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Written by Manu Dave Kacker, DDS, et al Thursday, 30 June 2011 18:42
Porcelain veneers serve as one of the more conservative restorative options available for improving aesthetics. The preparation design for porcelain veneers is driven in part by the room needed by the technician to recreate natural tooth structure and also by the restorative system being used. However, during the last 10 years, there has been a steady growth in veneers that have minimal to no preparation.
The idea of not removing tooth structure and pain-free dentistry has helped to create the demand for no preparation veneers. However, without proper preparation and appropriate prep design, the dental technician team has no room to recreate the morphology found in natural teeth. The absence of this anatomy often results in monochromatic and unnatural appearing smiles. The other common problem is a bulky/over-contoured result that is brought on by ceramists who are attempting to place internal anatomy or trying to achieve a layered look. These compromises have led to cases being accepted as if they were the best result possible (given the limitations), even though the outcome could have been more natural. Some clinicians have pointed out that no-prep veneers can only be done in very select cases. These are cases where the aesthetic results are achievable when the teeth need to be moved out facially or the teeth are being lengthened, which allows for more room to properly create the restorations.
This case report article will serve to introduce a new approach to no-prep veneer cases that can add vitality to your ultra-thin restorations (0.3 to 0.5 mm thick).
Diagnosis and Treatment Planning
Brooke is a 25-year-old woman who presented with wear on her central incisors (Before Image and Figure 1) and distinctive wear patterns on her posterior teeth. Her dentition presented with relatively good tooth morphology, but the patient's biggest concern was the aesthetics of her centrals. She had limited protective guidance with no posterior disclusion in lateral movements so her dentition was at risk for further wear and breakage. Only addressing the patient's concerns would have put any restorative work done on the centrals at risk due to the absence of cuspid guidance.
The patient was involved in discussions regarding the design of the case to get as much input of her concerns and desires as possible. She was eager to improve her smile but did not wish to have her virgin teeth prepared. She also expressed concerns about looking unnatural after treatment, based upon seeing the results of friends who were the recipients of poorly done cosmetic dental procedures.
This case was not the ideal case type for traditional no-prep veneers because the application of porcelains with traditional materials and techniques to the natural her dentition could have resulted in over-contoured, monochromatic, and bulky restorations that are often associated with no-prep cases. So, in this case, it was decided to proceed with no-prep veneers on teeth Nos. 6 to 11 using a material (Enamelette Ultra Thin Veneers [Opus One Laboratories]) and layering technique that are ideally suited for extremely thin no-prep/minimal prep veneers. A porcelain colorant layer is incorporated that replicates the structures found in natural dentition―all within 6 µm (Hilla Technologies). This allows veneers to be fabricated at 0.3 mm with the incisal translucency that is normally associated with a natural dentition.
The shade was selected using the Lumin Vacuum shade guide (Vita). A B1 was chosen and pictures were taken to help the ceramist in the fabrication process. Tooth characterization was determined using a special guide (Hilla Characterization Guide [Hilla Technologies]) (Figure 2). This guide provided an excellent way to educate the patient in the natural appearance of teeth and it gave Brooke the opportunity to participate in the decision making process. This guide is extremely simple to understand, making it easy for the clinician to show the patient what teeth look like without incisal characterization (monochromatic). It clearly demonstrates the different intensities of incisal internal anatomy to the patient, doctor, and technician team. The characterization guide is used to create a meaningful dialogue between the doctor and the patient about what makes teeth look natural, allowing the doctor to have a quick way to assess the patient's tolerance (or threshhold) for the type and degree of characterization indicated. In Brooke's case, she immediately understood the importance of the level and kind of characterization that would be required to make her teeth look as natural as possible.
The patient's case was first designed on the computer using software by Smileography (Figure 3). Using this software, the dental technician worked out the length, width, shape, and characterization of the case digitally. Each tooth involved was recreated on the computer as it would eventually be in porcelain. The information from the characterization guide was then used to develop the proper degree of incisal translucency in the digital image. Next, the resulting image was shown to the patient for approval (Figure 4). With this step, both the patient and the doctor knew what to expect in advance. This doctor-technician-patient triangle (or triad) of understanding was critical to the outcome and satisfaction of Brooke's aesthetic dental work.
Enamelette Thin Veneers can be fabricated using any pressing system, milled ceramic, or powder buildup. In Brooke's case, Noritake porcelain was used for the buildup. Opacious porcelain was used at the incisal edge to eliminate the demarcation lines, and the remaining structure was fabricated using enamel colors for proper blending.
