BLEACHING PROCEDURES

  BLEACHING  PROCEDURE

1) NON-VITAL/INTRACORONAL BLEACHING

a) In-office thermocatalytic bleaching

b) Walking bleach. 

2) VITAL/ EXTRACORONAL BLEACHING

a) In-office thermocatalytic bleaching

b) In-office power bleaching

c) In-office bleaching for fluorosed teeth

d) At home vital bleaching ( Night guard bleaching). 

1) NON-VITAL BLEACHING-

Pre- requisites for non-vital bleaching-

1) Good quality 3 dimensional obturation with gutta percha. 

2) Asymptomatic teeth. 

3) No periapical lesions. 

Indications-

1) Non vital bleaching is  best suited for intact anterior teeth that have discoloured due to intrapulpal hemorrhage or pulp necrosis. 

Contraindications-

1) Extensive tooth loss

2) Presence of cracks and hypoplastic areas

3) Presence of discolouration due to metallic salts

4) Extensive restoration. 

Preliminary preparation

1) Thorough cleaning and polishing of the tooth to check the degree of discolouration. 

2) Shade selection

3) Refining the access cavity to remove any pulpal remnants. 

4) A suitable base such as glass iononer cement should be placed to a thickness of 2 mm to serve as a barrier. 

Techniques

1) In-office thermocatalytic technique

After the preliminary steps, protect the labial and lingual gingiva using petroleum jelly. A heavy gauge rubber dam is used to isolate the teeth so that it fits tightly at the cervical margin and prevent leakage of the bleaching agent onto the gingiva. Dental floss can be used to secure the dam around the gingiva. 

Irrigate, clean and dry the access cavity. 

Place a cotton pellet in the chamber and cover the labial surface with a few strands of cotton to serve as a matrix for the bleaching agent. 

Introduce freshly prepared superoxol(30%H2O2) into the access cavity and on the labial surface drop by drop from a syringe. 

Activate the solution by applying heat using a instrument like a burniser or commercial heat applicators like touch and heat spreader. 

Periodically replenish the bleaching solutions and the cotton matrix. Repeat the procedure 4-6 times with breaks in between. 

Finally, rinse the tooth copiously with water, place a fresh dry cotton pellet in the pulp chamber and seal the access cavity with cavity. 

Recall every week and repeat the procedure till  desired lightening is achieved. 

Finally, restore the access with composite resin two weeks after the final bleaching procedures. 

2) walking bleach

Initially this procedure used a mixture of sodium perborate and 30% H202 ( superoxol) as the bleaching agent. 

Preliminary steps are the same as in-office thermocatalytic technique for non-vital teeth. 

1) After cleaning and drying the access cavity a thick paste of sodium perborate with water or 3%H2O2 is placed in the pulp chamber. Excess liquid is removed using a cotton pellet. 

2) A thick, well sealed temporary such as IRM Or cavit( at least 3mm thick) should be placed to seal the access. 

3) The rubber dam is removed and patient discharged. 

4) The bleaching action occurs over the next 3-5 days. 

5) The patient is recalled after 1 week and the procedure is repeated. 

6) The bleaching effect is visible after 1-2 treatment. 

Complications of non-vital bleaching-

1) Chemical burns-

Superoxol is highly caustic and can cause burns and sloughing of gingival. 

2) Invasive cervical resorption-

 

The concentrated H2O2 may diffuse through the dentinal tubules at the cervical region of the tooth and cause destruction of cementum and periodontal tissue leading to invasive cervical resorption. 

2) VITAL BLEACHING-

Indications-

1) Extrinsic stains due to food beverages, tobacco etc, which cannot be removed by polishing alone. 

2) Age related intrinsic stains. 

3) Mild to moderate tetracycline stains. 

4) Mild to moderate dental fluorosis stains. 

Contraindications-

1) Teeth with extensive cracks or craze lines. 

2) Patient with dentin hypersensitivity. 

3) Cases with extensive loss of enamel due to abrasion, erosion. 

4) Teeth with large restoration. 

5) severe tetracycline stains with banding. 

6) severe fluorosis with enamel pitting. 

7) coronal discolouration due to amalgam restoration. 

Techniques-

1) In-office traditional vital bleaching-

Preliminary preparation consist of thorough oral prophylaxis to remove stains, plaque and deposit. 

Baseline photograph is taken. 

