Journal of International Oral Health

: 2017  |  Volume : 9  |  Issue : 3  |  Page : 133--135

Management of discolored endodontically treated tooth using sodium perborate

Thamer Almohareb 
 Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia

Correspondence Address:
Thamer Almohareb
Department of Restorative Dental Sciences, College of Dentistry, King Saud University, P. O. Box: 60169, Riyadh 11545
Saudi Arabia


The aim of this report is to depict the successful management of a discolored central incisor subsequent to endodontic treatment and its follow-up for 1 year. Improper bleaching techniques can lead to cervical resorption and eventual loss of teeth. Management of the discolored endodontically treated tooth can be performed using sodium perborate (SP). A 22-year-old female who had undergone endodontic treatment of the central incisor reported with discolored maxillary central incisor tooth. The case was managed with “walking bleach technique” using SP and water. The case was followed up for 1 year and there was no relapse. Proper selection of bleaching agent and technique had resulted in the conservative and successful management of the case. Appropriate bleaching technique should be selected to manage discolored teeth.

How to cite this article:
Almohareb T. Management of discolored endodontically treated tooth using sodium perborate.J Int Oral Health 2017;9:133-135

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Almohareb T. Management of discolored endodontically treated tooth using sodium perborate. J Int Oral Health [serial online] 2017 [cited 2023 Dec 6 ];9:133-135
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Discoloration of the tooth results from trauma, loss of vitality, endodontic treatment, and restorative procedures.[1] The remnants of the blood stain consequent to trauma or incomplete removal of pulp during endodontic treatment lead to hemolysis.[2],[3] The chromogenic blood degradation products, such as hemosiderin, hemin, hematin, and hematoidin, get deposited in the dentinal tubules.[4] The accumulated breakdown products lead to grayish-yellow to brown discoloration of the teeth. Other causes such as obturation materials, remnants of pulp tissue in the pulp horns, intracanal medicaments, and coronal restorations may also cause discoloration.[5],[6] The discolored anterior teeth can cause significant esthetic concerns.[7]

Over the years, a number of bleaching and restorative techniques have been proposed for managing discolored nonvital incisors.[3],[8] Walking bleach technique is based on the use of chemicals that release active oxygen such as hydrogen peroxide (H2O2) or sodium perborate (SP). A combination of SP and water or H2O2 has been used in the “walking bleach” technique.[9],[10] The outcome of the bleaching depends mainly on the concentration of the bleaching agent, ability of the agent to reach the chromophore molecules, and duration and number of times the agent is in contact with chromophore molecules.[11] Although H2O2 exhibited excellent esthetic outcome, the undesirable consequences such as cervical resorption and irreversible damage to the dentin and surrounding tissues led the clinicians to look for alternative methods.

SP has been widely used to bleach nonvital teeth with predictable results.[3] SP is an oxidizing agent containing 95% perborate and is available in three forms: monohydrate, trihydrate, and tetrahydrate. In the presence of water, perborate will break down to form sodium metaborate, H2O2, and oxygen. SP is also synergistically used with H2O2 but when used with water released H2O2 in a controlled manner with remarkable esthetic outcome with little or no side effects.[12] The SP releases active oxygen radicals inside the pulp chamber and diffuses to the dentinal tubules.[13] It oxidizes and bleaches the iron sulfide and other pigments present in the dentinal tubules and the free radicals induces oxidative effects to lipids, proteins, and nucleic acids.[7],[14] A case of successful bleaching of discolored nonvital, endodontically treated tooth using walking bleach technique with SP and water was reported. The case was followed up for 1 year with no relapse or side effects.

 Case Description

A 22-year-old woman complained discoloration of her maxillary right central incisor [Figure 1]a. According to the patient's chief complaint, she experienced trauma 8 months ago and visited a local dentist. The management of the patient's tooth included root canal therapy followed by composite restoration. Informed consent from the patient was obtained. Clinical and radiographic examination revealed that the tooth had undergone acceptable root canal treatment and the access cavity was sealed with composite restoration. However, the restoration was not adapted to the internal wall, leaving a gap (of approximately 5 mm) between the restoration and the canal orifice. The periodontal ligament was continuous with no widening, and the lamina dura appeared normal [Figure 2]a.{Figure 1}{Figure 2}

At the patient's first visit, the tooth was isolated using a rubber dam (Hygenic ®, Coltène ®/Whaledent Inc., Cuyahoga Falls, OH, USA) and the prior composite restoration was removed. At the level of the cementoenamel junction, a resin-modified glass ionomer (GC Fuji II) was placed as a sealing barrier. A mixture of SP and distilled water was inserted as the common effective material for internal bleaching. The color change was satisfactory to the patient 5 days later [Figure 1]b; at this time, the SP was flushed out, and a temporary restoration with premixed zinc oxide-calcium sulfate material (Coltosol ®, Colten, Langenau, Germany) was placed. After 1 week, this temporary restoration was replaced with a permanent composite restoration. At a 1-year follow-up examination, the patient presented with no symptoms, a recall radiograph revealed a continuous periodontal ligament without any signs of root resorption, and the patient was satisfied with the tooth's color [Figure 1]c and [Figure 2]b.


Discoloration of the anterior tooth due to trauma or endodontic treatment can cause considerable esthetic compromise to patients. The management of postendodontic tooth discoloration includes full veneers, laminates, crowns, and noninvasive technique such as bleaching.[11],[15] Even though laminate veneer or a full porcelain crown is one of the most predictable methods of managing such cases, it involves the removal of tooth structure.[8],[16] Nonvital bleaching has many benefits since it is a noninvasive procedure, economical, and less time-consuming. The three most popular techniques for nonvital tooth bleaching are the walking bleach technique, inside/outside bleaching, and in-office bleaching. The walking bleach technique is a relatively reliable, fairly simple technique. The walking bleach technique is performed by application of a paste consisting of SP and distilled water or H2O2 in the pulp chamber.[17]

The pigmentation that causes the intrinsic discoloration of necrotic pulp consists of long-chain organic molecules. Bleaching using H2O2 will oxidize these long-chain molecules and transform them into carbon while releasing water and oxygen.[18] Internal bleaching requires healthy periodontal tissues and a root canal that is properly treated to prevent the bleaching agent from leaking into periapical tissues.[19]In vitro studies have concluded that SP in water, SP in 3% H2O2, SP in 30% H2O2, and 10% carbamide peroxide are efficient agents for the internal bleaching of nonvital teeth.[20],[21],[22] The use of a bleaching agent with a high concentration of H2O2 in combination with heating appears to promote cervical root resorption.[19],[23] This is attributed to the leakage of bleaching agent through dentinal tubules which initiate an inflammatory reaction.[24]

Cervical root resorption is a potential complication of nonvital tooth bleaching. Studies have shown that the use of a mixture of SP and water showed low potential to cause cervical resorption.[21],[23] However, in the present case, the use of SP and water as well as proper sealing technique prevented the development of resorption.[25],[26] The resin-modified glass ionomer was placed as a barrier sealant in the present case to avoid leaching of bleaching agent. SP in tetrahydrate form mixed with distilled water was used instead of H2O2 to avoid any potential risk of invasive cervical resorption, as shown in prior studies.[21],[23]


The case presented highlights the effectiveness of the nonvital bleaching using SP and water to achieve successful and predictable cosmetic outcome. The case was followed up for 1 year with no sign of relapse of the discoloration or cervical root resorption. Hence, it can be concluded that walking bleaching technique using SP can be used as a treatment of choice for nonvital, discolored endodontically treated cases.

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Conflicts of interest

There are no conflicts of interest.


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