Creating a beautiful smile can be arduous task for even the most experienced restorative dentist. With all of the wonderful materials and techniques that are available to the aesthetic dentist today … “beauty is still in the eye of the beholder!” For the patient looking for miniscule changes to improve tooth size discrepancies that are measured in tenths of millimeters, the “aesthetic makeover” can be much more difficult and demanding than “fixing a train wreck” of a smile. If one desires larger teeth, “addition dentistry”, by making small teeth bigger and filling spaces or diastemata is relatively easy to perform. The reverse is much more difficult … the patient with larger teeth and a fixed arch length, wanting to make their teeth appear to be smaller. This article is a case report describing one such patient and the creative use of smile design principles by the dentist and laboratory technician, to achieve the impossible … make big teeth appear smaller … the art of illusion!
Collecting Information To Develop The Treatment Plan
No one knows better than the patient, when it comes to visualization of the result they are looking for. The clinician can’t always find the answer in a textbook, learn about it in a lecture, or do the case the same way a previous case was treated. Another problem is that “patients don’t always know what they want, until they see what they don’t want in their face!” The preoperative interview is a very important first step before deciding upon a course of treatment. Let the patient tell you what they are looking for. Be a good listener and take notes. A good technique is to video record the patient interview so their exact words and desired outcome can be shared with the laboratory technician doing the case. This is the best prescription they could ask for! It is easy to lose in translation the true meaning of the patient’s descriptions or paraphrase and change the intended meaning when communicating to the lab with the written hand.
The Art of Illusion: Step 1 — Clinical Examination and The Master Diagnostic Model
Based on a comprehensive clinical and radiographic examination, including digital photography, and the patient interview, a preliminary treatment plan is formulated to meet the clinical and aesthetic requirements of the case. The patient has had porcelain veneer restorations placed approximately six years previous to her preoperative diagnostic visit. When the patient is asked, “What they would change about their smile”, the response is statements such as, ” I feel my teeth look too big, like dentures,” “They stick out too far,” “They are not feminine or youthful” … in other words, the patient wants smaller teeth and less overjet. The question is, can this be achieved by simply replacing the existing restorations?
A discussion with the laboratory technician is critical to conveying the patient’s aesthetic desires accurately. After this discussion and review of preoperative diagnostic data, a master diagnostic model (wax-up) is created following the patient’s input to see if the desired corrections can actually be achieved. There is no way to decrease the mesio-distal dimensions of the existing teeth as they appear in the arch form without either tooth preparation (Interproximal Tooth Reduction or IPR) or by opening spaces. The preoperative cervico-incisal height of the maxillary central incisors exceeds 12 mm (a more ideal size would be around 10 mm with a 75 to 80 percent width to length ratio). So, the length can be decreased through preparation. But, this will make the teeth more square, not slender. It will be the position of the proximal-facial lines angles (reflective angles) of the maxillary anterior teeth that will enable the technician to create the “illusion” that the teeth are narrower in the mesio-distal dimension than they actually are. So, these parameters will be incorporated into the master diagnostic model, which in turn, will be used as a template for the provisional restoration that can more properly evaluated by the patient when it is “placed behind her lips.”
The Art of Illusion: Step 2 — Preoperative Soft Tissue Correction
Figures 1 and 2 are a full smile and intraoral full arch view of a patient’s preoperative condition. The retracted full smile view reveals disparate gingival heights over tooth numbers 8 and 9 (11 and 21), the proximal-facial line angles, particularly of the maxillary central incisors are indistinct and rounded contributing to a more “square” silhouette of the facial outline form. The maxillary anterior teeth appear much larger in the cervico-incisal dimension with a dramatic decrease in height starting in the first premolar area (Fig. 3). Aesthetic harmony cannot always be achieved without addressing both hard and soft tissues and unfortunately some clinicians “only see the white and not the pink.” The fact that the posterior teeth are so short helps to contribute to the problem of the anterior teeth appearing to look too big. Prior to preparation, a soft tissue correction is made with a diode laser (Picasso Diode Laser: AMD Laser), the bulbous emergence profile of the existing veneer becomes painfully evident. Since there is no second premolar, due to extraction and orthodontics done when the patient was younger, symmetry of the positions of the gingival margins is very important to the overall aesthetics of the case. An imaginary line is drawn from the cervical height of contour of the maxillary cuspid to the gingival margin above the mesio-buccal root of the maxillary first molar. The gingival margin of the maxillary premolar needs to be on this line. If biologic width is violated, bony crown lengthening will need to be performed (Fig. 4). In this case a “closed flap” crown lengthening was performed with an ErCr: YSGG all tissue laser (I-Lase Plus: Biolase Technologies) to reestablish the proper 3 mm distance from the free gingival margin to the crest of bone. When healed, the new restoration will appear longer in the cervico-incisal dimension and gingival harmony will be achieved.