Gingiva around the teeth is protected  both labially and palatally with a liberal coating of Vaseline or petroleum jelly. 

Heavy gauge rubber dam is used to isolate the individual teeth and secured cervically with dental floss. 

A single ply gauge is applied over the labial surface of the teeth. 

Heavy gauge rubber dam is used to isolate the individual teeth and secured cervically with dental floss. 

A single ply gauze is applied over the labial surface of the teeth. 

The guaze is saturated with superoxol solution applied drop by drop from a syringe taking care not to spill the solution. 

A special bleaching lamp is placed two feet  from the patients face and left there for 20-30 minutes. 

Light and heat from the lamp accelerate the release of nascent oxygen from the superoxol this producing the bleaching effect. Hence this method is also known as thermocatalytic bleaching. 

Care should be taken to cover the patient eye with protective glasses and the rest of the face must be covered with cloth. 

Once the procedure is over, the gauge is removed and the teeth are rinsed with water followed by removal of rubber dam. 

The procedure is repeated several times till the desired colour change is observed. 

2) In-office power bleaching-

Preliminary steps consist of thorough prophylaxis followed by noting the shade of the teeth. 

Another innovation in this technique is the use of a light cured resin gel or liquid rubber dam. This is painted over the labial and lingual gingivae around the teeth to be bleached. 

The anterior teeth are exposed to the laser light or plasma arc lamp for the specified time. 

When the arch is complete the procedure is repeated if required. 

The gel is then left in contact with the teeth for an additional 5 minutes after which it is removed with wet gauze and teeth are cleaned with water. 

The procedure may be repeated for 2-3 more visits till the desired result is achieved. 

Advantages -

1) Rapid bleaching effect. 

2) Less heat generation than traditional vital bleaching. 

3) Not dependent upon patient compliance. 

Disadvantages-

1) Expensive

2) Tissue protection very important. 

3) In-office vital bleaching for fluorosed teeth-

Bleaching fluorosed teeth has been traditionally performed using McInnes technique. 

McInnes solution

5 parts of 36% hydrochloric acid (1ml) - Etches the enamel. 

5 parts of 30% hydrogen peroxide (1ml) - Bleaches the enamel. 

1 part of anesthetic ether( 0.2ml) - Lowers the surface tension of the solution, remove surface debris and allows deeper penetration of the bleaching effect. 

The  solution is freshly prepared before use  in a clean dappen dish. 

Preliminary steps are the same as in thermocatalytic technique. Then the solution is applied on the tooth surface using a cotton applicator. It is left on the tooth  for one minute followed by polishing the enamel surface using sandpaper disc. 

The procedure is repeated for 5 minutes. Finally the tooth is rinsed and neutralized using sodium bicarbonate. 

Complications of In-office vital bleaching-

1) High concentration of H2O2 can cause tissue burn if proper precautions are not taken. 

2) Tooth sensitivity may occur as a response to increased temperatures bon the tooth surface due to bleaching lamp. 

4) At home vital bleaching/ Night guard vital bleaching-

At present this has become the most popular vital bleaching technique. It is relatively simple, safe and easy. Carbamide peroxide (10% to 20%) is agent of choice. 

Preliminary steps include thorough prophylaxis and polishing to remove surface stains. 

Alginate impression of the patient maxillary and mandibular arches are made and casts are poured in dental stone. 

The base of the casts are trimmed for making the soft plastic tray by removing the palate and vestibule leaving only the teeth. 

Light cured block out resin is placed on the labial and lingual surface to create a reservoir for holding the bleaching agent. 

A soft, clear plastic sheet such as ethyl vinyl acetate 0.3 mm thick is heat softened in vaccum forming unit and adapted over the cast to form a custom tray for the patient. 

Upon cooling the trays are trimmed just beyond the gingival margins and their fit is verified in patients mouth. 

At night after routine tooth brushing the patient is instructed to place a small amount of bleaching gel in the tray to cover the facial surface of the teeth to be bleached. 

The bleaching action occur overnight while the patient is asleep. 

Advantages -

1) simple, safe procedure. 

2) Less chair time. 

3) Efficient for mild to moderate stains. 

Disadvantages-

1) Transient hypersensitivity. 

2) Gingival irritation may occur in some patients. 

3) Prolonged time for bleaching effect to be seen. 

4) Patients compliance is the major factor in the success of this procedure.