Oral Health Group
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COSMETIC DENTISTRY: Non-Orthodontic Correction of Class II, Division 2 Occlusion Using Porcelain Laminate Veneers

April 1, 2000
by Thomas Gleghorn, DDS


The trend in dental materials and techniques today is “newer, stronger, better.” Whether discussing porcelain systems, bonding agents, or luting resins, most of the clinical cases shown in trade publications today highlight some new technique or material.

Without the desire for constant improvement, our profession as well as every other aspect of our lives would soon grow stagnant. However, the trade-off of constantly upgrading to newer materials is that we give up the luxury of long-term clinical trials in exchange for current-generation products.

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It should be a boost to our collective self-confidence to see long-term success from products and materials that are no longer in use today because they have been supplanted by either improved versions of the same product, or by some entirely new category of product altogether.

Although the clinical case presented here could not accurately be described as a “long-term” follow-up, we have had the opportunity to monitor the results for several years. The patient is currently four years post-treatment, and has maintained twice a year recall visits at our office. The following article will outline the diagnosis, treatment, and results of the case.

DIAGNOSIS

The patient, a 29 year old female, had been receiving routine dental care at our office. She had commented that she was unhappy with the appearance of her smile, specifically the shade of her teeth, which exhibited tetracycline banding, as well as the fact that her teeth appeared “small and dull”, especially in photographs. The initial treatment consisted of whitening the teeth with 16 percent Carbamide Peroxide, administered with a take-home whitening kit. The results after whitening are shown in figures 1-3. The whitening process offered noticeable results, but the tetracycline banding was still evident and the patient was not satisfied with the aesthetic improvement.

Aside from the discoloration of the anterior teeth, there were some other aesthetic compromises. Most notably, the patient exhibited a Class II, Division 2 occlusion (Fig. 4). This factor, more than any other, accounted for her chief concern that “my teeth look dull in photographs.” When a photon of light strikes a reflective surface, that photon is reflected back at the angle of incidence. In an ideal situation, the facial surfaces of the maxillary incisors are roughly perpendicular to the horizontal. Therefore light striking these teeth is reflected back into the eyes of the observer, or into the camera lens, making the teeth appear brighter and more vital. In a situation where the incisal edges of the anterior teeth are oriented lingually, light striking the surface of these teeth will be directed downward, away from the observer or the camera lens, and creating the illusion of a darker, less vibrant smile.

The patient’s concern that her teeth were too small was also not without merit and would be addressed during treatment.

After performing an aesthetic diagnosis, which included a graphic analysis of the patient’s existing smile (Fig. 5) as described by Morley,1 it was determined that the ideal treatment would consist of placing porcelain laminate veneers on the 10 maxillary anterior teeth. When the patient was presented with this option, she was somewhat discouraged, as she had the idea that only the anterior 6 teeth would require treatment. When she was shown photographs of her smile it became obvious to her that indeed, more than 6 teeth would require treatment to obtain a good result. Due to financial concerns, the patient asked what the results would look like if only 8 teeth were veneered, leaving the second bicuspids untreated. This is a fairly common scenario in my office. The patient wants a perfect smile, but for financial reasons does not want to commit to the complete proposed treatment. When this occurs, several options exist. In this case, we presented her with the following treatment alternatives:

1.Place porcelain veneers on only the anterior 8 teeth, and attempt to blend the shade of the veneers on the first bicuspids to more closely match that of the untreated second bicuspids. This is accomplished by having the ceramist create a shade gradient from mesial to distal on those veneers, so that the mesial 1/2 closely matches the shade of the cuspids and the distal 1/2 blends into and more closely matches the shade of the natural dentition.

2.Place porcelain veneers on only the anterior 8 teeth, and fabricate the bicuspid veneers to match the other porcelain restorations. This will result in a more obvious transition from treated to untreated teeth, but the advantage of this option is that it allows the patient to have the second bicuspids veneered at any point in the future if she so chooses.

