November/December 2007, Volume 3, Issue 10
Published by AEGIS Communications
Elegant Esthetics: Restoring The Natural Beauty of Teeth With Composite
Lynn A. Jones, DDS
With the new generation of composites, it is fun and easy to build beautiful veneers and restorations that blend invisibly with the natural dentition. Composites allow for maximum artistic expression and are a perfect way to develop excellent color-matching and smile-design skills. A well-designed composite veneer can rival its porcelain counterpart in esthetics and longevity.1-3 Patients often prefer composites because tooth reduction can be minimized for a composite restoration. Composites are fast; patients love the same-day service; and when used in the right place composites can be quite durable.4,5
One of the challenges with Class 4 composites is hiding the change in color or translucency in the composite as compared to the tooth. This complication can also be an issue in large diastema closures, large Class 3 composites, or composite veneers that significantly lengthen the incisal edge of the tooth. Composite veneers that simply cover the same area as the tooth and are fully backed with dentin are simpler to match. Another concern is that the diagonal line still shows after the composite has been placed even though the color match of the composite seems to be good (Figure 1).
These obstacles can become much easier to overcome with a few simple techniques to enhance the blending of the composite into the tooth. The key challenges are to recreate the missing tooth contours; conceal the unnatural diagonal line between the tooth and the composite; and create adequate opacity to prevent the restoration from looking grey or translucent compared to the remaining tooth structure.
To make the bonding process easier, a diagnostic wax-up can be used to replace the missing segment of the tooth. This wax-up can then be replicated in a matrix that guides the shape and contours for the final composite (Figure 2A and Figure 2B). Starting with the lingual surface of the tooth, the composite is layered into the matrix and cured against the prepared surface of the tooth. In the author’s experience it is much easier to determine the exact thickness of the layers of the composite material when the restoration has the clearly defined reference points provided by this matrix.
The best way to prepare a Class 4 restoration is to make wavy lines that run vertically and horizontally (Figure 3).6,7 Diagonal lines should be avoided as much as possible because they are seldom seen on a healthy tooth. These lines should be carried through the fingerlike extensions prepared into the facial surface of the tooth to the wavy, step-like edge that is shaped into the dentin on the horizon line at the edge of the fracture.
An alternative preparation on the facial surface is to prepare the enamel right up to the edge of the free gingival margin with a long or infinity bevel. This design is required if the shade of the tooth is being altered. The amount of reduction should be increased with increasing color change because the color is concealed by the thickness as well as the opacity of the composite.8,9 The lingual surface of class 4 restorations is best beveled with at least 1-mm clearance in all directions from any occlusal contact points (Figure 4).
The adjacent teeth are wrapped in Teflon tape. The prepared tooth is etched at least 2 mm beyond the edge of the preparation, covered with iBond (Heraeus Kulzer, Armonk, NY) resin and primer, gently dried with air, and then cured with a Demetron light (Kerr Corporation, Orange, CA) (Figure 5A and Figure 5B).
The first layer of the composite is pressed into the matrix in a thin layer and shaped right out to the labial incisal angle of the tooth in the matrix. Depending on the desired outcome, one of three basic approaches to shade selection can be used at this step. When a white incisal halo is desired, Venus® SBO super bright opaque shade (opaque white dentin) (Heraeus Kulzer) can be used to block out shadows with the composite backing. When the tooth is very thick with extra room for opaque layers, or is very translucent already and needs extra incisal translucency to blend in accurately, an enamel shade in the matrix that matches the lingual shade of the tooth should be used. In the author’s experience, this method looks esthetically pleasing on the lingual of the tooth but can cause excessive translucency if the tooth is naturally thin or very opaque. If the tooth is quite opaque and lacking in characterization translucencies or halos, then it works best to use a dentin shade that matches the tooth as the first layer in the matrix.
The matrix is then carefully positioned onto the teeth and held firmly in place on the lingual of the prepared tooth. Excess composite is then worked into intimate contact with the edge of the tooth and the excess composite is scooped out of the incisal region, creating a hollow, cupped-out area to receive the selected layers of composite, tints, and opaques. The light will cure through to the lingual by exposing the composite on the facial surface. The author likes to double the curing time on the first layer before removing the matrix and then immediately cure the restoration one more time on the lingual after the matrix has been removed (Figure 6A and Figure 6B).
