Some Cavities Filled With No Drill And No Novacaine

[Anonymous]

With “virtually no pain” most cavities can now be filled without using the standard dental drill or a local anesthetic (Novacaine), according to the Academy of General Dentistry. This is done by the use of “air abrasion” devices. This relatively new technology is also called “micro abrasion,” which is accomplished by blowing a fine stream of air containing fine aluminum oxide particles with a special air-tip. In accordance with the principle of kinetic energy, the tiny particles bounce of the tooth and blast the decay away.

There is virtually no pain in most cases because there is no vibration, no heat from friction and annoying sound. Air-Abrasion cuts tooth surfaces with “utmost precision,” produces no vibration, and therefore does not contribute to the tendency for the tooth structure to fracture. In addition, this precision allows your dentist to remove mostly just the decayed tooth structure. Since decayed tooth structure has no functional sensory fibers, there is no sensation of pain when cavities are cleaned. For this reason there is hardly any need for local anesthetics in air abrasion procedures. A further advantage is that this technology is quick, saves time, and the treatment time is therefore, usually shorter.

Composites, or “white fillings,” are used to fill teeth prepared by air abrasion. While silver fillings required cutting sound tooth structure, so that the filling could be locked in, white fillings are bonded to tooth structure without the need for mechanical retention. For this reason, cavity preparations done with air-abrasion are smaller and approximate the actual size of the cavity.

Air abrasion is also used to repair cracks, discolorations, prepare teeth for bonding and even cleaning hard to reach stains, like those between teeth.

If you have abrasion fillings done, expect to find an accumulation of harmless, dusty particle debris in the mouth. This may give you a gritty filling. Rinsing easily eradicates the powder. Eyeglasses or eye cover may be used to serve as a particle barrier. A special vacuum machine may be used to reduce dust buildup.

Air abrasion technology is also an especially good option for children, who may be afraid of needles, noise and vibration. In fact, anyone who has anxieties regarding dental treatment will be relieved that it is now available in many dental offices.

Air abrasion cannot be used for procedures such as crown and bridge preparations. The dental drill is still required for these procedures. As a preventative measure, air abrasion may be used as an aid in applying sealants to teeth. Air abrasion cleans out the stained pit on biting surfaces of teeth, without the need to drill the teeth. Sealants or even composites can then be used to seal these weak spots in the teeth. Because the surfaces are micro0abraded, sealants and composites bond better against tooth structure.

        

[drsnehamaheshwari]

 The study of the use of air abrasion technology for dental applications initiated by Dr Robert Black in the 1940’s was successfully introduced in 1951 with the Airdent air abrasion unit (S.S. White). In spite of showing promising results, the concept did not gain popularity due to three major factors. Firstly, air abrasion was not able to prepare cavities with well-defined walls and margins, and the materials during that time (mostly amalgam and direct or indirect gold) demanded such preparations since the concept of bonding had not been introduced. Secondly, the introduction of the air turbine handpiece in the late 1950s made conventional cavity preparations less time consuming. Thirdly, as high-velocity suction had not been developed, evacuation of the powder was difficult.

Though the basic concept of the air abrasion device has remained the same, it has experienced a rebirth not due to changes in the device per se, but due to improvements in bonding, restorative materials, isolation, and high volume suction. Air abrasion can be best described as a pseudo-mechanical, non-rotary method of cutting and removing dental hard tissue. The terms “micro air-abrasion” and “kinetic cavity preparation” have been used synonymously to describe air abrasion. Studies have shown that the bonding of enamel and dentin surfaces prepared with air abrasion is much better than that with conventional carbide burs or acid etching; with the introduction of flowable and nano-filled composites it is easier to restore cavities which do not confer with the specifications of GV Black’s concepts. Another major concern regarding the powder particles has also been averted due to the use of isolation in the form of rubber dam and high volume evacuation devices. Air abrasion also has the advantage of decreased noise and vibration as compared to conventional rotary instruments.

        

[drsnehamaheshwari]

Air abrasion for restoration preparation removes tooth structure using a stream of aluminium oxide particles generated from compressed air or bottled carbon dioxide or nitrogen gas. The abrasive particles strike the tooth with high velocity and remove small amounts of tooth structure. Efficiency of removal is relative to the hardness of the tissue or material being removed and the operating parameters of the air abrasion device.

