A Winning Combination

The combination of ultrasonics and ergonomics enhance treatment options and ensure occupational health.

Jun 1st, 2005
Th 181691

The clinician supports the weight of the ultrasonic cord with the forearm.
Click here to enlarge image

Most recent hygiene graduates learned about ultrasonic scalers in school, but many seasoned professionals wonder how to best use these devices. From an ergonomic standpoint, ultrasonic scalers can reduce the risk of workplace-related repetitive stress injuries, which sideline untold numbers of dental hygienists each year. It is much easier ergonomically to gently guide an ultrasonic tip over a tooth surface than to hand scale with repetitive strokes, even when using the sharpest of hand instruments.1 A properly used ultrasonic scaler can be a personal dream machine.


The palm and thumb control the cord.
Click here to enlarge image

In addition to their ergonomic advantages, magnetostrictive and piezo electric ultrasonic scalers are capable of creating cavitation in the fluid irrigant. Ultrasonic tips generate thousands of cavitations, which are tiny, bubble-like vacuums. As quickly as they form, they implode and create sonic waves and acoustic turbulence. This energy release adds to the disruption of plaque biofilms.2,3,4 Are we using the best tools to provide optimal clinical treatment with less ergonomic stress?


The cord is managed with a "pinky" finger grasp.
Click here to enlarge image

The location of your ultrasonic scaler is a basic consideration.1,2 My first ultrasonic scaler was located on a sliding tray in a cabinet behind the patient chair. The tray was on the opposite side of the cabinet from where I sat, which created an ergonomic nightmare. Clinicians forced to lean across a patient for an uncomfortable reach will not be inclined to use their ultrasonic scalers regularly.


The nec supports the weight of the cord. Notice how the patient is turned with the head slightly elevated, which facilitates fluid evacuation.
Click here to enlarge image

Some hygienists work in treatment rooms where the scaler is not freestanding, but built into the cabinet. While this design frees valuable counter space, many early models have short cords, which creates a difficult situation if the scaler is stored on the other side of the cabinet.


The ultrasonic cord is draped through a metal support (photo by Robin Moye, RDH).
Click here to enlarge image

Modern ultrasonic scalers allow us to customize each situation. An easy-to-reach unit allows a clinician to modify power and water levels quickly and efficiently, change inserts or tips as needed, or adjust the frequency control on a tunable magnetostrictive unit.1,2,5


The cord is draped over the overhead light handle (photo by Harold Henson, RDH, MEd).
Click here to enlarge image

Patient positioning is also important. The fluid that irrigates an ultrasonic tip can annoy patients, especially those who have swallowing disorders.2 In most cases, it is possible to scale with an ultrasonic scaler using a few adjustments.


Insert tip is parallel to tooth surface (photo by Hu-Friedy).
Click here to enlarge image

First, partially recline the patient’s chair. Instruct the patient to turn his or her head so fluid can collect between the facial of the lower molars and buccal mucosa. This prevents excess fluid from accumulating in the back of the throat.2


Using a light pen grasp and extraoral fulcrum reduces hand fatigue.
Click here to enlarge image

Most hygienists use traditional saliva ejectors; however, there are several suction devices that contain multiple holes that facilitate fluid evacuation.2 It is possible to bend a traditional saliva ejector so it hangs hands-free in the vestibule, constantly providing suction while scaling.1 From an ergonomic standpoint, it is difficult for solo clinicians to control the weight of a high volume suction device while using an ultrasonic scaler.


A "pinky" fulcrum is shown (photo by Hu-Friedy).
Click here to enlarge image

Managing the ultrasonic handpiece cord is another way to improve power scaler ergonomics. Polishing and power scaling handpieces have similar issues - cord length, torque, weight, and balance. Older cords are heavy, short, and create significant torque on the wrist, forearm, and shoulder.1 Eventually these devices take a toll on muscles and joints, regardless of the unit location. New scaler designs eliminate these problems.


