Written by Thomas J. Dwork, DMD Monday, 30 June 2003 19:00
Is innovative as the founders of aesthetic dentistry were, I don’t believe they could have envisioned the state of affairs today. The ceramist/dentist team has the capability to regrow and rehabilitate decimated dentitions, and restorations are so vital that the human eye cannot distinguish them from natural teeth.
As a prosthodontist, I am frequently asked to restore to function and aesthetics severely broken down dentitions. Prior to our current “next-generation” adhesive dentistry, the treatment protocol called for multiple disciplines to gain retention for our conventionally cemented restorations. The periodontist was called upon for crown lengthening, and the endodontist was called upon for intentional pulp extirpation to provide for post-core retention. Now, with modern adhesives, if there is sufficient tooth structure, we are free to choose a metal-free option that is truly elegant and less invasive to the patient. With the myriad of veneer and three-quarter crown designs, we can restore while conserving tooth structure.
As a prosthodontist, I see a great deal of dental re-treatment, so I am biased in that I believe that dentin adhesion is not a predictable process. I have replaced many recently placed veneers, and upon removal, the enamel bond is solid while the dentin bond is inconsistent. I don’t know whether this is due to occlusion, thermocycling, or poor technique, but it’s not consistent, so I prefer as much enamel to be preserved as possible for predictability.
|Figure 1. Preoperative smile, full face.|
The case presented is a patient referred by a general dentist whom I had taught at the Atlantic Coast Research Clinic and at the Rosenthal Institute. The patient was a healthy 40-year-old male who was concerned with the loss of his teeth. He was beginning to experience pain in his jaw muscles, and he had been told about the significant wear of his teeth over the years. His general dentist was shocked at how severe his wear was for his age (Figure 1).
The patient’s dental history consisted of minimal restorations and frequent recommendations for bite splints to address his grinding habit. He was aware of his habit, and he told us he was “grinding for comfort” and drank a lot of citrus drinks. He denied having bulimia or any acid reflux problems.
|Figure 2. Preoperative smile.||Figure 3. Occlusal view. Note severe breakdown with pink pulp visible.|
|Figure 4. Retracted view of centric occlusion. Note bite collapse.||Figure 5. Preoperative maxillary occlusal view with severe dentin exposure.|
|Figure 6. Preoperative mandibular occlusal view with severe dentin exposure.|
His grinding habit—rhythmic clenching of muscles and vertical grinding—was visible as he sat in the dental chair. Chemical erosion was clearly a component of his tooth destruction. The clinical exam revealed advanced wear on all teeth, but particularly on the cingula of the upper anterior teeth. Pulp horns were seen “pulsing” on a few of them. The gingiva was a victim of poor home care, but the bone support was healthy. Palpation of masticatory muscles revealed soreness everywhere, but pain was most evident in the masseters, particularly the left masseter. The joints were healthy. The pain in his jaw muscles provided the impetus to begin therapy (Figures 2 through 6).
ENLISTING THE PATIENT
I believed the success of this case would rely on our ability to slow or stop the parafunction during the day, and at night we could protect the patient with a nightguard. Furthermore, my job was to design an occlusion that was in harmony not only with his function, but also his parafunction. He needed to accept his responsibilities. He was advised and understood that he had destroyed “God’s work.” Therefore, he certainly could ruin anything we put in! He was keenly aware of his habits and was willing to try to stop them. Home care instruction was also emphasized to improve the health of his periodontium.
Clearly, the weakest link in his stomatognathic system was his teeth, exhibiting massive wear. Now the muscles were beginning to fatigue and cramp. Luckily, the periodontium was solid despite average-to-poor home care. The TMJs had withstood the abuse to this point, but they could be the next problem area. He was putting food on both sides of his mouth when chewing in order to vertically open his bite for comfort.
We would test out our new occlusion—opening the vertical and centric relation bite first—with a splint to be worn for 1 or 2 months, then try out the occlusion with the provisionals to see if he was comfortable there as well.
