Enamel removal is aided aby mixing an abrasive paste with the acid. This is usually pumice, or silicon carbide. Non-absorbable colouring can be added to the mixture so you can see where it is going. Micro-abrasion is legal in the UK (2005) because it does not involve Hydrogen Peroxide. When the discolouration is severe, it is helpful to also whiten the teeth using Dental Bleach (Carbamine Peroxide) first or afterwards. This step is however not currently allowed in the UK.
Before treatment Ensure the patient's expectations are not unreasonable.
Inform the patient that their expectations may not be met. Inform the patient that some stains do not respond to micro-abrasion or bleaching.
Inform the patient that there may be some relapse over the next few weeks, and repeat treatments may be needed.
Warn the patient there may be some post-op sensitivity.
Get written informed consent in the notes.
Ensure gingival and oral health is good, and the tooth is caries free.
Record the shade. Photos are very helpful.
Assess the thickness of the buccal enamel. Thicker enamel can withstand more surface loss than thin enamel.
Hydrochloric acid is DANGEROUS to both the patient and the operators.
Patient wears protective spectacles, large plastic apron and rubber dam. Operators wear aprons and eyes/face/arms protection. Apply dam to isolate only the teeth being treated. Rubber Dam can leak. Apply caulk under the dam, to protect the gingivae (Copalite Varnish acceptable also) before putting on the frame. A mixture of bicarbonate of soda and water is also applied to the gum with a flat plastic (to neutralise any excess acid) before putting on the frame. Invert the edge of the dam around the neck of the tooth. Preliminary Surface Treatment
Optional Stage - Ask Staff. Very gently, apply a fine grit (composite finishing) bur in the air turbine to the stained regions of the tooth. This mild roughening of the enamel exposes more surface area for the acid to work on, and decreases overall treatment time.
One part hydrochloric acid and one part water is mixed to a creamy paste with pumice (if using 36% HCl - this gives a final conc'n of 18%). If using proprietary 6% Gel, it does not need dilution/mixing. It is loaded into a 1 ml syringe. A layer 1mm thick is applied, and rubbed onto the tooth surface for approximately 5 seconds with a flat plastic or a dental wood-stick. The bulk is then wiped off with a cotton roll, and the tooth washed thoroughly. If you just spray the tooth, acid globules will splash everywhere. Bicarbonate of soda mixture if reapplied to the gum margins. The procedure is then repeated until the stain disappears. (no more than 10 to 15 five second applications). Clean up - remove dam, caulk. Polish teeth with Soflex discs and Enhance polishers. After Treatment
Application of Fluoride Varnish immediately after the treatment can reduce sensitivity, and aid remineralisation. If sensitivity persists, consider a tray-delivered fluoride gel for home use. Sensitivity will normally subside in 3 to 5 days. Do not provide any aesthetic (composite) restorations for a few weeks, as there will be some relapse of colour over this time, making shade-matching difficult. Equipment List
Rubber dam equipment – including wedgits, floss, clamps Hydrochloric acid Bicarbonate of soda Water Caulking paste or Copalite varnish Two flat plastics Woodsticks Mirror, probe, tweezers Fine grit air-turbine composite polishing burs Cotton Wool 1ml syringe: dappens pots Soflex discs and Enhance discs for polishing
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