FIGURE 1. A preoperative smile view of a 26 year old patient whose chief complaint is that her “teeth look too big and look like dentures.”
FIGURE 2. A preoperative retracted full smile view. The restorations appear to be very “square” and “bulky”. The incisal embrasures are very small helping to make the teeth look very uniform and square.
FIGURE 3. This oblique view of the preoperative smile shows the extreme size difference between the large maxillary anterior teeth and the smaller, diminutive posterior teeth … the “posterior gummy smile!”
FIGURE 4. After apical repositioning of the gingival margin over tooth number 4 (14) with a diode laser (Picasso: AMD Laser), the overcontouring of the porcelain to accommodate the preoperative gingival position is evident. The excessive emergence profile on the disto-proximal aspect of the veneer restoration has caused a chronic marginal periodontitis in the area so that bleeding is always present regardless of the level of home care.
Preparation and Provisionalization of the Maxillary Arch: Planned Reduction To Compensate For Larger Tooth Size
In today’s world of “minimally invasive” and “no prep” scenarios, as Dr. Harold M. Shavell once said, “Many teeth (and restorations!) have been sacrificed on the alter of false conservatism.” Too often we see over contoured dental restorations that are the result of trying to “conserve” a few additional micrometers of tooth structure. The result … compromised aesthetics and strength and many times remake of the case and another assault on the tooth. How “conservative” is it to continually have to remake a case? Figure 5 shows the previous restorations removed on the patient’s right side and the facial portion of the restorations removed on the patient’s left side so that the outline of the previous restorations can be seen as well as the labial surface of the preparation. One can also see the difference in overbite and maxillary incisal edge position as it relates to mandibular facial surface display in the centric occlusion position. Based on the feedback of the patient, it can be easily seen that the prep size on the patient’s right side is more what she is looking for as the final shape and proportion after restoration. So from that point, room must be made for the restorative material. Looking at Figure 6, it is easy to see that the patients’ skeletal class is Class II, Division II. So, the most facially positioned tooth, the maxillary lateral incisor, will determine the final facial positions of the central incisors and canines. This is another problem missed in the original diagnosis. The lateral incisor needs to be more aggressively prepared so that the central incisors and canines won’t have to be over contoured in the facial direction to create a ideal facial arch form. Starting on the right side, the incisal edges will be further reduced to create space for 1.5 mm of porcelain at the incisal edge and yet maintain a final cervico-incisal height of 10 mm. Figure 7 shows the depth cuts placed at the incisal edge of tooth number 8.11 Figure 8 is a full-retracted view after the preparations have been adjusted. Figure 9 shows the reduction of the preparations from the facial proximal line angles in the lingual direction toward the proximal contact areas to open up the facial embrasures between the teeth. This preparation step is critical so that the ceramist will have enough space to have the proper thickness of porcelain when creating the reflective angles in the restorations that are accentuated enough to give the illusion of a narrower facial profile while deepening the facial embrasure between the teeth to move the interproximal contacts toward the palatal direction. A master diagnostic wax-up integrates all of the aesthetic changes to bring the reflective angles more toward the center of the maxillary incisors and create an illusion of smaller teeth. A stone model duplicate of the wax-up is created so that a clear thermoplastic stent can be made to use in the fabrication of the provisional restoration (Fig. 10). After tooth preparation is completed, the maxillary teeth are provisionalized (Fig. 11) with a rubberized urethane provisional restorative material (Tuff Temp Plus: Pulpdent Corporation). The patient will now wear a “trial smile” for a period of time and provide feedback as to the aesthetics of the case and any potential changes she would like to make. The goal of the next treatment appointment will be to gather feedback from the patient regarding the maxillary provisional restoration, discuss possible changes, master impress the maxillary arch, and prepare and impress the mandibular arch.
