Matrix placement hack: distal areas

Posterior isolation helps us prevent fluids and contamination from invading the area of our restoration when going direct, and that of our build up for indirect solutions. We have several solutions for interproximal area restorations, and for those cases in which when we have deep margins to restore, as you can read in our previous articles. On the other hand, sometimes we need to put a matrix exactly where the clamp is placed, and then our problem starts; if we want to put the matrix prior to the isolation, we can’t put the rubber dam, and if we want to do the opposite, the matrix will not adjust the cervical margin. We are going to show a clinical case and a solution for those types of situation to help you in daily practice.


Initial situation with a lower second molar fractured in the lingual area. When we see the situation we decide to go for an indirect restoration, but, due to economical reasons, the patient decided to have a direct restoration and wait until he can afford an indirect one.


After anesthesia infiltration, we isolate with the rubber dam and a wingless clamp.


Using the Direct Style bur kit we eliminate the old restoration with high speed at the beginning and a ceramic bur in 1:1 handpiece micromotor to remove the composite and respect the enamel.


Situation after the removal of the old restoration.


Now we get to our problem: how do I insert the matrix…?


In this case, any kind of matrix would collide with the clamp.


But here is the solution, step by step, of how we make the process.


First, we need to detach the clamp from the tooth surface only on the lingual side.


Of course we need the help of the dental assistant to hold the rubber dam and open the clamp a little bit with the rubber dam clamp forceps, to allow the dentist to insert the matrix.


After that, we check that we can restore the cavity.


We can now etch the enamel for 30 seconds.


Apply 2% chlorhexidine to stabilize the adhesion.


Then apply your adhesive system.


Polymerization with a deep cure polymerizing lamp.


Seal the margin with a flowable bulk fill material.


And convert the cavity in a class I design to make it easier with a A2 body shade material.


With the help of the spatulas and the Compobrush we build up the lingual area trying to imitate the natural shape of the molar.


We finish the build up and now we have a simpler class I situation.


Bending the brush with a plier helps us work in posterior areas.


We eliminate the matrix carefully and continue building up the occlusal anatomy with the same composite.


The LM Fissura instrument by Style Italiano allows an ideal design of the anatomy on the occlusal surface


And we can smoothen everything with the Compobrush.


After finishing and polishing, we take the rubber dam off.


Check the occlusion with two different articulating papers.


3 week check-up, after the healing of the gingiva the patient is satisfied with the result.


In the present case, the best thing would be to build up the damaged area or take an impression for an indirect restoration; as sometimes, due to the patient’s situation we need to go for a direct solution, here we show a solution for that specific moment. Can we do an indirect restoration later on? Have we done something that restricts indications for an indirect restoration in the future? We think this is another proper option to solve this particular situation.


Breschi L., Mazzoni A., Nato F., Carrilho M., Visintini E., Tjäderhane L., Ruggeri Jr A., Tay F., De Stefano Dorigo, E., Pashley D. Clorhexidine stabilizes the adhesive interface: A 2-year in vitro study
Dent Mater 2010; 26:320-325
Magne P., Spreafico R.C. Deep Margin Elevation: A Paradigm Shift. Am J Esthet Dent 2012;2:86-96
Hashimoto M, Sano H, Yoshida E, et al. Effects of multiple adhesive coatings on dentin bonding
Oper Dent 2004;29:416–423.