Oral Health Group
Feature

Direct Restoration of a Discoloured Single Anterior Tooth – A Multi-layer Approach

April 1, 2007
by Paresh Shah, DMD, M.Sc., FAGD


A 20-year-old male expressed displeasure with the color of his front tooth #21 (Fig. 1). The tooth was fractured in a skateboarding accident six years prior. There was a fracture of the incisal third of the tooth, into dentin with a near pulpal exposure. The treating dentist placed vitrebond on the dentin and restored the tooth with P-50 composite resin. The patient did not like the monochromatic appearance as well as the mismatch in shade compared to his natural teeth.

Although the tooth had been asymptomatic for six years, the patient was advised that there may be a risk of requiring non-surgical root canal therapy (NSRCT) when the existing restoration is removed since it was close to the pulp. It was still unclear how much original tooth structure was remaining. In order to create a more natural looking tooth in terms of shade, translucency and appearance, we chose to remove the entire existing composite and take a multi-layered approach.

Advertisement






Prior to removing the old restoration, digital photographs were taken and an initial shade map was made based on the adjacent teeth. The photographs were used as a reference to look back on as the procedure was performed. It’s best to take a shade prior to isolation and preparation so the adjacent teeth do not dry out. In examination, it was deemed that the base shade of enamel was a B1 with some lighter enamel around the periphery. The enamel around the mesial and distal was of higher value so this would be incorporated in the final restoration. The deeper dentin shade was chosen after the restoration was removed. It was deemed to be a D1 shade and so the remaining dentin core was built up in that shade to form the internal layer.

The existing restoration was removed using a coarse diamond bur (Brasseler) with copious irrigation. As the underlying tooth structure was approached, a fine diamond (Brasseler) was used with minimal irrigation to aid in distinguishing between tooth and composite. A chamfer margin was prepared circumferentially with a fine diamond as well. There was no pulpal exposure and an adequate ferrule was still available to prepare another restoration (Fig. 2). Dentin shade was close to D1 and the adjacent enamel was a base shade of B1.

An ultra-thin dead soft matrix strip was adapted around the tooth prior to restoring. This allowed protection to the adjacent teeth along with providing a matrix form to build up the lingual contour of the restoration. 35% phosphoric acid etching (Ultradent) was performed, followed by placement of a bonding agent (Bisco One Step). First, a thin layer of B-1 enamel shade composite (4Seasons) was placed to form a “shell of lingual enamel” (Fig.3). The matrix was then removed and any excess incisal composite is removed using a fresh #12 surgical blade.

After trimming incisal flash, D-1 dentin (4Seasons) was placed to build up the remainder of the body (Fig. 4). A diffuse layer of white opaque composite (Cosmedent) was then applied with a fine ceramist’s brush over the gingival third. By diffusing the material, one can make the demarcation of margins less obvious.

A thin layer of light enamel composite (4Seasons) was placed over the middle third of the tooth and around the mesial portion as well. This was applied with a ceramist’s brush and a flat composite instrument. The light enamel shade was chosen prior to lip retraction and isolation (Fig. 5).

A high value enamel composite (4Seasons) was then applied to the mesial and distal portions of the tooth to mimic the same on the adjacent teeth. This again was applied diffusely with a brush so as not to make the transition too obvious (Fig. 6).

Some white enamel composite (4Seasons) was then scattered throughout the facial surface in a random manner to once again mimic the pattern of the other central (Fig. 7). Care was taken to avoid the light enamel composite that was applied at the previous stage. Finally, a thin layer of clear enamel composite (4Seasons) was placed over the white opaque to give some depth to the facial surface and complete the facial contour of the tooth (Fig. 8). This allowed for the shade to remain consistent while the overall contour is defined. The flat end of a plastic cuticle pusher was used to shape the final contour prior to curing.

Final shaping and finishing was started with ET composite finishing burs from Brasseler (8 and then 12 fluted carbides), followed by the Astropol (Ivoclar-Vivadent) polishing system of cups and points (grey/green/pink). The interproximal was smoothed with medium and fine grit finishing diamond finishing strips (Brasseler). Lobing on the incisal third of the facial surface was created first with a 12 fluted carbide. To smooth it off and make the transition of the lobing less conspicuous, the soft polishing points were used. The final high shine was created using a fine polishing cup with no water spray.

The final restoration immediately after finishing and polishing. The layering process allows for a polychromatic shade leading to a more natural appearance (Fig. 9).

Follow-up after 15 months (Fig. 10).

Dr. Paresh Shah, DMD, M.Sc., FAGD is in private practice in Winnipeg, MB. He graduated from the University of Manitoba in 1991 and will be receiving a Proficiency Certificate in Esthetic Dentistry from the University of Buffalo (SUNY) this spring. He has completed Levels I and II of the Postgraduate Program in Esthetic Dentistry at the University of Minnesota and has been a clinical mentor in the level II program since 2002. Dr. Shah is a founding member of the Canadian Academy for Esthetic Dentistry. Enquires at drshah@drpshah.com.

Oral Health welcomes this original article.


Print this page

Related


Have your say:

Your email address will not be published.

*