April 1, 2004
by Thomas Trinkner, DDS and Matt Roberts
The modern era of esthetic dentistry incorporates techniques, materials and ceramics that have greatly impacted the approaches used by clinicians in the diagnosis, treatment planning, and case design of today’s compromised smile. Challenges in the early years of prosthetic dental reconstruction involved color, strength, tooth reduction, and periodontal health.
In the early 1980s, the advent of adhesive dentistry and ceramic veneers presented many opportunities for conservative changes that enhanced smiles, yet they were deficit in form, function, and artistry. Back then, the use of veneers seemed more appropriate for enhancing poor color (tetracycline staining) and correcting diastemas. Minimal tooth reduction was attractive to clinicians and patients; however, this often led to laboratory challenges and a compromised prosthetic result. The over-contoured restoration, abrasive in nature and simple in color, was easily detected by the trained eye. True dental artists developed skills with direct composite bonding to meet many of the early obstacles in esthetics, yet this restorative modality, also, was tested by requirements for longevity and predictability.
In the 1990s, clinicians witnessed further changes in material science, laboratory support, and educational teaching that stimulated them to use a new arsenal of esthetic modalities. Vital bleaching became a driving force for esthetic whitening, and for those that did not respond, alternatives became significant. Veneers, modified in design, were utilized and talked about more.
Clinicians that were once timid about their use now sought training and ceramists to facilitate implementation into their clinical setting. The esthetically dominated practice grew rapidly and drew attention from many more conservative schools of thought. Although controversial, their success in the marketplace continues to exist, if not grow. The clinical test of time will greatly influence the future and impact new developments in both adhesives and ceramics.
Today, esthetic minded patients are becoming more educated and exposed to the opportunities available through internet marketing, “Extreme Makeover” television, and other forms of media. Challenges for the dental profession today, therefore, include identifying the clinical protocol that preserve the natural dentition, achieve patient goals, and offer long-term success, functionality and stability.
To this end, the literature discussing vital bleaching details sound clinical protocol and long-term success with very few adverse effects.1 Challenges have presented with dark and severe intrinsic staining. Although recent long-term bleaching studies have shown success,1 some clinical situations have not been resolved to sufficient patient satisfaction. Compliance and methods of treatment vary among practices and from patient to patient.
However, the combination of tooth whitening and veneering has led the esthetic revolution. Patient demands for orthodontically correct, brightly colored smiles have driven the adhesive dentistry market. Laboratories that historically used metal-ceramic restorations to restore caries-damaged teeth were charged with replicating the color and form of adjacent dentition, but were then suddenly faced with full arch veneer cases in order to produce a youthful, beautiful, smile.
Producing such restorations required the ceramist to learn many new skills that were previously infrequently used. Relating tooth position and gingival position to facial features, and then creating a group of youthful appearing teeth with a symmetrically pleasing arrangement, became the focal point for success.2
In many instances, patient desires for symmetry and color took the ceramist away from what exists in nature. When all 28 teeth were restored to a color and shape dictated by the patient, the skills required for matching natural tooth shade and form became an unused talent that atrophied. Today’s esthetic and clinical challenge is producing restorative designs-and communicating those requirements to the laboratory-in such a manner that esthetic and functional success can be assured for the patient.3
In all, these authors have found one of the most challenging and rewarding styles of dentistry to be the combination of vital bleaching and conservative reconstruction in both the restoration design and numbers of teeth involved. This article addresses some methods for communication, planning, preparation, and material selection in order to achieve optimal conservative and esthetic results.
SEARCHING FOR SIMPLICITY
Trends in dentistry have moved many clinicians toward treatment modalities involving multiple restorations covering the entire smile. In many instances, there may be a dentition that, although clinically healthy, may fall into the treatment plan. The goal should be to look for minimal treatment first, so that only the compromised dentition is affected.
Accusations of over-treatment of patients by the dental community has driven some practitioners to pursue more conservative treatment options through which esthetic goals are met while preparing fewer teeth.
To this end, treatment plans that combine bleaching with resin augmentation, enamelplasty and a few strategically placed ceramic restorations are being developed to create a satisfying smile for patients who desire esthetic improvements, but without the need for preparing every tooth in the mouth.
Such conservative treatment, where fewer teeth are prepared, requires greater attention to shape, form and color matching, and matching post-bleaching shades presents a particularly new challenge (Fig.1). Therefore, it is incumbent upon the treating clinician to utilize excellent listening skills in order to balance patient desires and communicate initial parameters of case design.
Additionally, an orthodontic specialist should be utilized to manage some conservative approaches. Minor tooth movement can be an adjunct to simplistic treatment plans. Often the challenge is developing the communication skills necessary for excellent doctor and ceramist success.
