Chapter 5 Smile Design
Section A Smile Design
It is extremely difficult for a dentist to achieve a pleasing esthetic result without having a clear picture of what the patient desires and what his or her expectations and esthetic goals are. For a dentist to enter into any esthetic procedure blindly not only can be frustrating and time-consuming but often leads to patient dissatisfaction with the course of treatment and its outcome. If during or after treatment patients choose to “switch dentists” and “close their chart,” the dentist usually feels insulted and unappreciated, especially after all the hours of work that he or she put into the case. Sometimes the patient is so dissatisfied that he or she elects to redo the case with another practitioner. This is unpleasant for both the patient and the dentist as well as costly, painful, and inconvenient. One hopes that the patient will not pursue litigation, which would result in more aggravation for everyone.
On a daily basis dentists around the world try to achieve esthetic makeovers in a random manner with little or no preplanning or idea of what the final outcome will be. They simply take an impression of the patient’s prepared teeth and send it to the dental lab technician with little instruction and few requirements for the restoration. They on the most part leave the fabrication of the restoration up to the ceramist, assuming that the ceramist will “magically” create a beautiful restoration. The lab technician with no exacting parameters to follow designs the restoration to the best of his or her ability and delivers it to the dentist. The dentist then tries the restoration in the patient’s mouth and has the patient look in the mirror. If the patient responds, “I don’t like it,” the dentist then asks the patient, “What don’t you like?” The patient might answer, “I don’t know; maybe they’re too long.” The dentist then sends it back to the lab with instructions to make the restoration shorter. Sometimes there are not even specific details given on how much altering is desired. Often several appointments follow, with the restoration going back and forth to the lab. Eventually the patient gives in after becoming so tired of the process that he or she just accepts the outcome. But is the patient actually totally satisfied with the end result and how the smile and face appear? Does the patient regret undertaking treatment, or does he or she really wish to have the restoration removed and redone differently? If the dentist had provided the lab technician with an exact blueprint of what was desired, the ceramist would have had a guide to provide the patient with what he or she wanted, and the outcome would have been satisfactory.
The road map to all the clinical procedures to be done and the basis for treatment planning is the smile design. It is derived from a combination of what dentists know, the rules of esthetics, and listening to the patient’s desires. These come together in a plan to achieve all the goals set. The limitations of the materials available, the positions of the teeth, and the finances of the patient are among the considerations in this process. The treatment plan agreed on by the dentist and patient is what is best suited to the situation at hand with what is available.
Smile design and the whole concept of being able to plan a smile makeover have had an impact on patients’ perspective of dentistry. One must think of reconstructive dentistry as plastic surgery of the mouth with the aim of improving what currently exists. Modern smile design techniques and materials give dentists tools that do not exist in any other forms of plastic surgery. There is no other esthetic transformation procedure available in which patients can actually see and live with the changes they are obtaining before they commit to a permanent solution. For example, if someone wishes to have a procedure done to alter the shape of the nose or face, he or she must wait several weeks until the bandages and dressings are removed and even longer for the swelling to totally subside. In actuality it could take months before that person knows what he or she will finally look like. With dental temporization techniques, the key to modern smile design, the dentist can make changes to the patient’s provisional restoration so that the patient can visualize and live with potential smile possibilities. The patient is then able to look at it, go home with it, and show it to his or her spouse and friends if desires. Once the patient approves the provisional restorations, the dentist simply takes photos and accurate impressions of them to serve as a template for the lab technician to duplicate in ceramic. By using provisional materials made of bis-acryl, dentists have the ability to add and subtract composite resin, allowing them to create exactly the shape, form, and appearance that will satisfy the patient.
