977PPA News in Science


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977PPA News in Science

  1. 1. DENTAL NEWS IN SCIENCE EXCELLENCE WITH SIMPLICITY IN AESTHETIC DENTISTRY Bernard Touati, DDS, DSO T he advent and improvement of high standards consistently with simple con- Bernard Touati, DDS, restorative materials and tech- ventional techniques, provided they know DSO, is President of the niques have resulted in impressive how to optimize those techniques and how European Academy of Esthetic progress in aesthetic prosthetic to train their technicians to maintain high- dentistry. It is now possible to routinely level aesthetic dentistry. Dentistry, and a member of the achieve aesthetic dental restorations that emu- Without doubt, the new millennium will American Academy of Esthetic late natural dentition, without sacrificing bring the challenge of providing excellent aes- Dentistry. He maintains a strength, function, or longevity. This progress thetic dentistry at a reasonable cost to a wider has often been accompanied by an increase in segment of patients. This objective can be private practice, emphasizing sophisticated technology, equipment, and achieved in the United States and Europe Prosthodontics and Aesthetic armamentarium, thereby dramatically within the near future, and it is a moral duty increasing the overall cost and time required of every leader and teacher to prove that this Dentistry, Paris, France. for dental treatment. objective is at least attainable. New all-ceramic materials, computer Within the last decade, we have seen imaging systems, CAD-CAM, lasers, and exceptional aesthetic restorative work per- other innovations are examples of this tech- formed by clinicians and master technicians, nology, and a number of dentists believe that all of whom can be considered true artists in excellence in dentistry inevitably means their specialty. Due to their exceptional per- “high-tech” and additional cost. In some ceptiveness and skills, aesthetic dentistry has instances, this belief is true. For example, who reached new heights. Now is the time to could achieve an impeccable implant place- search for less costly materials and tech- ment in an irregular alveolar arch without the niques; it is also time to simplify these tech- guidance of CT scan imagery? However, it niques whenever possible in order to render must be understood that in prosthetic and them reachable by an increasing number of restorative dentistry clinicians can achieve clinicians in the interest of the community. 806 Vol. 9, No. 7 THE INTERNATIONAL AESTHETIC CHRONICLE
  2. 2. Figure 1. Case 1. Preoperative view of worn-out dentition with reduced vertical Figure 2. Preparations are performed on vital teeth, despite the reduced height dimension of a 60-year-old male patient, requiring complete oral rehabilitation. of the teeth. Improvements in the composition and polymerization of com- posite resins have resulted in the “second-generation” laboratory composite resins, which some manufacturers call ceramic optimized polymers. These biomaterials are less expensive than ceramics, and their handling characteristics are simplified and more efficient. When utilized for the fabrication of inlays and onlays, for example, the aesthetic result is similar to that of the ceramics. Their clinical longevity remains to be proven; however, they are now considered to be superior to ceramic inlays/onlays in various clinical circum- stances due to their slight resilience and high flexural strength. Although aesthetic inlays and onlays have long been consid- Figure 3. Once the PFM crowns with vertically reduced frameworks are tried in at the biscuit bake stage, a silicone impression is taken and a second ered an expensive and sophisticated treatment option for the for- plaster model is poured. The emergence profile achieves an accurate intimate tunate few, it is now safe to predict that this option will soon be contact with soft tissues during the last bakes. utilized in indirect and semi-direct techniques on a more popular level, due to its specific qualities. Reinforced with the addition of ultra-high molecular weight polyethylene fibers, these new labo- ratory composite resins are also indicated for metal-free single crowns, 3-unit bridges, resin-bonded bridges, and implant- supported restorations. Since this technology does not require waxing, spruing, investing, and casting, its utilization is less time- consuming and more cost-effective. The monobloc technique might prove to be an effective alternative in treatment of posterior dentition, when compared to the conventional metal cast post-and-core with a metal-ceramic Figure 4. A pleasing emergence profile has been created, reducing the black crown restoration. A considerable treatment time could be saved triangular spaces by bringing the proximal contact toward the soft tissues. in the laboratory and chairside, including two castings and the luting of the post-and-core. A fiber-reinforced composite (Targis/Vectris, Ivoclar Williams, Amherst, NY) monobloc preservation of tissues, biocompatibility, and harmonious func- crown can be safely bonded with single-component primer adhe- tion. They have been the scientific foundation of the European sive and dual composite cement; it offers an economic advantage, Academy of Esthetic Dentistry, and for next year’s meeting in yet is biocompatible and offers a highly aesthetic final result. Paris (May 1998) the theme of “Excellence with Simplicity” has In Europe, Drs. John McLean and Peter Schärer have been selected to underline the importance of the simplification of made a dramatic impact on aesthetic dentistry, and their influ- treatment modalities. ence has made this specialty highly respected. During the past During the 1980s, emphasis was placed on the color of the decade, they have focused on quality, aesthetics, and longevity of prosthetic restorations. Most scientific meetings on aesthetic restorations, and have trained several generations of dentists to dentistry were addressing the topic of how a ceramic material meet the requirements of excellence. They have lectured and (feldspathic, leucite-reinforced, glass ceramic, etc.) could repro- published throughout the world to introduce their concept of duce the vitality of a natural tooth, ie, hue, value, chroma, and aesthetic dentistry, which includes not only beauty but also translucence. It was the time of great interest in the ability of 808 Vol. 9, No. 7 THE INTERNATIONAL AESTHETIC CHRONICLE
