Darkness from Root Canal

Procedures >> Bleaching >> Darkness from Root Canal

Many people have an image that Root Canal Therapy leads to black teeth because so many people notice when an endodontically treated tooth gets dark.  After all, you don't see all those which stay the normal color.  Occasionally a tooth will darken after endodontic therapy.  It is especially noticeable when the enamel layer is very clear since the discoloration is in the dentin layer of the tooth. See anatomy of a tooth.
When the internal layers of the tooth are stained there are a few approached for treatment.  Traditionally internal or "walking" bleach was the treatment of choice.  A cotton pellet of a bleaching solution was placed into the nerve chamber of the tooth and sealed with a temporary filling.  The idea was this would bleach the dentin layer better, since the solution is in direct contact with the dentin.  The cotton pellet was changed until the tooth was an acceptable color.
Some dentists have tried opening up a hole on the back side of the tooth and having the patient use a home bleaching tray  and syringe the bleaching solution into the hole.   Once the tooth is an appropriate shade, the patient returns to the dentist to fill the hole.
In my experience, if the tooth is only slightly dark, bleaching alone can work well, but in many cases the bleach just doesn't get the tooth back to the correct color to match the adjacent teeth.  Bleached teeth also have a tendency to relapse in short order.
Because of the inadequacy of the bleaching techniques, many doctors have placed crowns to restore the correct color.  While this is effective, in my opinion, it may also be overly aggressive as far as tooth removal.  Sometimes there is no alternative to crowns if too much of the tooth is destroyed already, but more often than not there is an alternative.  Six years ago I developed a technique I call "Internal Bonding" in order to lighten root canal treated teeth.  In this technique, the tooth is hollowed out from the back side until all of the dark dentin is removed and only the enamel layer is intact.  Then composite resin bonding of the appropriate dentin shade is bonded inside the tooth.

This patient had a very dark left lateral incisor after having had a root canal..   Her other teeth were unrestored and beautiful.  We bleached her teeth for three weeks using 15% carbamide peroxide and home trays after opening up the hole on the back side of the tooth.  The teeth all lighten, but she felt that the neck of the tooth was still too dark, so we did internal bonding, which lightened the root and neck to a normal color.

This patient felt that her teeth were all too yellow and her upper left central incisor was too dark subsequent to a root canal therapy.  She tried home bleaching for her entire mouth.  We opened up an access hole on the back of her central incisor.   After bleaching for two weeks we were not completely happy with the color match of her central incisor, so we internally bonded that tooth.

This patient was unhappy with the color of his front tooth.  He did not even notice the brown and white stains on his other teeth, and therefore only wanted the front tooth treated.  Internal Bonding was complete in one visit and no bleaching was attempted.  You will notice that his teeth all look whiter in the postoperative photograph.  This is due to the dehydration effect of having your mouth open for half an hour.  As the teeth rehydrate the normal color will return.  You can also see how the outer surface of the tooth remains glassy and smooth.  This is due to the fact that there is not artificial material on the front surface of the tooth.  This is what creates such a natural effect.

It is difficult to see from these slides, but the right lateral incisor was dark due to root canal therapy and Internal Bonding was done in order to lighten it.  No other techniques were necessary.

This patient had a dark root canal treated tooth as well as chipped teeth.  We Internally Bonded his upper right central incisor and cosmetically contoured his front four teeth to smooth the rough edges.

This patient had two front teeth which had darkened after root canal therapy.   Only the left central incisor bothered him though and I couldn't convince him to lighten both teeth.  We did Internal Bonding on the central incisor and no other treatment was necessary.  Notice the vital, translucent effect possible with this technique.

This patient had an interesting problem.  His teeth were all dark due to moderate tetracycline stain.  Additionally his right central incisor was further darkened following root canal therapy.  We discussed lightening his teeth, but he decided to try just lightening the root canal treated tooth first, then he would decide if he wanted the other teeth lightened.  We Internally Bonded the central incisor and matched it to the tetracycline stained teeth.  Notice that since the enamel layer is left unaltered, the orange and white stains within that layer remain.  It turned out that the patient was happy with this result and opted to not lighten the other teeth.