Techniques for Predictable Aesthetic Smile Designs

INTRODUCTION
Predictable aesthetics can mean many different things. One definition of predictable is that it is an accurate predetermination of an outcome. As dentists, we can become better at predicting outcomes by understanding risk management.¹ Predictable is not the same thing as perfect. Predictable aesthetics does not always translate to perfect outcomes, but rather an end point that lacks surprises. Outside of dentistry, predictable is not always a good thing. For example, when we go to the movies, predictable is bad. For our aesthetic dentistry to not play out like a suspenseful film (with twists, surprises, and scary moments), there are protocols that can be implemented by the clinician to make dental treatments as predictable as possible. In order to finish a case with the outcome being a happy and satisfied patient, expectations must be very well understood from the beginning. One expectation that a clinician may have is that every patient is going to cry tears of joy when they look at their new teeth for the first time in the mirror (Figure 1). While this is not always the case, we can do a better job of controlling the patients’ expectations during treatments. Careful review of pretreatment images from a patient’s photographic series enables the practitioner and the patient to visualize areas of the smile that could use improvement, giving the patient choices for options that minimize risk factors.

When doing aesthetic dentistry, consultations utilizing detailed photographs enable the clinician to emphasize areas of the mouth and smile that will improve significantly with certain courses of action. If patients chose not to undergo those actions to make overall aesthetic improvements, then, at a minimum, they can fully understand where any compromises may exist in the final aesthetics of their smile or in the outlook for the success of the restorations. After reviewing a series of photographs and mounted study models (Figure 2), the clinician should make time to meet with the patient to discuss the steps necessary to get the smile looking as ideal as possible. Taking time to determine the ideal placement of the gingival margins on all patients (high, medium, or low smile-line?) will minimize patient concerns over final results.² Addressing limiting issues before treatment begins is a better way to add predictability to patient approval at the end of treatment. The patient should be given the opportunity to refuse or pursue treatment to idealize the situation prior to beginning any restorative work. Remember that patient expectations change dramatically when the tooth we treat is in the aesthetic zone versus in the posterior. Often, a patient may be satisfied with an occlusal composite filling that does not match the tooth exactly in the posterior. However, they may be completely unsatisfied with a treatment done to an anterior tooth that may be within the standard of care but falls short from an aesthetic standpoint if it fails to follow the proper principles of smile design.

CASE REPORT
Diagnosis and Treatment Planning
A 52-year-old female patient presented with a chief complaint of wanting a nicer smile. This is something she had been thinking about for quite some time. The patient was in good overall health and had a history of regular dental visits. Her consultation revealed that she wanted brighter teeth and a more youthful smile. She stated that some cosmetic dentistry had been done more than 10 years ago to help make her upper central incisors look straight before her wedding. The dentist improved her smile using direct composite veneers.

Figure 1. Patients can have unrealistic expectations; doctors can too, thinking that the patient will cry tears of joy when they see their new smile for the first time.	Figure 2. Pre-aesthetic visualization should include well-taken digital photos, study models, and a checklist to review before discussing the case with the patient.

A photographic series was taken of the patient at the first appointment in the photo studio. Then, the images were reviewed with her in the consultation room on a large, wall-mounted, flat-screen television. Evaluating the smile with her, while referencing principles of smile design, enabled the clinician and the patient to review all areas of immediate and potential concern (Figure 3). While the aesthetic issues were addressed in the consultation room using the photo series, other risk factors were identified and evaluated using a clinical exam which consisted of radiographs, clinical charting, and a temporomandibular joint exam.

The first step in treatment planning is determining the aesthetic end point, then the clinical exam will help determine the modality for achieving the desired results. Just like understanding what constitutes health when evaluating a patient for occlusal dysfunction, the dentist must understand what constitutes ideal aesthetics in order to provide suggestions for creating a more ideal smile. Treatment planning should start with the goal of making sure the anterior teeth are located in the correct position of the face. This can be accomplished by using incisal edge positions of the maxillary central incisors or maxillary canines with lip at rest.³

Both pictures and videos of the patient are used to analyze principles of smile design to assist in finding the most relevant values (Figure 4).4 In evaluating this patient’s full-face-at-repose image, she was informed that the average amount of incisal display with lip at rest is 3.0 to 4.0 mm for a 30- to 40-year-old woman, but that this parameter is quite variable depending on age, lip length, and gender. It was decided that showing slightly more incisal edge was more ideal and in center of the bell curve.

In reviewing her retracted images, discrepancies in tooth proportions of her maxillary anterior teeth were noted (Figure 5). When the previously done aesthetic treatment had been completed to make the central incisors look straight, the width-to-height proportions (W/H) of the centrals had gotten too narrow. This is common when treating cases with crowding. A more ideal W/H proportion of the central incisor is 80%; and the lateral incisor should be about 60% of the width of the central incisor.⁵ A graphic drawing can relate the ideal proportions based on the width of the teeth from distal of canine to distal of canine. The technique used in digital smile design enables the clinician to determine proportions of anterior teeth when viewed from the front.6 The equation [y = 3.92x] can recreate a graphic drawing in any scenario to assist in finding proportions of central incisors, lateral incisors and canines, where y = (distance from distal of maxillary canine to distal of maxillary canine) and x = (new width of the central incisor) (Figure 6).