After the lingual shell has been cured the dentin is replaced with the corresponding shade of opaque composite. Usually the Venus opaque shades will adequately block out all of the shadows, eliminating the need for extra opaque liners. The Venus Flow (Heraeus Kulzer) baseliner is a very opaque white and can be used in a thin layer like a tint right under the enamel if extra opaque is necessary to conceal the translucency. With a rigid shell to support the additional layers of composite, it is easy to roll the composite into tiny strings and balls to pick up and position exactly where they are needed to replicate the lobes in the natural dentin.
The additive technique is preferable to the author because the uncured oxygen-inhibited layer bonds more readily with the next layer of composite and it eliminates the need for cleaning up cut surfaces and then re-etching and bonding before adding the next layer. It also seems to reduce the incorporation of bubbles into the layers of composite. For the author, taking extra time to mold the dentin into shape from the beginning is ultimately a time saver.
At this point, the demarcation line from the fracture should be well blended into the natural tooth. If it is not, then this is the time to modify the color to block out the transition from tooth to composite, before the final layers of enamel and translucent shades can be used to characterize the color. The author likes to place a layer of Durafill® VS light (Heraeus Kulzer) over the completed restoration to get the high, sustainable shine of a microfill.
Using the techniques described in this case study, the author has found that the challenge of having a translucent line between the tooth and a Class 4 composite can predictably and consistently be eliminated so that there is no trace of a restoration visible on the damaged tooth (Figure 7).
The following people were some of the author’s original teachers. These dentists have been inspirational and influential in teaching her some of the nuances that help in obtaining consistently beautiful esthetic results: Norman Feigenbaum, DDS; Robert Nixon, DDS; Buddy Mopper, DDS; and Newton Fahl, DDS, MS.
The author has received honoraria and material support from Heraeus Kulzer.
References1. Christenson, G. Longevity of posterior tooth dental restorations. J Am Dent Assoc. 2005;136(2): 201-203.
2. Milnar F. A minimal intervention approach for treating a class IV Fracture. Journal of Cosmetic Dentistry. 2006;21(4):106-112.
3. Kelly PG, Smales RJ. Long-term cost-effectiveness of single indirect restorations in selected dental practices. Br Dent J. 2004;196:639-643.
4. Peumans M, Van Meerbeek B, Lambrechts P, Vanherle G. The 5-year clinical performance of direct composite additions to correct tooth form and position. Clin Oral Investig. 1997; 1(1):12-18.
5. Burke FJ, Shortall AC. Successful restoration of load-bearing cavities in posterior teeth with direct-replacement resin-based composite. Dent Update. 2001;28(8): 388-394,396,398.
6. Orser S. Accreditation Clinical Case Report, Case Type IV: Class IV Direct Resin Restoration (Teeth #7 and 8). Journal of Cosmetic Dentistry. 2003;19(2),51-57.
7. Featherstone R. Accreditation Clinical Case Report, Case Type IV Direct Resin Restoration (Tooth # 8). Journal of Cosmetic Dentistry. 2003;19(2):44-46.
8. Larson TD. 25 Years of Veneering: What Have We Learned? Reviewing options to correct perceived flaws in smiles. Northwest Dent. 2003;82(4):35-39.
9. Lowe E, Rego N, Rego J. A delayed subopaquing technique for treatment of stained dentition: clinical protocol. Prac Proc Aesthet Dent. 2005;17(1):41-48.
|Figure 1 Concealing the diagonal line in a Class 4 restoration has been identified as a challenge for many practitioners.||Figure 2A Fractured incisal edge (image taken from a different case).|
|Figure 2B Matrix molded over the wax-up or in this case composite mock up (image taken from a different case).||Figure 3 Wavy lines and finger-shaped grooves are cut into the enamel to blend in and conceal the edge of the composite.|
|Figure 4 Long lingual bevel that is over 1 mm from the occlusal contact in all directions. (Photograph was altered to black-and-white to increase the visibility of the margins.)||Figure 5A After placing the putty tape, the tooth is etched well beyond the margins of the preparation.|
|Figure 5B The tooth after it has been etched, bonded, dried, and cured.||Figure 6A Working the composite into the matrix. (Photograph was taken from a different case.)|
|Figure 6B Layering opaque composite into the lingual shell created with the matrix.||Figure 7 The final restoration.|
|About the Author|
|Lynn A. Jones, DDS |
Owner and Director
Bellevue Center for Cosmetic Dentistry