Bleaching the Single Dark Tooth Learning Objectives Changing the Color of Just One Anterior Tooth Presents Unique Challenges
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CONTINUING EDUCATION R AESTOR TIVE IN SIDE PERIODONTICS Bleaching the Single Dark Tooth Learning Objectives Changing the color of just one anterior tooth presents unique challenges. • identify the causes of tooth discoloration in the initial examination. By Van B. Haywood, DMD | Anthony J. DiAngelis, DMD, MPH • discuss how tooth trauma impacts the approach to tooth bleaching. • discuss how endodontic treatment impacts there is no reason to initiate endodontic the approach to tooth bleaching. AbstrT AC therapy based on vitality testing alone. • describe each possible bleaching approach, Single dark teeth represent a major challenge to obtain best esthetic outcome in a Often single dark teeth are the result of the indications for each, and its benefits. patient’s smile. Treatment options may include single crowns, veneers, bonding, or trauma, which should be determined in bleaching. Bleaching is the most conservative option to consider, but the potential the dental history. It can take anywhere Logno o t www.insidedentistryCE.com for a successful outcome varies based on the cause and extent of the discoloration. from 1 to 20 years after the trauma be- to take the FREE CE quiz. fore any pulpal problems develop. Additional considerations for the occurring injury in permanent teeth.10,11 single dark tooth are the color of the Also, studies have reported that 71% to hen a patient must be aware of the basic principles of gingival tissues around the tooth, as well 92% of TDIs occur by age 19.12 presents with changing the color of one or more teeth as whether there is any root structure T he etiology of dental injuries varies either intrin- in order to implement a successful treat- visible due to recession. A smile analysis by age. In the 0 to 6 age group, falls pre- sic or extrin- ment plan. is used to determine these conditions as dominate.13 As children enter school, sic staining or well as the movement of the lip during falls, collisions with other children discoloration The Initial Examination smiling and whether a “gummy smile” and objects, as well as participation in and seems to T he first and most important con- exists. The dentin in the root is differ- organized physical activities and sports be a candidate for tooth bleaching, there sideration is to determine the cause ent from the dentin in the anatomic contribute to dental injuries.9,14-16 TDIs Wis a variety of factors and options for the of the tooth discoloration. A clinical crown, and does not bleach well if at in the teen and young-adult age group clinician to consider. What is the cause examination is conducted, which in- all, regardless of whether internal or are more the result of sports and motor for the discoloration? Is there tooth cludes evaluation of the color of the external bleaching is attempted. Also, vehicle accidents.14 Several studies have trauma involved, or has the affected teeth and the adjacent gingiva (Figure discolorations of the gingiva may cause documented that approximately one tooth been endodontically treated? 1). Additionally, transillumination, ra- a tooth that may be a perfect color match third of dental injuries are sports-re- What is the best delivery method for diographs, and pulp testing may be ap- to not be harmonious. Either of these lated.15-23 Other causes of TDIs include the patient’s lifestyle, financial situation, propriate. Radiographs should always conditions is magnified if the lip exposes physical abuse, fights, and assaults—of- and commitment level to home care? be taken of a single dark tooth, as teeth much of the root or gingiva because of a ten involving alcohol as an aggravating Single dark teeth present a unique chal- can undergo pulpal necrosis without hyperactive lip or gummy smile. factor.24-26 lenge for color change and the clinician any other symptom than becoming dark T he pulp can respond to trauma in (Figure 2). From this examination, the Trauma and Calcific a limited number of ways. Primarily it VAN B. determination is made of whether the Metamorphosis can survive, die, or undergo pulp canal HAYWOOD, DMD tooth is vital or not. A vital tooth may Many studies suggest that the preva- obliteration (PCO), often referred to Professor be darker due to trauma and resultant lence of traumatic dental injuries (TDI) as calcific metamorphosis.27 The latter Director of Dental bleeding into the dental tubules with- is high, although significant variation represents a common finding subse- Continuing Education Department of Oral out loss of vitality. Vital teeth may also occurs between countries, populations, quent to luxation injuries, 3.8% to 24%, 1-4 2,28-30 Rehabilitation discolor from internal or external re- age, and gender. Epidemiological and root fractures, 69% to 73%. School of Dentistry sorption, calcific metamorphosis, as well studies, while not always comparable, The