By PDADCO payday loan
Written by Martin B. Goldstein, DMD Saturday, 01 February 2003 00:00
We live in a world of choices, yet veneer-based smile rehabs have typically come in only two flavors—porcelain laminates or direct composite veneers. Both demand considerable skill and are time intensive when performed in their respective classical manners. What if there were a variant, less demanding of chair time but capable of attractive results?
Few will argue that the most time-consuming, sweat-producing, anxiety-ridden aspect of direct composite veneers is the meticulous hand placement and sculpting of the composite material itself. A six- to eight-unit case can take the better part of a normal workday. One may go home feeling the satisfaction of having created a masterpiece, but for the most part the dentist is physically and emotionally spent. This drain on the mind and body may be partly responsible for our profession’s reluctance to offer direct composite veneers as a smile-enhancing option.
I have good news. The following text will outline a two-tiered approach to providing direct composite veneers for your patients. With tongue in cheek, I offer you “econo-direct veneers” as the entry-level direct composite veneers, which are placed via an injection-molded technique whose method is discussed. This same set of direct composite veneers can be brought to the next “custom level” at a subsequent visit, either optionally or as planned upon and with an additional charge in the original fee.
We all recognize that porcelain is king when it comes to smile rehabs, yet its respective fees are also known to be regal, and thus beyond many budgets. Additionally, temporization of the ceramic case takes on a life of its own, as do the technical aspects of meticulous impression taking and placement. When one steps back for an objective look, there’s considerable argument for being able to knock out a directly placed composite veneer case without having to pay the piper physically and emotionally.
|Figure 1. Close up of pre-op smile.||Figure 2. Pre-op portrait.|
Readers of past articles may well know that I rely upon digital imaging and smile simulation before beginning a cosmetic rehab. You’ve got to start somewhere! As can be seen in Figures 1 and 2, my friend and patient, Steve, was deserving of an aesthetic tune-up. Several aesthetic issues were evident. First and foremost, note the aging composite veneers on teeth Nos. 8 and 9, originally placed to mask a dark, nonvital incisor (tooth No. 9) and close a diastema. Further examination will reveal mismatched canines, with tooth No. 6 doing its own thing entirely. Finally, teeth Nos. 7 and 10, while remaining the least culpable of the offenders, exhibit size and shape discrepancies relative to their adjacent partners in crime.
|Figure 3. Smile Vision Resin Replica.||Figure 4. Hard/soft templates.|
In order to set a course, I enlisted the help of Smile-Vision (www.smilevision.net). Shortly after uploading a pretreatment portrait of Steve to my personal Smile-Vision web page, I received an e-mail notification to go online and download the new Steve. His digitally enhanced smile simulation, although brighter than we intended to go, lit the way as to the possibilities for Steve’s new smile. After Steve approved the look, I provided study models and a bite to Smile-Vision and requested that they return a resin replica with accompanying hard/soft templates, as well as a reduction template (Figures 3 and 4). The resin replica is a composite mock-up based upon the simulation, while the hard/soft templates are exquisitely detailed vacu-formed templates from which to fabricate provisionals or, as in this case, direct composite veneers. A clear reduction template accompanies the set, providing a preparation guide that allows the operator to know when his preparations are sufficiently reduced to permit veneer placement that is faithful to the mock-up. With respect to the technique described in this article, the soft component of the hard/soft templates is the key ingredient, in that it will be converted to an oversized “strip-off crown form” with which we are all familiar.
|Figure 5. Premier’s Tray Magic; it’s easy on your fingers.||Figure 6. Miris compule tested for size in template.|
This conversion can be accomplished by separating the individual teeth and creating labial port holes in each of the tooth forms that will involve a direct composite veneer. In essence the operator is creating a series of adjacent veneer forms, each with a composite injection port hole. The separation allows the operator to introduce successive mylar strips interproximally so that the veneers remain separate from one another. The separating cuts can be performed with a No. 15 scalpel blade or, more elegantly, with Premier’s Tray Magic, an electric knife designed for trimming bleaching trays that happens to be more than suitable for the technique described here. Certainly the likelihood of filleting one’s fingers is all but eliminated (Figure 5). The soft splint is further modified by placing centered, labial port holes in each of the veneer forms, into which the tip of the composite compule will be snugly inserted (Figure 6).