The clinician could also certainly elect not to perform the treatment if he or she felt like the results would be compromised aesthetically. My personal viewpoint is that since the treatment is elective in nature, I am willing to give the patient what they request as long as the treatment they choose does not interfere with the function or longevity of the restorations.

The patient liked the idea of being able to go back at a later date and complete treatment on the second bicuspids, so she chose the option to fabricate all of the veneers in the same shade.

Other clinical concerns prior to beginning treatment included the gingival recession that is obvious on the anterior teeth, wear facets on the cuspids, and existing large amalgam restorations on the posterior teeth, which the patient opted not to replace at this point. Mounted study models revealed a non-working interference on the second molar. This interference was removed by selective occlusal adjustment on the maxillary second molar.

TREATMENT

Anesthesia was obtained, and the teeth were prepared by selectively reducing the facial enamel. Using depth reduction burs, the central incisors were reduced .5 mm in the gingival 1/3, .3 mm in the middle 1/3 (Fig. 6), and no preparation was performed in the incisal 1/3. Definitive margins were then placed, and the depth cuts were connected with a chamfer diamond bur. The incisal edges of the teeth were reduced approximately .5 mm and the lingual incisal aspect of the incisors was thinned with a coarse football diamond bur. This was done to minimize the added thickness of the porcelain veneers at the incisal margin. A 45 bevel was placed at the lingual margin of the preparations. (Fig. 7)

The cuspids were reduced to allow for a uniform thickness of porcelain, and the bicuspid teeth were reduced a uniform .5 mm.

As the teeth were prepared, the tetracycline banding became more evident. The anterior teeth were sub-opaqued2 using resin opaquers (Creative Color, Cosmedent). This was accomplished by using a coarse football diamond bur to “saucerize” the most discolored areas of the preparations. The opaquer was then bonded to the teeth using a phosphoric acid etch followed by a 4th generation bonding agent. The preparations were then refined, the margins polished with aluminum oxide disks, and impressions were made using a VPS material (Extrude, Kerr).

The teeth were provisionalized using a direct technique. At that point in time, the automix bis-acryl resin materials (Luxatemp, Integrity) were not yet available, and direct provisionals offered one of the easiest methods of provisional fabrication. Care was taken not to bond the resin provisional material to the recently placed sub-opaque layer. A thin layer of glycerin was placed over the opaque layer to prevent any difficulty when removing the provisionals.

LABORATORY FABRICATION

The veneers were fabricated using a platinum foil technique and conventional feldspathic porcelain (Colorlogic Porcelain, Ceramco). Today’s porcelain materials, particularly pressed porcelains, offer improved fit, marginal adaptation and biocompatibility.3 However, conventional porcelain veneers fabricated using either a platinum foil technique or a refractory technique continue to offer outstanding results, particularly in the hands of an accomplished ceramist.

One advantage of conventionally fabricated veneers lies in the fact that these restorations allow for more conservative preparations than pressed ceramics. For a pressed ceramic veneer with ideal aesthetics, approximately .7 mm thickness is required. Veneers fabricated with a platinum foil or refractory technique can virtually be as thin as is desired.4-6

There are distinct advantages and disadvantages to both the refractory and foil techniques. A restoration fabricated on a refractory model requires that the porcelain powders be stacked on a special die material that can withstand the heat of a porcelain furnace. Most of these refractory die materials exhibit a neutral shade, making it easier for the ceramist to determine the final shade of the restoration while it is being built. With the refractory technique, the porcelain is bonded to the die material until the final glazing, after which the veneers are divested and cleaned.

With the platinum foil technique, ultra-thin foils are adapted to the working dies, and the porcelain is layered onto the foil material. The platinum foils, along with the porcelain, can be removed from the dies and fired in the porcelain furnace (Fig. 8). The advantage of being able to remove the veneers during fabrication is that the precise thickness of the restorations can be determined during fabrication. The disadvantage of the platinum foil technique is that the underlying foils alter the apparent shade of the restorations.