A multi-finger extraoral rest is demonstrated.
Click here to enlarge image

Dentsply SPS scalers feature the Steri Mate handpiece, an ergonomic breakthrough. It is long and lightweight with a 320° hose end swivel. The Steri Mate is compatible with some earlier units. Retrofitting a scaler with a new handpiece is more cost effective than buying a new unit. Hu-Friedy’s Satin Swivel inserts have a 360° fingertip swivel that facilitates tip adaptation. Clinicians can quickly gain optimal access to a specific surface rather than repositioning an insert.


An extraoral chin.
Click here to enlarge image

Even though most new scalers have improved cords, it is still important to eliminate as much weight and torque as possible.1,2 There are many ways to accomplish this. Place the bulk of the scaler cord around the back your neck, thread a loop of excess cord between your pinky and ring finger, or hold a portion of the cord in the palm of your hand. Other solutions include wrapping excess cord around your forearm, or balancing a portion on top of your forearm. Draping the cord on top of the overhead light handle works, but make sure it does not touch a hot light. Robin Moye, a hygienist in Florida, runs her cord through the metal support that attaches to an ironing board. If you don’t know what this device looks like, just ask anyone who grew up ironing their clothes.


A comparison of ultra-thin ultrasonic scaling inserts with a periodontal probe, explorer, and hand scaler is shown.
Click here to enlarge image

Holding an ultrasonic scaling handpiece is different than grasping a hand instrument. It is best to balance a magnetostrictive handpiece between the thumb and index finger using a regular pen grasp with light force, similar to holding a periodontal probe. This grip allows you to maintain control over the insert, rotate the handpiece in your fingertips, and results in maximum tactile sensitivity.2,6


Thin universal ultrasonic tips have padded grips.
Click here to enlarge image

Piezo electric handpieces have a design silhouette similar to a wide-body polishing handpiece. Initially piezo handpieces may feel different because the profile is different and the weight distribution is over a smaller area. To maintain control, use a wide body handpiece-like grasp. It should quickly become second nature to hold the scaler handpiece this way.


Right and left ultrasonic scaling inserts have a similar design to a curved periodontal probe.
Click here to enlarge image

Most clinicians who use ultrasonic scalers on a regular basis favor an extraoral soft tissue rest,2,6 and stabilize with one or more fingers on the patient’s chin, lips or cheek. Extraoral rests should be very light and comfortable for bothe patient and clinician. Patients who suffer from TMD dysfunction find this treatment comfortable.6 It may feel awkward at first, but it is impossible to have tight pinch/grip on any instrument or handpiece using a pinky finger rest.


The insert tip is poorly adapted to the root anatomy.
Click here to enlarge image

Fiber optic lighting is a feature in many high-speed handpieces. Both Brasseler USA-NSK and Satelec-Acteon have piezo electric scalers that feature ultrasonic handpieces with built-in fiber optic lights. The EMS lighted handpiece is currently available only in Europe. The footswitch in these piezo units activate the fiber optic light and the ultrasonic tip at the same time. This additional light improves visual acuity during scaling.


A curved insert tip provides easy access to molar furcations.
Click here to enlarge image

Manufacturers are responding to clinician demands for new tip designs. Today new tips are shaped like periodontal probes or delicate explorers. If we can probe an area, we can successfully gain access to complex tooth surfaces by selecting an insert compatible with the root anatomy.2,4-8 Today’s micro-ultrasonic tips can be viewed as probes with the power to disrupt plaque biofilm.


Radiographic image at right shows root damage created by hand scaling four times a year for more than 30 years (photo by Renee Marchant-Turner, RDH).
Click here to enlarge image

Micro-ultrasonics accurately describes what we can accomplish with today’s thinner tips.2,5,9,10 Dr. Tom Holbrook, a Tampa periodontist, modified traditional magnetostrictive inserts. His pioneering spirit resulted in ultrasonic tips thinner than anyone ever imagined. Dentsply Slimline inserts became commercially available 10 years ago, but today’s micro-ultrasonic tips have achieved a new level of clinical excellence.11 Ultrasonic Services (USI) manufactures the thinnest magnetostrictive tips. One design is virtually indistinguishable from a periodontal probe. An even thinner version resembles the diameter of an explorer.11 NSK has a remarkable number of ultra-thin periodontal tips that are interchangeable with both the NSK Varios piezo scaler and Satelec units.