The composite chosen for this particular case is a relative newcomer to the industry. It is called MIRIS, and comes to us from the Coltene\Whaledent corporation (www.ColteneWhaledent.com). MIRIS is classified as a universal-hybrid, and is said by the manufacturer to exhibit strength and wear characteristics similar to other contemporary mainstream universal composites such as DENTSPLY Caulk’s Esthet•X or Kerr’s Point 4.
Developed by Dr. Didier Dietschi at the University of Geneva, MIRIS focuses upon an interesting perspective with regard to composite shading. The MIRIS system is comprised of seven dentin “selections” (S1-S7) and six enamel “tints.” There are also four “effect” shades that include an opaquer and an incisal edge effect paste. The “S” classification refers to the perceived level of saturation or chroma of only a single dentin hue. The enamel tints are variations on white, neutral, and ivory, and of course the effect shades allow the operator artistic characterization possibilities. Dr. Dietschi conceived this system after having studied the color of 1,000 extracted teeth and concluding that while the basic dentin hue of the sample teeth was not significantly different among them, variations in appearance did occur as a result of changes in color saturation (or chroma) of the dentin resulting from the aging of the tooth structure, both dentin and enamel. Further subdividing, the shades were divided into Young, Adult, and Elder shades, reducing the maximum number of potential dentin and enamel shades to four for each age category—an economy of choices if you will.
|Figure 7. Miris shade tabs individually and nested.||Figure 8. Shade selection.|
|Figure 9. Nested Miris shade tabs.||Figure 9b. Calset Composite heater.|
The practical result is a shade guide system that allows the dentist to mix and match dentin and enamel shade tabs, in nested fashion, to obtain nearly any shade imaginable. As seen in Figures 7 through 9, enamel and dentin shade tabs are combined and rendered optically as one by placing a drop of glycerin between the shade tabs. Additionally, the nonslumping but moldable handling characteristics of MIRIS, combined with its creamy texture, make it a good match for the technique described below.
ONE OTHER WRINKLE
Should your composite lack the creamy texture of MIRIS and you’re not ready for a switch, you might consider a new device, Addent’s Calset Composite Compule heater.
Shown in Figure 9b, this mini warming device is said by the manufacturer to increase your composite’s flowability by 30% and decrease its film thickness. It’s also said that such pre-heat treatment will yield stronger restorations and enable deeper and faster curing—quite a bevy of benefits from simply increasing the composite temperature from room temp to 130º F. At the time of this writing, university-conducted research was being presented to the AADR to substantiate the manufacturer’s claims.
Although MIRIS will flow nicely on its own, I put the CALSET to the test in Steve’s case and found it to noticeably improve MIRIS’ ability to smoothly and homogeneously fill the soft template veneer forms.
|Figure 10. Prepped anterior dentition.||Figure 11. First layer of opaque using Dickerson Ditch.|
|Figure 12. Second layer of Opaque using EsthetX A2O.|
With all the ingredients assembled, and local anesthetic administered, Steve’s six anteriors were conventionally prepared for the composite injection molding technique as demonstrated in Figure 10. Finish lines were modest chamfers placed barely subgingivally, while ample space was created interproximally to allow for redistribution of tooth mass. In general, labial and incisal reduction averaged 1 to 1.5 mm, while tooth No. 6 was prepared more aggressively in an effort to bring it back into the arch without involving a very healthy pulp. As is easily observed, taming tooth No. 9 was an issue. This was accomplished via two steps following routine etching of tooth No. 9 with a 37% phosphoric acid gel and application of Parkell’s Touch&Bond bonding agent. In the first step, a subgingival Dickerson ditch was placed inside the finish line of the chamfer, creating a well for an opaque material to settle in. Dr. Bill Dickerson has outlined this technique in a videotape offered by the Las Vegas Institute. This technique is intended to mask the reflection of the inherently dark root substrate. As is noted in Figure 11, Miris’ flowable opaque is placed in the ditch and also scattered across the labial surface of the tooth. As seen in Figure 12, another favorite opaquer, DENTSPLY Caulk’s Esthet•X A2-O, is applied to bring the pre-veneering shade of tooth No. 9 as close as possible to tooth No. 8.
