Dental Health International Nederland
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Chapter 4 - Restoring One-Surface Cavities Using ART
In the previous chapters all the equipment and materials required to perform ART have been presented. This chapter describes the step-by-step stages and instruments needed for placing ART restorations for the treatment of one-surface cavities.
Preparing the Cavity
To start with, place cotton wool rolls alongside the tooth to be treated. This will absorb saliva and keep the tooth dry. Remove plaque from the tooth surface with a wet cotton wool pellet, and then dry the surface with a dry pellet. The extent of the caries can now be judged better.
If the cavity opening in the enamel is small, widen the entrance. Do this by placing the blade of the dental hatchet into the cavity and turning the instrument forward and backward like turning a key in a lock. This movement chips off small pieces of carious enamel. If the cavity is very small, place a corner of the blade of the dental hatchet in the cavity first and then turn.
Carious dentine can now be removed with the excavators. The small excavator is used for small cavities, the bigger one for larger cavities. Soft caries is removed by making circular scooping movements around the long axes of the instrument (Fig. 4.1). It is important to remove all the soft caries from the enamel-dentine junction before removing caries near the pulp.
Figure 4.1
Circular scooping movements of the excavator
Figure 4.2
Fracturing off unsupported enamel with a hatchet
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Removing soft caries from the enamel-dentine junction may leave enamel that is unsupported with dentine. The overhanging of enamel can break very easily and must be removed. Do this with the blade of the dental hatchet. Place the instrument at the edge of the enamel and fracture off small pieces (Fig 4.2).
Repeat this until all the thin unsupported enamel has been removed and no caries is left in the remaining enamel.
Remember, it is not necessary, and often not possible, to fracture off all unsupported enamel. Ensure that the dental hatchet is well supported with your fingers. As a result of removing this enamel, visibility and accessibility of the cavity is improved.
Particular care is needed when removing carious dentine from two places in the cavity:
- the enamel-dentine junction.
This part of the dentine is close to the surface of the tooth. It is also the part where the restoration must stick very well to the
tooth. If caries is not completely removed at the junction, a good join is not made. Then bacteria will be able to penetrate in
the gap between the restoration and the cavity wall, and caries will develop further.
- the floor in deep cavities.
When removing carious dentine near the pulp there is a risk of damaging or exposing the pulp. So it is important to remove
no more dentine than really essential, in the deepest part of a cavity. If during cavity preparation the pulp is exposed there
will be bleeding in most cases, in the bottom of the cavity. Then special treatment of the pulp or removal of the tooth is
required. The choice of treatment will depend on the care available locally.
The excavated carious dentine can be placed on the cotton wool roll, positioned alongside the tooth or held by an assistant.
Excavation is easier done when the tooth is dry. Therefore, change saturated cotton wool rolls for dry ones.
After all caries is removed, the cavity is cleaned with wet cotton wool pellets. Then ask the patient to bite the upper and lower teeth together. This will show you how the tooth to be restored fits together with the opposing tooth. It will help you in trimming of excess restorative material later. The cavity preparation is completed by drying the cavity with dry cotton wool pellets.
The procedure for caries removal for one-surface cavities step-by-step
1. Place cotton wool rolls alongside the tooth to be treated.
2. Remove plaque from tooth surface with wet cotton wool pellets.
3. Dry the tooth surface with dry cotton wool pellets.
4. If necessary, make the entrance of the cavity wider with a dental hatchet.
5. Remove the carious dentine with excavators starting at the enamel-dentine junction.
6. Fracture off unsupported thin enamel with the hatchet. Make sure the enamel does not contain any carious spots.
7. Clean the cavity with wet and then dry cotton wool pellets.
8. Remove the caries near the pulp carefully.
9. Clean the cavity again with wet cotton wool pellets.
10. Check the relation of the tooth to be restored with the opposing teeth by asking the patient to bite.
11. Complete the procedure by drying the cavity with dry cotton wool pellets.
Cleaning the Prepared Cavity
In order to improve the chemical bonding of glass-ionomer to the tooth structures, the cavity walls must be very clean. It is not effective to do this with wet cotton wool pellets and therefore a chemical solvent is used. There are two possibilities:
- a dentine conditioner or tooth cleaner, especially developed for this purpose or
- the liquid supplied with the glass-ionomer itself.
The dentine conditioner is usually a 10% solution of polyacrylic acid. Apply one drop of the conditioner on a pad or the slab. Dip a cotton wool pellet in the drop and then clean the entire cavity and adjacent fissures for 10-15 seconds. Do this holding the cotton wool pellets with a pair of tweezers (Fig 4.3). Then, immediately, wash the cavity and fissures at least twice with cotton wool pellets, dipped in clean water.
Figure 4.3
Application of dentine conditioner
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The glass-ionomer liquid can be used for cleaning the cavity if it contains the same acid as is used for conditioning. Usually the liquid is too strong and needs to be diluted. This is done by placing one drop of liquid on a pad or slab. Then moisten a cotton wool pellet by dipping it in water. Remove the excess water by lightly touching the pellet against a dry cotton wool roll, a tissue or gauze. Dip the moist pellet in the glass-ionomer liquid and then use it as a dentine conditioner in the way described above.
Read the manufacturers' instructions carefully as it may contain further information about the use of their product. For example, there are brands where all chemical components are in the powder, while the liquid is only de-mineralized water. The liquid would therefore not be suitable for conditioning the cavity and a special conditioner must be used.
