Aesthetics and Function: Conflict or Complement?

Dentistry Today
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In partnership with National Dental Network, Dentistry Today presents a brief, live-patient video on porcelain veneers featuring Drs. Dawson and Cranham.

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Advances in dental materials and related clinical techniques have made possible a new era of aesthetic dentistry. More treatment options are available to dentists and patients than ever before, and as a result more patients are requesting, and demanding, the best that dentistry has to offer in terms of an attractive smile. Has this boom in aesthetic or “cosmetic” dentistry come at the expense of proper occlusal function? Are certain patients being overtreated in the name of aesthetics? Or are aesthetics and function complementary in this new era?
Dentistry Today asked 2 renowned experts to express their opinions on these and other questions in an exclusive interview.
Dr. Peter E. Dawson has shared his knowledge of clinical dentistry with thousands of dentists through his teaching and writing. He is the author of the all-time best-selling text on occlusion, Evaluation, Diagnosis and Treatment of Occlusal Problems (Elsevier). His new book, Functional Occlusion: From TMJ to Smile Design (Elsevier) has exceeded all expectations. He is the founder and director of the Dawson Center for Advanced Dental Study, a teaching center and multidisciplinary think tank in which active clinicians from all dental specialties combine their expertise in a search for better understanding of dental diagnosis and treatment. He is a past president of the American Equilibration Society, the American Academy of Restorative Dentistry, and the American Academy of Esthetic Dentistry. His many national honors include the Distinguished Alumni Award from Emory University, the first Gold Medal for lifetime contributions to prosthodontics from the American Society of Prosthodontics, a Lifetime Achievement Award from the American Academy of Cosmetic Dentistry, and the Thaddeus V. Weclew Award from the AGD.
Dr. John C. Cranham has a contemporary dental practice in Chesapeake, Va, focusing on cosmetic, restorative, and implant services. He is associate clinical professor at the Medical College of Virginia, and is an internationally recognized speaker on the Esthetic Principles of Smile Design, Contemporary Occlusal Concepts, Treatment Planning, Restoration Selection, Digital Photography, Laboratory Communication, and Happiness and Fulfillment in Dentistry. He is the director of education at the Dawson Center for Advanced Dental Study, where he teaches Seminar II with Drs. Dawson and Dupont, along with two 3-day hands-on programs (Functional Esthetic Excellence I and II). Dr. Cranham founded Cranham Dental Seminars, which provides a combination of lecture and mobile hands-on programs. An active educator, he has provided more than 500 days of continuing education for dental professionals throughout the world.

Peter E. Dawson, DDS, (right) and John C. Cranham, DDS (left)

DT: Advances in dental materials science have provided dentists with more aesthetic treatment options than ever before. In your opinion, what are the most significant aesthetic advancements, and why?

Dr. Dawson: I don’t think we can limit aesthetic advancements to dental materials alone. Looking back, a major aesthetic problem that needed to be solved was related to the gingival contour mismatch around restorations that often resulted from periodontal treatment. There was no material that could make up for lost interdental papillae or poorly placed gingival margins. Advancements in periodontal cosmetic surgery plus innovative use of combined perio-ortho techniques have made it possible to achieve near-perfect aesthetic results even in severely compromised aesthetic challenges. When we bring in the magnificent material options we have today for restoring teeth to lifelike contour and color, the results can be undetectable from the most naturally beautiful smile.

Dr. Cranham: For me, the greatest advancement in aesthetic materials comes from the tremendous variety we have to choose from. This, however, can be a double-edged sword. While the variety gives us the opportunity to create lifelike restorations with a number of different porcelains, it can also lead to confusion on the part of the dentist as well as the technician. All of these choices have shifted much of our training toward specific materials as well as procedures necessary to handle the materials. While this is necessary, beautiful aesthetics, along with predictable function, has to do with understanding the principles of where teeth need to reside within the patient’s gnathostomatic system. These concepts have been the cornerstone of the Dawson philosophy from its inception and continue to be so today. Regardless of the material choice, teeth must be positioned properly and have the correct contour in order for them to look like the real thing, regardless of the material choice.
Materials, however, are making tremendous strides in making our life easier in difficult clinical situations. The classic example is the patient who is missing a lateral incisor and would like to have this tooth replaced and have the rest of her smile addressed at the same time. Not too many years ago this would have been a very difficult situation—trying to match the bridge to conservative veneers on the adjacent teeth. In other words, the optical properties of the core and layering materials would have been different.
Today we have many manufacturers developing layering porcelains that go on a variety of core materials. Venus porcelain by Hereaus Kulzer and IPS e.max Ceram from Ivoclar Vivadent are just 2 examples of layering porcelains that can go on many different core materials, and can even be used to create layered porcelain veneers on their own. This allows the restorative dentist to choose the core material based on the strength needs of the individual clinical situation, and the layering porcelain will match. This gives us tremendous control over a variety of clinical situations, satisfying the aesthetic needs of more of our patients, while at the same time not compromising strength.
So, while I believe that the concepts that teach us where teeth need to reside in space from an aesthetic and functional perspective are still the most important decision we have to make, there is no question that great strides have been made with regard to the restorative materials we utilize day in and day out.