In this patient, the central incisors were about a 70% W/H ratio and the laterals were 90% of the width of the central incisors. This relationship creates a violation of a smile design principle that makes the patient appear to have 4 central incisors.⁷ Restoring or maintaining central dominance in the smile is paramount to aesthetic success.

Figure 5. When viewed from the front, the lateral incisors should be about 60% the width of the central incisors and the canines should be about 60% the width of the lateral incisors.	Figure 6. A graphic drawing can relate the ideal proportions based on the width of the teeth, from distal of one canine to the distal of the other canine.

Figure 7. The necessary space would need to be created by directional preparation of the teeth toward the patient’s left side. The gingival zeniths must also be relocated slightly to the patient’s left.

The patient was also informed about the midline, plane of occlusion, incisal plane, buccal corridor, and color of her teeth. She had asymmetric gingival display that was hidden under the lip at full smile. The gingival margins were discussed with the patient and, together, we determined areas that could be improved by soft- or hard-tissue contouring and grafting. A referral was given to her for a periodontist with whom to consult for soft-tissue grafting of tooth No. 6 to make it more symmetrical with the gingival margin height of tooth No. 11. We also discussed some minor tissue contouring of teeth Nos. 9 and 10. The option for orthodontic treatment was also presented as a way to prerestoratively idealize the positions of the teeth. The patient immediately denied tooth-straightening options and also elected not to have the periodontal surgery.

A laboratory wax-up was ordered to represent a prototype of the final restorations. A wax-up serves as a valuable tool to indicate the preparation type and margin placement needed to complete the case. Additionally, communication with the dental laboratory team was facilitated with well-taken photos and videos; these communication tools allow the clinician to play a significant role in designing the case.

Figure 9. In this case, the first set of provisionals lacked the wow factor. The proportions were more ideal and the color was brighter, but the smile could still be improved for the patient by making the teeth whiter, the shapes more accurate, and correcting the facial morphology and incisal canting.	Figure 10. Nanohybrid composite (Venus Pearl Bleach Shade [Heraeus Kulzer]) was used as to directly veneer the anterior teeth in a brighter color, changing the shapes and correcting the cant.

In order to correct the proportions of the anterior teeth, it was determined that this could not be treated as a conservative preparation smile design. Re­viewing the laboratory wax-up confirmed that the necessary space would need to be created by directional preparation of the teeth toward the patient’s left side (Figure 7). When complex preparation cases present themselves in our offices, the attention to details during the preparation appointment is even more important.

Clinical Protocol
A silicone impression matrix (Sil-Tech [Ivoclar Vivadent]) of the completed diagnostic wax-up was loaded with a bis-acryl provisional material (Venus Temp 2 [Heraeus Kulzer]) and then seated over the patient’s unprepared teeth; this was done after only removing enough enamel (enameloplasty) to properly seat the matrix over the teeth. The resulting bis-acryl overlay closely resembled the finished product of the provisionals and was prepared into using ideal depth cuts for the finished ceramics (Figure 8). When case preparation is more complex and requires direction preparation, the initial mockup may not provide the most ideal final provisional design; this is due to the need for more enameloplasty (or arch realignment) prior to placing the depth cuts. In such cases, the operator suggests doing a second mockup toward the end of the preparation stage of the appointment, prior to making a final impression. The second mockup can then be prepared into for ideal prep design similar to the first mockup. This provides a double check for the ideal reduction needed for cases that have any uncertainty prior to impressioning and provisionalization.

After the teeth were prepared, a final impression was taken using a vinyl polysiloxane impression material (Virtual [Ivoclar Vivadent]) and a preparation bite in silicone bite registration material (Futar D [Kettenbach LP]). Preparation shades were recorded for the laboratory using a preparation shade guide (IPS Natural Die Material Shade Guide [Ivoclar Vivadent]).

Once the records were completed, the provisionals were fabricated using a shrink-to-fit technique. The operator performs this technique as follows: the teeth were isolated (OptraGate [Ivoclar Vivadent]), then the preparations were cleaned with a 2% chlorhexidine gluconate disinfecting solution (Consepsis [Ultradent Products]). (In preparations where the operator breaks contacts, no “spot” etching is necessary to help retain the provisionals.) After the 2% chlorhexidine gluconate was rinsed and the teeth dried, a glutaraldehyde-containing desensitizer was scrubbed onto the teeth (GLUMA Desensitizer [Heraeus Kulzer]) for its desensitizing and bacterial static properties. Next, the desensitizer was suctioned off the tooth and blot dried, rather than blown onto the soft tissues. The preparations were then wet with a primer solution (OptiBond FL Primer [Kerr]). It is the author’s opinion that the primer helps to add some adhesion and adaptability of the bis-acryl to the preparations in the shrink-to-fit technique. The prepared teeth in the matrix were then filled with the correct color of bis-acryl material (Venus Temp 2, bleach shade) and seated over the teeth for 2 minutes. After 2 minutes, the matrix was removed and any bis-acryl flash cleaned away. Any voids were filled with a flowable composite resin (Venus Diamond Flow [Heraeus Kulzer]), light-cured, and the margins trimmed with a Safe End Needle Carbide (H134 ET6 014 [Brasseler USA]). The contact areas were then opened up with a mosquito diamond (8392.31.016, Fine Needle Mosquito Diamond [Brasseler USA]) and checked with floss threaders (Super Floss [Oral-B]) to confirm that the patient could carry out proper hygiene at home.

