Ultrasonic Scaling
Question 1. Write short note on ultrasonic scaling.
Answer. Ultrasonic scaling is done by the ultrasonic instruments. They use a water-cooled instrument tip, vibrating at high frequency, to remove supragingival and subgingival calculus deposits from the tooth and bacterial plaque from periodontal pocket.
Types of Ultrasonic Scaler
Following are the types of an ultrasonic scaler:
- Magnetostrictive ultrasonic scaler: They operate inaudibly and instrument comprised of electronic generator, a handpiece assembly containing a coil to energize the insert and a variety of interchangeable inserts. The insert comprises either nickel iron alloy or a ferrous rod. The operator produces an alternating low voltage electric current in the handpiece. This current produces a magnetic field in the handpiece that causes the insert to expand and contract along its length and, in turn, causes the insert tip vibrate. The tip vibrates in an elliptical to orbital motion at 18,000 to 42,000 kHz (cycles per second).
- Piezoelectric ultrasonic scaler: They are also inaudible, vibrating within a range of 24,000–45,000 kHz. This type of powered scaler uses electrical energy to activate crystals within the handpiece to vibrate the tip. The motion of tip is linear in nature resulting in activation of mainly the lateral surfaces of the tip. This system is comprised of an electronic generator, a handpiece assembly containing piezo (ceramic) crystals to energize a scaling tip, and a variety of interchangeable screw on tips. The generator produces an alternating, high voltage in the handpiece. This voltage produces an electric field in the handpiece that causes the piezocrystals to expand and contract along their diameter and, in-turn, causes the scaling tip to vibrate.
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Principles of Instrumentation
- A modified pen grasp is used with an ultrasonic scaler, together with an extraoral fulcrum.
- Extraoral fulcrum allow operator to maintain a lighter grasp and easy access physically and visually to oral cavity. Alternate fulcrums using cross arch or opposite arch finger rests are the alternatives.
- Light pressure should be needed with powered instrument. The tip is travelling to a set frequency in a set stroke pattern.
- Ultrasonic instrumentation requires removal from coronal to apical portion of deposit. This stroke allows the insert to work at its optimal stroke pattern and frequency for quick and effective removal of deposits.
Water Flow
The water lavage has three benefits on the treatment site:
- Flushing action: Flushes calculus, blood, bacteria, plaque from treatment site.
- Cavitations: As the water exits from instrument tip, it forms a spray of tiny bubbles that collapses and releases shock waves in a process known as cavitation. It causes lysis of bacterial cell wall.
- Acoustic streaming: The continuous stream of water produces tremendous pressure within the confined space of periodontal pocket. This effect is called acoustic streaming. Bacteria, gram negative rods are sensitive to acoustic streaming.
Ultrasonic Scaling Advantages
- Efficiently remove plaque and stains.
- Gentle to the soft tissues as tips have no cutting edge.
- Used with light grasp and pressure this is less fatiguing to clinician.
- Provides less patient discomfort during use and postoperatively.
- Along with the water lavage fragments of calculus and necrotic sulcus tissue are flushed out.
Ultrasonic Scaling Disadvantages
- It decreases the tactile sensitivity.
- It is slight messy due to water spray.
- It does not accomplish effective calculus removal.
- Visibility gets decreased due to water spray.
- If used roughly can gouge root surfaces.
- It produces contaminated aerosols.
- Too much pressure of tip to the tooth surface lead to excessive heat build up, sensitivity and also permanent pulp damage.
Ultrasonic Scaling Indications
- For removing heavy tenacious calculus and stains.
- In overhanging margins of amalgam restorations.
- In orthodontic cement removal
Ultrasonic Scaling Contraindications
- In patients with a pacemaker, electromagnetic sound waves from ultrasonic unit can interfere with electronic function of pacemaker.
- In children vibrations can cause damage to growing tissues.
- In patients with contagious diseases such as hepatitis, tuberculosis, as these microorganisms spread through water spray.
- In local osteomyelitis.
- In uncontrolled diabetes.
- In chronic nutritional deficiencies.
- In local metastatic neoplasms.
- In patients on prolonged antibiotics and steroid therapy
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