How to get the most out of ultrasonic instrumentation

Today’s ultrasonic scaler is one of your most potent weapons in the war against periodontal disease. But you have to use proper technique, and “Proper Ultrasonic Technique” has changed dramatically in the past few years.

by Jill S. Nield-Gehrig, RDH, MA
Arden, North Carolina

Until the late ‘80’s and early ‘90’s, the ultrasonic scaler was used primarily as a dental jackhammer ... a high-power device to blast off tenacious accretions that resisted hand instruments.

Use of ultrasonics below the gingival margin was strongly discouraged. In fact, those early robust scaling tips wouldn’t even fit into a periodontal pocket. In those days, hygienists and dentists who relied heavily on ultrasonics were viewed with some condescension by purists. (The term “Cavitron Queen” suggested a somewhat lazy practitioner who had never mastered the true art of hand instrumentation.)

All this started to change in the ‘90’s. As the profession began to appreciate the role of bacteria and bacterial by-products in periodontal disease, ultrasonic instrumentation gained new respect. Research suggested that the cavitation and fluid streaming out from the vibrating tip could disrupt, dislodge and destroy bacteria even beyond the reach of the tip itself. Other studies suggested that ultrasonic irrigation removed endotoxins from root surfaces without stripping the cementum and creating hypersensitivity.

Research into biofilms has shown just how difficult plaque biofilm is to destroy. Once disparate species of bacteria organize into colonies, they are extremely resistant even to strong antimicrobial agents that would be utterly lethal were the same bacteria not in a biofilm. So biofilm research has reinforced appreciation of the role of mechanical debridement (i.e. ultrasonics) in treating periodontal disease.

Clinical studies have shown that periodontal patients who are maintained exclusively or primarily using ultrasonics experience outcomes at least as positive as those maintained by traditional means.

One result of all this research has been development of a wide variety of ultrasonic tip designs specifically for subgingival use: debriding (removing plaque rather than calculus) or for scaling in areas previously thought unreachable. And many dentists and hygienists have never learned how to use these newer designs.

So in this series of short articles I’d like to offer suggestions for getting the most out of your ultrasonic scaler. If you haven’t changed the way you use ultrasonics during the past decade ... if you’re using the newer tip designs the same way you used the older supragingival tips - these articles are for you.

During the next few months we’ll discuss topics as basic as adjusting the power and water for the specific job at hand - to how to maximize root access using straight and curved tips - to how to ultrasonically eliminate an amalgam overhang.

Preparing the patient and operator

As with any dental procedure, universal precautions must be used during ultrasonic instrumentation.

The clinician should wear a gown with a high neck and long sleeves, mask, protective eyewear or a face shield, and gloves.

Select a mask with a high bacterial filtration efficiency (BFE) [48]. By definition, a mask with a high bacterial filtration efficiency will effectively filter out 98 percent of particles that are three microns or larger in size. Because of the high level of aerosols generated by powered instrumentation, change masks every 20 minutes, as a damp mask will not provide adequate protection.

Personal protective gear for the patient should include a plastic drape, towel or bib, and protective eyewear. The patient may prefer to cover his or her nose with a flat-style mask to limit inhalation of aerosols.

Administering a pre-procedural rinse to the patient is recommended to reduce the number of bacteria introduced into the patient’s blood stream and for control of aerosols into the surrounding environment. A two-minute mouthrinse with either 0.12 percent chlorhexidine or an antiseptic mouthrinse, such as Listerine Antiseptic, before treatment is recommended for all patients.

Scaling with the right surface

Electronically powered instrument tips produce energy vibrations from each surface of the working-end. Knowledge of the energy output of each working-end surface is significant in adapting the tip to a tooth surface.

Different amounts of energy are produced by the face, back, lateral surfaces, and point of an electronically powered instrument tip.

Point of the tip-produces the greatest amount of energy vibrations.
Face of the tip (concave surface)-produces the second greatest amount of energy vibrations.
Back of the tip (convex surface)-produces less energy than the face or the point.
Lateral surfaces of the tip-produce the least amount of energy vibrations.

Adapting the tip to the tooth

Clinicians should follow manufacturer’s recommendations for tip-surface adaptation. In general, the following guidelines should be followed for all electronically powered instrumentation:

Point of the tip. The point of the working-end should never be adapted to the tooth surface. The high-energy output from the tip could damage the tooth. (The sole exception to this rule is the Beavertail tip, whose broad end is designed to apply the energy without gouging.)

Face of the tip. The face should not be adapted to the tooth surface because the high amount of energy it produces could damage the tooth surface.

Back of the tip. The back of most ultrasonic and sonic instrument tips can be adapted to the tooth surface, following the recommendations of the tip manufacturer.

The back of magnetostrictive instrument tips (convex surface) is most effective in debriding root surfaces.

Lateral surfaces of the tip. Adaptation of the lateral surfaces of the working-end is recommended with all sonic, piezoelectric and magnetostrictive ultrasonic instruments.

It is the vibration energy of a powered instrument tip that is responsible for calculus removal. The portion of the instrument tip that is capable of doing work is called the active tip area.

