FIGURE 5. After two weeks of treatment, both dark teeth exhibit a shade similar to the neighboring teeth. FIGURE 7. Patient portrait with full smile for esthetic evaluation. (Figure 4, page 23). An “X” was placed on the stone cast on the right canine (#6), right central incisor (#8), and left lateral incisor (#10) to ensure the tray was cut out in those areas. The design for the full- arch tray was also nonscal- loped, nonreservoir and covered all teeth in the patient’s maxillary arch. The patient was given 10% car- bamide peroxide bleaching gel and instructed to use the single-tooth tray, only apply- ing bleaching gel to the right lateral incisor (#7) and left central incisor (#9), and to wear the tray overnight for two weeks. At the conclusion of phase one, the shades of FIGURE 6. Completed treatment. All maxillary incisors were bleached using a conventional nonscalloped, nonreservoir tray. A horseshoe-shaped stone cast was made from an irreversible hydro- colloid impression of the patient’s maxillary arch to facilitate fabrication of a vacuum-formed thermoplastic tray for use as the bleaching carrier. The bleaching process was divided into two phases. The first phase included use of a modified single-tooth tray so that both dark teeth were isolated from the rest of the arch and bleached at the same time until they matched the adjacent teeth. The second phase included use of a maxillary full-arch tray to stabilize and achieve uniformity in the shades across the arch. The design for the single-tooth tray was nonscalloped, nonreservoir, with the teeth molds on either side of the discolored teeth cut out key takeaways • Histological changes in enamel, dentin or coronal pulp structures can affect a tooth’s light-transmitting properties.3 • Causes of tooth discoloration commonly include pulpal necrosis, intrapulpal hemorrhage, pulp tissue remnants after endodontic therapy, endodontic materials, coronal restorative materials, root resorption or aging.4 • Another common cause of tooth discoloration is partial or total pulp canal obliteration, which normally results from trauma. • Clinicians must understand the etiology of discolored teeth and carefully weigh all clinical options — including nightguard bleaching — before initiating treatment. 24 Decisions IN DENTISTRY • December 2017 the right lateral incisor (#7) and left central incisor (#9) matched the adjacent teeth (Figure 5). The patient was instructed to use the full-arch tray and apply the bleaching gel to all maxillary teeth, wearing the tray overnight for an additional two weeks. She reported no sensitivity or adverse side effects during the duration of the bleaching. At the con- clusion of phase two, a uniform shade was achieved to the patient’s sat- isfaction (Figure 6 and Figure 7). DISCUSSION In this clinical report, however, there is no radi- ographic evidence of blunting of the apical portion of the roots or other signs of excessive orthodontic forces. However, the presence of previous endodontic therapy on the left maxillary incisor (#9) — without obvious extensive decay/restoration — suggests the possibility of past trauma to the tooth. Root canal treatment of the right maxillary lateral incisor (#7) was not recommended because most of the literature does not support endodontic intervention unless periradicular pathosis is detected or the involved tooth becomes symptomatic.11 There are numerous treatment options for the esthetic improvement of discolored teeth, including procedures involving composite restora- tions, veneers, crowns, or internal bleaching in nonvital or endodonti- cally treated teeth. However, restorative options that consist of unnecessary, excessive removal of tooth structure could be considered overtreatment. For example, if veneers had been the treatment plan of choice for this patient, an estimated 0.7 to 0.9 mm of facial reduction Discolored teeth are a common concern in general dentistry practice, and patients do not always know the causative factor. The individual in this clinical report claimed the causative factor of her discolored teeth was orthodontic treatment, yet few studies have investigated a possible correlation between orthodontic treatment and PCO. In these studies, no evidence has been found to suggest that normal orthodontic forces contribute to PCO — but excessive forces cannot be ruled out as a potential cause.9,10 DecisionsInDentistry.com