The case was shaped and contoured as dictated through the computer-generated mock-up. This computer rendition of the case takes the guesswork out of what the final restorations will look like, giving the dental ceramist a true guide of where to take the case.
|Figure 2. The characterization guide (Hilla Characterization Guide [Hilla Technologies]) used to optimize aesthetics for the ultra-thin veneer restorations.||Figure 3. Digital mock-up (Smileography).|
|Figure 4. Digital mock-up for patient approval and signature.||Figure 5. Ultra-thin veneers (Enamelette Ultra Thin Veneers [Opus One Laboratories]) demonstrating detailed incisal |
|Figure 6. The completed ultra-thin veneers, ready to be delivered.||Figure 7. Left lateral close-up view.|
|Figure 8. Right lateral close-up view.||Figure 9. Postoperative close-up view.|
A porcelain colorant layer (Hilla Technologies) was added to the substructure that contained the complex anatomical details which replicate the natural structures of a tooth. This layer is 6 µm thick and adds virtually no visible thickness to the veneer. This allows the veneers to stay extremely thin, eliminating the bulky over-contoured appearance that is so often associated with no-prep cases (Figures 5 and 6). Although this porcelain layer is extremely thin, its structural accuracy creates an ultra-thin veneer with the appearance of 3-dimensional lobbing and incisal translucency. The internal anatomy provided by this technology resembles, and often exceeds, the results done by the most artistic ceramists.
No-prep veneers that are typically 0.3 to 0.5 mm thick can present a challenge for the doctor and team at delivery. While the veneers must be handled meticulously due to their minimal thickness, it is similar to how feldspathic type veneer cases are handled. It is best to use a very light viscosity try-in gel; in this case a clear shade was used (Prevue Try-in Gel [Cosmedent]). During the try-in, it was determined that accurate finish dimensions were met with regards to the margins, contour, color, and value. In addition, gingival, incisal, and interproximal emergence profiles were accessed. After this intraoral try-in was completed indoors, the patient was taken outside to evaluate sunlight and metamerism issues in outdoor lighting conditions. Upon doctor and patient approval, the veneers were steam cleaned, etched, silanated, and then placed in a seating grid guide.
No-prep veneer cases still involve some handling of the natural dentition to seat the veneers. First, teeth Nos. 6 to 11 were cleaned with plain fine pumice mixed with water. Then, coarse interproximal finishing strips (FlexiStrips [Cosmedent]) were used interproximally on Nos. 6 to 11. This is a crucial step in helping to eliminate enamel flash in the interproximal areas that can cause binding when attempting to seat these ultra thin veneers. This step minimizes the risk of fracturing the veneers on insertion. Next, the patient rinsed with a chlorhexidine gluconate 0.12% oral rinse (Peridex [3M ESPE]). This step helps to ensure a sterile surface prior to luting the veneers. Then, the working field from teeth Nos. 6 to 11 was isolated with retractors (Seemore [Discus Dental]) and cotton rolls. (Note: The veneers for teeth Nos. 8 and 9 were luted first, to ensure proper midline and incisal positioning.) The involved teeth were etched with a 37% phosphoric acid gel for 8 to 15 seconds and the enamel presented with the typical frosted surface texture. Resin adhesive (Optibond [Kerr]) was applied to the etched teeth (according to manufacturer's instructions) and the previously silinated veneers were carefully cemented into place with light-cured resin cement (Insure [Cosmedent]). Initial cleanup of any uncured excess cement was done with a perio stimulator (rubber tip) (Butler), then, the restorations were light-cured. Finally, after Nos. 8 and 9 were bonded into place, the rest of the teeth involved were simultaneously seated using the same technique as described above. All seating and delivery was preformed with no anesthetic.
Brooke was instructed on home care and asked to return for a postoperative appointment one week later to check all the restorations and to remove any residual resin cement that may have been inadvertently left behind. Since Brooke had already been educated on what to expect from the case as a result of the computer mock-up, this teamwork-based case went very smoothly. When the case was delivered, and since all of Brooke's expectations were met with absolutely no preparation, she was thrilled (Figures 7 to 9 and After Image).
This type of cosmetic transformation is absolutely a pleasure for the patient, doctor, and dental laboratory team. Because of new materials and techniques now available to doctor-technician teams, we are approaching a new frontier of options for smile transformations done in the most conservative ways. The ability to create veneers that are 0.3 mm with natural characterization opens the door for no-prep cases that can achieve excellent aesthetic results when properly treatment planned and executed.
Disclosure: Dr. Kacker reports no disclosures.
Disclosure: Mr. Yarovesky is the owner of Hilla Dental Transfers.
Disclosure: Ms. Jadali is a shareholder in Hilla Technologies.
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