A carbon composite implant tip (photo by Satelec-Acteon).
Click here to enlarge image

The size, diameter, and shape of the ultrasonic tip profoundly affects both patient and clinician comfort.12 Typically, micro-ultrasonic insert tips are more comfortable for patients because there is less soft tissue displacement.


Fiber optic lighting in the piezo handpiece improves visual acuity (phot by Brassler USA-NSK).
Click here to enlarge image

A recent study concluded that students who use ultrasonic scalers for 45 minutes have greater tactile sensitivity than a corresponding group of students who used hand scalers for the same amount of time.13 Repeated exposure to vibrating tools is considered a risk factor for cumulative trauma disorder; however, there are no studies that conclude regular use of an ultrasonic scaler will create increased risk for dental hygienists. Even though there is no solid research to guide us clinically, it seems wise to limit our exposure to vibration by using slimmer tips at reduced power ranges.

Click here to enlarge image

Effective deposit removal is possible with ultrasonic scalers, even at lower power settings.14 Magnetostrictive scalers produce either an elliptical or orbital tip pattern, in contrast to the linear movement of a piezo tip. The convex and concave surfaces on a magnetostrictive insert remove heavy, tenacious deposits more efficiently than the lateral surfaces. The lateral surfaces of a piezo insert produce smoother and quieter scaling than the convex or concave surfaces on a piezo tip. The greatest power generated by any ultrasonic scaler is at the point of the insert tip. Clinicians should avoid using the point because the force can damage tooth structure.2,6


A piezo handpiece, wrench, and tips are shown.
Click here to enlarge image

Most studies demonstrate that ultrasonic scalers are more gentle to root surfaces than either hand instruments or sonic scalers.9,15-18 Larger diameter insert tips used at high power levels have a greater potential to damage root surfaces.19 Root damage increases as clinicians apply more energy,7,19-21 even though increased pressure on the tip dampens the tip vibration.


Worn out or broken inserts should be replaced.
Click here to enlarge image

Every clinician must make a decision about which type of insert to use - larger, more robust designs, or thinner, more delicate tips. There is not one answer to this question. Tip selection is often made once we determine how easy it will be to remove the deposits.


Damaged magnetostrictive stacks are shown.
Click here to enlarge image

Although larger inserts have more potential to cause damage19 and patient discomfort, they remove heavy, tenacious deposits faster. Thin tips increase patient comfort, but take more time to remove resistant deposits. Every hygienist has faced the challenge of removing a small speck of incredibly stubborn calculus. Using a larger tip for a brief period may be the answer. Using a more powerful tip surface or increasing the power can facilitate deposit removal. Adjusting the frequency control on a manually tuned unit will also improve scaling efficiency.2,5,6,10

Early research demonstrated that ultrasonic inserts could damage cosmetic restorations.21 Initial studies used large tips activated at high powers. Today’s ultrasonic scalers can be operated at very low power levels using ultra-thin tips2,5,6; however, it is advisable to open the angle up slightly so the ultrasonic tip is not in direct contact with a cosmetic restoration.2


Magnetostrictive scaler is automatically tuned and has swivel handpiece and power boost foot control (photo by Dentsply Professional).
Click here to enlarge image

Composite materials are much harder than the metal tips. Placing the tip in direct contact with a composite restoration has the potential to shorten the life span of the insert tip.2,6 A gray slurry around the tip indicates that the composite material is wearing down the metal tip.