Looking back in time, little or no attention was placed on smile esthetics. Dental concerns placed very little importance on looking good, as if esthetics were for the vain and not within the realm of science and medicine. The past two decades have witnessed an esthetic revolution. Because of advances in materials, techniques, and the ever-growing demand of people to look and feel better about themselves, dentists have learned to “change a smile,” which can sometimes “change a life.” Incredibly, what is regarded today as “esthetic” or “cosmetic dentistry” is still not recognized and is frowned on by some dentists. They believe that it is unnecessary and that dentists who promote and offer these services are interested only in “making a quick buck.” Admittedly there is significant charlatanism in dentistry, but isn’t this true of many services and professions? The majority of our patients no longer accept “ugly” teeth—nor do they drive horse and buggies, live without computers, and desire amalgam restorations. A coordinated treatment plan yielding a healthy, balanced, easily maintainable restorative esthetic result is a beautiful thing.
When I attended dental schools in the 1970s, each student was given a mold guide of available denture teeth. Different manufacturers created their own guides for the teeth they designed. Common to all was the philosophy that tooth form was determined and should be selected based on the shape of a person’s face and head. The teaching was that patients with round-shaped faces were given ovoid teeth (Figure 5-1), whereas tapering teeth went with a long face (Figure 5-2).
Written rules were used, and if students did not follow them, they would not receive a passing grade. Some students questioned what was being taught. If a dentist chose to place tapering teeth in someone with a long skinny face, the face would look even longer. If round teeth were given to someone with a round face, the round face would appear even rounder. In actual fact, there was really no smile design or thought process regarding changing and improving a patient’s overall appearance. There were set rules that everyone followed because that was the way it was.
Incredibly, and probably accidentally, some third-world countries demonstrated superior smile design to what was being done in North America. For instance, in India it is possible to purchase dentures from street merchants (Figure 5-3). The buyer can select a denture, try it in his or mouth, and then look at the appearance in a mirror. When the buyer finds a set of teeth he or she likes, the merchant (denturologist) relines the denture with acrylic, and the buyer leaves with new teeth. The buyer has immediate gratification from being able to see exactly what he or she is getting before approving the purchase.
The dentist performing removable prosthetic procedures has long been able to allow their patients to have a wax try-in so that they can preview the new smile before the denture is processed and finished. However, smile design for fixed prosthetics over the last 50 years in North America has often been haphazard. Dentists took an impression, sent it to a lab, and wrote the lab technician some basic instructions as to what they wanted. There was no real way of knowing exactly what the patient would be getting. As well, the standards and skills of lab technicians and the materials available to them were not sophisticated enough for them to be able to fabricate imperceptible, lifelike restorations.
The key to achieving a predictable smile design, eliminating guesswork and satisfying the patient’s expectations on the first attempt without having to return the restoration to the lab for modifications, is to set the teeth up in a well-made provisional restoration. This temporary restoration provides a blueprint for both the desired function and esthetics. The dentist takes photos, bite records, and impressions of the patient’s teeth, studies them, and decides what functional and esthetic changes are needed. The dentist then has the models mounted on an articulator and fabricates a diagnostic wax-up to act as a guide for the temporary restoration (Figure 5-4).
The dentist normally would choose to have the diagnostic wax-up fabricated in a cuspid-guided occlusion so that the canines can disclude the posterior teeth in lateral movements. Cuspid guidance allows the facial muscles to have the chance to not receive continuous stimulation, which can result in facial pain. This discomfort is often confused with temporomandibular joint (TMJ) disorder but actually is of purely muscular origin and not joint related. If the patient is comfortable in the temporary restoration, the dentist can then simply tell the lab to duplicate the temporary restoration when fabricating the permanent restoration. All the functional and esthetic requirements will have been worked out and tested in the temporary restoration.
It is not always possible that a smile that has been designed purely for ideal esthetics will work in the function or parafunction of a patient’s mouth. If there are limitations, the dentist must point out the compromises to the patient. This is extremely important so that there are no false expectations or disappointments. There must be impeccable communication between dentist and patient. If the dentist knows that what the patient wants to achieve is not possible without considerable major changes to the patient’s dentition, he or she must inform the person about the problems that can arise. It may be possible that orthodontics would be required to move the teeth or periodontics needed to augment or reduce the gingiva. If what the patient desires is totally impossible, the dentist must be totally honest instead of assuming that the patient would settle for a different result. The patient must be given realistic expectations and be guided to understand what is possible and by what alternative means he or she can achieve what is desired. If patients are presented with all the facts and options that are available to them, they usually make the right choice. On a daily basis patients electively undergo periodontal surgery to alter gingival levels to reduce a gummy smile or to increase their gingival width. Patients electively undergo maxillofacial surgery to alter their mandible and/or maxilla. For example, some people have chins that are too retracted, so they choose to have an oral surgeon advance their mandible surgically. All dentists should educate their patients about what is possible, what is not possible, and what may be possible.
