Author: Edward Lowe, BSc, DMD Adjunct Faculty University of British Columbia Private Practice Vancouver, BC, Canada
Article published in the journal Inside Dentistry | December 2011, Volume 7, Issue 11
Using whitening to treat the single dark non-vital anterior tooth. This article will demonstrate a technique of conservatively restoring an endodontically treated tooth using both internal and external whitening cosmetically to create an esthetic outcome.
It is not a mystery that the majority of our patients are seeking whiter teeth. In North America there seems to be an affinity for white teeth as a sign of health and beauty, whereas other countries prefer natural teeth to the artificially enhanced. In some countries, having any teeth at all is a luxury.
Before the advent of home and office-dispensed whitening, patients did not have many choices to change the color of their teeth without the intervention of cosmetic, restorative, or prosthodontic procedures. The author’s first recollection of a “whitening“ dentifrice was Pearl Drops, an abrasive paste that claimed to whiten teeth by removing all of the yellow stain from them. In Hollywood, some actors, like Clark Gable, opted for full crowns or dentures to obtain that pearly white smile.
With the development of better bonding agents and composite resins in the early to mid-1980s, teeth were “whitened” with composite bonding. The development of porcelain veneers followed this, providing a restoration that did not stain easily. The demand for cosmetic dentistry boomed in the 1990s with the development of home-whitening products from virtually every dental manufacturer to satiate the trend. Now, the concept of laser or light-assisted whitening provided by dentists in the office appears to be the way to go in today’s dental practice. Walk down the aisle of a local drugstore and you will likely find whitening everything—toothpaste, brush-on gels, strips, and oral rinses. The craze for white teeth is not over.
The author can remember when Vita shade B1 was considered white when restoring teeth. If he used B1 today, most patients would certainly complain that the color was too yellow and demand a brighter shade. Our eyes have become so skewed from seeing white teeth that we have accepted that as being normal. Others who fall in this category include the artificially tanned look from tanning beds or spray-on tanning treatments, body-enhancing implants, and faces sculpted with Botox and/or dermal fillers.
Whitening products are used commonly in the author’s office three different ways: take-home whitening when a patient wants an inexpensive professional whitening treatment; in-office whitening when a patient is not willing to wear trays every night for 7 to 14 days; and intracoronal treatment to bleach non-vital endodontically treated teeth.
This article will demonstrate a technique of conservatively restoring an endodontically treated tooth using both internal and external whitening cosmetically to create an esthetic outcome.
The patient was a healthy 26-year-old female patient of record with an excellent dental history. She presented with a traumatized lip and chipped incisal edges on teeth Nos. 7, 8, and 9 after fainting and falling in the shower. Sutures were present on the lower lip because she bit into it on the way down. There was no sign of lingual displacement of the teeth; however, they were sensitive to touch (Figure 1).
|Figure 1. Preoperative smile 1 day after trauma showing chipped maxillary teeth Nos. 7, 8, and 9|
Because the trauma happened 2 days prior to her visit, the initial assessment for pulp vitality could be incorrect. Teeth Nos. 7, 8, and 9 were all sensitive to percussion. All three teeth were slightly mobile and tested positive for vitality. The teeth were not sensitive to hot and were mildly sensitive to cold.
Simple composite repair using Tetric EvoCeram® (Ivoclar Vivadent) was carried out using shade A2 to restore the shape and general esthetics. Teeth Nos. 7, 8, and 9 were monitored for signs of impairment to the pulp (Figure 2).
|Figure 2. Preoperative smile after restoring shape and contours with composite resin|
Within a month, tooth No. 8 began to show signs of color change accompanied by a maximum reading of 80 with the pulp-vitality tester, which indicated that the pulp was now non-vital. This was confirmed with a negative cold test, a positive heat test, and a positive percussion test. The diagnosis was pulp necrosis and endodontic therapy was initiated on tooth No. 8 to halt the progressive discoloration of the tooth (Figure 3).
|Figure 3. Preoperative smile 1 month after the initial trauma. Note the lower value of tooth No. 8|
After the completion of root canal therapy on tooth No. 8, it was clearly noticeable that it was lower in value than tooth No. 9 and the remaining upper anterior teeth. The patient expressed a desire to whiten her teeth (Figure 4).
|Figure 4. Close-up of discolored tooth No. 8 after endodontic therapy|
The internal discoloration of tooth No. 8 was treated first. Because the pigmentation of the dentinal tubules occurred within a month of the trauma, the odds of a successful outcome in removing the stain appeared promising if a whitening agent was used.
