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Creating a beautiful smile can be an arduous task for even the most experienced team. Regardless of all the myriad materials and techniques that are available today, beauty is still in the eye of the beholder. For the patient who desires miniscule changes to improve tooth-size discrepancies that are measured in tenths of millimeters, the restorative team may find that the “esthetic makeover” can be much more difficult and demanding than a full-mouth reconstruction. The patient seeking larger teeth by making small teeth bigger and filling diastemata is relatively easy to restore in comparison with the patient who has larger teeth and a fixed-arch length and wants to make the teeth appear smaller. This article presents a case report describing a patient with the latter condition and the creative use of smile design principles applied by the dentist and laboratory technician to achieve the difficult task of making big teeth appear smaller.
Developing the Treatment Plan
No one knows better than the patient, regarding visualization of the end result. The clinician cannot always find the answer in a textbook, learn about it in a lecture, or perform the case the same way a previous case was treated. Another problem is that patients do not always know what they want, until they see what they do not want. The preoperative interview is a vital first step before deciding on a treatment approach. Encourage the dentist to let the patient describe what he or she is looking to achieve. A good technique is for the dentist or dental assistant to video-record the patient interview so the exact words and desired outcome can be shared with the laboratory technician fabricating the case. Otherwise, when the dental office relies on using written instructions to communicate with the laboratory, the team may lose the true meaning of the patient’s descriptions.
Case Report: Clinical Findings and Master Diagnostic Model
Based on the findings from a comprehensive clinical and radiographic examination, including digital photography, and the patient interview, a preliminary treatment plan was formulated to meet the clinical and esthetic requirements of the case. The patient had porcelain veneer restorations placed approximately 6 years before her preoperative diagnostic visit. When the clinician asked the patient, “What would you change about your smile,” she gave statements such as: “I feel my teeth look too big, like dentures,” “They stick out too far,” and “They are not feminine or youthful.” This meant the patient wanted smaller teeth and less overjet. Can this be achieved by simply replacing the existing restorations?
A discussion between the clinician and laboratory technician was critical for conveying the patient’s esthetic desires accurately. After conferring with the dental technician and reviewing the preoperative diagnostic data, a master diagnostic model (wax-up) was created, based on the patient’s input, to analyze if the desired corrections could be achieved. Decreasing the mesio-distal dimensions of the existing teeth as they appeared in the arch form was not possible without either tooth preparation (interproximal tooth reduction [IPR]) or by opening spaces.
The preoperative cervico-incisal height of the maxillary central incisors exceeded 12 mm (a more ideal size would have been approximately 10 mm with a 75% to 80% width-to-length ratio). Therefore, the length would have to be decreased through tooth preparation. However, such preparation would make the teeth look more square, not slender.
Creating the appearance of more slender teeth would need to be achieved by the technician using the position of the proximal-facial line angles (reflective angles) of the maxillary anterior teeth to create the “illusion” that the teeth were narrower in the mesio-distal dimension than they actually were. So, these parameters were incorporated into the master diagnostic model, which in turn was used as a template for provisional restorations that, when placed, the patient can more properly evaluate.
Preoperative Soft Tissue Correction
Figure 1 and Figure 2 show full-smile and intraoral full-arch views of the patient’s preoperative condition. The retracted full-smile image revealed disparate gingival heights over teeth Nos. 8 and 9. The proximal-facial line angles, particularly of the maxillary central incisors, were indistinct and rounded, contributing to a more “square” silhouette of the facial outline form. The maxillary anterior teeth appeared much larger in the cervico-incisal dimension with a dramatic decrease in height starting in the first premolar area (Figure 3). Esthetic 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 decreased height of the posterior teeth helped to contribute to the problem of the anterior teeth appearing too large. Prior to tooth preparation, a soft tissue correction was made with a diode laser (Picasso Diode Laser, AMD Lasers, amdlasers.com), which made the bulbous emergence profile of the existing veneer painfully evident. Because the patient had no second premolar due to extraction and orthodontics performed when the patient was younger, symmetry of the positions of the gingival margins was very important to the overall esthetics of the case. An imaginary line was 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 needed to be on this line. If biologic width was violated, bony crown lengthening would be required (Figure 4). In this case, a closed-flap crown lengthening was performed with an ErCr: YSGG all-tissue laser (iLase® Plus, Biolase Technologies, biolase.com) to reestablish the proper 3-mm distance from the free gingival margin to the crest of bone. When healed, the new restoration would appear longer in the cervico-incisal dimension and gingival harmony would be achieved.