The active tip area ranges from approximately 2 to 4 millimeters of the length of the instrument tip. This means that the power to remove calculus is concentrated in the last 2 to 4 mm of the length of the tip.

The higher the frequency of an electronically powered device, the shorter the active tip area.
A 50 kHz device-active tip area is 2.3 millimeters long
A 30 kHz device-active tip area is 4.2 millimeters long
A 25 kHz device-active tip area is 4.3 millimeters long

When the instrument tip is adapted to a tooth surface, it should be kept moving at all times using a combination of overlapping vertical, oblique, and horizontal strokes. Instrumentation strokes should be short and overlapping to cover every square millimeter of the root surface.

Removing stubborn calculus

A common misconception among clinicians who are new to powered instrumentation is the belief that a single quick tap against a deposit will remove it. Powered instruments are very effective at removing calculus deposits, but they are not magic wands. Adequate time must be spent on a deposit to remove it. A calculus deposit will not vanish in a single tap, but rather, tiny pieces will fall away from the deposit as it is exposed to the instrument tip during a series of gentle strokes. Effective strategies for removing stubborn calculus deposits include:

Proper tip selection. As with hand instruments, the instrument tip is selected based on the size and location of the calculus deposit.

Use standard-diameter tips to remove moderate to heavy deposits above the gingival margin and in shallow pockets.

Use straight slim-diameter tips to remove light to moderate calculus deposits on anterior teeth and on posterior root surfaces up to 4 millimeters below the CEJ.

Curved Slim-Diameter Tips. Use curved right and left slim-diameter tips to remove light to moderate calculus deposits on posterior root surfaces greater than 4 millimeters below the CEJ.

Attack the Deposit from all Directions. Approach a deposit from a variety of directions. For example, interproximal deposits can be approached from both the facial and lingual aspects.

If the deposit fails to dislodge ...

If you are using a manually tuned device and intentionally lowered the frequency to reduce the power, use the tuning control knob to bring the device into tune. This will increase the stroke of the tip.

Increase the Power. If the above strategies fail to remove the deposit, it will be necessary to increase the power setting.

TIP ADAPTATION

The point of the working-end of an electronically powered instrument tip should never be adapted to the tooth surface. The high-energy output from the point of the tip could damage the tooth surface.

Powered instrument tips should be adapted with either the lateral surface or back parallel to the tooth surface being treated. The working-end’s face-to-tooth surface angulation should be as close to 0-degrees as possible and should never exceed 15-degrees.

Keep moving

The powered instrument tip should be kept in constant motion when adapted to a tooth. There are two basic techniques for moving the vibrating instrument tip.

To repeat, calculus removal is accomplished using a series of gentle tapping motions against the deposit from different directions.

Subgingival deplaquing is accomplished using a series of gentle sweeping motions over the root surface. For deplaquing, short, over-lapping strokes should cover every millimeter of the root surface. Imagine that the tip is a crayon. Your goal is to gently color the entire root surface using the side of a crayon tip--rather than the point.

Okay, so much for the basic introduction. In the next articles we’ll discuss use of the various slim tip designs. Ever wonder what those strange left and right-curving inserts are for? We’ll demonstrate them, and show where and how they’re used, plus a lot more.

About the Author:

Former Dean of Allied Health and Public Service Education at Asheville-Buncombe Technical Community College, Jill S. Nield-Gehrig, RDH, MS, has been a dental hygienist for 31 years and an active educator for 25 of those years. She received her RDH from Temple University, her BS from Millersville University and a Masters Degree from St. Mary’s University.

A sought-after lecturer and consultant, Jill recently co-authored Foundations of Periodontics for the Dental Hygienist and was the sole author of Fundamentals of Periodontal Instrumentation & Advanced Root Instrumentation - 5th Edition (both published by Lippincott Williams and Wilkins.)

She can be reached at jng_consulting@bellsouth.net.

Recent books by Jill S. Nield-Gehrig, RDH. MS

Foundations of Periodontics for the Dental Hygienist edited by Jill S. Nield-Gehrig, RDH, MA and Periodontist Donald E. Willmann, DDS, MS is a heavily illustrated, easy-to-understand text that uses an evidence-based approach to show how the latest research (biofilms, host responses to pathogens, etc.) is influencing hygiene therapy. According to Dr. Larry Burnett, Foundations is destined to become “a standard for dental hygiene programs everywhere.” $51.95 423 pages http://connection.lww.com/go/nieldfoundations

Fundamentals of Periodontal Instrumentation & Advanced Root Instrumentation by Jill S. Nield-Gehrig, RDH, MA is a lavishly illustrated “cookbook” for the dental hygienist as well as the GP or periodontist who personally performs hand- or power instrumentation. The rationale for each procedure is clearly explained, as are the proper technique and contraindications. $57.95 640 pages http://www.lww.com/eproduct/0,0,72924,00.html

Both books are available from Lippincott Williams & Wilkins (www.lww.com or 1-800-638-3030), Amazon.com, or from your local health sciences bookstore

Soft-tissue periodontal models are recommended by the author both for study and practice. All soft-tissue models in this article were supplied courtesy of Kilgore International (http://www.kilgoreinternational.com/, 1-800-892-9999)