biomimetic dentistry overlays

What is Biomimetic Dentistry?

• Biomimetic Dentistry is a type of Adhesive Dentistry that uses the natural tooth as the model to restore.
• Biomimetic Dentistry utilizes the flexibility of modern bonding agents to restore with a minimally invasive approach – because we can bond to the tooth we can preserve much more healthy tooth structure that may be otherwise removed in order to gain mechanical retention of our restorations with traditional approaches.

• The more tooth structure we save, the stronger the remaining tooth will be, the less likely the need for intervention of root canal therapy, and the longer a patient can expect to keep a tooth in their mouth.
• In order to achieve long term stability of both the restoration & the surrounding tooth, our goal is to mimic the natural tooth in form and function. In order to achieve this a few goals must be accomplished, the first goal is to use gold standard adhesives to bond to a similar strength as the Dentin-Enamel Complex and/or the cohesive strength of enamel. Next, we strive to use materials that are similar flexibility and hardness as the tooth structure they are replacing such that not only is the tooth reconnected at a similar strength but also biomechanically behaves as similarly as it did prior to damage. Last, form follows function and so not only do we use the natural tooth as our guide to proper layering, material placement and thickness, but also final esthetic parameters.
• The natural tooth is beautiful both from an artistic standpoint but from a natural engineering view – emulating this and adhering to minimal intervention in order to preserve the restored natural tooth as long as possible is the essence of Biomimetic Dentistry

A full ceramic crown preparation removes 70-75% of the weight of the coronal tooth structure

A full ceramic crown preparation removes 70-75% of the weight of the coronal tooth structure

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

Notice no large or visible gaps between the filling and the tooth – a large crack is visible on the left

The bond between the composite resin and the tooth failed either initially or over time leading to microscopic gaps between the tooth 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