Photopolymerization in Dental Resins

Chemical compounds that start the polymerization process in dental composite materials when exposed to light.

Different photoinitiators react best to specific wavelengths of light, typically violet (380-420 nm) or blue (420-490 nm).

A common photoinitiator that is effective with violet light, known for its fast polymerization reaction.

A widely used photoinitiator for dental composites, often paired with co-initiators to improve performance.

A photoinitiator that can be used in conjunction with CQ for more control and flexibility over the light-curing process.

Molecules needed by some photoinitiators to enable the polymerization reaction.

The process of converting monomers (small molecules) into polymers (large molecules) through chemical reactions, like bonding of C=C chains.

The tendency of light to bend or change direction when passing through different materials like fillers/resin in composite. Difference in Index between components is important for light curing effectiveness.

The power of light per unit area (measured in mW/cm^2). It is crucial to curing composite material.

The total energy of a light beam that is delivered to an area per unit.

Different types of LCU's (e.g., halogen, plasma, LED) use different light sources and technologies for curing composite.

Halogen units use heat but also generate blue wavelengths, requiring filters to focus on precise light wavelengths needed by photoinitiators.

LED curing units provide high irradiance without heat, and their light can often be tailored directly for optimizing the wavelengths needed for composite.

The duration required for effective light curing of the composite, depending on factors like the quantity and type of the components being used.

A type of light curing unit that emits both blue and violet light for polymerization of dental composites.

A polymerization program that emits light at a constant irradiance level, maintaining a high, medium, or low intensity.

A polymerization program that alternates between low and high irradiance levels.

The variation in irradiance across the cross-section of a light beam.

Areas within the curing tip with higher irradiance.

Areas within the curing tip with insufficient irradiance.

The size of the light-emitting area of a curing tip, affecting the light's focus and irradiance.

Different ways to control the light output during curing, including staged, exponential, and pulsed modes.

Different types of dental composite materials requiring different light curing units based on the dominant wavelengths used

The reduction in volume that occurs when liquid monomers bind to form solid polymers, causing stress on the composite and surrounding tooth.

It can lead to gaps between the composite and tooth, increasing the risk of microleakage and secondary caries.

It's the ratio of bonded to unbonded surfaces of a composite restoration. Higher C factor means more stress from shrinkage.

Use light-curing techniques that extend the 'pre-gel' phase, allowing polymer chains to form longer and stronger.

Uncured composite layer due to the presence of oxygen in the last layer, which can disrupt polymerization.

Use a glycerin gel to block oxygen access during curing, ensuring proper polymerization.

A device that measures the irradiance (light strength) of a curing light. It's essential for ensuring proper curing.

A device that measures various parameters of a curing light, like irradiance, time, and radiant exposure.

A measure of how well the composite has polymerized. Higher conversion means a stronger, more durable restoration.

The initial stage of polymerization where monomers are still fluid and can move, allowing for maximum chain bonding.

The stage where the polymer chains start to solidify, becoming less flexible and prone to shrinkage.

It extends the 'pre-gel' phase, allowing for maximized chain bonding and reduced shrinkage.

It can be due to polymerization shrinkage, improper marginal finish, or inadequate bonding.

A break that occurs within the bulk of the composite material itself due to stress or internal forces.

A break that occurs at the interface between the composite and bonding agent or tooth, usually caused by poor adhesion.