INTRA CORONAL LIGHTENING OF DISCOLORED PULPLESS TEETH: A MODIFIED WALKING BLEACH TECHNIQUE Introduction: Discolored anterior teeth is of serious esthetic concern to the patient. Various treatment options are available for discolored anterior teeth which includes bleaching, composite laminates, porcelain laminates etc. Although bleaching of teeth has a long history it was disregarded for some time due to certain disadvantages. But bleaching is back again as one of the treatment modalities for anterior discoloration. Various bleaching techniques exists for vital and non vital teeth. For non vital teeth walking bleach technique was previously used. This however has certain disadvantages such as long duration of treatment and cervical resorption. To overcome these disadvantages modified walking bleach technique was developed. This technique employs 10% carbamide peroxide. Modified walking bleach technique minimizes the risks, because treatment time is reduced to days rather than weeks as required in the original walking bleach technique. Here is a case presentation of the modified walking bleach technique.
Case selection: A discolored anterior tooth that has been endodontically treated is selected. The tooth should be asymptomatic. Percussion and radiographic examination should indicate a successful endodontic treatment without any periapical or periodontal lesions. Materials and Method: This includes • Nupro gold tooth whitening gel which is specially formulated with the active ingredient of 10% carbamide peroxide a proven and extremely effective tooth whitener. The gel has a high viscosity and exceptional adhesive properties to extend contact time with the patients enamel surface. • Dycal • Glass ionomer cement • Clear custom made splint to retain and seal the intra coronal medicament. This photograph shows the discolored central incisor prior to bleaching. 10% carbamide peroxide breaks down to 3.6% hydrogen peroxide therefore the intra coronal technique is a little harmful due to the potential risk of cervical root resorption. Thus obtaining an adequate
cervical seal that will prevent hydrogen peroxide from penetrating the root at the cements enamel function is important. -
The coronal restoration is removal carefully.
The coronal gutta-percha is then removed using gates glidden drill. Approximately 3mm of root canal gutta-percha are removed apical to the cements enamel function. The objective of removing root canal gutta-percha is to create space for the restorative cervical seal and to expose dentinal tubules directed toward the cervical region of the tooth.
A calcium hydroxide plug approximately 1mm in thickness is applied to the freshly exposed gutta-percha. This prophylactic step aims to maintain an alkaline medium because cervical resorption has been associated with a drop in pH at the cervical level.
The remaining 2mm depth of the cervical root canal access is sealed with glass ionomer cement. This is crucial as to seal the root canal from bacterial ingress during bleaching and to prevent contamination of the gutta-percha fillings.
An impression is made of the patients arch and a cast is prepared.
A soft splint is fabricated on the working cast and trimmed to the dimensions of a custom sports mouth guard.
The patient is given a tube of neutral pH, 10% carbamide peroxide and instructed to fill the pulp chamber every 2 hours until the desired tooth lightening is reached. A syringe is used to flush the pulp
chamber with warm water each time prior to placement of the carbamide peroxide gel. -
The splint is used to retain the bleaching agent and to prevent ingress of debris into the access cavity. Patients are encouraged to limit applications to daylight hours when reliable assessment of color can be made.
This photograph shows the whitened central incisor after bleaching using the modified walking bleach technique. On achieving the desired tooth lightening the access cavity is
restored with the tooth colored resin composite. Result: Two cases were selected for this study. The result obtained was good following the application of 10% carbamide peroxide containing bleaching agent. The technique developed by William H. Riebenberg focuses on obtaining an adequate cervical seal. The resorptive potential of hydrogen peroxide has highlighted the importance of preventing hydrogen peroxide from penetrating the root through the attachment apparatus. Conclusion: Advantages: Are as follows
• Concentration of the bleaching agent used is low • Heat is not required for this technique. • The bleaching agent used is safe for both the patient and dental staff. • Duration of treatment is short compared to traditional walking bleach technique. Disadvantage: The only disadvantage of this technique is patient compliance as it requires the patient to fill the pulp chamber with the bleaching agent every 2 hours.