Composite Restorations

Composite Resin Restorations

• When a silver filling is placed it is metal that has been packed/wedged into a prepared space. A properly bonded Biomimetic composite resin restoration is placed incrementally and reconnects the sides of the tooth. Not only do these restorations look more natural but they also function more naturally. Like all hard materials, the hard metal filling does not absorb chewing stress but transmits the forces to the inside of the tooth. Composite Resin restorations are more flexible and similar to the flexible stress absorbing dentin found inside the tooth. These materials absorb chewing forces and when properly bonded dissipate them.

• evenly and similarly to the natural tooth structure they are replacing and mimicking. The decreases the risk of cracks forming under cusps and/or marginal ridges as seen over time with metal fillings
• Unfortunately, poorly bonded and/or poorly placed composite restorations will perform worse that metal fillings. The disconnected parts of the tooth will flex back and forth much like with metal fillings and in large fillings can lead to cracking under cusps and/or through marginal ridges. Additionally, one of the benefits of metal amalgam fillings is that they are bacteria resistant (bacteriostatic). Therefore it is difficult for bacteria to grow underneath them without a very large gap being present. Composite Resin restorations are not bacteria resistant at all and bacteria can grown under very small and imperceptible gaps between the restoration and the tooth. A poorly bonded composite resin is not a restoration but simply a white colored filling – that generally perform more poorly than silver amalgam fillings.
• This is why it is important to use proper isolation, bonding agents, and composite layering techniques to ensure the composite restoration stays bonded long term so that you can receive the benefits of a bonded composite restoration long term. Biomimetic Dentists undergo specialized training in bonding, material science, and composite placement techniques after dental school.”

Cracks can often develop over time with large non-bonded fillings

Cracks can often develop over time with large non-bonded fillings

Composite resin shrinks when it hardens, if it is not bonded well and/or placed incorrectly gaps will form between the composite & the tooth which can lead to sensitivity to cold and biting and result in infiltration of decay causing bacteria – when gaps form the tooth is disconnected much like a metal filling and cracks can form under cusps that flex excessively

Cracks can often develop over time with large non-bonded fillings

The bond between the composite resin and the tooth failed either initially or over time leading to microscopic gaps between thetooth and the composite – this can occur due to the technique sensitivity of bonding & placing large composite resins – the microscopic gaps lead to micro leakage and growth of decay under the restoration – these gaps also leave the tooth disconnected causing the large crack to form on the left, this crack also had micro leakage & decay forming

How Can These Issues Be Avoided?

• Biomimetic Dentists are trained to use a variety of techniques to minimize and/or eliminate these issues.
• Single bottle adhesives are popular because they are easier and quicker to use, but they also result in lower and less durable bond formation especially the inner part of the tooth – Dentin
• biomimetic dentist use “Gold standard” bonding agents. These are adhesives that are more time consuming and require more steps. these adhesives are labeled gold standard because they have been shown to display the highest bond strengths and l0ng term durability in the peer-reviewed literature.
• composite resin shrinks when it is cured and hardens. the lager the volume of composite the stronger the force of shrinkage. additionally the more and closer together bond walls of the cavity multiply the force/stress of the shrinking composite.

When composite is cured & hardens it shrinks towards the center of mass – the higher the cavity configuration factor – bonded to unbonded surfaces, the higher this shrinkage stress

Gaps typically forms in the weakest & slowest bond form in area – deepest part of cavity – this relieves the shrinkage stress allowing the stronger bonds to stay adhered

Inner Dentinal Fluid Fills this space leading to bond degradation, sensitivity, and increased chance of leakage

How Can These Issues Be Avoided?

• When a dentist places an adhesive on the tooth structure and cures it, the adhesive takes time to develop strength. anyone that has built a toy model with glue, glued a floor, or glued anything knows that you need to let the glue set before pressing or pulling on it or gaps will form. the same is true inside a tooth.
• When these gaps form between the tooth and the composite inner dentinal fluid from the tooth leaks inside and causes biting & cold sensitivity. additionally, these gaps can lead to leakage underneath the restoration.

• Biomimetic dentists work slower and place small increments of composite when restoring a tooth with composite resin to allow the adhesive to set undisturbed and prevent gap formation.
• This results in less to no post-operative cold or biting sensitivity and stronger more durable composite restorations.

Dentists can place their composite in small incremental layers to reduce the initial stress of shrinkage to allow the bond time to develop strength & eliminate gap formation – this is a more time consuming & technique sensitive procedure

How Can These Issues Be Avoided?

Additionally, no adhesives or glues work well on wet surfaces, same in the mouth.
wet tooth surfaces and/or contamination from blood or saliva will significantly decrease the performance of the dental adhesive.

biomimetic and Advanced Adhesive dentists use rubber dam isolation to seal off the tooth from the oral cavity, this has many benefits: makes it easier to dry and keep the tooth dry for bonding, prevents cross contamination form oral bacteria, prevents contamination of blood or saliva, allows the dentist more light, open space, and focus for the tooth being worked on

This leads to quicker, more efficient procedure and aids the doctor in diagnosis – which is easier with more light and a dry tooth, patient does not feel like they are drowning in water, patient is not at risk of objects or instruments dropping in the throat, and last the patient is not ingesting materials, chemicals, or old restorative materials being removed such as metal fillings

Here is a case from Dr. Alex May of SofTouch Dental – placing a rubber dam is like taping off a room before painting, the better the tape job, the better the result – this patient had flossing cavities visible on the X-Ray between the teeth

The decay was removed carefully while conserving as much tooth structure as possible, some stained dentin can be observed where the decay used to be

The dental adhesive was given 5 minutes to set before layering the composite resin incrementally, Dr. May created a thin “enamel shell” of composite first as seen here, he then followed with smaller 1-1.5mm increments of composite layers.

This is the final result – a natural looking esthetic restoration that is bonded at high strength and durable.
*Note how the rubber dam sealed off the working area from saliva and blood.