precise mechanism of PCO is not Medical College of Georgia as decay or leaking restorations on the support the growing body of evidence known but disruption of the neurovas- Augusta, Georgia proximal or lingual surfaces. A non-vital that TDIs represent a significant chal- cular bundle appears to stimulate the tooth may have become darker from the lenge for clinicians.5 A study by Koste rapid formation of hard tissue (dentin ANTHONY J. same reasons as a vital tooth, but also and colleagues reported that 25% of or osseous) beginning within the pulp DIANGELIS, DMD, MPH have experienced pulpal death. A tooth 6- to 50-year-olds in the United States chamber and progressing along the Chief Department 6 31 of Dentistry that has received endodontic treatment had experienced a TDI. Approximately pulp canal walls. It may present as Hennepin County may also later darken, especially if there 30% of children have sustained a TDI to partial or total obliteration of the pulp Medical Center is a poor seal of the endodontic access their primary dentition, and 25% of all canal space. Although radiographs may Minneapolis, Minnesota opening (Figure 3). school-aged children have experienced reveal what appears to be total oblitera- E ven if a tooth tests as non-vital, it a TDI.7-9 Other reports document that tion of the pulp canal, generally there Professor University of Minnesota may not require endodontic therapy. If luxations represent the majority of remains clinical evidence of a pulp 32,33 Minneapolis, Minnesota there is no radiographic evidence of pa- primary teeth injuries, whereas crown canal and pulpal tissue. Clinically, thology and no clinical symptoms, then fractures constitute the most commonly the tooth will appear dark yellow due 42 INSIDE DENTISTRY | S eptember 2010 | insidedentistry.net INSIE D CONTINUING EDUCATION to the increased deposition of under- restorative procedure. A recent article the form of a discolored incisor presents bleaching efficacy.44 It is not possible lying dentin. Additionally, there may by daCunha and colleagues suggests a long-term esthetic challenge. The most to “spot bleach” a tooth either, because be a gradual diminution in response implementing endodontic therapy prior conservative approach to managing the bleaching material goes through to electrical and thermal pulp testing. to development of a periapical radiolu- PCO-induced discoloration is bleach- the enamel and dentin to the pulp in 5 PCO occurs more frequently in teeth cency in a tooth with PCO, based on two ing without endodontic therapy. to 15 minutes, and bleaches under res- with open apices and in more severe major considerations: (1) the technical torations and from one surface to the luxation injuries involving displace- difficulty and complications that may Tray Bleaching other (facial to lingual). It has also been ment.2,34 Extrusive and lateral luxation occur in treating these teeth; and (2) T here are a number of types of bleach- shown to bleach beyond the borders injuries in immature permanent teeth their review of a study that demonstrat- ing techniques to consider for both vital of the tray, generally to the cementoe- have demonstrated high rates of PCO.35 ed a 97.9% success rate for teeth treated and non-vital teeth, but these types may namel junction (CEJ), even if the tooth A recent study by Netto and colleagues without periapical radiolucencies vs a be divided mainly into those performed is only partially erupted. reported the chances of PCO in in- 62.5% success rate for teeth treated with in-office or those continued at home. T he ideal bleaching tray is fabricated truded permanent teeth to be six times periapical radiolucencies.42 Specific With the advent of nightguard vital on a horseshoe-shaped cast with no greater than in mature teeth, open vs clinical situations will dictate clinical bleaching involving tray application vestibule to provide good adaptation closed apex, and that PCO occurred in decisions; however, given the relatively of 10% carbamide peroxide, a method of the bleaching tray material. Also, the 26.7% of such injuries.36 PCO can oc- low incidence of pulp necrosis in teeth for bleaching single dark teeth became cast should be trimmed such that the cur in subluxated and crown-fractured with PCO, endodontic treatment usually more readily available, and did not in- central incisors are vertical to avoid teeth, although with less frequency.37 is not recommended in the absence of volve the use of highly caustic chemi- folds on the facial. One challenge in As mentioned previously, PCO is a a periapical radiolucency or symptoms. cals.43 The original recommendation fabrication of the single-tooth or regu- common occurrence after root frac- N onetheless, if a periapical lesion de- for a single dark tooth was to make a lar bleaching tray is trimming the cast tures. The location of PCO is thought velops, endodontic therapy can be both non-scalloped, no-reservoir tray, and without abrading either the teeth or the to be indicative of the type of healing.