A number of parameters such as the amount of air pressure, particle size, quantity of particles passing through the nozzle, nozzle diameter of the handpiece, angulation of nozzle of the handpiece, distance from object, and time of exposure to the object vary the quantity of tooth removal and depth of penetration.

·         Generally, air pressures range from 40 to 160 psi. The recommended levels are at 100 psi for cutting and 80 psi for surface etching.

·         The most common particle sizes are either 27 or 50 μm in diameter. The larger particles allow the clinician to work faster but will result in comparatively larger-sized cavity preparations than those with the 27 μm particles.

·         Higher particle flow rate will allow more particles to abrade the working surface faster.

·         The speed of the abrasive particles when they hit the tooth depends upon the gas pressure, nozzle diameter, particle size, and distance from the surface.

·         Typical operating distances from the tooth range from 0.5 to 2 mm. Further distances produce a more diffuse stream that results in a diminished cutting ability.

·         A number of variations in tip angulations and nozzle diameters are available. Smaller nozzle diameters can be used for areas that are difficult to access. The various tip angulations allow easy placement and orientation of the handpiece thus easing the strain off the operator’s hands. 

        

[drsnehamaheshwari]

Specific indications for use of air abrasion include caries removal; removal of small existing restorations; preparation of tooth structure for cutting or etching for the placement of composites, porcelain and ceramics; and as an adjunct to the conventional handpiece bur.

Some of the situations where the air abrasion has particularly proved a boon include:

1.      Removal of superficial enamel defects – these are much easier with the air abrasives since they result in removal of less tooth structure than the drill.

2.     Air abrasion is an excellent tool for detection of pit and fissure caries – when clinical, radiographic, and patient risk factors make pit and fissure caries suspect, air abrasion can be used to remove the organic debris and determine if caries is present. Use of burs for this procedure would remove far more sound enamel than the few micrometers removed with air abrasion.

In the event of the operator not locating any carious lesions, the area can easily be sealed using a pit and fissure sealant.

If caries is limited to enamel, then a sealant or flowable resin-based composite can be placed.

If caries penetrates into dentin, then the preventive restoration can be used with a heavily filled resin in deep or wide areas subjected to forces of mastication. Sealant material may be used to cover non-carious pits and fissures.

Additionally, caries detector dyes may also be used in conjunction with air abrasives to detect incipient lesion and treat them appropriately.

3.     Air abrasion can also be used for the removal of pit and fissure surface stain on enamel before placement of a resin-based composite restoration or porcelain veneers.

4.     Teeth where the caries is restricted only to a small section of the tooth can also be prepared using air abrasives for conservation of sound tooth structure. Box-preparations for Class II cavities can also be prepared.

5.     Surface preparation of abfractions and abrasions – air abrasion breaks the glaze of the highly polished surface that is not suitable for bonding and produces a highly textured surface that is excellent for the wet dentin-bonding technique.

6.     Removal of existing restorations – the particles of the air abrasives can be used at higher pressures for removal of old amalgam restorations for replacing them or for removal and repair of composites, glass ionomers, and porcelain restorations.

7.     The use of local anesthesia while working in dentin may be avoided because of their cooling action through high pressure air. 

        

[drsnehamaheshwari]

Optional accessories for the air abrasion system

In addition to the different grades of the powder particles and the various tip diameter sizes and tip angulations for the air abrasion handpiece, there a few more accessories which will provide the clinician a better working environment:

1.      Air abrasion resistant intraoral mirror: Majority of air abrasion operative dentistry procedures “eat up” an average of two to three mirrors per procedure, particularly when indirect vision is used. In an effort to conserve mirrors, the dentists will have a tendency to migrate towards direct vision, which in turn leads to obvious long-term deleterious effects on one’s back. This mirror designed by CrystalMark Dental Systems, Inc. can withstand the indirect blasts of abrasive powder that are part and parcel of air abrasion dentistry. These mirrors come gold-plated for ease of identification by the staff and fit the standard no. 5 cone socket handle.

2.     Sand trap: These are soft plastic spheres that slip onto office suction and have a top opening through which the air abrasive system tip is introduced. This device traps the abrasive particles within the sphere from where they can be evacuated through the suction. This prevents the abrasive particles from entering the patient’s oral cavity [Figure 3].

