Esthetic Opportunities and Challenges: The Restorative-Periodontal Relationship

Esthetics in dentistry, however, is not solely determined by the quality of the restoration or the shade of the crown. The relationship among periodontal health, patient expectations, diagnosis, and treatment planning is a complex one, and often a team approach among the restorative dentist, periodontist, and sometimes the orthodontist is needed. I (Dr. Clem) invited two colleagues, Drs. Jim Janakievski (periodontist) and Markus Blatz (prosthodontist), to help develop a framework regarding these relationships and gain some insight from their perspectives.

Clem: Often times I will have a patient referred for esthetic crown lengthening, an anterior implant, or treatment of periodontitis, all of which involve esthetic considerations. Patients are generally unaware of how their periodontal status and current attachment levels can limit the restorative result.

Janakievski: It is critically important for the periodontist to not only make an assessment on disease status, but on how the form of the periodontium will affect the restorative effort. This is where I think close communication between the periodontist and restorative dentist is critical. For me, after my comprehensive periodontal evaluation, I begin an interview with patients, asking them to explain why they were referred and what they expect of the overall treatment. The most difficult patients are those who come largely uninformed with a referral slip that says "crown lengthen 7 through 10." This is an important conversation because it allows me to develop a rapport with the patient and at the same time support the restorative dentist's treatment plan that has been previously discussed. I inform the patient that I will guide the treatment course from a biologic perspective to achieve the framework best suited for the intended result. The patient should view the communication between the team members as seamless.

Blatz: I concur. While esthetic desires are expressed by the patient, the realities of achieving these desires requires a close cooperation between the periodontist and restorative dentist. What am I and the patient trying to achieve? Is it a more harmonious gingival level, whiter teeth, closure of embrasures, larger teeth, smaller teeth, lip position improvement? These considerations and many more require periodontal health and/or modification to establish that framework within which we can set goals, manage expectations, and execute treatment. Beyond the standard dental examination, a detailed esthetic analysis frequently involves study models, photographs, videos, and the emerging field of digital scanning and 3-dimensional (3D) design. These provide a basis for communication between treating doctors and the patient. Once established, the treatment goals should always be visualized through intraoral mock-ups, either direct, retrievable, or with provisional restorations. The real value comes in that the patient now has the confidence to move forward with all members of the team progressing toward a common goal. The patient is the center, and the team functions to support each other's treatment.

Clem: Where does virtual and digital workflow fit in?

Blatz: Digital diagnostic, planning, and design technologies are key elements of modern esthetic dentistry. Current face scanning and virtual/augmented reality technologies allow for customized 3D digital smile design on the computer screen, limiting valuable chairtime with the patient to a minimum. A mock-up or provisional restoration can easily be fabricated from the digital design and tried in the patient's mouth. Transferring the ideal mock-up to a definitive restoration is quite simple with current CAD/CAM technologies, which have become standard for most dental laboratories. In addition, chairside CAD/CAM solutions have become increasingly popular, also for restorations in the esthetic zone.

Clem: What do you consider the most important periodontal determinants for establishing anterior esthetics?

Blatz: For me, the amount of gingival display and consistency of gingival levels are most important. This is confirmed by a number of studies in the field and they are what patients notice most.

Janakievski: In a healthy periodontium, these issues are easy to modify if needed. But if there is loss of attachment, this compromises normal scallop and contour of the gingival marginal tissues, and the esthetic framework may be difficult to achieve. This may require not only periodontal enhancements, but also orthodontics.

Clem: This is a good point. Judicious orthodontic movement, primarily with selected extrusion can help improve the esthetic framework by changing tissue levels and interproximal papilla.

Janakievski: Changing papilla levels through extrusion is a less obvious consideration but many times critical to the case. If the maxillary anterior teeth have different amounts of periodontal attachment loss, then orthodontics can be used to level the interproximal soft-tissue levels, which are unpredictable to change from a surgical approach. In this example, the facial tissues will adjust accordingly, but will likely be at uneven levels due to the deferential orthodontic eruption of each anterior tooth. Periodontal surgery will then be needed to adjust and create the final scallop and symmetrical gingival contours.

Blatz: From a restorative perspective, surgical alterations of gingival heights and contours can affect both the length and contour of the anterior teeth. There are limitations especially in a patient who has very tapered roots and the root diameter gets narrower very quickly. If crown lengthening is done based only on amount of gingival display, without taking into account root taper, the result will be very difficult to restore in an esthetic manner.

Clem: I think it gets back to the close communication among the team so that all have an appreciation for these and other limitations. The other issue I see with esthetic crown lengthening is that some patients, many times post-orthodontics, will have thickened bony contours in the maxillary anterior segment, giving the patient an appearance of a thinned upper lip or stretched smile. Many times esthetic crown lengthening results not only in more tooth display, but also in a fuller upper lip and a more natural drape of the smile. This enhances the esthetic outcome, although the outcome may be difficult to predict for the patient.

Blatz: I find, in fact, that orthodontic movement is necessary in most cases that require a new smile design, especially when the intent is to minimize the incidence and/or invasiveness of restorative and periodontal treatment. In these cases it is usually not just periodontal or orthodontic enhancements that can set the framework for me to manage esthetics most predictably, but both.

