3) Bleaching :-
This procedure has many methods and techniques involving various solutions in each technique.
Advantages:
1) easy
2) time saving
3) cheaper
4) patient acceptance better
5) can be carried out both in office & at home
Disadvantages:
1) requires patient cooperation(especially for home bleaching)
2) cannot be used where teeth have large pulps
3) cannot be used where teeth are too dark
4) cannot be used where the patient expectations are too high
5) cannot be used in impatient patients
6) causes cervical resorption
7) cannot be used in attritioned teeth which might cause sensitivity
8) cannot be used where teeth are bonded, laminated or have extensive restorations
9) not a perfect technique & merely changes colour to variable depths
10) lasts for only 1 – 3 years (short period)
A) Vital tooth inoffice power bleaching
This technique uses a combination of 37% phosphoric acid & 35%hydrogen peroxide.the oxidation reaction is generally promoted by a heated instument or with intensive light.in this method, one application is carried out weekly for 2 – 6 appointments with each treatment lasting 30 minutes. Use of phosphoric acid by this technique is optional.
Advantages:
1) caustic chemicals are totally under dentist’s control.
2) soft tissue protection is better achieved by dentist.
3) bleaching of tooth is achieved more rapidly
Disadvantages:
1) slightly costly procedure.
2) unpredictable results.
3) uncertain duration of treatment
4) soft tissue damage possible for both dentist & patient.
5) rubber dam causes discomfort.
6) can cause post operative sensitivity.
B) Night guard home bleaching
This procedure involves making an impression of the teeth & pouring a cast of the same, trimming of the cast, application of a blockout resin & fabrication of a night guard tray by a vaccum former machine. After cooling, the tray is trimmed & a 10 – 15% gel of carbamide peroxide is recommended for the same. In this procedure the total treatment time is 2 – 6 weeks.
Advantages:
1) use of lower concentration.
2) ease of application.
3) minimal side effects.
4) lower cost (as compared to veneers)
5) lesser chair time.
6) much lesser labour intensive.
Disadvantages:
1) have to rely a lot on patient compliance for results.
2) longer treatment time.
3) unknown potential for soft tissue changes with excessive use.
4) treatment results are time & dose dependent.
5) peroxide solution may cause irritation of gingival papilla.
6) teeth become sensitive to temperature changes.
Another method using macken’s solution has been described
1 part anaesthetic ether 0.2 ml – removes surface debris 5 parts hcl 38% 1ml — etches 5 parts hydrogen peroxide 30% 1 ml — bleaches
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Our Approach For Inoffice Bleaching
Indications:
1) Fluorosis stains / systemic fluorosis
2) Tetracycline stains
Contra indications:
1) Hyperaemic gingiva
2) Persistant periodontal problem cases
3) Fractured incisors / anteriors
Clinical application
The various steps are
1) Cleansing
2) Isolating
3) Etching
4) Rinsing
5) Dehydration
6) Application of solution
7) Scrapping
8) Rinsing
9) Filling
The Steps in detail:
1) cleansing the tooth surface with a nylon tooth brush & a mixture of pumice and water to remove surface debris.
2) isolation is done by application of rubber dam.
3) then dry the tooth surface & do enamel etching with 35% hcl for 20 – 25 seconds.
4) copious rinsing is done to eliminate acid residues & the tooth is subjected to thorogh drying.
5) application of 95% ethyl alcohol to dehydrate the enamel surface.
6) now,the application of 30% hydrogen peroxide(h2o2) is done first for 1 minute followed by alternative application of 5.25% sodium hypochlorite (naohcl) is done for 5 minutes during which it can be re-applied to the tooth surface to keep it wet.
7) the removal of staining molecules can be accelerated by gently scrapping the tooth surface.
8) this is followed by thorough rinsing of tooth surface.
9) this procedure is repeated at the interval of three days for successive sittings till the results are satisfactory.
10) in the end, fill the microcavities caused in the tooth by this solution with a light cure dental adhesive.
Advantages:
1) HCl etches enamel,but does not penetrate.
2) Tooth structure is not damaged.
3) Very very few chances of post – operative sensitivity of tooth.
4) No heat / application is required.
5) Very economical as all the three solutions in quantity of 50 ml. Each cost rs. 250 – 300 (total ).
6) Very low quantity of solutions required at each sitting.
Disadvantages :
1) Fluorosed teeth require larger & repeated sessions to decolorise Them.
2) Some blanching of gingiva can occur which is reversible within Half an hour.
3) Transitory decrease in bond strengh occurs when composite is applied to bleached / etched enamel.however,after a week,no decrease is seen.
4) Unknown duration of treatment
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