The access opening to tooth No. 8 was re-opened and the cotton pellet was removed. The gutta-percha in the coronal portion of the pulp chamber was extricated with a #8 round bur to a level of 2 mm below the cemento-enamel junction (CEJ).1
GC Fuji IX™ Glass Ionomer cement (GC America) was placed as a barrier at the CEJ to seal the root-canal filling from the effects of the overlying carbamide peroxide that was about to be introduced (Figure 5).2 To keep the levels of extra-radicular diffusion of hydrogen peroxide below the safety limit, it is imperative that an effective intermediate base cement of at least 2 mm be placed at the level of the buccal CEJ over the root-filling before introducing the bleaching agent.3 This can be done with glass ionomer, resin-modified glass ionomer, or any cement that bonds to dentin.1 It has been well documented in the literature that if this step is not taken, there is a risk of external root resorption.4,5 This type of resorption initiates in the periodontal ligament (PDL) with osseous cells becoming osteoclasts. It is believed that the hydrogen peroxide diffuses around the gutta-percha and leaches into the PDL space, stimulating osteoclastic activity.
|Figure 5. Glass-ionomer cement was placed level of the CEJ|
A 22% carbamide-peroxide (NiteWhite® ACP, Philips Oral Healthcare) gel was introduced into the canal space to fill up the pulp chamber (Figure 6). Using carbamide peroxide is not a novel idea.6,7 Carbamide peroxide was chosen because it has been shown to be the least likely to alter the extra-radicular pH and has the lowest hydrogen peroxide (HP) diffusion compared with pure hydrogen peroxide or sodium perborate.8-10 A cotton pellet soaked with the whitening gel was placed to hold the viscous material in place (Figure 7). After the excess gel was removed, the access opening was sealed with a temporary filling material (Cavit™, 3M ESPE).
|Figure 6. A 22% carbamide peroxide was introduced to fill up the pulp chamber|
|Figure 7. A cotton pellet soaked with the whitening gel was placed|
The patient returned every 2 days to change the peroxide-soaked cotton pellet for a fresh one until the desired shade of 110 from the Chromoscop shade guide was reached (Figure 8 and Figure 9). The lingual access enamel periphery was etched and bonded, but not the dentin in the pulp chamber. This was to leave the dentin tubules patent in case the tooth needed to be bleached again in the future. The opening was subsequently sealed with an opaque bleach white shade of composite and cured (Figure 10). Note that tooth No. 8 is now a little lighter than tooth No. 9. This “overbleaching” allows some flexibility for the rebound in color that typically occurs when tooth shade is stabilizing.1
|Figure 8. Tooth color after three sessions of internal bleaching|
|Figure 9. A shade of 110 was achieved, with tooth No. 8 being slightly higher in value|
|Figure 10. The access opening was sealed with an opaque bleach, white shade of composite|
The patient’s teeth were whitened externally with Zoom! 25% whitening gel and the Zoom Advanced Power Plus in-office whitening lamp (Philips Oral Healthcare) (Figure 11 and Figure 12). The shade of the teeth ended up at a Chromoscop Bleach 020 (Figure 13). Treating the internal color discrepancy before whitening the teeth externally helped to ensure a predictable outcome as the teeth all started out externally with the same shade.
|Figure 11. After internal bleaching and before external whitening|
|Figure 12. After external whitening with light-assisted in-office whitening|
|Figure 13. A shade of 020 was achieved|
The teeth were allowed to “relax” for a week in order for them to reconstitute from any dehydration effects of the peroxide whitening gel so that the true shade could be obtained for the definitive composite-bonding procedure.
|Figure 14. Putty lingual matrix in place for layering composite|
A PVS putty matrix was made of the lingual aspect of the upper six anterior teeth and set aside. The monochromatic composite build-ups that were initially placed to restore the chipped teeth were removed and the teeth were prepared for definitive direct-resin restorations using IPS Empress® Direct composite (Ivoclar Vivadent). With the assistance of the incisal matrix, Dentin A1 was used to resurrect the dentin layer and Enamel Bleach L was used to develop the enamel layer. Incisal Trans 30 completed the restorations by enhancing the translucency of the incisal edge (Figure 14). The restorations were shaped with carbide and fine-diamond finishing burs and Sof-Lex™ contouring discs (3M ESPE). The OptraPol polishing kit (Ivoclar Vivadent) was used to bring out the gloss in the definitive restorations (Figure 15 and Figure 16).
|Figure 15. Finished composite-resin restorations on teeth Nos. 7-9|
|Figure 16. The final postoperative smile|
This case demonstrated the cosmetic use of tooth whitening for two purposes; internally to lighten a discolored tooth and externally to brighten all the teeth. Combining these uses of whitening products with conservative composite-resin bonding enabled the author to provide a simple solution to a restorative challenge in a young patient and embodies the term “responsible esthetics.”