Comprehensive examinations that include full mouth radiographs, mounted diagnostic study models, occlusal analysis, periodontal status, and temporomandibular screening become the foundation for planning regardless of the complexity of the case. Digital photography and high speed internet access have broadened the detail and organization of the pre-treatment and treatment phases of esthetic cases.
Mock-ups & conservativism
The utilization of chairside mock-ups has greatly helped elevate esthetic awareness of patients. In addition, they provide clinicians with excellent opportunities to visualize potential treatment outcomes and direct toward conservative approaches.4 The following case (Fig. 2) yielded clinical success for the patient by re-evaluating the treatment plan of another clinician, which originally called for 6 anterior veneers.
Using a chairside mock-up of 2 lateral veneers and 2 bicuspid ceramic restorations (Fig. 3), the patient’s original chief complaint regarding an unattractive left cuspid could be addressed. By utilizing ceramic preparation, tissue recontouring and enamelplasty (Fig. 4), patient satisfaction was achieved (Fig. 5) in a more conservative manner.5
Direct bonding–a valuable lesson in conservation
Often, direct composite bonding can be a clinical trial for patient perception of esthetics and function. One should not forget that, many times, direct bonding is also the most predictable and conservative treatment modality available. In the following case, the patient’s esthetic concerns were easily addressed by the placement of one of the new esthetic composite systems (4 Seasons, Ivoclar Vivadent) (Figs 6 & 7). These new direct composite systems offer a multitude of colors in dentin and enamel shades. In addition, highly bleached dentition can be easily accommodated.
Certainly advances in handling, color, system organization, and clinical properties have led many clinicians to rejuvenate their direct composite bonding skills.
ion approach–communication is key
The combination of direct composite bonding and placement of ceramic restorations offers more variation to the clinician’s restorative repertoire. The classic peg lateral, diastema, or undersized tooth is common in clinical situations and often responds well to thin ceramic restorations (Fig. 8).
The ability of the clinician to communicate the esthetic and functional requirements of the case to the ceramist through a well-designed provisional is essential to a successful final outcome. Additionally, a diagnostic wax-up often gives the clinician a first glance at the treatment objectives. Meeting these objectives through minimal preparation using preparation guides assures that over-reduction will be avoided and proper restoration thickness can be achieved.
The fabrication of provisional prototypes prior to final impressions offers a view of the thickness, shape and color masking potential of the anticipated ceramic restorations. In the following case (Fig. 9), there is an improper midline, shapes and proportions. Previous bonding failed to establish esthetic harmony. The diagnostic wax-up (Fig. 10) created more ideal esthetics and facilitated preparation success when the provisionals were fabricated. Areas requiring further reduction are easily recognized (Figs. 11 & 12).
Appropriate reduction is critical to the success of bonded, laboratory fabricated restorations, where underlying color plays an integral role in the final esthetic result. Currently, there is no universally applicable rule for the appropriate amount of preparation for bonded ceramic restorations, since required depth varies with deviation of color from the existing tooth structure relative to the desired final shade. Teeth that exhibit color and optical qualities similar to the desired result require much less reduction than teeth to significant changes in color and opacity must be made.
It is important to note also that refractory based systems can be used to produce the thinnest of all-ceramic restorations and offer the most conservative alternative for the treatment of patients requiring changes in shape but not color. If the color is being modified, this type of system also allows variations in opacity and chroma to occur in specific areas with in the restoration creating desired effects or strategic masking of underlying color.6
Therefore, when trying to mask undesirable underlying color, more aggressive preparation must occur to enable the appropriate opacity to be introduced deep enough within the restoration for natural optical properties to be replicated.
Any attempt to block out color without sufficient reduction will result in the introduction of materials unnaturally reflective or opaque at a level much too close to the surface of the restoration for the enamel and dentin coverage to scatted the reflected light. The result is a very unnatural appearing, reflective restoration.
Here, after satisfying preparation requirements (Fig. 13), two prototypes were fabricated7 (Fig. 14). One could be utilized for the patient provisionals, and the second could be sent to the ceramist as a visual reference of the projected thickness and form of the restorations. The final ceramics would correct the clinical and esthetic deficits (Fig. 15). Vital bleach shades for bonding contributed to the success of this case when combined with the ceramics.
It is important to note here that ceramic systems have been predominantly developed in Europe, where tooth whitening is less prevalent, and the need for brighter shades has been slowly recognized. As a result, the selection of available bleach-shaded materials is still limited in many systems.
Post-bleaching, unrestored natural teeth exhibit shades 3 and 4 shades brighter than A-1 or B-1 (Figs. 16 & 17), so the ceramist must now not only use his or her natural morphology skills, but also learn the layering techniques required to reproduce the color and translucency effects of natural teeth that have been bleached.