Ultrasonic scaler in manually tuned and has a multiple power level in foot control (photo by Ultrasonic Services Inc).
Click here to enlarge image

Implants pose another clinical challenge. Most research suggests that traditional metal ultrasonic tips can create scratches on the surface of implant abutments.2,23 EMS offers a plastic-coated piezo tip, and Satelec has carbon composite tips designed for safety with implants. The Tony Riso Company has the ITS (Implant Titanium Scaler) magnetostrictive insert that can be covered with a single-use, plastic sheath.2,23


The above scaler is a piezo electric unit (photo by Brasseler USA-NSK).
Click here to enlarge image

Most clinicians begin scaling with a universal insert design. Right and left curved inserts are invaluable for accessing complex tooth anatomy. These inserts are particularly beneficial when faced with the following clinical situations: tilted or crowded teeth, interproximal areas, furcations or reaching teeth in lingual version, orthodontic appliances, fixed retainers, and periodontal splinting.2,5,6

Clinicians cannot instrument all areas of the mouth on every patient with only one ultrasonic insert tip. It is important to have a sufficient supply of different tips to meet complex clinical challenges.2,5,6,11

Ultrasonic inserts or tips do not last forever. As the tip wears, the overall effectiveness of ultrasonic scaling diminishes. Worn out tips will not produce proper tip vibrations. Tip wear is especially evident when using inserts in an automatically tuned unit. Dentsply offers a guide that helps determine tip wear for inserts used in automatically tuned magnetostrictive units. Manually tuned scalers can result in longer tip life because the effective area on an insert tip can be changed by altering the frequency delivered to each tip.

Slim tips activated at low power ranges require less fluid flow to the tip, and improve visual acuity while still providing continuous lavage.2,5,6 At lower power settings, a fast drip and a smaller diameter mist replace heavy water flow. While it may take a bit longer to remove some deposits at low power ranges, the ability to see more clearly is a reasonable tradeoff.

Many times it is not possible to use direct vision. Water droplets and fogging interfere with visual acuity. Periodically wiping or spraying the mirror surface with a standard mouthwash changes the mirror’s surface tension.2 The result is a clear mirror reflection. It is difficult to see well with a scratched mirror. In addition, these surface imperfections attract and hold water. New or unscratched mirrors allow the water to sheet off.

Automatically tuned magnetostrictive scalers adjust the tip frequency to the power setting selected by the clinician, resulting in a heavier flow of water than what is required by either a tunable magnetostrictive unit or a piezo electric scaler, which can obscure the view of the image on the mirror surface. A reduced water flow improves the ability to use indirect vision via the mirror, which can result in improved posture for the clinician.

Clinicians who use magnification loupes during ultrasonic scaling procedures have a precise view of the clinical field, as well as improved posture.2,5,6 Fiber optic headlights coupled with magnification improve visual acuity even more.6

The Cavitron SPS SteriMate, NSK Varios and EMS Piezon Master 600 scalers each have a water control feature on the handpiece, which gives clinicians fingertip control over the amount of irrigant flowing to the tip.

The first magnetostrictive inserts were all metal, with an external water tube that sprayed fluid directly to the back of the activated tip. If the water tube was displaced, it was difficult to reposition the tube correctly. In response, manufacturers developed inserts that imbedded the water tube in resin. Hu-Friedy and USI all-metal inserts have spring steel water tubes that do not distort and are easy to reposition.

Some of the most recent insert designs have a small opening at the base of the tip that allows water to flow directly to the tip, eliminating the water tube entirely. In addition, many new tips have comfortable color-coded cushion grips. Most hygienists who use tunable magnetostrictive units feel that all-metal inserts produce smoother vibrations.2,6 Today’s wide variety of insert designs should satisfy the most discriminating clinician.

Noise-induced hearing loss can occur when the noise level exceeds 85 dB.23,25 Even though ultrasonic scalers fall below this, what are the long-term effects of frequent exposure to the sound? Many factors affect the noise produced by ultrasonic scalers: type of machine, size of tip, and amplitude and frequency settings.24,26 Suction systems are also noisy. Sound intensifies in rooms with primarily hard surfaces compared to rooms with sound-absorbing materials such as carpet or drapes.

