CLINICAL SCIENCES

A review of esthetic alternatives for the restoration of anterior teeth

Antonio Bello, DDS, a and Ronald H. larvis, DDS, MSD b Universidad Naciona[ Autonoma de Mexico, Lomas de Chapu]tec, Mexico, and State University of NewYork at Buffalo, Buffalo, N.Y.

Purpose. This article describes different options for the esthetic treatment of anterior teeth, starting with minimally invasive procedures, such as facial surface bleaching and bonding with composites. Methods. The importance of metal ceramic restorations, porcelain shoulder techniques, and metal free ceramics are also emphasized. The options are carefully demonstrated to identify advantages and limita- tions of each technique. (J Prosthet Dent 1997;78:437-40.)

In the restoration of anterior teeth, there are many factors to be considered that depend on the patient's expectations and the expertise of the dental practitio- ner. The purpose of this article is to provide a checklist of esthetic systems for the restoration of anterior teeth and to cover important factors to consider before choos- ing a specific treatment.

M IN IMALLY INVASIVE PROCEDURES

Bleaching

Patients frequently desire improvement in their smiles because fashion magazines emphasize innovative meth- ods to improve esthetics. However, potential patients are unaware of treatment options, so it is the responsi- bility of the dentist to suggest the most conservative, desirable treatment. When patients complain of "ugly teeth," the dentist must determine whether the term uglyis the result of color or shape of the dentition. There- fore the following questions are appropriate: (1) Are you comfortable with the shape of your teeth and (2) do you approve of the color of your teeth?

I f the answer to question one is affirmative and color is the main concern, bleaching the teeth is a reasonable choice? However, the patients should understand that this procedure is only considered a temporary measure. Furthermore, whiter teeth are merely an interim mea- sure if smoking or excessive drinking of liquids that stain are continued.

Resin bonding

When a patient wishes to improve their smile because of dark spaces between the teeth (Fig. 1), esthetic bond- ing may be the resolution. I f the configuration of the teeth is modified, the patient can achieve satisfaction. I f the patient does not smoke or drink dark-colored liq- uids that can alter the color of the teeth, esthetic bond-

Fig 1. Patient with diastemata between central and lateral in- cisors.

Fig. 2. Diastemata were closed with composites, following natural outline of teeth.

Presented before the American Prosthodontic Society, Chicago, Illi- nois, February 1996.

aAssociate Clinical Professor, Department of Prosthodontics, Universidad Nacional Autonoma de Mexico.

%ssociate Clinical Professor, Department of Prosthodontics, School of Dental Medicine, State University of New York at Buffalo.

ing with composites is the most conservative approach for several reasons; namely, (1) sound tooth structure will not be removed, (2) anesthetics are infrequent, (3) one appointment is common, and (4) the professional fee is usually inexpensive.

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Fig. 3. Bonding on central and lateral incisors. Fig. 5. Porcelain fused to metal crowns on central and lateral incisors are deficient in length, color, and margins.

Fig. 4. Porcelain veneers to replace bonding on central and lateral incisors.

Fig. 6. New porcelain fused to metal crowns on central and lateral incisors blend with natural dentition.

I f the natural outline of the patient's tooth is followed, an esthetic result can be ensured (Fig. 2).

IRREVERSIBLE PROCEDURES

Porcelain laminate veneers

Porcelain vencers were described in dental literature in the early 1980s 2 and introduced a conservative op- tion for esthetics. The esthetics and life expectancy of these restorations surpass composite esthetic bonding. The patient in Figure 3 had composite bonding placed on the maxillary incisor teeth 4 years previously. How- ever, patient decided to have new restorations with a more natural appearance. Porcelain laminate veneers were placed with use of the translucent ceramics on the maxillary incisors and maxillary right canine for a more natural appearance (Fig. 4). 3'4

This method ofadhcring porcelain to tooth structure was also used for artificial crowns, inlays, and onlays.

The restorations were made on refractory dies, but un- fortunately were met with limited success.

Meta l /ceramic restorat ions

Porcelain fused to metal (PFM) crowns are selected for most clinical situations for several reasons: (1) PFM crowns arc stronger than other ceramic restorations; (2) they possess more durability; (3) they are esthetic in the presence of thick gingival tissue; (4) fabrication is a fa- miliar procedure to dental laboratories; (5) PFM crowns are selected for anterior and posterior teeth; (6) they are suitable for fixed partial dentures (FPDs); (7) they are indicated for implant prosthesis; and (8) PFM crowns are acceptable for extremely dark teeth.