While the provisional design corrected the proportions of the anterior teeth in this case, there was a lack of wow factor. This was determined to have come from the patient’s desire for a brighter color, slight cant in the incisal plane, as well as some shape improvements that could be made to the existing provisionals (Figure 9). Rather than simply assuring our concerned patient that she would like the lab-fabricated ceramics and sending her home, she was brought back to the office for a contour session to directly add some composite and to contour the provisionals until a result that was more pleasing had been achieved. Nanohybrid composite (Venus Pearl [Heraeus Kulzer]) was added to the provisionals in a direct veneering method. This was performed without the need to etch or place adhesive to the bis-acryl material. We were able to create slightly more volume, brighten the color, and change the shapes (Figure 10). An impression was then taken of the approved provisionals for the laboratory team to follow closely as they created the restorations in all-ceramics.

The pressed lithium disilicate (IPS e.max [Ivoclar Vivadent]) restorations were created in a way to closely resemble the new provisionals, with only slight improvements detailed in the laboratory script. IPS e.max was chosen for its strength, aesthetics, and its optimized translucency. In the posterior, it is routinely chosen by the author due to its flexural strength (360 to 400 MPa) when fabricated as a full-contour monolithic restoration.⁸

At the cementation appointment, the provisionals were removed, the preparations cleaned, and the all-ceramic restorations were tried in to check the fit and contacts. Next, the aesthetics were evaluated using try-in pastes that resembled the final color of the restorations. Digital photos were taken in the studio before bonding in the restorations to allow the patient to see what the before and after would look like. It should be noted that the patient evaluation part of this process can take up to 45 minutes to ensure that there has been adequate time to see the restorations in the mouth and to address all of the patient’s concerns. The ceramics were bonded in with a light-cure resin cement (Variolink Esthetic LC [Ivoclar Vivadent]) utilizing the tack-and-wave technique. The excess cement was then removed, the occlusion adjusted, and the ceramics polished. In one week, the patient returned for a postoperative visit to address any remaining potential aesthetic concerns, check for any excess cement, finalize the occlusion, and to complete a post-op digital photo series in the studio (Figure 11).

CLOSING COMMENTS
While it is true that the clinician should not expect all patients to cry with happiness upon seeing their new smile in the mirror, we do have the ability to control patient expectations. This is done by first analyzing the principles of smile design with the patient and then thoroughly discussing any areas of limitation that may prevent us from achieving an ideal smile. Although surprises can sometimes be a good thing related to matters outside of dentistry, the patient and the entire dental team benefit from more predictable outcomes.

References

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2. Tjan AH, Miller GD, The JG. Some esthetic factors in a smile. J Prosthet Dent. 1984;51:24-28.
3. Misch CE. Guidelines for maxillary incisal edge position—a pilot study: the key is the canine. J Prosthodont. 2008;17:130-134.
4. Duchenne GB, Cuthbertson RA. The Mechanism of Human Facial Expression. New York, NY: Cambridge University Press; 1990.
5. Fradeani M. Esthetic Rehabilitation in Fixed Prosthodontics: Volume 1, Esthetic Analysis: A Systematic Approach to Prosthetic Treatment. London, England: Quintessence Publishing; 2004:21-56.
6. Coachman C, Calamita M. Digital smile design: a tool for treatment planning and communication in esthetic dentistry. Quintessence Dent Technol. 2012;35:103-111.
7. Olitsky J. Seven worst violations of smile design. Inside Dentistry. 2015;11:60-68.
8. Guess PC, Zavanelli R, Silva N, et al. Mouth motion fatigue and durability study [executive summary]. June 20, 2009. ivoclarvivadent.us/emaxchangeseverything/durability-study/summary.php. Accessed April 8, 2016.

Dr. Olitsky, a 2001 graduate of Temple University School of Dentistry, maintains a private practice in Ponte Vedra Beach, Fla. He is past president of the Florida Academy of Cosmetic Dentistry and an accredited member of the American Academy of Cosmetic Dentistry. An accredited Digital Smile Design Master, he is director of aesthetics for Clinical Mastery Series, teaching portrait and clinical photography and live-patient anterior aesthetics courses. He is a clinical adjunct faculty with the Arizona School of Dentistry and Oral Health as well as a clinical consultant with THE DENTAL ADVISOR. He can be reached via email at jason@smilestylist.com.

Disclosure: Dr. Olitsky reports no disclosures.