Are Resin Composites a suitable material to restore primary teeth?
Resin composites (RC) are commonly used in restorative paediatric dentistry. This post will review the indications and contraindications in primary teeth.
HOW OFTEN ARE COMPOSITE RESINS USED IN PAEDIATRIC DENTISTRY?
Carious lesion management in children and adolescents by Australian dentists (ADJ, 2018), examined this and found the following. The question was for a compliant 7 year old patient; choose your preferred restorative material.
When looking at the data. RCis the preferred material for dentists in occlusal restorations and second favoured in approximal. For OHTs and DTs it was not commonly chosen (~10%). It would be interesting to research the discrepancy amongst professionals one day!
Resin Composites Overview
Resin composite is a restorative material bonded to tooth structure via an intermediary bonding agent or adhesive. It bonds well to enamel and poorly to dentine. Concerns include its low elasticity, its deformation under loading and polymersiation shrinkage. These properties have improved somewhat over time.
The use of RC as a restorative material in both primary and permanent occlusal and approximal (restricted to TWO-surfaces) restorations is supported by the literature. However, it MUST be placed under rubber dam and generally local anaesthetic. Two previous posts address these topics:
Local Anaesthetics and Children – What to use, when and how much? — Ki — Kids Dental Tips
One Simple Step To Improve Your Restorative Success in Primary Teeth — Kids Dental Tips
WHAT ARE THE SUCCESS RATES OF RCs IN THE PRIMARY DENTITION?
The use of RCs in PRIMARY OCCLUSAL and SMALL APPROXIMAL restorations is supported in the literature. It is contraindicated in multi-surface restorations (greater than 2 surfaces). For permanent teeth, resin composite is well supported in both occlusal and approximal restorations.
At 4 years, in primary teeth, the success rate is around 80%. However, this is when it is restricted to occlusal and SMALL approximal restorations placed under rubber dam. Failure rates without rubber dam increase by up to a massive 350% for intra-coronal restorations.
WHAT ARE THE LIMITATIONS FOR USING RCs IN PRIMARY TEETH?
Resin composites rely exclusively on mechanical retention for bonding. In primary teeth, there is substantially less enamel, as well as enamel of lower mineral density. Therefore, the bonding strengths are greatly reduced compared to permanent teeth for all materials. This is important as we are already starting off with a weaker substrate prior to selecting our preferred restorative material.
Furthermore, in primary teeth they have very broad contacts and minimal distance to the pulp. As such, what you can think may be a small two-surface restoration can very quickly become multi-surface and close to the pulp. At this stage, RCs are no longer recommended.
WHERE WOULD WE USE RCs IN PAEDIATRIC DENTISTRY?
Resin composite is our preferred intra-coronal restorative material. It is aesthetic and has the best strength properties compared to GIC containing options. However, we are very judicious in our placement. It is placed under local anaesthetic with rubber dam and clear margins. We also restrict it to small approximal restorations. Once lesions get quite large, or are multi-surface, we will place a SSC or Zirconia crown.
CONCLUSION
Resin composites are a very familiar material for dental practitioners. They are indicated in primary teeth, but you require a very compliant child to place them under the correct conditions. Failure to do so is asking for problems. Keep in mind, when placing them, restrict them to occasions where you still have enamel on the margins to bond to and they do not extend onto buccal or lingual/palatal surfaces.
Future posts will examine SSC and atraumatic restorative techniques.
As always, we hope that you found this post useful.
Tim and Sarah