FIGURE 5. On the patients’ right side the restorations have been removed revealing the prepared teeth. On the patients’ left side, only the facial ceramic has been removed so a comparison can be made between the incisal edge positions of the prepped and restored teeth. The cervico-incisal length of the maxillary left central incisor is about 13 millimeters.
FIGURE 6. This oblique view shows the original facial position of the maxillary left central incisor. This position would dictate the final positions of the adjacent teeth, which would need to be thicker in the facial direction to make up for their lingualized preoperative location.
FIGURE 7. One millimeter depth cuts are placed in the incisal edge of the maxillary right central incisor to make space for porcelain in the new restorations maintaining a ten millimeter overall cervico-incisal length.
FIGURE 8. A full arch retracted view of the completed maxillary preparations. Note the maxillary premolars have been reduced sufficiently to accommodate a slight addition to the buccal cusps of the opposing mandibular teeth to help correct the dual plane of occlusion on the lower arch.
FIGURE 9. A close up view of the maxillary anterior preparations on the master model. Note how the facial proximal line angles of the prepared teeth are located closer toward the center of the facial surface, opening up the angle of the facial embrasures between the teeth to give the ceramist sufficient space to move the reflective angles of the porcelain restorations in the same fashion to make the facial surfaces of the teeth appear more narrow in the mesio-distal direction.
FIGURE 10. The maxillary diagnostic wax up and stone model duplicate is shown. These will serve as a template for the provisional restoration…the patients’ “trial smile.”
FIGURE 11. The maxillary provisional restoration is shown in this retracted intraoral full arch view.
The Mandibular Arch: Is A “No Prep” Approach Possible?
Figure 12 shows the preoperative model of the patients’ mandibular arch and the master diagnostic wax-up. The Class II skeletal patient will typically exhibit a dual plane of occlusion. Because of the antero-posterior position of the maxillary and mandibular arches and excessive overjet, combined with a deep bite, the lower incisors are often “super-erupted” above the posterior occlusal plane. Another consideration, because of the greater than 2 mm of overjet, is that additive dentistry to the facial surfaces of the mandibular anterior teeth may be possible if the incisal edges are slightly shortened. Since the occlusal-vertical dimension will not be altered in this case, the plan will be to slightly shorten the mandibular incisal edges and blend the incisal and occlusal planes so that there is not such an abrupt difference posterior to the canine positions. The palatal cusps of the maxillary first premolars are shortened (Fig. 13) creating space to accommodate the slight occlusal position of the buccal cusps of the mandibular first premolars, making the dual plane of occlusion less noticeable.
FIGURE 12. A view of the preoperative mandibular arch from the facial aspect and the corrections made on the mandibular master diagnostic model.
FIGURE 13. This view of the maxillary master model shows the compensation in the preparation of the palatal cusp of the maxillary premolar to accommodate the addition to the opposing facial cusp of the mandibular first premolar.