|Figure 13. Injection molding veneer of tooth No. 8.|
Following the etching and bonding of the other five teeth in similar fashion to that described above, the pre-prepared soft matrix was seated firmly over the prepared teeth, mylar strips were inserted interproximally to isolate tooth No. 8, and MIRIS “S1” was injected into the veneer form as shown in Figure 13. Once any obvious uncured excess had been removed via a composite placement instrument or explorer, the veneer was cured first on the mesial contact, angling the light away from the distal, and then on the distal contact. The mylar strips may be cinched tight gingivally as one would do when restoring a class III restoration, so long as the soft matrix was sectioned deeply enough to allow the strip to settle into the embrasure space. The same process is conducted for each tooth. It is up to the operator to determine how many veneers are placed before removing the template. In a case such as the one described here, I typically do teeth Nos. 8 and 9, remove the template, accomplish gross trimming, and then return the template to complete the right side and subsequently the left side. In other instances, I’ve done all six before removing the template. As one might guess, the bulk placement can be accomplished quickly.
Finishing and polishing can be accomplished in the usual manner, putting to good use the operator’s favorite selection of finishing diamonds, carbides, strips, and polishing pastes. MIRIS’ tough shell, however, will dictate the use of no less than a medium grit diamond instrument to remove gross excess in a timely fashion. More subtle finishing is accomplished best with Brasseler’s carbide finishing burs, such as the ET9 and H50A-010. Further gloss can be achieved via DENTSPLY Caulk’s Enhance polishing cups and Enamelgloss polishing pastes, medium and fine grits.
|Figure 14. Phase one veneers completed.|
As observed in Figure 14, a reasonable result has been obtained, albeit a monochromatic one. My patient might have been quite content to end it there had I not suggested that the bicuspids be included at a subsequent sitting to decentuate tooth No. 6 even more. It was also suggested that the central incisors be lengthened somewhat and characterized to create a more individualized appearance. Having bitten the fruit of improved dental aesthetics, Steve was game.
TREATING THE BICUSPIDS
On the return trip, bicuspids Nos. 4, 5, and 12 were prepared and veneered via the more conventional free hand technique, as the sculpting demands of the bicuspids are minimal. I prefer to conservatively shoe the buccal cusps to reduce the incidence of chipping.
The next step involved addition of more S1 MIRIS to the incisal edges of teeth Nos. 8 and 9 as shown in Figure 15. This is accomplished by roughening the previously placed MIRIS with a diamond, applying an unfilled resin, and simply patting additional material in place. The shape-retaining characteristics of MIRIS facilitate this process.
|Figure 15. Additional Miris added to lengthen centrals.||Figure 16. Hollowing out the incisal edges.|
|Figure 17. Placement of translucent enamel shade in lingual hollows.||Figure 18. Phase two completed.|
|Figure 19. The new smile.|
Once the additions were completed, a cut back was completed in two areas. As shown in Figure 16, the lingual incisals of the incisors (teeth Nos. 7 through 10) are hollowed out at varying depths, and (what is not shown) 0.5 mm of labial reduction is quickly carried out on the same teeth to allow for the addition of MIRIS’ enamel tint “NT” in the newly created incisal hollows and atop the labial surfaces of the incisors (Figure 17). Creating non-uniform depths will result in a less contrived look, playing upon nature’s propensity for variance.
The enamel tint placed on the surface serves the purpose of toning down the S1 shade and providing a more natural-looking enamel appearance. Once this is accomplished, the new surface is again refinished and polished, and then may be coated with a final layer of glaze such as Bisco’s Fortify, or simply left in the satiny polished state characteristic of MIRIS. As is seen in Figures 18 and 19, the end result can take on an appearance not very far removed from a ceramic veneer, exhibiting a natural enamel shade, incisal translucency and even an occasional, strategically placed hypocalicification, courtesy of the MIRIS system.
CONCLUSION: IT’S GETTING BETTER OUT THERE
With each successive year, it seems the composite systems available to us improve dramatically. Not only is composite durability improving, but manufacturers are providing us with palette-like systems not unlike a painter’s box, putting dental art at our fingertips. Doesn’t it behoove us as smile artists to explore new and easier ways to facilitate this creative process while working in the ever improving medium of creative composite resins?
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