Therefore, it takes an experienced ceramist to mentally compensate for the drop in value that the restorations will exhibit during fabrication.

SEATING

The restorations were tried-in with water-soluble try-in pastes (Fig. 9). After evaluating different shades, it was determined that the best option would be to use a neutral shade of composite luting resin.

After ascertaining a passive fit and marginal integrity of the restorations, the veneers were removed and cleaned with a 37 percent phosphoric acid gel. In preparation for bonding, the veneers were silane treated and a thin coat of filled adhesive resin (Optibond bottle 2, Kerr), was applied to the internal surfaces. The veneers were carefully filled with Insure Clear luting resin (Cosmedent) and placed in a light-safe box.

The teeth were isolated, retraction cord was placed, and the preparations were cleaned with a chlorhexidine liquid (Consepsis, Ultradent) (Fig.10). After rinsing and lightly air-drying, the two central incisors were etched with a 37 percent phosphoric acid for 20 seconds, then rinsed and lightly air-dried. The preparations were then re-wet with a damp cotton pellet and multiple coats of a 4th generation dentin primer were applied to the teeth. (NOTE: The current preferred method for dentin bonding involves leaving the preparations moist after rinsing the etchant gel from the teeth, and at no time thoroughly drying the exposed dentin).

After applying the dentin primer, the teeth were again lightly dried to evaporate the alcohol solvent, and a thin coat of lightly filled resin adhesive (Optibond bottle 2) was placed on the teeth. The veneers were seated with positive pressure and excess resin was removed to insure complete seating. Once seating was verified, the veneers were cured for approximately 10 seconds from the facial and 10 from the lingual with a conventional curing light. At this point, the remaining excess resin was removed with a #12 Bard-Parker scapel blade, prior to complete polymerization of the cement. (Again, the author does not currently use or recommend this procedure. Rather, the cement should either be removed prior to an initial set, or after complete polymerization). Following excess resin removal, a glycerin medium was placed at the margins and the restorations were light-cured for 60 seconds from the lingual and 60 seconds from the facial surfaces.

The remaining veneers were subsequently bonded in pairs in a similar manner. Further clean up and finishing was accomplished utilizing diamond and carbide finishing burs, aluminum oxide disks, and rubber wheels. The patient’s occlusion was checked and adjusted, and the patient was appointed for a 2-week post-op appointment.

POST-OP COMPLICATIONS

The patient returned to our office approximately one week post-op complaining of severe generalized pain. She said it felt like “all of her teeth were being pushed backward.” She also complained of pain in the TMJs bilaterally. Her occlusion was checked, and anterior premature contacts were noted in centric occlusion. The contacts were removed and the patient felt almost immediate relief. I assumed that we had somehow missed the premature contacts when the veneers were seated.

Several days later, the patient was back in our office, again complaining of the same discomfort. At this time, I consulted with a TMJ specialist, Dr. Charles Holt, who fortunately was familiar with the phenomenon I described.

The etiology for this specific set of symptoms arises from the fact that we altered the patient’s incisal edge position of the anterior teeth in a labio-lingual direction. By building out the incisal edges of the teeth, thereby changing the radius of the maxillary arch and decreasing the naso-labial angle, we had accomplished our aesthetic goal of eliminating the dull, small appearance of the teeth. At the same time, however, we had upset the neuromuscular balance of the patient’s oral musculature, specifically the obicularis oris muscle. As a result, entire maxillary arch was being orthodontically moved, in a lingual direction for the anterior teeth, and distally for the posterior teeth. The lingual forces exerted on the anterior teeth were creating premature centric contacts. This in turn was causing the mandible to be retracted distally, which was responsible for the TMJ pain she had been experiencing.