OCCLUSAL WORK-UP AND SPLINT
For occlusal and vertical study, centric relation records were taken with a Lucia Jig and Futar D bite material (Kettenbach). The casts were mounted on a Hanau articulator utilizing a spring facebow. Looking at the wear patterns and the evident bite collapse, we knew we needed to open his vertical. A mandibular acrylic splint was fabricated on a simple hinge articulator because it was mounted at the vertical dimension we had selected; arc of closure was not an issue. The heat-processed acrylic splint was adjusted with a Leaf gauge to centric relation, and the anterior guidance was adjusted until smooth. There was no fermitis on the maxillary anterior teeth. We relined the splint intraorally with Snap Clear (Parkell) for added retention. (If the splint had been too tight or rocked, Fit Checker (GC America) could be used to find the offending areas and assist in seating.) The patient was asked to wear the splint as much as possible day and night, eating with it if possible.
We fabricated the splint (1) to see how destructive his parafunction habits were (I have seen splints crushed); (2) to see if the centric relation position and anterior guidance helped slow the parafunction, or if not, to see if the forces could be controlled; and (3) to see if he could tolerate the open vertical (which we knew would not be a problem).
After wearing the lower splint with no difficulty and minimal wear, the patient reported that he stopped grinding but was still aware of some clenching. His muscles had relaxed, and overall he was more comfortable. We remounted the case and sent the casts to DaVinci laboratory for a wax-up for study and the provisional fabrication. The provisionals would be fabricated from a Siltech (Ivoclar Vivadent) putty matrix of the wax-up with Luxatemp (Zenith/DMG).
Our aesthetic evaluation began as taught by Spear, with central incisor incisal edge position. We evaluated his incisal edges with his lips at rest, and he had a reasonable 3-mm display of tooth below his lip. His central incisors were of average size (9 to 11 mm). We evaluated the E position of his smile line, which was also reasonable for him. The occlusal plane was within aesthetic limits, although we felt we could widen the narrow arch form to fill out the buccal corridors. We wanted to eliminate the canting and overlaps. He desired a “whiter smile.”
|Figure 7. Occlusal view of preparations. Contacts are broken.||Figure 8. Cast of maxillary preparations.|
|Figure 9. Cast of mandibular preparations.||Figure 10. Posterior onlay preparations.|
The upper arch was prepared for porcelain onlays on the posterior teeth and “taco” veneers or three-quarter crowns on the anterior teeth (Figure 7). On the anterior teeth, we tried to preserve as much enamel as possible. We chose stackable porcelain for lifelike aesthetics and minimal (0.5 mm) reduction on the facial aspect. The lingual surface of every maxillary anterior tooth had been worn beyond the cingulum and to the pulp due to parafunction and chemical erosion. We also wanted to eliminate overlaps and correct the cant, so the contacts were broken (Figures 8 through 10). The posterior teeth involved smoothing and creating a chamfer finish line for the Empress porcelain (Ivoclar Vivadent), with 0.8 mm reduction on the facial surface. Occlusal clearance was not as critical due to the degree of opening needed. Empress was chosen for its strength.
|Figure 11. Approval of provisionals; smile aesthetics verified.||Figure 12. Retracted view of provisionals; vertical, bite, and aesthetics verified.|
Impressions were taken with Impregum mixed by a Pentamix with a Permadyne wash syringe (3M ESPE). Cord was used sparingly because most areas were at the gingival crest. The provisionals were made from B-1 Luxatemp utilizing a Siltech putty matrix made from the original lab wax-ups (Figures 11 and 12). Both upper and lower provisionals were final-cured out of the mouth. They were cemented with Optibond FL (Kerr), cleaned up, and light-cured. These provisional restorations would allow us to test the occlusion.
The response of the patient and his family and friends was immediate. The excellent provisionals produced confidence in our treatment approach. The majority of our adjustment period was designed to provide the anterior space he needed for his parafunctional habit. (“Getting his front teeth out the way” was the patient’s description of this process.) Once the patient was comfortable with the provisionals and we observed that he did not wear or damage them, we proceeded to the maxillary final restorations.
