Restoration of a fractured upper incisor
This patient presented with a fractured upper left lateral incisor. The tooth had previously been restored successfully for many years using a direct composite resin restoration, but the patient was now considering a crown. The medical and dental history was unremarkable and the treatment options were:
• Composite resin restoration
• Porcelain jacket crown
• Porcelain fused-to-metal crown
• Porcelain inlay/veneer.
The patient sought a long-lasting aesthetic restoration and was advised that a crown would necessitate further removal of healthy tooth tissue simply to prepare the tooth. A composite restoration was again recommended, and the lamellar composite technique was advised because it would fulfil the restoration criteria.
Step 1: Creating an incisal guide
To begin with the occlusal features were assessed. This patient had a canine-guided occlusion and the centric occlusion coincided with centric relation. The dentition was heavily restored with several cast restorations.
In order to prevent repeated failures of the restoration that we were planning, a temporary composite was placed into the cavity (without etching or bonding) and cured. This was shaped to conform to the occlusal features palatally, thus reducing the chances of failure in excursions of the mandible. Once this had been established, a simple putty ‘jig’ was created to record the palatal contours.
Step 2: Tooth preparation
Isolation is essential to prevent contamination of the prepared dentine and enamel surfaces. A rubber dam is used to achieve isolation following shade selection. The shade selection is carried out prior to isolation as the enamel is liable to dehydrate and lead to a lighter shade.
Unsupported enamel surfaces are then removed and a bevelled enamel surface created to enhance bonding area to enamel. This will also reduce the ‘white line’ effect sometimes visible post-operatively when a thick layer of resin is applied prior to placement of the composite.
The tooth is completely etched for 30 seconds using 37% phosphoric acid. The etchant gel is washed away for the full 30 seconds and gently air-dried for 10 seconds (following the composite manufactures guidelines). Care is taken not to desiccate the enamel as this has been shown to reduce the bond to some degree.
Unfilled resin (Bis GMA) is then applied and allowed to percolate the etched enamel and dentine. This is left for 20 seconds before light curing for a further 20 seconds.
Step 3: Restoration
A combination of shades were selected from our shade selection to mimic the tooth tissues. Initially the dentine was restored using a darker A3 shade. This was placed in small increments and light cured.
It is possible to recreate the natural tooth colours by selecting the shades to replace the tooth tissues. Translucent composites can be used to recreate incisal tips where this effect is required.
The putty ‘jig’ was applied to the tooth to start recreating the desired palatal contour. Composite A2 was then applied to the palatal aspect of the tooth and light cured.
The next stage of restoration was to recreate the inter proximal tooth contact. A mylar separating strip was used to prevent the composite from bonding to the adjacent tooth (which had a small distal composite restoration). The chosen enamel shade (A2) was used to restore this and the composite was light cured (30 S) and stoned to enable the correct depth of composite to replace the enamel.
The final layer of composite was then applied and light cured. This was a shade A2. Shade combinations are specified by the composite manufacturers who suggest mixtures for obtaining a desired end-result shade. The bevelled margin prevents a visible join.
Step 4: Finishing
The composite was then smoothed with diamond paste to provide an even finishing surface. The final restoration was a conservative aesthetic option which fulfilled the criteria for restoring this particular tooth.