Oral Health Group
Feature

Restorative/Preventive Dentistry: Ultrasonics — Ultra Confusing? What You Need to Know to Keep Up

June 1, 2003
by Barbara Frost, RDH


The use of hand instrumentation for scaling and root planing has long been the standard by which periodontal therapy has been judged. In the eleventh century, the concept of scaling and root planing was described by Albucasus in The Sayings of Pythagoras on Scaling the Teeth with Iron Instruments. Dentists and hygienists were as consumed with attempting to achieve plaque-free root surfaces as we are today.

Nearly all therapy begins with scaling and root planing which is, unarguably, the most difficult, arduous and frustrating of periodontal procedures. It is also the most basic, essential and necessary. Understanding that periodontal disease is an infection, and since the term ‘scaling and root planing’ refers only to the tooth surface, a more appropriate term for the procedure, periodontal debridement, is being recognized in the literature. Treatment objectives, as well as the introduction of powered instrumentation by the Densply Company in the late 1950s marked the beginning of a long, slow reapprasial of the principal role of hand instrumentation.

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Today, while some practitioners may use powered scalers only as a secondary means of therapy, concepts have changed. For example, it is now known that accumulations on the tooth surface are more superficial than previously thought. Endotoxins are not as deeply embedded in cementum, and the biofilm associated with periodontal infections may not be firmly attached to the tooth surface. Shown to be at least effective as, and faster than hand instrumentation in periodontal debridement, powered scalers are actually more effective in furcation and fluted areas. Prevention, treatment and control of periodontal diseases can now be achieved by combining ultrasonics, ultrasonics with medicaments, and heated irrigation (pre- and post- procedurally) depending on the unit you choose. The ability to include an anti-infective procedure before, with, and after instrumentation denotes a dramatic shift from the old tooth associated model to the medical model of infection control and treatment.

The use of powered instrumentation presents the practitioner with an entirely different set of instrumentation techniques and skills from those of hand instrumentation. The technique is not haphazard, but definitive, and instrument specific. Unlike hand instruments, which have specific cutting edges, ultrasonic and sonic instruments are active on at least two sides. The power is concentrated in the last few millimeters of the tip. The practioner is most involved guiding the powered instrument rather than providing the energy required with hand instrumentation. The appropriate amount of lateral pressure applied is considerably smaller with powered instruments.

Finger rests with powered instruments are easier, more casual, and can often be soft tissue rests. The practitioner can accomplish the instrumentation in a more relaxed fashion. Here the phrase “let the instrument do the work” is quite meaningful.

There are two categories of powered scaling devices:

1) Sonic scalers: Operating frequencies are in the range of 4-7,000kh (cycles per second), and their envelope of motion is, for the most part, orbital. Sonic scalers are operated by air and are, therefore, used only with high-speed handpiece delivery units. They have a high noise level and are not very efficient for definitive scaling and root planing.

2) Ultrasonic scalers: These units are divided into the categories of magnetostrictive or piezoelectric devices.

Magnetostrictive: These devices operate in the range of 18,000 to 40,000kh. Their actions result from a magnetic field set up around a stack of dissimilar metals in a handpiece. The vibrating metal stacks create considerable heat, so these units are cooled by a copious stream of water. The tip vibrates in an elliptical motion with a moderate to high amount of noise. Newer models operating at 30,000kh are quieter.

There is a dampening effect when the tip makes contact with the tooth surface so the actual number of times the tip actually hits the tooth is reduced considerably. This hammering effect often results in patient discomfort. The elliptical motion of the tip allows for a fairly even dissipation of energy, which can be utilized by using any surface of the tip.

Piezoelectric: Piezoelectric scalers denote the latest advance in ultrasonics. Piezoelectric effect describes the property by which certain substances have the abiltiy to produce electric charges on their surface when deformed mechanically. When an alternating electric current is applied to a crystal it causes a mechanical deformation in a piezoelectric ultrasonic scaler and creates a vibration from 30,000 to 45,000kh. The motion of the tip is a linear, two-dimensional arc, the same motion used with hand instrumentation.

It has often been incorrectly stated that only the very lateral side of the tip in piezoelectric scalers is usable. While it is true of most piezoelectric scalers, the fact is the entire circumference of the tip of the Pro-Select 3 ultrasonic scaler can be used for calculus removal. Unlike magnetostrictive units, water is not needed for cooling a piezoelectric handpiece since there is no heat created within the handpiece itself. There is only slight frictional heat created by the action of the tip on the tooth surface, so that the reduced lavage is for flushing the site or delivering a medicament,and requires only low volume evacuation.

There are a variety of ultrasonic scalers on the market today. Choosing a scaler based on price alone rarely translates into quality and service. Going through the following checklist may lead to an informed decision, and prevent buyer’s remorse.

What is the company’s policy on training and support? Is there an additional charge for training? Is there a technique video available for continual in office training? (all units are technique specific).

What is the cost of the unit, and how many tips/inserts are included? How many handpieces are included?

Who’s going to use the scaler? The doctor, hygienist, or both?

How easy is the scaler to set up and move from room to room? Is it self contained, or hooked up to external water systems?

Are there any special water/air pressure adjustments or adapters required, resulting in additional labor costs?

What are the recommended maintenance procedures? Do you need to be concerned with biofilms, or is the unit a closed system?

Will it be used on the majority of patients, or infrequently?

What is the frequency of the vibrations? (Usually the higher the frequency the more comfortable for the patient.)

Is there a power dampening or fluctuation effect on the tip? Does the unit change voltage under load to provide the same frequency and arc movement when used? (Like cruise control on a car.)

Are the power adjustments hand-free (digital) or do you need to continually adjust dials (analogue) at the box ?

How many patient set-ups are included with the basic unit?

How many tips are available? What are the designs, how many are included with the unit, and how many of them will you actually use or need to complete a mouth?

What is the tip plane of motion and how adaptable is it to different clinical situations?

What are the tips made of? Are they susceptible to breakage?

What is the cost of the tips/inserts and how long do they last? Is there a way to measure the tips/inserts?

Are the handpieces, tips/inserts, cords and bottles autoclavable? If only a sleeve is available, how long does it last?

How many reservoir bottles are included in the price? How easy are they to remove and replace?

How comfortable is the handpiece? Is it balanced in my hand? Is my hand grasp open or tight?

Are the cords heavy or is there a pull back on your hand?

How much lateral pressure is required? (Ultrasonics range from 3-50 grams.)

Will I need high or low volume evacuation during treatment?

Where will you store the equipment? Is a wall mount available?

Can you irrigate subgingivally using antimicrobials with the system? (Scaling and using anti-microbials as a coolant is lava
ge, not irrigation. Unlike lavage, irrigation is billable.)

Our goals in treating periodontal disease have not changed over the years. However, our concepts and methods for reaching those goals have significantly evolved. While a flashy sign may bring new patients into your practice, how well you treat and care for your patients, keeps them. Since most, if not all, of your patients spend significant time in the hygiene department, investing in equipment that provides kinder and gentler treatment shows your patients that you care, and are “keeping up on things”.

Barbara Frost, RDH, graduated with a diploma in Dental Hygiene at the University of Manitoba in 1986. She has worked in general, periodontal, prosthodontic, public health and extended care dental clinics. Since 1995, she has been the clinical representative for Pro-Dentec in Toronto.

Oral Health welcomes this original article.