If the cavity is contaminated with blood, stop the bleeding by pressing with a cotton wool pellet on the wound. Wash the blood away with water and dry the cavity with cotton wool pellets. Place dry cotton wool rolls on both sides of the tooth to prevent recontamination. Then apply the conditioner in the cavity as described above. If a cavity becomes contaminated after having been conditioned, it is essential to wash, clean and recondition the cavity again.
Note: It may happen that the first drop of liquid contains air bubbles. Such a drop should not be used for mixing with the glass-ionomer powder. The powder-liquid ratio would not be correct. However, if the glass-ionomer liquid is used as the conditioner, such a drop can well be used for conditioning.
It is advisable to dispense one drop for conditioning and a second drop for mixing, keeping the bottle in the vertical position between dispensing (Fig. 4.4)
Figure 4.4
Mixing pad with two drops of liquid
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The Procedure for conditioning one-surface Cavities step-by-step
If manufactured dentine conditioner / tooth cleaner is used.
1. Apply one drop of conditioner on a slab or pad.
2. Dip a cotton wool pellet in the conditioner.
3. Clean the cavity and adjacent fissures with the conditioner for 10-15 seconds.
4. Wash the cavity and fissures immediately at least twice with cotton wool pellets, dipped in clean water.
5. Dry the cavity with dry cotton wool pellets.
6. Repeat procedures 3-5 if the conditioned cavity becomes contaminated with saliva and/or blood.
If the glass-ionomer liquid is used as a dentine conditioner.
1. Apply one drop of liquid on a slab or pad.
2. Dip a cotton wool pellet in clean water.
3. Remove excess of water from the cotton wool pellet by lightly touching against a dry cotton wool roll, tissue or gauze.
4. Dip the moist cotton wool pellet in the glass-ionomer liquid.
5. Follow the procedure for the dentine conditioner, as for points 3-6 presented above.
Restoring the Cavity
Make sure that the tooth is kept dry during the restorative phase. If necessary place new cotton wool rolls. An assistant is very useful at this stage, especially for mixing the glass-ionomer material.
Ensure that all necessary materials and instruments are available and ready for use. After the cavity is conditioned, washed and dried, you can start mixing the glass-ionomer. Insert the mixture into the cavity in small amounts using the blunt end of the applier/carver instrument. This will avoid inclusion of air bubbles. Push the mixture into place with the round surface of a medium excavator. Make sure the mixture goes into small cavities and under any enamel overhanging. Also place a little extra material on the adjacent pits and fissures (Fig 4.5a). Rub a small amount of petroleum jelly on the gloved index finger and press the soft restorative material firmly into the cavity and fissures (Fig 4.5b). This is called: 'the press-finger technique'. Remove the finger sideways after a few seconds. The time from the start of mixing until removal of finger should be no more than one minute.
Excess glass-ionomer material will be displaced by the press-finger technique towards the slopes of the cusps and between the cusps in the direction of buccal/lingual and proximal surfaces. Quickly and carefully remove any excess material with a medium or large excavator.
Then do not disturb the restoration during the hardening period and keep the tooth moisture free.
After about 1 to 2 minutes (depending on climatological conditions) check the bite. Place a piece of blue/red articulation paper on the restored tooth. Ask the patient to close the mouth and bite from side to side. Make sure that the patient does not bite on the cotton wool rolls. If the ART restoration is too high, blue/red spots appear. The height of the restoration can then be adjusted by scraping away some of the colored stained restorative material with the carver blade of the applier/carver (Fig 4.5c).
Finally, cover the ART restoration with a new layer of petroleum jelly. Then remove the cotton wool rolls. The restorative procedure is finished (Fig. 4.5d). Ask the patient not to eat for at least one hour.
Figure 4.5
The restorative process of a one-surface cavity in various stages
a. The cavity and adjacent pits and fissures are overfilled
b. Press the restorative material with gloved finger. Excess material is visible
c. Removal of excess material by the carver blade of the applier/carver
d. A restored one-surface cavity.
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The Procedure for Restoring one-surface Cavities step-by-step
1. Check that all instruments and materials are available and ready for use.
2. Ensure that the tooth is kept dry during the restoration phase.
3. Mix restorative material according to earlier description (20-30 seconds).
4. Insert the mixture in small amounts into the cavity and into the adjacent fissures, using the blunt blade of the applier/carver.
Use round surface of a medium excavator to push the mixture into deeper parts of the cavity and under any overhanging.
5. Rub some petroleum jelly on the gloved index finger.
6. Place the index finger on the restorative material, press and remove finger sideways after a few seconds.
7. Remove visible excess of glass-ionomer with a medium or large excavator.
8. Wait 1-2 minutes till the material feels hard, whilst keeping the tooth dry.
9. Check the bite using articulation paper and adjust the height of the restoration with the applier/carver if needed.
10. Apply a new layer of petroleum jelly.
11. Remove cotton wool rolls.
12. Ask the patient not to eat for at least one hour.
Figure 4.6
A cavity is restored and the adjacent fissures are sealed with glass-ionomer at the same time.
This is called a
'sealed restoration'
a. Caries in occlusal surface of molar
b. prepared cavity ready for applying ART restoration material
c. Cavity filled.
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