DT: With all the attention focused on aesthetics by both clinicians and patients, do you feel that the traditional principles of proper function are being threatened?

Dr. Dawson: The reason I wrote my last textbook, Functional Occlusion: From TMJ to Smile Design, was precisely to address this issue. The big increase in malpractice suits related to cosmetic dentistry is evidence that essential principles of functional harmony are too often being violated in the restorative process. Good smile design cannot be isolated from the rest of the masticatory system, including the temporomandibular joints and the musculature. Nor can the functional requirements for anterior teeth ignore the critical relationship to the posterior occlusion. The anterior teeth have tremendous importance for long-term stability of the entire dentition. A correct anterior guidance is critical for protection of the posterior teeth and an important requirement for a peaceful neuromusculature. The rules for both function and aesthetics are understandable and learnable, but even slight variation from these rules can lead to problems of stability and discomfort as well as compromised aesthetics. It is evident that much of the cosmetic dentistry being done in recent years violates critical principles. The good news is that a growing number of dentists are learning the rules and are treatment planning for health and comfort of the total dentition.

Dr. Cranham: While this was an initial concern, I actually think that aesthetic dentistry is driving clinicians to increase their knowl-edge about occlusion and functionally related topics. At the Dawson Center we believe that when a dentist decides to add elective cosmetic procedures into the practice (ie, porcelain veneers), he or she has to be an absolute expert on occlusal treatments. I think the industry is starting to recognize this, for the last thing any dentist wants is to iatro-genically cause a dental problem by placing restorations that were not needed. We have a tremendous re-sponsibility anytime we remove tooth structure in the absence of disease. While bonded porcelain restorations can fail in a variety of ways, creating a functional disharmony is the primary way aesthetic materials do not reach their maximum potential with regard to longevity.
Occasionally, at our hands-on courses we do hear dentists referring to one of their cases as “a simple veneer case.” Dr. Dawson has made the point for years that there is no such thing. When we change any part of the anterior segment of the system, we have to have a clear picture of where we are going and why it will work, and have systems for quality control over the entire process. Missing the incisal edge position as little as 1 mm vertically and/or horizontally can be the difference between a comfortable, long-lasting restoration versus one that is uncomfortable and fractures.
Thankfully, the dentists who come to the Center understand this. Their goal, as is ours, is to create beautiful, functionally correct aesthetic restorations.

Peter E. Dawson, DDS, (right) and Dr. John C. Cranham, DDS (left) review patient files.

DT: Are you concerned about “overtreatment” due to the current focus on “cosmetic” dentistry, ie, where aesthetics “drives” the treatment plan even if it compromises the patient’s oral health and proper function? Do you see this as a problem in the profession?

Dr. Dawson: For many years we have taught that honest treatment of our patients consisted of doing the minimum required to achieve optimal oral health, function, and aesthetics. There is reason to be concerned about promotion of concepts that are designed to maximize the number of restorations regardless of an actual need. I have no reservation about restoring teeth that need restorations either for aesthetics or improved function. With the fantastic materials and technical skills available today, it should rarely be necessary to do multiple restorations solely for the purpose of matching color. And astute clinicians can mix and match different types of restorations to achieve beautiful results without having to restore 28 teeth when more conservative treatment is all that is needed. Repositioning teeth is almost always a better option than unnecessary restorations. Whitening procedures can often eliminate the value of laminates on teeth that can be made beautiful without restorations. Plenty of dentistry can be done without putting patients through unnecessary procedures and unwarranted expense.
But the problem of overtreatment goes far beyond adding expense. Over-treatment can, and often is, harmful to patients. The most problematic overtreatment we see on a growing scale is the misguided process of bite-raising to accommodate restorations on posterior teeth that have no functional need for an increased VDO and often no need for extensive restorations. If the increased VDO is combined with forward displacement of the TMJs, as some are advocating, it can result in overload of the posterior teeth, a dysfunctional anterior guidance, and masticatory muscle pain. Dentists who don’t have a good understanding of the principles of functional occlusion are easily influenced to accept treatment rationales that eventually lead to problems for both patients and dentists.

