Why Analog Impressions Are Still State of the Art in Dentistry
By: Dr. Jose-Luis Ruiz DDS, FAGD
In dentistry we are inundated with experts who with ulterior motives, tell us the “next best thing” is now the new state of the art, and that if we don’t have it or use it, we are behind and maybe obsolete.
I love technology and I have loved technology for my entire career. In fact, my first lecture was on technology and how it was changing dentistry. With my eagerness to be on the cutting edge of technology, I purchase many pieces of equipment and technology based on a manufacturer claims and a few “experts” opinions, only to discover that few pieces of technology really live up to their initial expectation of making dentistry, easier, faster, better. I have often been faced with the reality that some expensive technology is very sexy, flashy, and great for marketing purposes, but also shallow in their real ability to improve the quality of dental life.
Digital impressions scanning technology is here to stay and it has a real present and future. In this article I want to share my real-world dentist perspective on whether or not the average dental professional should think that when making the large investment of a digital impressions system, they can assume PVS or any type of analog impression, is no longer needed. Also are digital impressions better and the new state of the art?
There are at least 8 issues to consider in making such a decision: Accuracy, tissue displacement, cost, simplicity and time, accuracy on large cases, bells and whistles.
Accuracy:
While digital scanning has achieved excellent accuracy, model printing and duplication has not achieved the same degree of accuracy in the dental market. Having been trained as a laboratory technician, I know a waxed and pressed restoration will have a better internal fit and marginal fit than a modeless milled restoration. Also technicians prefer die stone dies and solid models to insure the ultimate fit of a restoration with minimal adjustment. This amplifies with minimally-invasive preparations, where minor contact separation and very slightly supra-gingiva or equigingival preparations, margin definition is less crisp and defined with printed cast and dies.
Tissue displacement:
One important reason minimally-invasive supra-gingival restoration will never do as well with digital scanners is the inability of digital scanners to achieve any tissue displacement. Materials like Panasil with it’s superior tissue displacement ability, records slightly supra-gingival or equigingival margins better, as it has the ability of gently pushing the gum away from the margins, achieving better definition.
Cost:
Savvy sales people will quickly remind the buying dentist of the cost benefits of digital scanner, vs impression material, and provide a breaking point, “if you take x number of impressions you will save, as your impression material cost is higher than the monthly lease”. Usually the peripheral cost are rarely factored, high cost of learning and implementing, the expensive cost of printed casts needed for many cases, or the maintenance agreement, and repairs, never mind the fact that the technology will be obsolete in 5 years and you need a new machine. Digital impressions are valuable, but costly.
Simplicity and time:
As a busy clinician, I like the ability to, as soon as I’m done preparing the teeth, get from my assistants Panasil light body (Kettenbach), start mixing the heavy body, and in 30 second insert the triple tray in the mouth, say bite to the patient and I’m done. Panasil with it’s superior hydrophilicity and tear strength, combined with supra-gingival dentistry means retakes are extremely rare. Digital impression scanners can also be fast in the hands of an experienced operator, I can scan a top and bottom quadrant and bite in 2 minutes, as long as the machine is in the room and ready and patient data has been entered in advance. Certain parts of the mouth and certain patients can make scanning more complicated and time consuming. Other complications arise in busy offices with multiple room and multiple operators where the machine may need to be shared, creating delays, and ultimately forcing users to have to purchase multiple units.
Large cases:
Digital impressions are still second best to PVS for large cases. Large cases require multiple mounted cast on semi-precision articulators. Currently digital impressions and dies are best suited for traditional crown and bridge dentistry, with deeper chamfer, more aggressive interproximal cavo-margin separation, as well as modeless single crowns. Larger cases are not currently suited or practical with digital or modeless fabrication.
Bells and Whistles:
This is the area where digital technology excels, and while flashy, is mostly gimmicky. For example, some manufacturers promote the great educational value of showing patients the wear of their teeth over the years by using scanned dental arches. The same education can be easily shown with dental photographs.
While digital impression scanning technology is valuable, it is not for every dental practice at this point in time, nor is it a substitute for high quality impression materials.
About the Author
Dr. Jose-Luis Ruiz has a reputation as a talented dental artisan in Burbank, Los Angeles, and now in Studio City, California. For over 20 years, his skill as a premiere Burbank aesthetic dentist has created authentic, unique smiles for thousands of successful and discerning patients in Burbank and throughout the Los Angeles area. Dr. Ruiz is considered one of the top aesthetic dentists not only in Los Angeles and throughout California, but in the entertainment industry as well.