distinct enough, it is advisable that the user add on distinguishing matching points by using flow resin or latex marker.