Dental Composite Composition
- Dental composites are made of synthetic resins.
- They contain Bis-GMA and other dimethacrylate monomers.
- Silica is commonly used as a filler material.
- Photoinitiators are added for light curing.
- Dimethylglyoxime may be added to achieve specific properties.
Comparison to Amalgam Restorations
- Studies have compared the longevity of resin-based composite restorations to amalgam restorations.
- Depending on various factors, composite restorations can have similar longevity to amalgam restorations.
- Resin-based composite restorations have a superior appearance compared to amalgam.
- Composite restorations are on the World Health Organization's List of Essential Medicines.
- Resin-based composites are widely used in dentistry.
History of Use
- Traditional resin-based composites set through a chemical reaction between two pastes.
- Light-curing resin composites were introduced in the 1970s.
- UV light-curing units were replaced by visible light-curing systems with camphorquinone.
- Composite resins were initially used as an alternative to silicates and unfilled resins.
- Microfilled composite resins were introduced in 1978, offering improved clinical properties.
Types of Composites
- Hybrid composites, also known as resin-modified glass ionomer cements (RMGICs), were introduced in the 1980s.
- RMGICs consist of a powder containing a radio-opaque fluoroaluminosilicate glass and a photoactive liquid.
- RMGICs can be used for Class II cavities and have superior adhesive properties.
- They release fluoride and are recommended for basing cavities.
- Hybrid composites have undergone significant improvements in terms of strength and durability.
Advantages and Disadvantages
- Dental composites offer improved tooth tissue-mimicry and can be closely matched to the color of existing teeth.
- Composite fillings bond to tooth structure, strengthening the tooth and restoring its integrity.
- Tooth-sparing preparation is possible with composite fillings, as they do not require significant removal of healthy tooth material.
- Composite restorations can be a less costly alternative to dental crowns and can preserve more of the natural tooth.
- Composite fillings can repair chipped, broken, or worn teeth that may not be repairable with amalgam fillings.
- Composite resins can shrink during curing, leading to inferior bonding interfaces.
- Shrinkage can cause microleakage and subsequent decay (secondary caries).
- Dental hygiene and regular checkups can help mitigate the risk of secondary caries.
- Some newer materials, like silorane resin, have lower polymerization shrinkage.
- Composite fillings may not last as long as amalgam fillings, especially for large cavities.
- Composite materials can chip off the tooth.
- Successful outcomes depend on the skills of the practitioner and placement technique.
- Keeping the prepared tooth completely dry can be difficult, especially for posterior teeth.
- Composite restorations may take longer than amalgam restorations.
- The cost of composite restorations may be higher than amalgam restorations.
Dental composite resins (better referred to as "resin-based composites" or simply "filled resins") are dental cements made of synthetic resins. Synthetic resins evolved as restorative materials since they were insoluble, of good tooth-like appearance, insensitive to dehydration, easy to manipulate and inexpensive. Composite resins are most commonly composed of Bis-GMA and other dimethacrylate monomers (TEGMA, UDMA, HDDMA), a filler material such as silica and in most applications, a photoinitiator. Dimethylglyoxime is also commonly added to achieve certain physical properties such as flow-ability. Further tailoring of physical properties is achieved by formulating unique concentrations of each constituent.
Many studies have compared the lesser longevity of resin-based composite restorations to the longevity of silver-mercury amalgam restorations. Depending on the skill of the dentist, patient characteristics and the type and location of damage, composite restorations can have similar longevity to amalgam restorations. (See Longevity and clinical performance.) In comparison to amalgam, the appearance of resin-based composite restorations is far superior.
Resin-based composites are on the World Health Organization's List of Essential Medicines.