Treatment consisted of non-steroidal anti-inflammatory medication, frequent visits to check and adjust the occlusion, until a state of equilibrium was reached, and fabrication of a hard acrylic nightguard. The patient’s pain subsided completely within 3 weeks, and to date she has remained asymptomatic.

Following this experience, any time the treatment calls for building out the facial surfaces of the anterior teeth, the patient will be advised of the possible sequella, and will be appointed for several visits within the first week post-operatively to check and adjust the occlusion.

DISCUSSION

Dentistry can be a very tricky business. Even when 99 percent of the treatment goes as planned, the margin of error is still large enough to allow for unanticipated complications. Fortunately, in this case the symptoms were resolved relatively quickly and easily. As dentists, we should neither be too hard on ourselves when things don’t go as planned, nor congratulate ourselves too much when everything goes right.

RESULTS

The patient’s desire was for a “Hollywood Smile.” As shown in figures 11-15, there is a dramatic improvement in the appearance of the teeth as well as the overall facial appearance. Although the results would have been improved if the patient would have chosen to restore the second bicuspids as well, she is content with the improvement that 8 veneers achieved.

Unfortunately, the patient was initially unhappy with the results. She was assured that the veneers looked great and to give herself some time to get used to her new look. After approximately 3 weeks, she reported that she was very happy with the results. The initial uncertainty could have resulted from the dramatic change in appearance that the veneers created, or it may have arisen from the fact that the reddened and inflammed gingiva detracted from the overall appearance. Either way, she remains very happy with her smile, years later.

CONCLUSION

Modern dentistry is a dynamic science. The exponential increase in the area of bonding materials can seem overwhelming at times. It is encouraging to see that yesterday’s materials have withstood the test of time. Our current generation of bonding materials was built on the foundation of those products that came before. When s
ound scientific principles are applied in the development of new products, it is only logical that today’s materials, as well as the materials of tomorrow, should continue to yield improved results.

The case described here demonstrates a straightforward method for treating aesthetic discrepancies. The unforeseen complication with the patient’s occlusion was fortunately handled before it became a major issue. However, the pain could just have easily continued or worsened had we not discovered the source of the pathology when we did. When correcting a class II, division 2 case restoratively, it is prudent to be aware of and plan for this possibility.

The functional and aesthetic results of the case presented here could be described as a success. The patient is happy with the appearance of her smile, there has been no continuing maintenance required other than routine exams and prophylaxis, and at this time there is no evidence of chipping, microleakage, or gingival irritation. From the appearance of the porcelain restorations at this point in time, there is every indication that the patient will enjoy her smile for years to come.

r. Thomas Gleghorn is a 1991 graduate of the University of Texas at Houston Dental Branch. He is a member of the Editorial Board for Dentistry Today, and has published numerous articles on adhesive and cosmetic dentistry. In addition to maintaining a private practice in Colleyville, TX, he enjoys speaking to dentists on aesthetic restorative techniques. He can be reached at 817-514-8899, e-mail smiledr@aol.com.

Special thanks to Paul Westbrook for the Ceramics.

Oral Health welcomes this original article.

REFERENCES

1.Morley J, Smile design–specific considerations. CDA Journal 1997 Sep; 23(9): 633-37.

2.Nixon RL, Masking severely tetracycline-stained teeth with ceramic laminate veneers. Pract Perio Aesthet Dent 1996 Apr;8(3):227-35.

3.Gleghorn T, A guide to all-ceramic restoration materials. Dent Today 1999 Mar;18(3): 93-98.

4.Freedman G, Ultraconservative porcelain veneers. Esthet Dent Update 1991 Apr; 2(2):24-28.

5.Barghi N, Achieving maximum esthetic results with direct composite veneers. Contemp Esthet Rest Pract 1999 Jun; 3(6): 14-19.

6.Rouse J; McGowan S, Restoration of the anterior maxilla with ultraconservative veneers: clinical and laboratory considerations. Pract Perio Aesthet Dent 1999 Apr; 11(3): 333-39.