Clinicians concerned about hearing loss can minimize the effects of sound by wearing commercial earplugs designed to block sound, or custom-made earplugs fabricated by an audiologist. A recent pilot study concluded that noise from an ultrasonic scaler might contribute to hearing loss at a frequency level of 3000 Hz.27

Another ergonomic solution is foot controls.6 Traditional foot switches are small and lightweight, and repositioning a renegade foot control wastes valuable time. New foot switches are larger and heavier, which makes them less apt to scoot across the floor or turn upside-down.

The multiple power level foot control on several models of the USI scaler allows a clinician to scale without constant contact with the foot control. The Odontoson handpiece has a unique fingertip activated on/off switch. Either one of these units offers a significant benefit to those with hip pain from constant pressure on a foot control.

The Cavitron SPS footswitch has a built-in, dual stage power control. The power level at the tip increases by 25 percent with a light tap on the foot control. The EMS Piezon Master 600 and the Satelec PMax piezo scaler have multifunction footswitches designed to help clinicians scale more efficiently, however, constant contact with the foot control is necessary.

Most dental hygienists who graduated in the 1970s and 1980s believed that hand scalers allowed for the best clinical results for patients. The physical price paid after years of hand scaling never came up. Many of us lived with muscle fatigue, chronic neck and back pain, and restless nights of incessant tingling and numbness in our hands and forearms.

Our bodies are precious. Our physical health is priceless.

No one is paying us enough to get hurt. Do a reality check. Getting hurt is not acceptable, and unfortunately, the micro-traumas that hygienists experience can result in a haunting legacy. Learning to use quality ultrasonic scalers can help clinicians prevent stress injuries. These outstanding devices should be a cornerstone of our clinical armamentarium.

The author wishes to gratefully acknowledge the assistance of Harold Henson, RDH, MEd, with the preparation of photography appearing with this article.

Anne Nugent Guignon, RDH, MPH, is an international speaker, has published numerous articles, and authored several textbook chapters. Her popular programs include ergonomics, patient comfort, burnout, and advanced diagnostics and therapeutics. Recipient of the 2004 Mentor of the Year Award, Anne is an ADHA member and has practiced clinical dental hygiene in Houston, Texas, since 1971. You can reach her at anne@ergosonics.com or (713) 974-4540 and her Web site is www.ergosonics.com.

References

1. Guignon AN. Ergonomics. In MD Cooper, L Wiechmann (Eds.) Dimensions of preclinical dental hygiene: A practical approach. New Jersey: Prentice Hall, 2004: 173-197.

2. Herremans K. Ultrasonic periodontal debridement. In K Hodges (Ed.) Concepts in nonsurgical periodontal therapy. New York: Delmar Publishers, 1998: 320-343.

3. Scientific American. Emerging Trends in Oral Care. New York: Scientific American, Inc., 2002: 1-30.

4. Khambay BS, Walmsley AD. Acoustic microstreaming: detection and measurement around ultrasonic scalers. J Periodontol. 1999; 70(6): 626-31.

5. Holbrook TE, Low S B. Power driven scaling and polishing instruments. In JF Hardin (Ed.), Clark’s clinical dentistry. Philadelphia: J.P. Lippincott 1991: 1-24.

6. Guignon, AN, Henson H. Essentials of Dental Hygiene: Clinical Skills. Power Driven Scaling. New Jersey: Prentice Hall, 2005: 83-114.

7. Folwaczny M, et al. Influence of parameters on root surface roughness following treatment with a magnetostrictive ultrasonic scaler: an in vitro study. J Periodontol. 2004; 75(9): 1221-6.

8. Kocher T, et al. Substance loss caused by scaling with different sonic scaler inserts--an in vitro study. J Clin Periodontol. 2001; 28(1): 9-15.