When appropriately constructed, PFM crowns can reverse an esthetic (Fig. 5) problem with naturally ap- pcaring crowns on the maxillary incisors (Fig. 6). The PFM crowns were selected for the patient in Figure 6

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Fig. 7. Porcelain fused to metal crown on natural tooth struc- ture displays gray appearance at gingival margin.

Fig. 8. Grayish appearance at margin is avoided because of porcelain facial margin.

because the gingival tissue S allowed the disguise of the margins of these restorations.

Porcelain margin for meta l /ceramic crowns

There are certain clinical situations in which PFM crowns do not meet the expectations of either the den- tist or the patient. This is commonly seen because of extremely delicate gingival tissue, with a grayish color evident in the cervical third (Fig. 7). One method of verifying this clinical condition is the placement of a periodontal probe in the gingival crevice. I f the tip of the periodontal probe is observed through the gingival margin, a conventional PFM crown should be avoided and a porcelain gingival margin substituted. The gray shadow in a conventional PFM crown will disappear when the facial margin is constructed in porcelain (Fig. 8).

The porcelain margin for PFM crowns was first intro- duced in the 1960s. 6 It was later popularized by differ- ent researchers in the 1970s7-9 and in the 1980s the tech- nique was improved with introduction of shoulder por- celain. This new porcelain made it easier to fabricate the gingival margin and increased its popularity. This type of modified PFM crown can be selected for most clini- cal situations, and when indicated, possibly including a short span FPD.

ALL CERAMIC RESTORATIONS Porcelain jacket crowns

The porcelain jacket crown (PJC) was introduced over five decades ago. The porcelain available then was high fusing and not resistant to fracture. Later, alumina ox- ides were added to the composition of porcelain, 1 cre- ating aluminous porcelain. This innovation in metal-free ceramics provided a stronger and more durable restora- tion. This aluminous technique is still used with the ap- plication of opaques during fabrication, but occasion-

Fig. 9. Three-unit FPD replacing maxillary right central incisor, with In-Ceram ceramic prosthesis.

ally restricts adequate translucency in teeth where mini- mal tooth reduction is allowed. I f adequate tooth re- duction is possible, an aluminous PJC is an excellent selection. However, it is considered the weakest (RH Jarvis and R Tallents oral communication, 1995) and most susceptible restoration to fracture in the metal- free ceramics category of esthetic restorations.

In-Ceram ceramic restorations

In-Ceram ceramic is another all ceramic system (In- Ceram ceramic, Vita Zahnfabrik, Bad Sackingen, Ger- many) that will provide a satisfactory alternative for es- thetics. ~ It is considered the strongest of metal-free ce- ramic systems currently available. ~2 It is the only system used in a short span FPD 13 (Figs. 9 and 10), replacing the maxillary right central incisor. When appropriately used, it provides an acceptable margin, but adequate tooth reduction is required for esthctics.

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Fig. 10. Occlusal view of three-unit FPD in In-Ceram ceramic.

Fig. 11. Fractured maxillary left central incisor in 18-year-old man.

Empress ceramic system

Although the first reports were available in 1987, this heat-pressed ceramic system was introduced in 1990.14 Empress ceramic restorations are indicated for anterior crowns, posterior inlays, and onlays with impressive es- thetic results. The advantages of this system are (1) suit- able marginal fit, (2) minimal abrasion, I~ (3) acceptable esthctics, and (4) conservative tooth preparation.

When a qualified ceramist is engaged, the dentist can achieve desirable results, even in critical clinical situa- tions, including the crown on a fractured maxillary left central incisor (Fig. 11), and the final result with an Em- press ceramic crown (Fig. 12).

CONCLUSIONS

Selection of a restoration should depend partly on preservation of natural tooth structure, with the least trauma. Nevertheless, it is important to be aware of the limitations of specific techniques, such as avoiding por- celain veneers in extremely dark teeth. The sophistica- tion of all ceramic systems should be limited to those

Fig. 12. Maxillary left central incisor has been restored with Empress ceramic crown.

clinical situations when gingival tissues compromise the esthetics of conventional PFM restorations.

We acknowledge the ceramic work done by Thomas Graber and Marco Reyna.

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