Stains And Microabrasion
Microabrasion represent coservative alternatives for the reduction or elemination of superficial discolourations.As the term imply,the stained areas or defect are abraded away.this technique results in the physical removal of tooth structure & are indicated for stains or enamel defects that do not extend beyond the few tenths of a millimeter in depth.If the defect or discolouration remains after treatment with microabrasion a restorative alternative is indicated.
In 1984,McCloskey reported the use of 18% hydrochloric acid swabbed on teeth for the removal of superficial fluorosis stains. Subsequently, in 1986, Croll and Cavanaugh modified the technique to include the use of pumice with HCL to form a paste applied with a tonuge blade. This technique is microabrasion and involves the surface dissolution of the enamel by the acid along with abrasiveness of pumice to remove superficial stains or defects. Since that time, Croll modified the technique, reducing the concentration of the acid to approx 11% and increasing the abrasiveness of the paste using silicon carbide particles ( in a wter soluble gel paste) instead of pumice. This product, marketed as Prema compound or Opalustre, represents an improved and safer means for the removal of superficials stains or defects. This technique involves the physical removal of tooth structure and does not remove stains and defects through any bleaching phenomena.
Before treatment , the clinician should evaluate the nature and extend of the enamel defect or stain and differntiate between non heriditary developmental dysmineralization (i.e. abnormal mineralization) defects (e.g., white or light brown fluoretic anamel and the idiopathic white or light brown spots ) versus incipient carious leisions. Incipient carious leisions usually are located near the gingival margin. These leisions have a smooth surface (i.e., macro appearance), and appear opaque or chalky white when dried, but are less visible when hydrated.
Incipient caries is reversible if treated immediately. Changing the oral environment by oral hygiene and dietary asjustments allows remineralization to occur. If the carious leision progressed to have a slightly roughened surface, however, microabrasin coupled with a remineralization to occur. If this approach is unsuccessful, it can be followed by restoration. Cavitation of the enamel surface is an indication for restorative intervention. As the location of smooth-surface enamel caries nears the cementoenamel junction, the enamel is too thin to permit microabrasion as a treatment option.
A developmental discoloured spots (opaque white or light brown) is the result of an unknown, local traumatic event during amelogenesis and is termed idiopathic. Its surface is intact,smooth, and hard.It usually is located in the incisal(occlusal) half of enamel, which contributes to the unsightly appearance. The patient (or patient’s parents) must be informed that an accurate prognosis for microabrasion cannot be given, but that microabrasion will be applied first. If microabrasion is unsuccessful because of depth of the defect exceeding 0.2 to 0.3mm, the tooth will be restored with a tooth-coloured restoration. Surface discolourations resulting from fluorosis also can be removed by microabrasion if the discoloration.
A rubber dam is placed to isolate the teeth to b treated and to protect the gingival tissues from the acid in Prema paste or compound. Protective glasses should be worn by the patient to shield the eyes from any spatter. The Prema paste is applied to the defective area of the tooth with a special rubber cup that has fluted edges. The abrasive compound can be applied with either the side or the end of the rubber cup. A 10x gear reduction, low speed handpiece (similar to that used for placing pins) is recommended for application of the Prema compound to reduce the possibility of removing too much tooth structure and to prevent spatter. Moderately firm pressure is used in applying the compound.
For a small, localized, idiopathic white or light brown areas,a hand application device also is available for use with Prema compound. periodically, the paste is rinsed away to assess defect removal. The facial surface also is viewed with a mirror from the incisal aspect to determine how much tooth structure has been removed. Care must be taken not to remove excessive tooth structure. The procedure is continued until the defect is removed or until it is deemed imprudent to comtinue further. The treated areas are polished with a fluoride containg prophy paste to restore surface lusture. Immediately after treatment, a topical fluoride is applied to the teeth to enhance reminearlization.