Dr. Cranham: As professionals we have to consider not only the issues that are driven by disease (ie, caries, periodontal disease, and occlusal problems), but we also must consider the things that the patient would like to change from an aesthetic perspective. I don’t think we can separate one from the other today.
Not too long ago, the profession viewed elective aesthetic dentistry as unethical. It is interesting to note that a decade prior to that, elective cosmetic plastic surgery was viewed in exactly the same manner. Our feeling is that cosmetic dentistry that is treatment planned as a separate entity is a mistake. Changing the size and shape of the maxillary anterior teeth has a profound impact on the occlusion. Therefore, aesthetic dentistry must always be performed within the context of complete diagnosis. Conversely, we also believe that if a practice is doing dentistry that is only focused on eliminating disease, it is missing an unbelievably fun and rewarding aspect of our profession. These dentists are probably not satisfying the expectations of their patients. They are incomplete in their treatment planning. Dentists today must learn how to develop a clear picture in their mind’s eye of the patient’s final outcome—a treatment plan that will provide “optimal oral health” and one that provides a beautiful smile. The end result may require a restorative solution, but many times it may be orthodontics, orthognathic surgery, or a combination. The goal of every treatment plan is to do the least amount of dentistry possible to solve the patient’s disease-driven dental problems and to provide them with the aesthetic changes to their dentition that they desire.

DT: Are there clinical situations where the goal of proper function dictates a less than optimal aesthetic result… or vice-versa? Do you have any advice for clinicians who must decide how to balance aesthetics and function?

Dr. Dawson: It would be an extreme rarity for proper function to require any compromise in aesthetics, or vice-versa. Our entire concept of naturally beautiful aesthetics that we teach at the Dawson Center is based on the principle of a functional matrix. The best aesthetics is achieved when the teeth are in functional and an-atomic harmony. That includes harmony with the neutral zone established by the musculature; harmony with the lip closure path; harmony with phonetics; har-mony with vertical dimension of the occlusion; and harmony with the individual envelope of function.
Ten critical factors determine the function and long-term stability of every occlusion. The same factors also determine comfort and best possible aesthetics. These factors are the key to clarity in treatment planning. My advice is to start with a clear understanding of all 10 factors and how they are used.

Dr. Cranham: It is extremely rare that we ever have to compromise on the aesthetics to achieve optimal function. In fact, it is amazing how many times that, when things look right, they function properly.
Many dentists think that the Dawson philosophy is only about occlusion. It is about learning how the teeth, joints, and muscles are designed to function in harmony with one another. Functional harmony describes chewing, speech, and how the teeth occlude and disclude. The nuances of beautiful smiles are also a very important piece of this puzzle, and I might add that nothing is left to chance or guesswork if the step-by-step process is followed.
On that note, it is possible to design stable occlusions that look bad. As I said earlier, our goal is to provide stable, healthy mouths that look beautiful. I think it is a myth that you have to sacrifice one for the other.

DT: Overall, has the boom in “cosmetic” dentistry been good for the profession and its patients, or has it created more problems than benefits?

Dr. Dawson: I believe the boom in cosmetic dentistry has been exceptionally positive for both patients and those professionals who have a complete picture of health as their goal. I think it has been problematic for dentists who have not put aesthetics into a total concept of complete dentistry. Many patients are seeking cosmetic dentistry who have other needs that would not be diagnosed if a desire to improve appearance didn’t initiate the appointment. Patients can understand that cosmetic dentistry in an unhealthy mouth is not a good idea. So there has never been a better time in dentistry to become a complete dentist. By that I mean a true health professional and masticatory system physician who can diagnose for long-term maintainability of a healthy dentition as well as a beautiful smile. There is no shortage of patients who are seeking that level of professionalism.

Dr. Cranham: The cosmetic boom has been tremendous for dentistry in general. It has patients ar-riving at our offices wanting our services in a way that 20 years ago few of us could have imagined. We also believe, however, that with the cosmetic revolution, there is increased responsibility. The temptation is great to focus only on what patients say they want, leading to an “aesthetics only” view of treatment planning. The average patient may seem to be focused on aesthetics, but it is important to remember that they are also assuming they will be healthy. For his entire career Dr. Dawson has taught that the average intelligent patient wants health. He or she may be focused on a beautiful smile, but the patient assumes that when the treatment is finished he or she will not only smile bigger, but will chew properly, speak correctly, have restorations that will last a long time, and of course, will increase the longevity of the dentition.
Doing cosmetic/aesthetic dentistry within the context of comprehensive care as we teach at the Dawson Center is win-win-win. Great for the patient, great for the practice, and great for the profession.