As more dental practices become amalgam-free, interest in composite resins is increasing. Composite can be a more desirable option because the material satisfies patient requirements for a more aesthetically pleasing restoration and because of the less invasive nature of the placement technique.
Esthetic demands have been met by the introduction of opaque dentin, translucent enamel shades and body shades, making it possible to place lifelike, direct restorations using a multi colored layering technique. Some composite systems have more than 30 different shades and opacities, and a skilled clinician has the ability create a restoration that is virtually indistinguishable from a natural tooth.
Composite resins have been in use for decades but the material has improved significantly since their initial introduction. Today there are many different classifications and this is mainly due to the filler system used. High density or packable composites have a higher filler content and a higher viscosity which may be useful in creating good interproximal contacts. Flowable composites have a lower viscosity and a lower filler content and tend to be useful in repairing marginal defects, or for lining deep cavities such as a pit or fissure sealants.
Essential Factors in a Successful Composite Restoration
A successful restoration depends largely on choosing the right composite resin combined with the proper bonding system. Some dentists may also be using light-curing devices that do not transmit sufficient energy rendering them unable to complete polymerization. Unfortunately, this can result in tooth sensitivity and early discolorations. In spite of improvements in materials, placing composite resins is still very dependent on the technique and the results can sometimes be unpredictable.
Placing More Predictable Composite Resins
Predictability concerns are often due to patients experiencing sensitivity to cold or discomfort when chewing. In the past, these issues may have been due to polymerization shrinkage but, provided they are properly placed, newer materials have largely addressed this issue and are generally low-shrinkage.
If a patient is experiencing pain when chewing on a specific spot, this could be due to an adhesive error rather than the restoration being too high. This type of problem is becoming less common as most dentists recognize that placing a composite does require close attention to detail. Additionally, more clinicians are using self-etch adhesives as opposed to etch and rinse techniques.
Sensitivity to cold can occur with all types of materials and especially so after numerous operative procedures. When teeth are restored with composite resin, they are always sealed with an adhesive and generally, this type of problem should be reduced with this material.
Another concern is being able to achieve a proper contact which is largely a matricing factor. The introduction of newer sectional matrix systems over the past few years has helped to largely eliminate this problem.
Composite Resins Do Require Additional Time and Effort
Even with the introduction of newer materials, the actual placement of composite resin does require additional time and effort. Composite resins now have high physical properties of flexural strength and hardness combined with low shrinkage and low wear. Until recently, resins with a high filler content and high viscosity required multiple layers, each of which had to be separately cured. Manufacturers have responded to these concerns by introducing composite resins designed specifically for restoring posterior teeth. These resins require fewer cured layers, decreasing the time required to place them. Today, most preparations can be filled in just two increments.
Case selection is another vital factor in determining long-term success and good esthetics. The size of the cavity and a patient’s history must be considered when planning direct composite resin restorations. Sometimes indirect restorations, indirect composites made by the lab, or porcelain inlays and onlays, may offer greater protection and longer-lasting results.
As always, we are here to help. Should you have any questions or want to discuss a specific case, please schedule a call with one of our expert technicians.