Any and all types of dental rehabilitation and reconstruction should be treated in exactly the same manner. For each and every single crown, and so on, the same principles should be applied. Even a simple one- or two-unit case is initially worked out and tested in provisional restorations to assess the desired function and esthetics of the permanent restoration. Impressions are taken of the temporary restoration, and photos are taken with a shade tab alongside the bis-acryl provisional restoration and the natural teeth (Figure 5-5).
This shows the lab technician the shade that is desired. Every single case has the same smile design protocol, even posterior molars. It is the author’s process to work out the buccal position and the cusp heights of the teeth in the temporary, and then instruct the lab to duplicate it exactly.
Even a posterior lower or upper molar can have the cusp height, buccal position, and width of the tooth redesigned. The lab technician is given exact instructions so that when the restoration is returned it is exact. When the restoration arrives from the lab, it is compared with the models and photos of the provisional restoration—they should look identical (Figure 5-6).
If the extra few minutes are taken to design the temporary restoration properly with all the standards of smile design, the result from the lab will always be predictable. Today’s superior lab technicians prefer working in this manner—that is, using photos and templates. They find that restorations are not returned to them as often for modification and correction.
The key to achieve a pleasing smile design is having the dentist interview the patient and listen to exactly what the patient wants. Photos of the patient show what the teeth initially look like, and both the dentist and patient can study and assess the situation. It is possible to draw what is wanted, make the teeth longer or shorter, or change the midline or gingival position on the photos (Figure 5-7).
These basic tools help the team visualize what they want to achieve. This vision must then be communicated to the lab technician, who will create a diagnostic wax-up, which is basically a template or mock-up of what was discussed while looking at the photos.
The diagnostic wax-up is poured in high-quality, low expansion stone and mounted on a semi-adjustable articulator so that the teeth are oriented on the lab bench exactly as they are in the patient’s mouth. An articulator is nothing more than a chewing simulator of the person’s function. The lab technician will create preparations of the teeth on the model in a realistic fashion to accommodate the design of the desired restoration. The technician uses dental waxes in natural tooth colors to produce the anticipated result. The diagnostic wax-up should resemble the projected finished look of the patient’s dentition. On the diagnostic wax-up the lab technician can make all the changes needed by correcting occlusion, changing the incisal or midline cant of the teeth, changing the dimensions of the teeth, expanding the arches, and so on. Every physical change can be made on the diagnostic wax-up. However, it is absolutely essential that the lab prepare the teeth in a realistic fashion. Once the diagnostic wax-up has been completed, the lab technician or dental assistant fabricates a silicon putty template that can be used to make the bis-acryl provisional restoration after the dentist similarly prepares the patient’s actual teeth (Figure 5-8).
Today’s standard of fabricating a provisional restoration is to create a diagnostic wax-up of the desired result, fabricate a putty template of it, and flow a bis-acryl temporization material into it, which is then placed over the patient’s prepared teeth and allowed to set. This technique yields provisional restorations that are a facsimile of the diagnostic wax-up. The introduction of bis-acryl materials dispensed from cartridge guns paved the way for dentists to be able to easily assess and to modify a proposed smile design (Box 5-1).
Box 5.1 Resin-Based Systems
The advantages of these materials are several. Bis-acryl material is a liquid composite resin that sets hard, is lifelike, does not give off any heat, flexes so it does not break off the teeth easily, adheres to the teeth, and offers the teeth protection. However, the main advantage of this material is its easy ability to be polished. It can achieve a polish similar to a composite resin, with a series of diamond points, carbide points, and disks. All that is required to finish it is to paint on a finishing glaze. If the dentist believes that it is necessary to change or modify this material, any type of composite resin can be added in the appropriate color. These additions can be remodified as well.
