Black Hawk

Black Hawk System

Dental composite resin can appear black under certain lights due to a phenomenon called "optical fluorescence." Fluorescence occurs when a material absorbs light at one wavelength and then emits it at a different wavelength.

Most dental composite resins contain materials that fluoresce under ultraviolet (UV) light. In some lighting conditions, especially when certain wavelengths of light are used (like UV light), the composite can absorb these wavelengths and emit light that might not be in the visible spectrum. This can sometimes cause the composite to appear dark or black.

The optical fluorescence in dental composite resins primarily comes from certain components and fillers that are added to the resin matrix. These constituents include:

1. Photoinitiators :
Compounds like camphorquinone are used in light-cured composite resins to start the polymerization reaction. Camphorquinone can fluoresce under UV light, contributing to the visible effect.

2. Fillers:
Inorganic fillers, such as certain types of silica or glass particles, can exhibit fluorescence. These fillers are often treated with silane coupling agents to bind better with the resin matrix, but they can still contribute to the composite’s optical properties.

3. Fluorescent Dyes:
Some manufacturers add fluorescent dyes to enhance the aesthetic properties of the composite. These dyes are specifically chosen to mimic the natural fluorescence of dental tissues.

4. Resin Matrix:
The organic resin matrix itself, typically composed of materials like bis-GMA (bisphenol A-glycidyl methacrylate), UDMA (urethane dimethacrylate), or TEGDMA (triethylene glycol dimethacrylate), can also contribute to the fluorescent properties.