13 December 2021

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Scanning Under the Dental Dam Isolation.

Edoardo Mancuso

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Digital systems are becoming tools used by many dentists and they have been successfully integrated into clinical dentistry. It has already been proved that digital scanning techniques are a clinically acceptable alternative to conventional impressions for unitary and short-span teeth and implant-supported fixed prostheses.

However, several clinical factors such as moisture, saliva, blood, and optics’ fogging may cause excessive light reflection that may reduce the quality and sharpness of the captured image. Moreover, tongue and soft tissue movement may wet the scanning surface reducing in this way the scan quality.

An interesting article written by Dr. Lucas Caponi and his team has proposed a technique that could help to ease the process of digital scansion helping indeed in the control of many scan distortion factors, such as moisture and saliva.

The technique proposed consists to effectuate the impression with the dental dam placed on the prepared teeth for the indirect restoration.

 

Technique

The article continues with a detailed step by step guide of the procedure that is herein reported:

1) Scansion of the arch to be treated and the antagonist dentition using an intraoral scanner.

2) Scansion of the intermaxillary relationship in the desired treatment position.

3) Placing of the dental dam on the teeth to be treated (the authors advise extending the isolation to at least 2 to 3 more teeth from those that require dental preparation).

4) Realization of tooth build-up if needed, dental preparation, and immediate dentine sealing under dental dam isolation.

5) Duplication of the arch’s scan data to be treated and trimming of the tooth area to be prepared. It is recommended in the article to extend the trimmed area only to the adjacent teeth contact points to guarantee more reference surface for matching the next scan

6) Intraoral scansion of the prepared teeth filling the previously trimmed scan. Available space for restoration can be checked with the scanner’s space evaluation tool.

7) Exportation of all scans aligned to the same XYZ spatial coordinates in STL files and manufacture realization with CAD software and a CAM milling machine.

 

Discussion and Conclusion
The authors assess that scanning with the dental dam in place allows an outmost control of some distortion factors, such as the presence of saliva and blood. The dam also minimizes the interruption of the scanner’s stitching process caused by tongue or soft tissue movement, resulting in quicker and higher-quality scans. Then, scanning under dental dam isolation may shorten the operative time and maximize preparation margins’ visibility, providing a stress-free environment.
In the article also a limiting factor is noted: the necessity for this technique, of a supragingival preparation margin for all of the restorations scanned.

 

The dental dam isolation is a necessary step in most of adhesive dentistry procedures, so maintaining it when restorative treatment is finished while making the digital scan may be beneficial for scanning accuracy and time efficiency.

 

 

For additional information: Protocol for Indirect Restoration Intraoral Scanning Under Dental Dam Isolation: A Dental Technique