9. Copulos TA, et al. Comparative analysis between a modified ultrasonic tip and hand instruments on clinical parameters of periodontal disease. J Periodontol 1993; 64(8): 694-700.

10. Dragoo MR. A clinical evaluation of hand and ultrasonic instruments on subgingival debridement. Part I. With unmodified and modified ultrasonic scalers. Int J Periodont Rest Dent 1992; 12(4): 310-323.

11. Clinical Research Associates. Ultrasonic Scalers 2003. Utah: CRA Dental Hygiene 2203 : 3(5) : 1-2.

12. Croft LK, et al. Patient preference for ultrasonic or hand instruments in periodontal maintenance. Int J Periodont Rest Dent 2003; 23(6): 567-573.

13. Ryan D, et al. Effects of ultrasonic scaling and hand-activated scaling on tactile sensitivity in dental hygiene students J Dent Hyg 2005; 79(1): 9.

14. Chapple, et al. Effect of instrument power setting during ultrasonic scaling upon treatment outcome. J Periodontol 1995; 66(9): 756-760.

15. Jacobson L, Blomlof J, Lindskog S. Root surface texture after different scaling modalities. Scand J Dent Res. 1994; 102(3): 156-60.

16. Busslinger A, et al. A comparative in vitro study of a magnetostrictive and a piezoelectric ultrasonic scaling instrument. J Clin Periodontol. 2001; 28(7): 642-9.

17. Ritz L, Hefti AF, Rateitschak KH. An in vitro investigation on the loss of root substance in scaling with various instruments. J Clin Periodontol. 1991; 18(9): 643-7.

18. Schmidlin PR, et al. Tooth substance loss resulting from mechanical, sonic and ultrasonic root instrumentation assessed by liquid scintillation. J Clin Periodontol. 2001; 28(11): 1058-66.

19. Jepsen S, et al. Significant influence of scaler tip design on root substance loss resulting from ultrasonic scaling: a laserprofilometric in vitro study. J Clin Periodontol. 2004; 31(11): 1003-6.

20. Flemmig TF, et al. Working parameters of a magnetostrictive ultrasonic scaler influencing root substance removal in vitro. J Periodontol. 1998; 69(5): 547-53

21. Brine EJ, et al. Comparison of the effects of four different power scalers on enamel tooth surface in the dog. J Vet Dent. 2000; 17(1): 17-21.

22. Vermilyea SG, Prasanna MK, Agar JR. Effect of ultrasonic cleaning and air polishing on labial margin restorations. J Pros Dent 1994; 71(5): 447-52.

23. Gantes et al. The effect of hygiene instruments on dentin surfaces: scanning electron microscopic observations. J Periodontol. 1992; 63(3): 151-7.

24. National Institute on Deafness and Other Communication Disorders. Noise induced hearing loss. www.nicd.nih.gov. Accessed April 13, 2005

25. Clinical Research Associates. Ultrasonic Scalers 2003. Utah: CRA Newsletter 2203: 27(10): 1-3.

26. Sorainen E, Rytkonen E. High-frequency noise in dentistry. AIHA J 2002; 63(2): 231-3.

27. Wilson JD, et al. Effects of occupational ultrasonic noise exposure on hearing of dental hygienists: a pilot study. J Dent Hyg. 2002; 76(4): 262-9.


Contact information for companies mentioned in this article

• Dentsply Professional, (800) 989-8825

www.dentsply.com

• EMS, (972) 690-8382

www.emsdent.com

• Hu-Friedy Instruments, (800) 729-3743

www.hu-friedy.com

• NSK-Brasseler USA, (800) 841-4522

www.brasselerusa.com

• Odontoson, (800) 368-5776

www.odontoson.com

• Satalec-Acteon Group, (800) 289-6367

www.satelecusa.com

• Tony Riso Co., (305) 466-5681

www.tonyriso.com

• Ultrasonic Services Inc., (800) 874-5332,

jfeine@usiultrasonic.com

More in Personal Wellness