Before the introduction of bis-acryl materials, dentists mostly used methylmethacrylate acrylics created by mixing a tooth-colored acrylic powder with a liquid monomer. These materials are smelly, give off heat, take a lot of time to set, and are difficult to add to and modify. Bis-acryl changed the standard of dental temporization. It gives dentists a means to creatively do bonding additions to the provisional restorations and customize a look for each individual (Figure 5-9).
Bis-acryl provisional restorations can be easily remodified and repolished, and patients can wear them for long periods of time with few adverse effects on the gingival tissue. The main advantage of bis-acryl temporary restorations is that they allow the patient to live with the new look, evaluate it, and give the dentist feedback as to what they like or dislike. The dentist is then able to modify the provisional restoration to please the patient. Photos and an accurate impression are then taken of the final provisional restoration and are sent to the lab technician as a blueprint for creating the final ceramic restoration. This is the state of the art of predictable creative smile design.
Dentists have come to realize that the old rules of selecting a tooth shape that were taught in school may not apply in the real world. These protocols were created in order to select appropriate tooth molds to fabricate dentures. Formerly, a patient who had a long face was given long teeth. Today patients with long faces are often better off with square or more symmetrical flat teeth. These make a long face appear to be wider and more symmetrical (Figure 5-10). Similarly, someone with a round face can receive longer teeth to counteract the roundness (Figure 5-11).
FIGURE 5-10 A and B, Symmetrical teeth with a flat incisal plane make a long asymmetrical face appear wider and more symmetrical. C, If a flatter smile line is designed, a narrow face will appear wider.
FIGURE 5-11 A and B, Longer teeth can make a round face appear longer. C, A wide circular face can be made to appear narrower by designing longer upper teeth. It centers the viewer’s eyes at the bridge of the nose, minimizing the round facial form.
From a technologic point of view, dentists stopped thinking like scientists, following the rules of science taught in school, and started taking an artistic approach to dentistry. This began in the 1990s. Dentists started thinking like designers of smiles and stopped thinking of just rules and formulas. Rules and formulas may be great on paper, but they do not always look good on people. Human beings exist in different variations—people come in different sizes, colors, and forms and have different personalities. Dentists began to think of technologic and artistic ways to create teeth to match and enhance personalities (Box 5-2). Dentists are today more than ever regarded as artists.
Box 5.2 The Goal of Esthetic Dentistry
To Enhance What Mother Nature Has Given Us
Standards in dental labs have also changed dramatically. For many years ceramists were limited by the materials available to them. However, these professionals now have access to lifelike new porcelains, pressed ceramics, zirconium, lithium disilicate, and other new technologies. Ceramists have become more and more artistic. Today’s premiere technicians have raised the bar and distinguished themselves, pushing the barrier of what is possible. They are able to provide lifelike restorations that meet today’s high esthetic standards.
An artistic approach and the coordination between laboratory and dentist continue to improve the ability to achieve a beautiful smile. Science and technology have changed every aspect of smile creation.
Every dentist has been preached the golden proportions. The golden proportions state that if a person’s teeth are viewed straight on and using the lateral incisor as the reference tooth, the adjacent central incisor should be 1.6 times the size of the lateral incisor, and the visible part of the canine 0.6 times the size of the lateral incisor (Figure 5-12).
These are the scientific principles of smile design. But science is one thing and art is another. Artistically, the central incisors must be totally symmetrical. Their incisal edges should be equal, and the incisal corners should be the same shape. If the mesial of one is square, the mesial of the other should be square. The gingival levels should also be equal. However, aside from the central incisors all the other teeth can have some form of variation. The lateral incisors should not be totally symmetric. The dentist can make one lateral incisor shorter than the other or turn one lateral incisor to give character and personality to the patient’s smile. The lateral incisor is regarded as the personality tooth, so one can create a sexy or mischievous look by simply turning and playing with the angles of the these teeth. In a similar manner a canine can be made sharp or pointed to create a strong look, or it can be rounded for a softer appearance. It is also possible to expand and widen the dental arches and create a fuller buccal corridor. Even though there are scientific principles involved, it is really the dentist’s eye and creativity that are the best tools for creating a beautiful smile. The dentist must think like an artist, study the patient’s face, and try to enhance what is already present.