The laboratory fabricated the final veneers and onlays utilizing the provisionals as the template. The patient wanted a lighter shade 030.
|Figure 13. Posterior Empress onlays (daVinci Studios).|
We delivered the final restorations utilizing the Rosenthal Institute’s protocols. The maxillary provisionals were sliced individually and twisted off gently. I utilized local anesthesia for patient comfort. After confirmation of fit on the master casts (Figure 13), the restorations were tried in the mouth with water to confirm fit. If a shade alteration is desired, a try-in paste may be used. The restorations were rinsed, porcelain-etched, silanated, painted with Optibond FL, and placed in a container shielded from light.
The preparations were cleaned with flour of pumice, Cavidry (The DFL Co) was applied, then they were microetched. Tissue “weeping” was controlled with copious rinsing with Superoxol. The teeth were treated with 37.5% phosphoric acid etch, Hurriseal (Beutlich Pharmaceuticals), Prime and Bond NT (DENTSPLY Caulk) with the wet bonding technique, and light-cured.
The cementing technique was a “rapid cementation” technique with multiple units done at one time. The cement (Variolink II; Ivoclar Vivadent) was loaded into the restoration, seated carefully, and the excess was cleaned off. Each unit was spot tacked, and the interproximal areas were cleaned with saws and Glide Floss (W.L. Gore and Associates) until immaculately clean and cement-free.
After final light-curing, the excess was cleaned off with composite scalers and scalpels. This is usually accomplished with minimal rotary instrumentation unless tissue hemorrhage requires an area to be prematurely cured before complete cleanup. Polishing cups finish the job.
The occlusion was adjusted against the lower provisionals on the lower unprepared arch. The palatal contour of the veneers was duplicated closely from our provisionals, and although it required some tweaking over time, no gross adjustment was necessary. The shallow guidance was in harmony with the patient’s functional and parafunctional envelope.
|Figure 14. Postoperative occlusal view of maxillary arch.||Figure 15. Postoperative occlusal view of mandibular arch.|
|Figure 16. Retracted side view. Note vertical change.||Figure 17. Postoperative retracted view.|
|Figure 18. Postoperative mandibular veneers.|
The patient was overwhelmed with the result. Everyone was pleased. The translucency, internal coloration, and lifelike aesthetics—despite the very light 030 shade chosen—were remarkable. The protocol on the lower arch was identical, except we prepared the lower arch in segments to maintain our vertical and centric position, with the provisional restorations segmented (Figures 14 through 18).
In this case, the occlusion was established using provisional restorations over several months, and the provisionals served as a template for the final restorations. The shallow anterior guidance resulting from opening the vertical dimension helped protect the patient’s dentition against his parafunction, and the centric relation position stabilized his TM joints, which made his muscles comfortable. The anterior teeth were hollow ground to give him room for his parafunction as part of the final adjustments, for a long centric. Ultimately, a nightguard will protect him against his nocturnal parafunction.
|Figure 19. Postoperative smile.||Figure 20. Postoperative full face…delighted!|
The overall transformation for the patient was astounding. His mouth was rejuvenated with modern metal-free restorations that “seemingly grow from the gums” (his words). After 6 months, he said he smiles more and shows his teeth to everyone. He has become a passionate emissary for modern dental technology (Figures 19 and 20).
The author would like to thank daVinci Studios for its exceptional work.
Dr. Dwork is a prosthodontist with an aesthetically oriented reconstructive practice in Jupiter, Fla. He is a co-chairman of the aesthetic dentistry section at the Atlantic Coast Research Clinic. Most recently, Dr. Dwork became a clinical instructor for Dr. Larry Rosenthal’s Aesthetic Advantage hands-on course taught in Palm Beach, Fla. Dr. Dwork has lectured nationally on aesthetic dentistry and has particular expertise in occlusion.
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