  3. 3. Figure 5. Due to the second model technique, the transmucosal aspect of the Figure 8. A silicone impression (double mix technique) is taken during try-in ceramic restorations is biologic and naturally aesthetic. of the single crowns. margin ceramics, clinically proving that similar vitality can be obtained with metal-ceramic crowns as with all-ceramic crowns. Even when the supporting teeth are discolored, predictable results with superior aesthetics can be achieved (Figures 1 through 6). Now that color is no longer a serious concern, shape, posi- tion, and arrangement are the major factors affecting the natural integration of the prosthetic restoration. The form of a dental prosthesis is highly determinant in the creation of the illusion of natural teeth. The aesthetic outcome depends on the gingival integration, soft tissue scalloping, and re-creation (or mainte- Figure 6. The final result displays harmonious intimacy between the crown nance) of the interdental papillae. Therefore, the primary efforts restorations and the soft tissues. in a prosthetic treatment are focused on creating harmonious cervical contour, supporting the papillae, avoiding or reducing the black triangular spaces, and creating a pleasing emergence profile, which must be analyzed and created by the dentist and the technician in three dimensions — the buccal, transversal, and horizontal planes. These dimensions represent the transmucosal aspect of the dental restoration and are the crucial region of the overall tooth shape, which determine the natural aesthetics of the restoration and its longevity. A prosthetic emergence profile cannot simply emulate the emergence profile of natural teeth, particularly in case of gingival Figure 7. Case 2. Preoperative facial view of the anterior dentition with a recession or diastemata. The role of the neocervical contour is to pronounced overbite in a 30-year-old male patient. create new architectural conditions to achieve the illusion of a harmonious emergence of the artificial crown. In an adult patient, the effect is generally an apicalization of the crown con- each ceramic system to emulate the color of natural dentition and tour for improved support of the papillae, in case of slight-to- to provide alternative treatment options without any metal sub- moderate passive eruption. The cervical contour is augmented in structure. Clinicians learned the language of color and the vari- the interproximal aspect, reducing the unaesthetic black spaces ous ways to communicate color to the dental technician. The two and the compromise in phonetics and salivation. primary concerns with porcelain-fused-to-metal (PFM) crown The creation of an optimal emergence profile is even more restorations at that time were the high reflectivity of the opaque important in implant-supported restorations, due to the circular metal layer and the shadowing effect of the substructure on the marginal gingiva, ie, “whitish teeth on grayish gums.” cross section of the implant and its reduced width. Therefore, the Master Ceramist Willy Geller developed the “cut-back” step of creating an optimal transmucosal contour cannot be omit- technique — vertically reduced metal frameworks — which ted in current prosthetic treatments. It is a simple and cost- allows the transmission of light to the marginal gingiva and the effective step with an outstanding effect on the final aesthetic and improvement of opaque and semi-opaque dentins, opaquers, and soft tissue integration (Figures 7 through 12). 810 Vol. 9, No. 7 THE INTERNATIONAL AESTHETIC CHRONICLE
  4. 4. Figure 9. All proximal contacts are carefully evaluated and adjusted to allow Figure 12. Occlusal view of the complete arch rehabilitation. Note the enhanced complete seating of the crowns. The emergence profile and texturization have aesthetic result and soft tissue integration. been finalized during the final bake. required, and take a silicone impression with a double-mix technique. A second hard plaster model is poured in the labora- tory, reproducing the soft tissues, and the ceramist proceeds with the last baking of the ceramic restorations. During this step, the focus is on the relationship between the soft tissues and the con- tour of the crown, particularly in the interproximal region, creat- ing a small convexity to support the papillae. The proximal surface contact is brought closer to the soft tissues, thereby avoiding or greatly reducing the black triangle effect. The technician has been instructed of the Tarnow rule — Figure 10. The final result following cementation with a resin-reinforced the well-known interdependence between the presence of the glass-ionomer cement. papillae and the location of the proximal surface contact. During the try-in, the clinician places a small notch on the proximal sur- face of the crown to indicate the maximum distance of 5 mm between the bone crest and the apical aspect of the proximal contact — a reference point of great importance. This objective is generally achieved during provisionalization, and the patient is instructed in optimal oral hygiene techniques pertaining to the particular circumstances (eg, flossing, proximal mini-brushing, use of chlorhexidine gel, etc.). State-of-the-art ceramic restorations in the anterior region now require that not only the color but also the shape be per- Figure 11. Note how the embrasures (and the cervical aspect of the PFM crowns in general) present a natural appearance. fectly natural. The double model technique is cost-effective and provides excellent aesthetic results in a simple manner. Metal ceramic crowns with a vertically reduced substructure are now routinely fabricated by average technicians without expensive Conventionally, all laboratory master model dies are cervically equipment. It is apparent that the procedure demonstrated in the trimmed below the cervical margins, with the intent to suppress two case presentations allows aesthetic restorations, well inte- marginal gingiva and interdental papillae. When the technician grated into the soft tissues. As previously emphasized, the efforts builds up the ceramic, this lack of information is highly detri- must concentrate on simple techniques for achieving excellent mental to the final shape of the restoration. Soft tissue models aesthetic and biologic results without additional cost to the are not the optimal solution, due to their elasticity and insuffi- patients. During the next decades, the dental profession will cient stability; they also register the architecture of the soft tis- have to prove that aesthetic dentistry is not reserved only for the sues at the time of the impression, with the presence of the fortunate few. retraction cords, which is not the actual contour following complete gingival healing. ACKNOWLEDGMENT A more appropriate solution is to try-in the restoration at The author would like to thank Ceramist Jean Marc Etienne for the the biscuit bake stage, perform necessary alterations, if ceramic work in cases used to illustrate this presentation. 812 Vol. 9, No. 7 THE INTERNATIONAL AESTHETIC CHRONICLE