Preparation and Provisionalization of the Maxillary Arch
In today’s world of minimally invasive and no-preparation scenarios, too often dentists see over-contoured dental restorations that are the result of their colleagues trying to conserve a few additional micrometers of tooth structure. The outcome may involve compromised esthetics and strength, and many times a remake of the case is needed and another assault on the tooth takes place. Figure 5 shows the previous restorations that were removed on the patient’s right side and the facial portion of the restorations removed on the patient’s left side. The outline of the previous restorations may be seen as well as the labial surface of the preparation. One may also see the difference in overbite and maxillary incisal edge position as it relates to mandibular facial surface display in the centric occlusal position. Based on the patient’s feedback, the clinician could see that the preparation size on the patient’s right side was more of what she was seeking as the final shape and proportion after restoration. To achieve this, room had to be made for the restorative material.
Figure 6 shows that the patient’s skeletal class was Class II, Division II. The most facially positioned tooth, the maxillary lateral incisor, would determine the final facial positions of the central incisors and canines. This was another problem missed in the original diagnosis. The lateral incisor needed to be more aggressively prepared so that the central incisors and canines would not have to be overcontoured in the facial direction to create an ideal facial arch form. Starting on the right side, the incisal edges would have to 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 No. 8. Figure 8 is a full-retracted view after the preparations have been adjusted. Figure 9 demonstrates 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 was critical for giving the ceramist enough space to create the reflective angles in the restorations. The reflective angles would provide 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 integrated all the esthetic 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 was created so that a clear thermoplastic stent could be made to use in the fabrication of the provisional restoration (Figure 10). After tooth preparation was completed, the maxillary teeth were provisionalized (Figure 11) with a rubberized urethane provisional restorative material (Tuff-TempTM Plus, Pulpdent Corporation, pulpdent.com). The patient was instructed to wear the “trial smile” for a period and provide feedback regarding the esthetics of the case and any changes she would like to make. The goal for the next treatment appointment was to gather the patient’s feedback regarding the maxillary provisional restoration, discuss possible changes, master impress the maxillary arch, and prepare and impress the mandibular arch.
The Mandibular Arch
Figure 12 shows the preoperative model of the patient’s mandibular arch and the master diagnostic wax-up. A patient with Class II skeletal will typically exhibit a dual plane of occlusion. Because of the anteroposterior position of the maxillary and mandibular arches and excessive overjet combined with a deep bite, the lower incisors are often “supererupted” above the posterior occlusal plane. With the overjet measurement being greater than 2 mm, another consideration was that additive dentistry to the facial surfaces of the mandibular anterior teeth may have been possible if the incisal edges were slightly shortened. The occlusal vertical dimension would not be altered in this case, so the plan was to slightly shorten the mandibular incisal edges and blend the incisal and occlusal planes to prevent such an abrupt difference from the posterior to the canine positions. The palatal cusps of the maxillary first premolars were shortened (Figure 13). This created space for accommodating the slight occlusal position of the buccal cusps of the mandibular first premolars, which made the dual plane of occlusion less noticeable.
In order to minimize preparation for the mandibular teeth, a provisional trial smile using a stent created from the master diagnostic wax-up was constructed (Figure 14). By forming ideal preparations into the rubberized urethane material, only the part of the actual tooth that is “in the way” of the restorative material was to be removed by the bur. Figure 15 shows using a 0.5-mm-depth cutting bur on the facial surfaces of the mandibular anterior teeth. Because of the patient’s desire to decrease the overjet between the maxillary and mandibular teeth, the depth cuts did not reach tooth structure. Figure 16 and Figure 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 was minimal to none. Therefore, these teeth would not 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 0.5 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 were constructed in a high-value, translucent ceramic material according to the patient’s desire to have a “bright smile” (Figure 20 and Figure 21). Prior to cementation, they were tried in and approved by the patient. Figure 22 and Figure 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 Figure 25 show 1-year postoperative retracted and smile views of the completed case.
A case has been presented that demonstrates some details of smile design that can easily be overlooked when performing esthetic reconstructions. Such aspects are the relationships of the hard and soft tissue in representing an esthetic parameter. 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 esthetic and functional result can be compromised, leading to a remake. Although conservation of tooth structure is extremely important, the overall outcome must be taken into consideration along with the patient’s expectations when making treatment decisions regarding tooth preparation and design of the completed restoration. Both the clinician and ceramist can gain valuable information from a well-designed provisional restoration that can be evaluated in the mouth. Once the patient approves the provisional restoration, the ceramist can use the essential tools of digital photos, a video interview, and models of the final provisional restoration when completing the definitive restorations for the case.
About the author
Robert A. Lowe, DDS