What is today being referred to as “pink esthetics” is fundamental in achieving a natural- and healthy-looking smile. The patient’s gingival levels should be in the most natural-looking position. Usually as people age, their gingival levels change. The tissue may have receded because of disease, tooth abfraction, or overbrushing (Figure 5-13). Often with patients who are “long in the tooth,” gingival grafting must be performed.
The new patient is the lifeblood of the dental office. Without new patients, dentists would have to rely on finding new work or redoing the dentistry of their existing clientele. The new patient experience begins when the patient first telephones the office. In our office we try to determine over the phone if the patient requires major or minor dental work. Dental offices that focus on and have a reputation for major restorative dentistry are more likely to receive patients with more serious needs than offices focused on family dentistry. The receptionist must carefully screen the new patient phone call to determine what type of new patient visit to schedule. The needs of a patient with full-mouth breakdown are far different from the needs of one who has a healthy dentition. Sometimes when patients call and say they require something major, it could actually be something very minor. Everyone has his or her own perspective.
In our office, when the receptionist believes that a major dental treatment is anticipated, an appointment for a screening consultation is made. The patient comes in on a lunch hour or at 5 o’clock for a consultation. At this time the dentist can sit with the new patient one on one with no distractions. Four photos are taken of the patient: (1) smiling full face, (2) at-rest full face, (3) smiling close up, and (4) smiling with a tissue retractor. The photos are printed, and the dentist sits with the patient at a consultation table and listens to what the patient desires. The dentist uses the photos to illustrate to the patient the situation that currently exists and possible changes that can be made. No treatment plan is established at this time, as this is not a formal examination. The dentist tries to open the patient’s eyes to what can be done. There may be many things visible on the photos that the patient never actually recognized. In fact, they may be the things that actually bother the patient but that he or she could never pinpoint. It may be that the gingival tissue heights are not aligned, buccal corridors are not expanded enough, teeth are too short, and so on. The dentist must use a pen and draw on the photos to help the patient visualize some of the potential changes that are possible. On this initial consultation the patient is given an idea about what may be involved with respect to time, discomfort, and cost.
If the patient is still interested after the consultation, he or she then receives an appointment for a full new-patient examination, which is scheduled for 2 hours of time. At this appointment intraoral photographs of every single tooth are taken, as well as a full-mouth series and panoramic radiographs. Creation of a set of study models, bite registration, periodontal charting, occlusal evaluation, TMJ assessment, and a head and neck examination are also conducted. The majority of these records are gathered by a hygienist. The dentist usually enters the room only when all the information has been put together and is available, including the study models and photos. The dentist then performs the intraoral examination and tries to instill confidence in the patient. It is important to understand that a treatment plan is not usually proposed at this time, as the case has not actually been totally analyzed.
The patient’s next appointment is made 1 to 2 weeks later for a review of the entire case. This is often referred to as the case presentation. In the meantime, the models, radiographs, and photos are studied and scientific principles applied to formulate a treatment plan. The dentist studies the photos first to see how much tooth is showing when the patient smiles. A study by Vig and Brundo in 1978 concluded that at age 30 years, people show 3 mm of upper tooth, and for every decade thereafter they start showing more molar teeth. At age 60 years they show virtually no upper teeth and 3 mm of lower teeth. Reviewing the photos, the dentist determines if sufficient maxillary teeth are displayed and if the patient’s smile can be made more youthful in appearance. The planned changes can be drawn on the photos. It can also be determined if periodontal surgery, orthodontics, or other procedures are needed. The entire treatment plan is worked out by the time the dentist next meets with the patient.
Before presenting the case, the dentist must have a clear vision of what is required. Otherwise the dentist will look lost and incompetent. Once the treatment plan has been worked out, the dentist is ready for the case presentation.