Digital Impressions vs. Analogue Impressions
Which Benefits Prevail?
When Francois Duret introduced CAD/CAM processes in the early 1970s, it was evident that the face of the dental industry was about to go through a digital transformation. Today, traditional, labour-intensive laboratory methods are exchanged for more innovative and advanced techniques intended to improve the process of diagnostics and facilitate treatment.
Although the changes have been gradually implemented over several decades, some dental experts are still loyal to several traditional methods. Analogue impressions, in particular, are still a popular procedure despite the fact that the digital ones were designed as an overall better alternative.
The fact is that both procedures come with a list of benefits that cannot be easily overlooked and at this point, the decision between the two boils down to an individual dental professional’s preference. At this point, both are used for diagnosis and treatment planning, prosthodontics, orthodontics, restorative dentistry, maxillofacial prosthetics, as well as oral and maxillofacial surgery.
The following article weighs the pros and cons of both methods and is intended for those who are still indecisive.
Digital impressions are intended to be more patient-friendly and should be easier and faster to complete. They are taken by an intraoral scanner which resembles an ordinary camera used to produce a photo or video. Nowadays, digital scanners are able to obtain high-quality video footage or photographs and deliver a clear image of what needs to be done to improve the patient’s oral health and aesthetics.
Some of the most frequently cited benefits are patient-related. So far, digital modelling proved that it can provide a more predictable, comfortable, and stress-free treatment. What is more, some dental professionals prefer digital impressions because, in their experience, the technique simplifies certain clinical procedures and streamlines communication with the dental laboratory. Such modern procedures are revolutionising the relationship between a dental practice and dental laboratory.
Nevertheless, further evidence is needed to prove the extent of digital impressions efficacy and patient preference. Digital modelling is still not perfected and requires further research and development to guarantee 100% accurate results. In conclusion, analogue impressions are still considered a better method.
This method involves the use of elastic impression materials which are poured with dental stone. It is actually a negative imprint of the patient’s teeth and soft tissues. The materials used are either semi-liquid or liquid when they are prepared to be placed in the mouth. Depending on the specific material used, it can take several minutes to thicken and become an elastic solid.
There are several different techniques for taking analogue impressions which differ in the type of material and tray used to make a dental impression.
In terms of materials, the two most common are:
- Mucocompressive, during which the mucosa material is subject to compression and is more stable during a function.
- Mucostatic, which means the impression is taken with the mucosa in its regular position and is a good fit during the rest. For this reason, some dental professionals claim that mucostatic impressions deliver better results.
It is also important to note that some dentists opt for other, special techniques, like wash impression, functional impression, neutral zone impression, window technique, and others.
When it comes to trays, there are two main types:
- Stock trays that come in a range of shapes and sizes and are made of either plastic or metal. They can be rounded (for people who have no remaining teeth) and squared (for people who have some remaining teeth). Depending on a specific stock tray, it can cover all upper or lower jaw teeth (full-arch), or can cover up to three teeth (partial coverage tray).
- Special trays are custom-made for a patient, from acrylic or shellac. However, customised trays have been used less frequently since the advent of putties, as they provide excellent support and deliver good results.
There has been an ongoing debate regarding the accuracy of analogue impressions, but so far, no research has proved that it delivers lesser quality results in comparison to digital impressions.
In conclusion, there is still insufficient evidence which proves that the benefits of digital impressions overshadow the traditional, analogue approach. At this point, it seems that both techniques deliver equally accurate results.