Conservative Aesthetic Treatment of Dark Necrotic Teeth: Efficient Internal Bleaching

In dental school, in the mid-1980s, we learned of the “walking bleach technique.” A cotton pellet soaked with superoxol bleaching material was placed in the pulp chamber, and then a cherry red hot heat carrier was stuck into the tooth while it smoked. The patient would get a funny look when he heard sizzling inside his head. Then we sent the patient home with some sodium perborate and superoxol paste stuck inside the tooth for a few days. If the tooth wasn’t light enough, we re-cooked it. The main problems with this procedure were that it didn’t work predictably and there was a tendency to cause root resorption.

Prosthetic means were more financially rewarding and results were sometimes more predictable for some practitioners, but matching the shade of a single anterior restoration can be very challenging for many of us. It wasn’t long ago that patients who presented with a dark, anterior, necrotic tooth were treatment planned for a PFM because of its opaquing ability. Then we advanced to trying to block out the stain with opaquers and dentin shade composites, which were followed up by more definitive all-porcelain restorations.

There are certainly challenges with these treatments. The metal under a PFM doesn’t always lend itself to aesthetic margins, natural contours, or coloring that matches the surrounding natural dentition. All-porcelain restorations can give awesome results, but the more opaquing that is needed under the porcelain, the less the vitality and reality of the restoration. Moreover, to cut down tooth structure just to modify the shade of a single tooth seems to contradict the conservative treatment nature of today’s dental theology.

Today, with the powerful and effective new bleaches that are available, we can offer more conservative and predictable treatment. We can take a darkened nonvital tooth, and consistently bleach it both internally and externally, and provide a conservative operative treatment that is hard to rival any other way. While not always a perfect result, the more tooth structure we save and the less we cover, the better. The less invasive we are this time, the more treatment choices we have next time!

The following three cases were done in our office during a 2-month time frame. They are examples of cases we see routinely, and the way they are treated can work on many patients in almost any practice. The fee for internal bleaching should be around the same as a single arch of take-home bleaching, $150 in our office. Therefore, our total fee for both internal and external maxillary bleaching is about $300. Our post and core fee is $160, and a four-surface composite is $130. This will give you an idea of what the patient’s responsibility will be. Even if their insurance doesn’t cover the bleaching, the amount they pay will be about what the insurance would pay with 50% coverage on a $600 PFM.

CASE 1

Figure 1. Case 1, compromised smile because of a dark central incisor. Figure 2. No restorative history with tooth No. 8, virgin tooth. Conservative treatment plan always preferred.

This lady has had an “ugly brown tooth” for about 15 years (Figures 1 and 2). She remembers no trauma, has no symptoms, and has never had endodontic treatment. A specialist deemed the canal unnegotiable and could not do conventional endodontic treatment until surgery was needed. She wanted our office to “Do whatever it takes!” to correct the tooth color. The necrotic stain was throughout the tooth.

The assistant first took an alginate impression on which to make a take-home bleach tray. The pulp chamber area was opened, remnant pulp horn areas were removed, and Cavit G (3M ESPE) was placed over the occluded pulp canal area to make sure no bleaching agent could find its way down any patent canal. All of this was done with no anesthetic and no patient sensations. A clear warning of possible apical surgery was given to the patient should signs or symptoms present in the future.

Opalescence Xtra (Ultradent) is a 35% hydrogen peroxide “power bleach” that is highly rated and works extremely well for this purpose. It is easy to dispense, no mixing is needed, and it can be placed directly onto the tooth. Hydrogen peroxide bleaches are much stronger than carbamide peroxide of the same percentage strength. For example, a 9.5% hydrogen peroxide bleach has about the same potency as a 30% carbamide peroxide formula; 35% hydrogen peroxide formulas are much more potent than 35% carbamide peroxide.1

Figure 3. Alginate taken and poured, conservative pulp chamber preparation completed and sealed, tooth pumiced and etched, and 1-mm layer of Xtra place 2 mm away from gingiva. Figure 4. Pulp chamber and lingual aspect of tooth lined with bleaching agent. The material was then cured for 5 seconds from lingual and facial.

The facial of the tooth was then pumiced, the pulp chamber was cleaned and roughened with a course diamond, and all external and internal surfaces were etched with 37% phosphoric acid for 15 seconds and rinsed for 30 seconds. This ensures a non-contaminated tooth surface and provides more surface area for the bleach to oxygenate. Opalescence Xtra was applied carefully to the facial, lingual, and internal aspects of the tooth in a uniform 1-mm layer of this thick red gel (Figures 3 and 4).

