April 5, 2017
by Paresh Shah, MS, DMD, Cert. Esthetic Dent.
The use of a diagnostic wax-up has always been beneficial in the planning and execution of restorative and surgical procedures. It serves multiple purposes from treatment planning, communication with the interdisciplinary team and showing patients what possibilities exist for treatment. Traditionally, impressions and a bite record are taken and sent to the lab. Information is conveyed on a lab prescription to ask for a diagnostic wax-up based on the parameters requested to achieve the patient’s goal for treatment. Nowadays, photos might be provided to the lab so they have a better visualization of what the facial esthetics are like and how those results may be optimized. This method still leads to an inherent challenge as the lab often doesn’t have accurate details as to lip dynamics, facial expression and function. For that reason, accurate communication is essential to minimize remakes or chair time if the diagnostic wax-up is significantly different than expected.
What if we could convey more information in a simple, effective manner to allow the lab to better understand what the patient’s condition is without someone having to meet the patient? As technology continues to evolve we now have the advantage of digital workflows. Through photography, video and impression scanners we can perform similar procedures using digital smile design protocols. We have been exposed to many great interdisciplinary examples of digital smile design cases that involve full mouth restorative. However, we can use these protocols to also execute simple everyday dentistry as well.
The following is a clinical case of an everyday bonding procedure that many general practitioners might perform on a regular basis. It was planned using a Digital Smile Design (DSD) protocol and all lab procedures were digitally created.
A 42-year-old female patient had has some large composites on her four anterior teeth that have been breaking down and staining for some time (Fig. 1). She was interested in having new composites placed with improved contours and balanced shading. She was hesitant whether to treat the entire facial surfaces of her four anterior teeth or simply replace the fillings that had stains around the margins. A procedure like this is typically performed by “free-handing” the shape using direct composite bonding. However, creating symmetry and proportional restorations can sometimes be challenging. The use of a stent or guide can facilitate a more predictable result.
Failing restorations on teeth #12-22.
The planning of this case was performed using a Digital Smile Design (DSD) protocol rather than conventional methods. The protocol is simple and involves a few specific photographs or videos that can be taken on an iPhone or digital SLR. These are combined with a digital impression (True Definition scanner – 3M Dental) to create a smile design proposal and treatment guide (Fig. 2). By using high resolution video on an iPhone, it’s possible to extract individual photographs for the smile design. Six simple views were used to create a digital diagnostic wax-up from the lab (Fig. 3). The other advantage of video is that you can provide the lab with some dynamic parameters for them to evaluate a patient’s smile and speech. A short video of the patient talking as well as doing some chewing and excursive movements provide the lab with valuable information that often is hard to convey in writing.
Digital scan of maxillary arch with TrueDefinition scanner.
DSD video and photo series.
The video, photos and digital impression were used by the lab (Aurum Group–Calgary, AB) to create a 2D proposal or a “digital diagnostic wax-up” (Figs. 4 & 5). After approval of the digital rendition, a 3D model of the smile design was printed along with a PVS treatment stent (Fig. 6). The patient was brought back for her treatment appointment and the diagnostic stent was used to provide an intra-oral “mock-up” to show the patient what the contours of the new restorations might look like. The mockup was created using an A1 shaded bis-acyl resin (Tempsmart – GC America) that was not bonded into place, but stayed secure long enough to allow the patient a chance to evaluate her smile (Figs. 7 & 8). A wall mirror was used to give the patient an idea of what the new smile would look like from “conversation distance.”
Digital smile design creation using the DSD protocol.
Virtual rendition of the 2D smile design prior to 3D processing.
Printed model based on the 2D to 3D DSD protocol.
Bis-acryl resin being placed inside stent for intra-oral “mock-up”.
Full face view of Intra-oral “mock-up” based on the DSD protocol.
The mock-up was kept in place and used as a preparation guide to provide even reduction based on the desired outcome (Fig. 9). The remaining fragments were removed prior to restoring. Each tooth was restored separately before moving on to the next. Mylar matrices were placed between individual preparations prior to bonding (Fig. 10). To simplify placement of the composite a clear matrix material based on the 3D design was used (Fig. 11) Memosil – Heraeus Kulzer. The clear matrix allowed the composite to be placed with sufficient adaptation to prevent voids and cure through Each tooth was restored sequentially in a similar manner and then finished and polished at the same time (Renamel – Cosmedent-Clinical Research Dental). Should the patient decide to treat more teeth at a future date, the same design may be used if significant changes have not been made (Figs. 12 & 13).
3D mock-up used as a prep guide.
Isolation of individual tooth to perform bonding protocol.
Clear PVS matrix.
Retracted view of final restorations.
Full face smile of final restorations.
Although there are some offices that have cad/cam technology and software to create their own digital smile design proposals, the majority doesn’t have the full technology. For those that continue to use their lab, the process is simple and can allow accurate and predictable results in less time. The communication is fast as it can be done via a secure email portal. The use of a digital protocol can simplify the procedure and communication with the lab. As one gets comfortable with simple restorative cases the DSD protocol may be used for more advanced cases. The digital impression and photos can be superimposed with a conebeam image to help plan implant cases. This also allows for facial esthetics to be addressed. The records may then be shared with the appropriate specialists to make treatment planning more effective. Most people know how to use a handheld phone and as more continue to adopt digital scanners, the need for time-consuming impressions, plaster and wax will become far less necessary. These digital workflows are predictable and easy to implement with the help of an experienced lab. OH
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About the Author
Dr. Paresh Shah maintains a private practice in Winnipeg, Canada with a focus on implant, cosmetic and interdisciplinary care. Dr. Shah has a proficiency certificate in Esthetic Dentistry from the University of Buffalo (SUNY). He is a member of Catapult Education, the industry’s leading educational bureau. Dr. Shah is also a founder and co-director of a Seattle Study Club in Winnipeg. He has used digital technology in his practice for over 8 years and lectures on all aspects of restorative, interdisciplinary care and digital dentistry. Email: firstname.lastname@example.org (www.drpareshshah.com).
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