In order to minimize preparation to the mandibular teeth, a provisional “trial smile” using a stent constructed from the master diagnostic wax-up is constructed on the teeth (Fig. 14). By performing “ideal preparations” into the rubberized urethane material, only the part of the actual tooth that is “in the way” of the restorative material will be removed by the bur. Figure 15 shows using a .5 mm depth-cutting bur on the facial surfaces of the mandibular anterior teeth. Because of the patients’ desire to decrease the overjet between the maxillary and mandibular teeth, the depth cuts do not even reach tooth structure! Figures 16 and 17 show tissue retraction prior to making the master impressions. With the exception of the slight reduction (< 1 mm) of the anterior incisal edges, the preparation of the mandibular teeth to accommodate the final planned positions of the ceramic material is minimal to none. Therefore, these teeth will not even require provisionalization prior to restoration delivery. Figure 18 shows the master impression of the maxillary anterior segment. Note that the impression captures not only the restorative margin, but also .5 mm of tooth or root surface apical to the margin for exact duplication of the emergence profile in the restorative material. A close up of the master maxillary model is shown in Figure 19 that illustrates precise margins and emergence profiles on the master model, making it easy for the ceramist to duplicate natural emergence angles in the ceramic restorations. The porcelain veneers are constructed in a high value, translucent ceramic material according to the patients’ desire to have a “bright smile” (Figs. 20 and 21). They are tried in and approved by the patient prior to cementation. Figures 22 and 23 show preoperative and postoperative full arch views for comparison of final tooth size, gingival correction of tissue levels in the maxillary arch, and occlusal plane correction in the mandibular arch. Figure 24 and 25 show one year postoperative retracted and smile views of the completed case.
FIGURE 14. A retracted facial view of the “provisional preparation guide” in rubberized urethane (Tuff Temp Plus: Pulpdent Corporation) over the unprepared mandibular teeth.
FIGURE 15. A .5-millimeter depth-cutting bur is used to create “ideal preparations” into the provisional plastic. Only the part of the tooth the is “in the way” of the placement of the final ceramic will be prepared making this technique extremely micro invasive.
FIGURE 16. The mandibular final preparations are seen in this full arch facial view after retraction cords are placed to take the master impression. So little actual tooth structure is removed so that the patient will not require provisionalization of the mandibular teeth.
FIGURE 17. A retracted view of the
maxillary preparations after retraction cord placement. The final margin placement will be slightly intracrevicular to avoid root surface being visible, since the patient can show gingival tissue with an exaggerated smile.
FIGURE 18. A view of the master impression of the maxillary preparations shows accurate margins and a “cuff” of impression material apical to the margins capturing the emergence profile information of the teeth.
FIGURE 19. A facial view of the master model of the maxillary teeth.
FIGURE 20. The completed ceramic restorations on the maxillary master model are shown.
FIGURE 21. The completed ceramic restorations on the mandibular master model are shown.
FIGURE 22. A preoperative retracted full arch view of the patient’s teeth slightly separated to show the incisal edges of the maxillary and mandibular teeth. Note the super eruption of the mandibular anterior segment and dual plane of occlusion on the lower arch.
FIGURE 23. Compare this postoperative retracted full arch view to the one shown in Figure 22. The mandibular occlusal-incisal plane is more continuous with correction of the dual plane of occlusion and Curve of Spee. The maxillary restorations give the illusion that the teeth themselves are smaller with a more natural progression of incisal embrasures and gradual apical movement of the contact areas moving from the midline toward the posterior segment giving more youthful appearance for this young patient.
FIGURE 24. A full smile view of the patients’ new smile. Notice the more youthful appearance and proportionality of the new ceramic restorations. Buccal corridor cervico-incisal tooth proportions are also significantly improved.
A case has been presented that demonstrates some of the details of smile design that can easily be overlooked when performing aesthetic reconstructions. The relationships of the hard and soft tissue represent an aesthetic parameter that is often ignored and correction of these minor asymmetries can make a profound difference in the final outcome. Too many clinicians are so concerned with the amount of tooth structure that is removed that often the final aesthetic and functional result can be compromised leading to remake. While conservation of tooth structure is extremely important, the overall outcome must be taken into consideration along with the patients’ expected outcome when making treatment decisions regarding tooth preparation and design of the completed restoration. It is important to stress the value of the information that is gained for both the clinician and the ceramist from a well-designed provisional restoration that can be evaluated in the patients’ face. Once approval of the provisional restoration is received, digital photos, a video interview, and models of the final provisional restoration will be invaluable to the ceramist when completing the definitive restorations for the case.OH
Acknowledgement: The author would like to acknowledge the ceramic artistry of Jenny Wohlberg from Valley Dental Arts in Stillwater, MN for her exceptional work on this case.
Dr. Robert A. Lowe maintains a private practice in Charlotte, North Carolina. He can be reached at 704-450-3321 or at email@example.com.
Oral Health welcomes this original article.