It must be stressed that proper gingival isolation and cheek retraction are critical because this material will burn the tissue within seconds of contact. The Xtra should be kept 2 mm from the gum tissue, making sure the material flows freely out of the syringe before taking it to the patient’s mouth. Eye protection must be used by all staff and the patient, and retractors must always be used on the patient, with an assistant staying nearby at all times. Paint-On Dental Dam (Den-Mat), OpalDam (Ultradent), Discus Dam (Discus), or some other light cure dam should be applied to protect the gingival tissues. A rubber dam would also be a prudent safety feature if properly applied.

A plasma arc curing light was shined at the tooth for 3 to 5 seconds (or 10 to 15 seconds per surface when using a halogen light) to activate the bleaching material per manufacturer’s instructions. The bleach was left on the tooth for about 15 minutes, suctioned, and then carefully rinsed off. It was then reapplied once in the same manner for the same amount of time. Significant shade changes are noticed after two applications (Figure 5).

Figure 5. Results after two 15-minute Xtra applications. Very noticeable shade change, but more bleaching needed. Figure 6. While the bleaching agent was on the tooth, a standard take-home bleach tray was made and marked where bleach will be applied to the lingual of the tooth.
Figure 7. The patient is given routine take-home bleaching instructions and shown how to put bleaching material into open access hole with root canal area still sealed.

The rest of the bleaching treatment was accomplished with a take-home bleach system, in this case Day White 2Z 9.5% hydrogen peroxide (Discus). The assistant made a suckdown take-home bleaching matrix. A mark was placed on the tray with a permanent marker to help show the patient where the internal bleaching takes place; this was the only place bleach was placed on the lingual tooth area in the tray (Figure 6). The patient was shown where to put the tip of the bleaching syringe so that it would go to the floor of the pulp chamber (Figure 7). The patient was instructed to squeeze gently as the syringe is backed out, and then the tray is placed with bleaching material as with any other take-home bleaching. Many of the quality bleaching agents work well for this. The patient then was instructed to apply material to the bleaching tray and wear the tray 30 to 45 minutes twice a day for 2 weeks.

Figure 8. After 1 week of take-home bleaching and 2 weeks of waiting for bleach relapse, a lingual composite was placed. The treatment was inexpensive, conservative, and appreciated.

The results were dramatic after 2 weeks of bleaching. A definitive restoration was placed on the lingual after the patient had not bleached for 2 weeks so that bleaching relapse could take its course. The dentist must avoid the temptation to just fill the hole with the whitest and most opaque composite in the office because this will create  aesthetics almost as artificial as the dark tooth did. Use a material that is natural in translucency to the tooth and a shade that matches the bleached tooth. The patient can continue bleaching externally as desired at this point. The patient was ecstatic, and her friends were quick to notice the positive changes (Figure 8).

CASE 2

Figure 9. Case 2, discolored necrotic tooth. Endo completed and restorative options considered.

Several years ago, this patient came in contact with a swinging tennis racket. She was referred to our office following completion of orthodontic treatment when she complained of a “funny sensation” and expressed a desire to have her discolored tooth fixed (Figure 9). She had a treatment plan for a PFM from another office, but she was insistent that her tooth not be cut down to a “nub.”

Figure 10. Removal of coronal composite and residual endo materials lightened the tooth very little. Figure 11. The root canal sealed with a glass ionomer cement to decrease chances of apical migration of bleach material. Excess material removed from other areas of pulp chamber.
Figure 12. Results after two 15-minute Xtra applications as described in Case 1.

Endodontic therapy was completed after canal debridement with files, Gates Glidden drills, sodium hypochlorite, sealer, and ThermaFil obturation (Tulsa Dental). Merely removing necrotic pulpal tissue lightened the tooth a small amount (Figure 10). The root canal was sealed with glass ionomer cement (Shofu) to help prevent the apical migration of bleaching material (Figure 11). After the cement set, a diamond was used to roughen and clean the inside of the pulp chamber. Composites should be avoided as the bonding agent will coat the tooth and prevent contact with the bleach. The tooth was etched, and Opalescence Xtra was applied as described in case 1. Just two 15-minute applications resulted in a great improvement in the shade (Figure 12).

The patient was given a bleaching tray that was marked as in case 1, shown where to inject the bleach material, and given a take- home bleach kit. In this case Opalescence F 15% carbamide peroxide (Ultradent) was used. After 2 weeks, this patient bleached all night for only half of the nights and wanted the “final hole filling” put in with an acceptable result. The bleaching in the necrotic incisor was sufficient, but take-home bleaching was continued to even out the color.

Figure 13. Tooth after 2 weeks of inconsistent take-home bleaching and after lingual tooth restoration placed.