To further complicate this endeavor, most bleached teeth exhibit a color that is higher in value and has a slightly warmer chroma range than most commercially available shade guides. This makes high quality photographic communication essential to restorative success.
Specifically, a photograph with the shade tab that is closest to matching the color of the tooth, is imperative so that the ceramist can visualize the deviation of color from a known value.8 It is also critical to include a photograph of the prepared tooth (Fig. 18) so the ceramist can evaluate the influence that this underlying color will have on the final restoration.
The ceramist can then select a pressing ingot (Fig. 19) or ceramic powder appropriate for replacing the tooth structure removed during preparation and develop a layering strategy to reproduce the optical properties of the adjacent natural dentition (Figs. 20 & 21).
Note that pressed ceramic ingots are available in a variety of opacity and chroma choices. When developing a strategy for treatment, underlying dentin color should be evaluated and preparation thickness determined (Fig. 22) by the degree of color change desired. This is especially important when trying to match very brightly colored teeth (Fig. 23).
The clinician must also estimate the thickness of the proposed ceramic material in order to filter the underlying color and produce the desired optical result. The greater the deviation between existing preparation color and final desired restoration color, the more aggressive preparation necessary to achieve an acceptable color match (Fig. 24).
The use of direct composite bonding to block out strong, undesirable underlying color during the preparation appointment greatly improves the predictability of esthetic outcomes (Figs. 25 & 26).
Preparation depth may vary in different regions of the tooth depending on where more or less masking is desired. Ingot selection will then be based on the amount of filtering of the underlying color necessary and the amount of translucency desired in the final restorations. The optimal results are obtained when the restorations serves as a filter and some color comes from the underlying dentin.
Obviously, for this technique to work, underlying dentin color must be in an acceptable chroma range, not grey, purple or black. The best ingot choices in the IPS Empress system for this purpose are the ETC1, ETC0 and ET2 ingots, all of which demonstrate a translucency level that allows color to radiate through from underneath.
Where more masking and brighter teeth are desired, EO1 and EO2 ingots provide greater levels of opacity and brighter final results. EOC1 is similar to the EO1 ingot in opacity, but it has some chroma introduced and is useful where masking is desired without excessively bright results. In such cases, bleached dentition can be replicated with ETC0, EO1 and EO2 ingots.
Communicate for conservative technique success
The following case (Fig. 27) exemplifies detailed communication and planning for minimally invasive treatment. Esthetic concerns could have been improved by minor tooth movement, but would not improve tooth size discrepancy at the laterals. Mock-up, diastema closure with bonding (Fig. 28), preparation (Fig. 29), and ceramic veneers at the laterals produced a conservative and beautiful result (Figs. 30 & 31).
Minor tooth repositioning with veneers
Oftentimes clinicians are able to implement minor changes in contour and position utilizing esthetic veneers, without compromising the entire smile line or other natural teeth (Figs. 32 & 33). The power of recontouring and additive/reductive diagnostic mock-ups allows for the planning and preparation of such cases (Figs. 34 & 35).
The final outcomes (Fig. 36) demonstrate improvements in contour, position and proportions that might otherwise not be achieved with orthodontic movement. Utilizing this diagnostic approach yields predictability, even when proportion and soft tissue challenges still exist.
Today’s esthetic and restorative dentist is faced with many clinical challenges. However,
as true professionals, we must remain educated, develop an excellent doctor and ceramist relationship, and master the art of communication.
We are often faced with highly demanding esthetic dilemmas (Fig. 37) that require the involvement of specialties (Fig. 38), a working knowledge and plan for occlusal stability, conservative tooth reduction (Fig. 39), exact provisionals (Fig. 40), state-of-the-art ceramics (Fig. 41), and perfect biological acceptance, all of which lead to esthetic success and functional longevity (Fig. 42).
With time, patience and practice, we can even accomplish the most difficult challenge in dentistry–the single anterior crown –which can often become a non-profitable effort when patient expectations are high (Figs. 43 & 44). However, by following the suggestions and examples provided in this article for the use of mock-ups, communication with the ceramist, and more conservative approaches to treatment, success with less invasive approaches can be achieved.
Dr. Trinkner maintains a private practice in Columbia, South Carolina. He is a Teaching Associate at the Pankey Institute and currently Editor for the American Academy of Cosmetic Dentistry Journal.
Dr.Roberts is an accredited member of the American Academy of Cosmetic Dentistry. He lectures nationally and internationally and has worked with many of the leading clinicians in the world. He is on the editorial board of many of the leading dental and laboratory journals.
Oral Health welcomes this original article.
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