| GC Gradia Direct
The need for beautiful aesthetics, simply achieved.|
Advances in aesthetic dentistry and wide-spread publicity of what nowadays can be achieved, have led more and more patients to expect that a restoration will perfectly match their surrounding teeth. The choice of a direct restoration however, can present the dentist with a dilemma. Not surprisingly, aesthetics is often compromised for the sake of simplicity and cost. Indeed, 95% of direct restorations are carried out with just one shade even though the patient may not get the look they want.
With Gradia Direct from GC you can forget compromise! A new direct restorative created for today’s dentistry, it meets the needs of both patients and dentists by giving a superb natural-looking restoration in most cases with a single shade. And if higher-end aesthetics is required or if the class of restoration demands, a selection of special shades can be added very easily. It also means the dentist has more opportunities to perform modern minimum intervention dentistry to the aesthetic satisfaction of the patient.
Aesthetic 'invisibility' with one shade simplicity.
Optical properties determine the 'look' of a natural tooth
Colour is the optical property which contributes most to the appearance of a tooth.
It is actually a three-dimensional space composed of:
- hue - the pure colour itself
- chroma - the saturation of the colour
- value - the lightness or darkness of the colour
In dentistry, the nature of tooth structure also brings into play other optical properties:
- translucency - parts of the tooth structure are translucent so some light passes through, whilst other parts are opaque so no light goes through
- opalescence - some structures within a tooth such as the enamel layer, produce shimmering pale colours
- fluorescence - is the ability of teeth to absorb UV wavelengths and emit visible, mostly bluish light
How these optical properties are perceived and hence the tooth’s appearance, is determined by the way the tooth reflects light back into the viewer’s eye. There are two types of reflection:
- Mirror reflection is when all wavelengths are reflected back to the eye. This occurs with the highly polished enamel surface of a tooth and is responsible for its glossy appearance.
- Diffuse reflection is when only certain wavelengths are reflected back to the eye as some of the light is absorbed by the tooth. This occurs when light within the tooth is reflected off the complex series of interfaces formed by the multifaceted internal structures of enamel crystals, dentinal tubules, peritubular dentin and the dentine/enamel junction. This type of reflection is responsible for how the tooth's hue, chroma and value are actually perceived as well as its translucency and opalescence.
The final optical property, fluorescence, is emitted directly from the tooth and is seen as a slightly bluish light.
Particle structure imitates reflectivity of a natural tooth
By studying the tooth’s optical properties it became clear that the closer a restoration material could mimic the internal structure of a natural tooth, the closer would be their appearance within the mouth.
To achieve this, the material of GC Gradia Direct consists of a micro-filled matrix of resin composite with compounds mainly of silica and pre-polymerised fillers. The amount of each constituent and its particle size distribution has been carefully chosen so that when added together, many different interfaces occur with different reflective properties. The result is a diverse, multifaceted internal structure, similar to the natural tooth, which creates an internal reflectivity that accurately reproduces the reflectivity of natural tooth.
Natural reflectivity means natural aesthetics
The tooth-like reflectivity of a GC Gradia Direct restoration means that its optical properties are perceived as extremely natural and life-like. Indeed, the chameleon effect with the surrounding natural teeth is so good that the restoration is aesthetically 'invisible' often with a single shade layer and gives outstanding high-end aesthetics when further shades are used.
In contrast, compared to GC Gradia Direct, traditional direct restoratives do not have such a diversity of multifaceted particles and so a single shade has more limited reflectivity and hence gives poorer aesthetics. The only way further multi-reflections can be created to improve appearance is to add more layers.