FibreKor Post (Pentron) is a fiber-reinforced resin post that is easy to place, aesthetic, works well clinically, and is a great value. In this case the tooth was etched and a dual-cure adhesive, Cabrio (Discus), was applied to the tooth and the post. Build-It FR (Pentron), a fiber-reinforced dual-cure automix composite core material, was injected directly into the tooth. The post was seated, buildup material cleaned away from the facial aspect of the pulp chamber, and then cured. Excess post was cut with a diamond, Cabrio was reapplied, and a matching composite (Matrixx AH, Discus) was used to fill the chamber (Figure 13).

The patient was extremely pleased and was glad that her tooth had not been “ground down.” She was encouraged to continue take-home bleaching, and at recare appointments she will be evaluated for incisal edge composites to blend in color variations.

CASE 3

Figure 14. Case 3, young lady with desire to have smile improved. Figure 15. Tooth No. 9 with history of trauma, endo and four-surface composite. There are also several craze lines and incomplete vertical fractures.

This high school senior was in a hurry to fix a tooth that had been dark for several years; it became an emergency when she was asked to the prom (Figures 14 and 15). We had 2 weeks to correct it (a good date can be a great treatment motivator). Ten years ago, endodontic therapy had been done and a composite had been placed as a transitional restoration. At that time, we let her family know that further treatment would be needed in the future. The future was now, and disappointing her was out of the question.

Figure 16. Composite was removed from the facial and lingual of the tooth, obturation material sealed, tooth etched, and bleach material applied twice.

Composite that overlapped enamel was removed with a rough diamond, the internal and external surfaces were roughened, and all surfaces were acid etched as described previously. Lip retractors, cotton rolls, and safety glasses were applied as in the other cases. The gingiva was coated with a protectant (KY Jelly), and a 1-mm layer of Xtra was applied inside the pulp chamber, on the facial surface, and then light cured as before (Figure 16).

After 15 minutes a second application was done, but the gingival protectant was disturbed and not reapplied well enough. The patient complained of a “tingling sensation” in the gums, which went away when the material was suctioned and rinsed off. The white areas turned red in about 15 minutes, and the gums were healthy the next day. Even though the affected area was small and no real damage was done, we need to remember just how irritating this material can be.

After two 15-minute applications there was significant improvement. Again, we followed up with take- home bleaching, Nite White Excel 2Z 16% carbamide peroxide (Discus), and instructed the patient how to apply it to the pulp chamber. The gutta-percha was sealed with Shofu GI cement. Because we only had 2 weeks, we had her bleach for 1 week only and stop for 1 week, so we could build up the tooth the day before the prom.

Figure 17. After 1 week of take-home bleaching, and 1 week where she was told to stop (she probably didn’t listen), we fit an aesthetic post. Figure 18. Dry, roughed-in view of Esthet-X Hybrid over Fibercore Post and Build-It FR.
Figure 19. Contours completed and polished.

After the week of bleaching and the week of rest, the old composite was removed and a FiberKor Post was fitted. Bleaching occurred clearly throughout the tooth (Figure 17). This certainly increased the list of restorative options for us at this point. The entire tooth was etched, dual-cure Cabrio was placed, Build-It FR was injected into the canal, and the post was inserted. The core material was wiped away from the facial and only left where dentin would be found, because of its opacity. The tooth was restored with Esthet-X Hybrid composite (DENTSPLY) using incisal and enamel shades, and inspected for cracks, white lines, and marginal integrity while dry, as all composites should be (Figure 18). Final shaping and contouring was then completed with finishing burs. Then polishing with rubber points was done by the assistant  (Figure 19).

Figure 20. Improved smile, possibly awaiting more definitive treatment in the future.

A porcelain veneer or all-porcelain crown may be indicated in the future for this patient, but that restoration will be easier to complete because of the natural color of the tooth achieved through the bleaching process. She was obviously happy and liked her tooth (despite “a lousy date”) (Figure 20).

CONCLUSION

As healthcare providers, we are to provide a reasonable service, and above all else do no harm. The more conservative we are now, the more natural tooth structure we will have to work with later. This will leave us with more treatment options. Bleaching as described in this article provides such conservative treatment in appropriate cases.


Reference

1. Miller MB, ed. Reality. Reality Publishing Co; 2002:39-58.



Dr Griffin has maintained a general practice in Eureka, Mo, that focuses on efficiency in almost all phases of general dentistry while providing state-of-the-art care for affordable fees. He enjoys teaching on practice efficiency and predictable posterior techniques, and is available to give courses for groups or for charitable causes.

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