Caries removal and esthetic direct composite restorations

Research conducted at Temple University has verified that a new instrument made from a unique polymer resin technology is able to remove decay, and unlike carbides and other burs, is the only rotary cutting instrument that is incapable of cutting healthy tissue.

 

The Smartburs II works because it is harder than decay, but not as hard as healthy dentin.

Mode of operation

The Smartburs II uses an extraordinary concept in blade configuration and material structure, allowing it to remove carious dentin only, and rendering it incapable of cutting healthy dentinal tissue. By eliminating contact with the dentinal tubules, pain is virtually eliminated.

During the removal process, patients have reported only a feeling of pressure, thereby eliminating the need for anesthesia.

This improvement in clinical efficiency translates into savings of both time and cost and an increase in patient referrals.

In cases where the lesion is deep and anesthesia is required, pulp exposure can be greatly reduced, providing safer, more comfortable and effective treatment; making patient outcome — especially in deep preparations — more predictable.

Removing decayed dentin with Smartburs II

Step 1: In order to use the Smartburs II properly, an operating range of 5,000–10,000 rpm in a standard slow speed is ideal and increases the longevity of the bur. In addition, a light brushstroke is used during operation, essentially teasing out the carious tissue.

This is a significant departure from previous techniques using traditional carbide and diamond burs.

Step 2: When treating a carious lesion, it is critical that sharp and ragged enamel edges be removed with an appropriate high-speed bur before introducing the Smartburs II to avoid dulling the instrument.

The Smartburs II is then introduced into the center of the lesion. This helps to avoid unnecessary initial contact with healthy enamel and dentin that could prematurely dull the bur.

Step 3: Starting in the center of the lesion, the most superficial, softest decay is removed using the largest size Smartburs II. The next smaller size Smartburs II is then worked laterally, removing layer by layer throughout the lesion, finally cleaning the entire cavity floor.

The removal of caries to the cavity floor in one area only will prematurely dull the instrument and make caries removal in adjacent areas more difficult.

It is important to emphasize that contact of Smartburs II with hard enamel, healthy dentin or restorative materials will result in dulling and premature failure of Smartburs II.

Step 4: The last action with the Smartburs II is to clean the cavity floor with more forceful strokes. Here you will have increased tactile sense when encountering decay versus using standard carbide burs.

This enables the conservation of healthy tissue when the self-limiting action of the Smartburs II instrument is experienced. After using the Smartburs II instrument, a careful examination of the area is required to confirm complete decay removal.

Case report

A patient reported with the chief complaint of having cavities in his upper front teeth (Fig. 1a). He reported no discomfort, but was self-conscious about his appearance.

Upon examination, the maxillary anterior teeth were diagnosed with both Class V and Class III carious lesions.

A treatment plan was formed that would include the restoration of these teeth using a direct composite resin technique with the possibility of root canal therapy where required.

Following the administration of local anesthesia, the cavity preparation for the maxillary right central incisor was initiated. Retraction cord was used to expose subgingival caries.

Ragged and sharp enamel edges were removed and the enamel opening was expanded using a 330-carbide bur (Fig. 2).

A #6 Smartburs II instrument (SS White) was used at 15,000 rpm to begin gross caries removal (Fig. 3). This instrument was used until the size of the bur head could no longer access smaller areas for effective caries removal (Fig. 4).

This was followed by complete removal of the remaining infected tooth material with a #4 Smartburs II instrument (Fig. 5).

In order to achieve a harmonious, seamless and esthetic transition at the marginal interface, a beveled chamfer was created using an 868-024 flame-shaped coarse diamond (SS White) (Fig. 6).

In class V composite cavity preparations, bevels have been shown to enhance retention, decrease micro-leakage and improve esthetics. To maximize the amount of light diffraction and the final esthetic outcome, a wavy striation pattern was created.

Following total acid etching and the application of a primer/bonding agent (Optibond, Kerr), composite resin was applied. A thin layer of flowable composite resin in shade A3.5 was placed along the cervical margin and light cured.

It has been reported that the application of a thin layer of flowable composite at the cervical margin enhances the marginal adaptation of the restoration.

An initial base layer of medium-flow shade A3.5 composite resin was then placed along the pulpal floor as a complete dentin substitute and light cured.

The restoration was completed with a micro-hybrid enamel shade composite (shade A2) and white tint to mimic calcification patterns (Fig. 7). Studies have shown that the use of micro-particle size composites demonstrates lower polymerization contraction stresses and a decrease in marginal leakage when compared to hybrid composites.

The remaining Class V and Class III carious lesions were prepared (Fig. 8) and restored (Fig. 9).

At the next appointment one week later, the patient was seen for continued treatment.

The gingival margins demonstrated significant improvement owing to the corrected emergence profiles (Fig. 10).

About the author

Ian Shuman, DDS, MAGD maintains a full-time general, reconstructive and esthetic dental practice in Pasadena, Md. Contact him at ian@ianshuman.com.

Editorial note: This article was originally published in Cosmetic Tribune Vol. 4 No. 2, February 2011.