3.     Power plus booster: Available as an accessory to the Prep Start (Danville Engineering) recompresses the compressed air up to 135 psi to increase the air pressure to allow for faster cutting thus reducing the patient chair-time.

4.     Disposable air abrasion handpiece: The Airbrator^® (North Bay/Bioscience, LLC) is a single-use air abrasion handpiece that connects to your existing air-line. It is a direct alternative to traditional, expensive, self-contained air abrasion units. The Airbrator comes in three grades.

High Performance – For small incipient lesions and cavity preparations.

Medium Performance – For sealants, etching, bonding, and heavy stain applications.

Light Performance – (Sodium Bicarbonate Powder) For removing stains, cleaning, and polishing.

Others like the EtchMaster and PrepMaster^® (Groman Inc.) are pre-filled disposable air abrasion systems that can adapt to your handpiece connection for etching and intra-oral cavity preparations, respectively.

5.     Super high volume evacuation systems: Like the RapidVac or Union Medical Evacuation System is the ideal companion for all air abrasive systems. Delivering super high volume suction, these devices completely eliminate the chances of contamination of the dental operatory with abrasive particles.

 

        

[drsnehamaheshwari]

DOES IT HAVE ANY LIMITATIONS?

Though air abrasives can be used in a large number of clinical situations there certainly are some limitations to their use such as

·         Air abrasion is not an efficient means of removing large amalgam restorations especially, and there is concern for the levels of mercury released when amalgam is abraded. Air abrasion of amalgam for 1 min releases mercury vapor four times in excess of the OSHA standard. Same is true regarding removal of full coverage restorations.

·         Air abrasion is also not effective for removal of gross caries because it does not cut substances that are soft or resilient. In such cases, however, hand instruments like spoon excavators can be used to scoop out the soft lesions followed by air abrasives to remove the relatively hard carious tooth structures.

·         Also the depth of penetration during cavity cannot be controlled, so it has to be accompanied with visual inspection in regular intervals.

·         The splattering of the powder particles within the oral cavity and/or their accidental ingestion is another area of concern for which use of rubber dam isolation is a must. Additionally, patients, operator, and office staff must be equipped with protective eyewear to prevent the abrasive particles from accidentally entering the eyes.

·         Air abrasive systems also cannot be used in conjunction with magnification devices such as loupes or dental operating microscopes as the rebound particles could cause damage to the lenses.

·         Care must be taken when working near soft tissues due to risk of laceration, air dissection, and emboli. An inadvertent spray to soft tissues is not likely to cause damage, but a prolonged direct spray could potentially cause injury.

·         Air abrasion produces a rounded textured cavosurface margin and thus is not suitable for restorative preparations requiring definitive walls and sharp, well-defined cavosurface margins such as those needed for conventional amalgam and metal or porcelain inlays/onlays. It is also not suitable for crown preparations for either metal or porcelain coverage.

 

        

[drsnehamaheshwari]

Method of clinical use

A number of air abrasion systems are available today such as the PrepMaster or EtchMaster (Groman Inc.), Airbrator (North Bay/Bioscience, LLC), PrepStart and PrepAir (Danville Engineering), or CrystalMark (CrystalMark Inc.) all of which work on the same principle. Some like the RONDOflex plus (KaVo) work on the principle of air abrasion technology with water spray. Operator controls are either mechanical or digital. Mechanical control is standard in most devices, and their control of powder flow rate (the primary determinant of overspray and consequent mess to be evacuated, washed or otherwise removed) is more tenuous than with digital control, which provides a consistent and minimal amount of powder while maintaining high efficiency. In selected devices digital control also allows for pulsed mode of operation, providing an interrupted air abrasive stream at settings from 0.5 to 2.0 seconds.

Air abrasion handpieces and nozzles are removable to facilitate sterilization and have working angles ranging from 0° to 120°. For precision cutting, as might be required for a preventive resin restoration, the 80° tip is more appropriate than the 45° tip. When shallow preparations are needed, as in the case of cervical erosion, the cutting patterns of the 45° tip are more appropriate.

For facial and lingual preparations, a 60° angle produces a shallower preparation and allows for evacuation of reflected spray.

Nozzle orifice diameters range from 200 to 800 μm. Larger nozzle orifices require higher powder flow rates and gas pressures to maintain cutting efficiency.

 

        

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