While we are talking about crown length and gingival display, it is important to remember that most patients begin to negatively judge display as excessive at about 4 mm. It is interesting to note that excessive gingival display during smiling may be correlated with negative personality traits. Interpretation of smiles are a fascinating part of how people are being judged by others.

Clem: Given this discussion about smile perceptions, in compromised cases which do you find a patient is more likely to accept: a compromised papilla height or prosthetic alteration of restoration width?

Blatz: I think it is fair to say that no patients like "black triangles," but it is always an individual decision based on the level of severity of the tissue loss and the aberration of the restoration contours from the ideal. This is where I think mock-ups or provisionals are most needed. I see many patients for second opinions after alterations have been done who say, "I didn't know it was going to look like that!"

Janakievski: Clearly, patients' least acceptable result is large "black triangles," especially if they are asymmetric. Sometimes with some judicious crown lengthening and/or orthodontics, the restorative dentist can create contours that, while not ideal, are at least not as obvious. Pink porcelains and composites continue to improve, and I see these being used more often in difficult cases.

Clem: Speaking of materials, I would like to ask Dr. Blatz about his perspectives on zirconia? It seems like I am seeing more and more of these restorations, and I can't help but think we are in danger of overuse.

Blatz: We have been working with zirconia for two decades. It has shown to be a viable material option for all-ceramic restorations, either veneered with a veneering porcelain or as a full-contour monolithic material. The newer, more translucent zirconia materials have especially broadened the range of indications tremendously. Esthetic optical features are excellent, and the material's value offers distinct advantages. Current high-translucent, multi-layer zirconia materials are progressively used for full-contour monolithic restorations in the esthetic zone.

I came across two major misconceptions that may lead to improper use of the material and possible failures. The first is the erroneous believe that zirconia is a metal. While zirconium is indeed a metal, the polycrystalline ceramic zirconium dioxde (zirconia) is not, and this affects a wide range of physical, chemical, and biological properties. One of the key differences is the modulus of elasticity. Inherent flexural strength and brittleness of ceramics must be recognized to avoid fractures, especially for high-translucent zirconia, which has a lower fracture strength than the conventional zirconia. The other misconception is that all zirconia materials are the same. There are vast differences in composition and, consequently, optical and physical properties when comparing various zirconia products. Even more so, manufacturing (milling, sintering, etc.) processes have a significant effect on the properties of the ultimate restoration, and even small deviations from the recommended handling can have detrimental effects on the outcomes and clinical success of the restorations.

With that knowledge, it is imperative that the material is used correctly and not applied to indications that it simply cannot handle based on its properties. And the material certainly should not be "abused" by failing to strictly follow laboratory and clinical handling requirements.

I would also like to comment on the issue of the use of pink materials such as porcelain or composite. While we should consider these to be a last resort option in cases of periodontal attachment loss, I think they are almost essential in full-mouth implant-supported fixed restorations.

Clem: This is a nice segue into the question of implants in the anterior segment and when do you consider replacing an anterior tooth with an implant?

Janakievski: There are three major considerations, in my estimation: Is the tooth restorable? Does the periodontal attachment loss pose a risk to the overall esthetic result? What is the age of the patient? The answers to these questions circle back to treatment that may improve the condition of the tooth, such as regeneration, combined orthodontics and crown lengthening, root coverage procedures, as well as alternative options for tooth replacement. All need to be undertaken with the esthetic goals in mind.

Blatz: Implants are excellent when all restorative, endodontic, or periodontal treatment to save a tooth fail. They should in this scenario be considered as a last resort, especially in younger patients. Nowadays, it seems that some clinicians tend to go to implants too early, without fully appreciating the complexity of the surgical and restorative procedures and the difficulty to achieve an esthetic result.

Clem: I couldn't agree more. We were once told that implants were lifelong and "bulletproof." I think we are finding that this is an exaggeration. I had a 28-year-old girl in my office with a fractured maxillary lateral incisor requesting an implant. My answer to her was that with her life expectancy, and her esthetic demands, it is doubtful that this implant would be a "permanent fix" as she described. Sometimes patients want what they want based on hype. It is our responsibility to guide them toward informed, evidence-based decisions.

Finally I'd like to talk about healing times following surgical treatment.

Janakievski: If a patient has undergone regenerative periodontal correction or a clinical crown lengthening procedure in the esthetic zone, it is important to allow an appropriate amount of time for healing before proceeding with restorations. While supracrestal fiber attachment is completed by 6 weeks, remodeling of bone and subsequent soft-tissue changes can occur for up to 6 months. So, in general, I like to wait 6 months before starting the next restorative phase.  Another advantage to waiting is the time it allows to test esthetics with mock-ups or provisionals, as Dr. Blatz suggests.

Blatz: I would agree thatlonger wait times, especially if the patient is in provisionals, is especially critical in complex cases with high risk.

Clem: I would like to thank you both for your time and expertise in this discussion. As our diagnostic and treatment options change, the patient's framework for success remains essentially the same.

Donald S. Clem, III, DDS
Adjunct Professor, University of Texas Health Science Center, San Antonio, Texas; Private Practice, Fullerton, California

Markus B. Blatz, DMD, PhD
Professor of Restorative Dentistry, Chairman, Department of Preventive and Restorative Sciences, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania

Jim Janakievski, DDS, MSD
Affiliate Assistant Professor, University of Washington, School of Dentistry,
Seattle, Washington; Private Practice,
Tacoma, Washington