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Protecting the Deep Cavity Surface Case Presentation

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A 28-year-old woman presented with an old, failing amalgam restoration on the occlusal surface and a missing filling on the buccal sur­face of tooth No. 19 (Figure 1). Bitewing and periapi­cal x-rays were taken to ensure that no interproximal caries or periapical lesions were present (SuniRay, Suni). Then, an intraoral photo was taken to present and confirm the caries (CS 1200, Carestream).

Failing amalgam restoration on occlusal surface

After distributing 2% Lidocaine with 1:100,000 epinephrine on the inferior alveolar block, a rubber dam was placed (Figure 2). The existing amalgam was then removed using an inverted cone diamond bur (Figure 3) and all soft caries were removed using carbide round burs with a slow-speed handpiece (Midwest Shorty, Dentsply Sirona).

Placed rubber dam after distributin lidocaine


removing existing amalgam using inverted cone diamond bur

To ensure a clean, neat cavity preparation, the superficial caries and stains were removed conservatively with a small round diamond bur. Intraoral photos were taken to confirm no caries were left behind (Figures 4-5). To ensure absolute isolation, a liquid dam was placed around the tooth (Figure 6).

occlusal view after soft caries removal


buccal view after soft caries removal


Liquid dam placed around the tooth to ensure absolute isolation

 Creating a Durable Restoration

TheraCal LC (BISCO) was placed on the cavity surface to decrease sensitivity and mask the dark amalgam stain that could potentially show through the planned translucent composite restoration (Figure 7). TheraCal LC is a resin-based calcium silicate containing material that is ideal to use as a protective liner in deep cavity preparations; it can be easily placed through its syringe delivery system. It also is highly durable and allows for immediate placement. In this case, I placed TheraCal LC on the deep cavity surface and light-cured it for 20 seconds.

A wide bevel was placed on the occlusal and buccal surfaces and a selective enamel etching technique was performed using 37% phosphoric acid (Figure 8). The area was rinsed and dried and a bonding agent was placed and then lightly air dried.

TheraCal LC is placed on deep cavity surface


selective enamel etching techniqeu using 37% phosphoric acid

Using a condenser, composite shades A2 and A3 (Estelite Sigma Quick, Tokuyama Dental) were placed on the occlusal and buccal surfaces, respectively. Before light curing, some occlusal anatomy was created using several hand instruments (21B Burnisher, Hu-Friedy; Blue Titanium CIB3, Pioneer Solution; CEEX3A, Nordent). Then, occlusal adjustments were made and more detailed anatomy was created using football- and needle-shaped diamond burs (Brasseler USA).

Polishing and Final Outcome

Polishing was completed using a large coarse polishing disc (Sof-Lex, 3M), a fine needle-shaped diamond bur, and a White Arkansas Stone (Dedeco). The final restoration blended nicely to the tooth after occlusal adjustments and polishing (Figures 9-10).

My patients never leave the office without a clear view of the final outcome, and this patient was completely relieved and happy to see such a healthy, natural-looking restoration before she left the chair.

selective enamel etching technique

Postop view of the final restoration

Product used in this case:

TheraCal LC®

A light-cured, resin-modified calcium silicate filled liner, TheraCal LC is indicated for direct and indirect pulp capping and as a protective liner under composites, amalgams, cements, and other base materials. The proprietary hydrophilic resin formulation creates a durable liner, while its light-cured set permits immediate placement.

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