• Teeth are polychromatic, color varies among the gingival, incisal and cervical areas according to the thickness, reflections of different colors and translucency of enamel and dentin (Fig. 24.1). • Color of healthy teeth is primarily determined by the
translucency and color of dentine and is modified by: – Color of enamel covering the crown
– Translucency of enamel – Thickness of enamel
– Normal color of primary teeth is bluish white whereas color of permanent teeth is grayish yellow, grayish white or yellowish white.
CLASSIFICATION AND ETIOLOGY OF TOOTH DISCOLORATION Classification • Extrinsic discoloration • Intrinsic discoloration • Combination of both. Etiology Intrinsic Stains A. Pre-eruptive causes i. Disease • Hematological diseases • Disease of enamel and dentine ii. Medication
• Tetracycline stains and other antibiotic use • Fluorosis stain
B. Post-eruptive causes of discoloration i. Pulpal changes
ii. Trauma
iii. Dentin hypercalcification iv. Dental caries
Extrinsic Stains
A. Daily acquired stains i. Plaque
ii. Food and beverages iii. Tobacco use
iv. Poor oral hygiene B. Chemicals
i. Chlorhexidine ii. Metallic stains
WHAT ARE CONTRAINDICATIONS FOR BLEACHING?
Contraindication
• Poor patient and case selection: Psychological or emotional patient.
• Dentin hypersensitivity • Extensive resorted tooth
• Teeth with hypoplastic marks and cracks • Defective and weakly restoration
– Defective obturation
– Discoloration from metallic salts as mercury.
WHAT SHOULD AN IDEAL BLEACHING AGENT HAVE?
An Ideal Bleaching Agent should
• Be easy to apply on the teeth. • Have a neutral pH
• Lighten the teeth efficiently
• Not irritate or dehydrate the oral tissues • Not cause damage to the teeth.
WHAT ARE EFFECTS OF BLEACHING AGENTS ON TOOTH?
Effects of Bleaching Agents on Tooth
• Tooth sensitivity
• Alteration of enamel surface
• Effects on Dentine: Bleaching has shown to cause uniform change in color through dentine
• Effects of bleaching on pulp:
– Transient reduction in pulpal blood flow – Occlusion of pulpal blood vessels.
• Effects on Restorative Materials: Application of bleaching on composites has shown following changes:
– Increased surface hardness – Surface roughening and etching – Increased microleakage
• Mucosal irritation • Toxicity.
HOME BLEACHING TECHNIQUE/NIGHT GUARD VITAL BLEACHING FOR VITAL TEETH
It involves use of chemical agents within the coronal portion of an endodontically treated tooth to remove tooth discoloration.
Composition
• Superoxol • Sodium perborate
Indications
• Mild generalized staining • Age related discolorations • Mild tetracycline staining • Mild fluorosis.
Contraindications
• Teeth with insufficient enamel for bleaching
• Teeth with deep and surface cracks and fracture lines • Teeth with inadequate or defective restorations • Severe tetracycline staining
• Teeth exhibiting extreme sensitivity to heat, cold or sweets
• Teeth with opaque white spots.
Advantages
• Simple method for patients to use • Less chair time and cost effective.
Disadvantages
• Patient compliance is mandatory
• Color change is dependent on amount of time the trays are worn.
Composition of Solution
• 10 percent carbamide peroxide solution • 3 percent hydrogen peroxide
• 7 percent urea.
Technique
• Take the impression and make a stone model • Trim the model
• Place the stock out resin and cure it • Choose the tray sheet material
• Cast the plastic in vacuum tray forming machines • Trim and polish the tray
• Checking the tray for correct fit, retention and over extension
• Demonstrate the amount of bleaching material to be placed.
Treatment Regimen
When and how long to keep the trays in the mouth, depends on patients lifestyle preference and schedule. Wearing the tray during day time allows replenishment
Bleaching of Discolored Teeth 109
of the gel after 1-2 hrs for maximum concentration. Overnight use causes decrease in loss of material due to decreased salivary flow at night and decreased occlusal pressure. Patient is recalled 1-2 weeks after wearing the tray.
IN OFFICE BLEACHING FOR VITAL TEETH Various Available Light Sources are
• Conventional bleaching light • Tungsten halogen curing light • Xenon plasma arc light • Argon and CO2 lasers
• Diode laser light.
Procedure
• Isolate the teeth with rubber dam. • Mix power bleach gel or solution.
• Apply 2-3 mm thick over labial surface using a disposable brush.
• Depending upon light, expose the teeth/tooth (Fig. 24.1) .
• Remove gel with the help of wet gauge.
• Repeat the procedure until desired shade is produced. • Polish teeth and apply neutral sodium fluoride gel. • Instruct the patient to avoid coffee, tea, etc. for 2 weeks.
Second and third appointment is done 3-6 weeks after. This will allow pulp to settle.
Advantages
• Patient preference
• Less time than overall time needed for home bleaching
Disadvantages
• More chair time • More expensive • Dehydration of teeth.
WALKING BLEACH OF NONVITAL TEETH/ ENDODONTICALLY TREATED TEETH
It involves use of chemical agents within the coronal portion of an endodontically treated tooth to remove tooth discoloration.
When paste is placed in pulp chamber, it causes oxidation of the stain and thus its lightening.
Indications of Intracoronal Bleaching
• Discolorations of pulp chamber origin • Moderate to severe tetracycline staining.
Contraindications of Intracoronal Bleaching
• Superficial enamel discoloration • Defective enamel formation.
Steps
1. Assess the quality of obturation. 2. Evaluate tooth color with shade guide. 3. Isolate the tooth with rubber dam.
4. Prepare the access cavity, remove the coronal gutta- percha, expose the dentine and refine the cavity. 5. Place mechanical barriers of 2 mm thick, preferably of
glass ionomer cement, zinc phosphate, IRM on root canal filling material.
6. Now mix sodium perborate with an inert liquid and place this paste into pulp chamber (Fig. 24.2). 7. Place a temporary restoration over it.
8. Recall the patient after 1-2 weeks, repeat the treatment until desired shade is achieved.
Fig. 24.2: Placement of bleaching mixture into pulp
chamber and sealing of cavity using temporary restoration
Complications of Intracoronal Bleaching
• External root resorption.
• Chemical burns if using 30-35 percent H2O2.