Use of Intraoral Scanners in Digital Denture Fabrication

Recent studies have increasingly explored the use of intraoral scanners (IOS) for capturing denture-bearing tissues in edentulous patients, although certain clinical limitations remain.^30-34 The listed advantages of IOSs include the capability of registering a truly mucostatic (no pressure) impression, decreased patient discomfort, elimination of stresses associated with impression deformation, and efficient space utilization.³¹ However, the scan accuracy is affected by the length and distribution of the edentulous area, the skill of the operator, and the size of the IOS tip.^30-34 From a technical standpoint, IOS systems capture small intraoral regions sequentially, requiring multiple images to be stitched together to reconstruct the full arch. In edentulous patients, the relative uniformity of oral tissues reduces distinct anatomical landmarks, making thealignment of the sequential images more challenging and potentially leading to incomplete datasets or stitching distortions.

Other limitations of this technology include the following:^30-35

• Inaccurate registration of highly mobile tissues as the software deletes the areas that are not steady over time thereby making it impossible to incorporate functional movements.³²

• Challenge to capture the borders and posterior palatal seal area in a consistent and reproducible way

• Inability to use various methodologies of impression-making such as pressure, selective pressure, or minimal pressure

• Difficulty in assessing the compressibility of the oral mucosa

• The complexity of recording the mandibular edentulous arch due to the movements of the tongue

• Morphological limitations of the scanner also restrict access to certain anatomical regions, such as the retromolars pad and hamular notches.

Though there are a few practitioners who can successfully use the IOS for recording denture-bearing tissues of edentulous patients (Figure 3), most still need to use conventional impressions until there are further advancements in this technology.^30-34

Figure 3. (A) Intraoral scanner (B) Scanned image of the maxillary edentulous arch (C) Scanned image of the mandibular edentulous arch (Lower right image)

Figure 3. (A) Intraoral scanner (B) Scanned image of the maxillary edentulous arch (C) Scanned image of the mandibular edentulous arch (Lower right image)

Image A obtained from 3shape.com