Written by Tarun Agarwal, DDS Friday, 30 September 2005 19:00
There is very little doubt that one of the most difficult procedures in dentistry is matching the single front tooth. The process involves meticulous photographic documentation of preoperative tooth condition and shade(s), detailed communication with a master ceramist, and exquisite duplication and artistic sculpting by the ceramist. This process often involves higher fees from both the dentist and ceramist, thus leading to a higher fee for the patient. Luckily for many situations there is another option: anterior direct bonding.
With the proven long-term results of direct composites, manufacturers have recently been able to focus their attention on the handling and aesthetics of direct restorative materials. This focus has led to materials that very closely mimic the aesthetics of natural teeth and provide the handling necessary to allow dentists the confidence and time to sculpt these restorations artistically. Anterior direct bonding gives the clinician complete artistic control of tooth shade, tooth morphology, and tooth characterizations.
This case study will detail step by step the single-visit direct restoration of grossly decayed teeth Nos. 7 and 8 using the shaded build-up technique with 4 Seasons direct restorative composite (Ivoclar Vivadent).
When is a direct composite an appropriate restoration for anterior dentition? One must look at a multitude of factors in order to make this determination. First, look at the amount and condition of remaining tooth structure. Second, determine the degree of difficulty in matching shades using indirect laboratory versus direct restorations. Finally, evaluate the functional and occlusal load the direct restorative will be required to bear.
|Figure 1. Preoperative view.|
In this case (Figure 1), it has been determined that a significant amount of sound tooth structure will remain after removal of decay and unsupported tooth structure. Because of the significant shade characterizations, the author felt that having complete control intraorally would yield a more predictable artistic result than would sending the case to a laboratory. Finally, these restorations will face minimal occlusal stress because the opposing teeth are part of a lower partial denture. After careful evaluation it was determined that a direct composite restoration would be an appropriate solution.
SHADED BUILD-UP TECHNIQUE
|Figure 2. Frontal view of teeth layers.||Figure 3. Cross-section view of teeth layers.|
The objective of any restoration is to replace missing tooth structure with artificial materials that appear natural. The first step is to understand the dynamics of tooth structure. Natural teeth consist of both dentin and enamel, each of varying opacity and translucency (Figures 2 and 3). Our thought process to produce natural-looking restorations must be to replace each section as it was created in nature, using materials that closely mimic it's opacity and translucency.
|Figure 4. Shaded layering technique.|
The shaded build-up tech-nique replaces each layer of tooth structure with a single-shade composite with an appropriate opacity and trans-lucency (Figure 4). First, the final desired shade is chosen. Then each layer is replaced with the dentin and enamel shade. For example, if your desired tooth is a Vita B3 (Vitapan), then you replace dentin with Dentin B3 and enamel with Enamel B3 (4 Seasons, Ivoclar Vivadent).
|Figure 5. Shaded build-up technique.|
In situations where surface characterizations are required, the enamel layer would be built to approximately 0.5 mm shy of full contour. The characterizations would be placed through use of tints and/or composites, followed by a layer of clear enamel to full contour. By placing a layer of clear enamel over the characterizations, you allow the characterizations to be covered and protected against wear and allow the tooth shade and characterizations to "show through." Figure 5 shows a color diagram of how this layering would look in cross-section.
|Figure 6. Close-up view of teeth Nos. 7 and 8.|
Clinical examination revealed gross decay on teeth Nos. 7 and 8 (Figure 6). A clinical and aesthetic decision was made to restore using direct composite, which would allow the clinician complete control of the artistic result. The appropriate shade must be chosen prior to beginning any work while the tooth is completely hydrated.
|Figure 7. Waterlase used for initial preparation.||Figure 8. Round bur used to remove decay.|
|Figure 9. Diamond finishing bur to complete preparation.||Figure 10. Close-up view of completed preparation.|
Since the patient exhibited apprehension and fear of needles, it was decided to avoid the use of needles by utilizing the Waterlase (Bio-lase Technologies) to perform the majority of tooth preparation (Figure 7). After removal of enamel and the subsequent "anesthetic effect" of using the laser for tooth preparation, a large, round bur on a slow-speed handpiece was used to remove gross decay (Figure 8). Finally, a finishing diamond was used to remove any unsupported tooth structure as well as create a long bevel to help hide the restorative margin (Figure 9). Tooth preparation was completed, and the area was cleansed (Figure 10).
After completion of the preparation and cleansing of the restorative area, bonding was initiated using a total-etch technique. Each preparation was treated and restored individually to allow for proper anatomic buildup and contours. The etchant was placed on enamel followed by placement on dentin of tooth No. 8. Total etch time was 15 to 20 seconds on enamel and 10 seconds on dentin. A fifth-generation adhesive was placed on the tooth and agitated for 20 seconds to allow complete penetration of resin adhesive. The tooth was lightly air-dried to allow for solvent evaporation and light-cured.
|Figure 11. Lingual shelf built with Enamel D2.||Figure 12. Dentin replaced with Dentin D2.|
|Figure 13. Characterizations placed using tints.||Figure 14. Super Clear Enamel placed.|
|Figure 15. Restoration being contoured to final shape.||Figure 16. Restorations being finished.|
|Figure 17. Completed restorations.||Figure 18. After.|
Next, the shaded build-up technique was utilized to begin restoration of tooth No. 8. First, the Enamel D2 shade was used to create a lingual shelf and was completely cured (Figure 11). Dentin D2 was then placed and cured to replace lost dentin. Any mammelons and lobing should be placed in the dentin layer (Figure 12). Enamel D2 was again placed approximately 0.5 mm shy of full contour and cured completely. At this point any surface characterizations are placed using appropriate tints and composite colors (Figure 13). Finally, a layer of Super Clear Enamel (4 Seasons, Ivoclar Vivadent) was placed over characterizations and built slightly beyond ideal contours (Figure 14). A coarse sandpaper disc was used to contour the overbuilt tooth back into ideal form and shape (Figure 15). Tooth No. 8 was contoured and polished to a smooth surface interproximally, lingually, and facially. Tooth No. 7 was then restored using the same bonding protocol, shade selection, and layering technique. Occlusion was checked and adjusted, both restorations were polished facially and lingually (Figure 16), and strips were used to smooth the contact area. The restorations were then completed (Figure 17).
Thanks to advances in composite handling and artistry, the direct composite restoration is a fantastic option to artistically create polychromatic anterior restorations that defy detection. By understanding the layering of natural teeth and using an appropriate composite system, we are able to mimic tooth structure with artificial materials that appear natural (Figure 18).
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