Do you struggle with sensitivity after placing composites? Are your patients reluctant to proceed with treatment because they have had sensitivity in the past after having composites placed by you or another dentist? Have you yourself come to believe that sensitivity after placing composites is normal?
If you answered yes to any of these questions, keep reading for four easy tips to help make sensitivity with your composites a rarity.
This is No. 1 because without this you are sunk and can in fact expect sensitivity no matter how well you do everything else. For me, hands down, this means an Isolite, Isodry (Figure 1) or rubber dam in the posterior since I believe cotton roll isolation and dry angles are just too risky in the posterior. The risk for contamination is high.
When it comes to the anterior, you can at times safely use something like cotton roll isolation. If that is not enough, then you are best to go to an Isolite, Isodry or rubber dam just like the posterior. The key thing to remember is even the tiniest bit of contamination means you are sunk.
With the advent of self-etching bonding resins, this has in some way gotten easier. However, the fact of the matter is with most, if not all, bonding agents (even the self-etching ones) it is best to etch the enamel. With some agents, like the universal bonding systems such as Adhese Universal from Ivoclar and Scotchbond Universal from 3M, it can be advisable to still etch the dentin depending on the case.
The trouble with sensitivity usually comes from improper etching of the enamel; over-etching is usually the biggest culprit. The typical time for dentin is 10-15 seconds, but you should check the instructions for the specific product you are using. When it comes to enamel it is way harder to over-etch it, but the typical time is 15-20 seconds. The key here, if you are pre-etching the dentin, is remembering that time is critical. You need to be right on time, not over and not under.
As we know, after etching we must rinse and dry the tooth. Here we have another big potential source for sensitivity if we have etched the dentin. That source is over-drying the dentin and collapsing the dentinal tubules. This results in poor penetration of our bonding resin and, therefore, sensitivity.
It is important to note that even if you get the drying part right in that you do not over-dry (think moist dry not bone dry), it is also important to be sure you are using clean air to dry the teeth. What I mean by this is it is not uncommon for our air-water syringes to blow a little water or – worse – oil with them when using the air. In my office I have switched to Adec warm air tooth dryers (Figure 2) to eliminate this risk. If Adec tooth dyers are not in your future or you just want an immediate way to help check for contamination coming from your air-water syringe tips, then blow air across your clean mouth mirror. You should see nothing on your mirror.
This one is simple: We have to make sure our composite is fully cured all the way though, otherwise we can expect bad things. The key here is to make sure our layers are not too thick and to get as close as you can to whatever you are curing without touching it. You must also cure for the length of time specified by the manufacture for the material you are curing.
I cannot stress enough the need to get close enough with your curing light; small increases in distance greatly decreases your lights curing intensity. Another important thing to consider is periodic testing with a light meter (Figure 3) to assure your light’s intensity is as it should be. Playing with these meters is also a great way to see just how fast the intensity drops as distance increases. Lastly you also need to assure your light guide is undamaged and the tip is clean.
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John R. Carson, D.D.S., P.C., Spear Visiting Faculty and Contributing Author - www.johncarsondds.com