Keeping the sharper edge

April 1, 1999
The proper selection, sharpness, and care of manual instruments are essential. The right instruments that are maintained correctly reduce operating time, clinician fatigue, tissue trauma, and grooving or scratching of the root surfaces. Sharp instruments increase tactile sensitivity, instrument control, patient comfort, and productivity. The dental practice that makes wise decisions regarding the selection and maintenance of manual instruments encourages optimum results for the dental hygienist

A program for instrument replacement is easier than you`d think.

Mary D. Cooper, RDH, MS

The proper selection, sharpness, and care of manual instruments are essential. The right instruments that are maintained correctly reduce operating time, clinician fatigue, tissue trauma, and grooving or scratching of the root surfaces. Sharp instruments increase tactile sensitivity, instrument control, patient comfort, and productivity. The dental practice that makes wise decisions regarding the selection and maintenance of manual instruments encourages optimum results for the dental hygienist and the patients.

Hygienists often work in offices where they deal with conditions such as broken and misaligned tips. These conditions require the hygienist to use additional lateral pressure against the tooth surface while scaling. This pressure decreases instrument control and necessitates working harder and longer on a patient, likely increasing patient discomfort.

In addition, the hygienist experiences an increase in hand fatigue and risks developing carpal tunnel syndrome (CTS), the most common type of repetitive-strain disorder. The development of CTS is of growing concern among hygienists since 41 percent surveyed by RDH magazine report they suffer from carpal tunnel syndrome or have symptoms indicating future CTS problems. To decrease the incidence of CTS, it is important to:

* Select balanced instruments (the blade is lined up with the center of the handle).

* Use wide-diameter handles with serrations.

* Keep instruments sharp.

Instrument design

Several considerations should be reviewed before purchasing new instruments. When deciding on which designs to select, it is also important to consider the number, cost, brand, and ultimate value of the instruments. In addition, it is imperative to establish an instrument replacement policy.

To help make these decisions, a better understanding of how instruments are made will be beneficial. Every instrument has a handle and working end (blade and shank). The handle is machine-made and considered the "low-tech," lower-cost component of the instrument. It is manufactured in many different materials, weights, and styles.

Often, inexpensive instruments have handles that are made of brass with chrome-plating, which can chip and peel. Other handles are constructed from plastic. Caution is advised when selecting these instruments, since plastic can be affected by chemical and heat sterilization. Stainless steel is usually regarded as the best material for an instrument handle. Stainless steel handles can withstand any sterilization process without chipping, cracking, and/or melting.

The ergonomic design of a handle is another important consideration. The instrument handles revealing such a design have a larger diameter and are lighter in weight, which help reduce hand fatigue. They are recommended to be used in conjunction with regular-sized handles to help control the onset of carpal tunnel syndrome.

One example of an ergonomically designed instrument is DuraLite, manufactured by Nordent Mfg. Inc. The instrument is made of stainless steel, is manufactured in an hexagonal shape, and weighs 17.5 grams. Nordent also has a new round-handled design, which allows unlimited finger positioning and weighs 13.2 grams. Hu-Friedy offers an ergonomically-designed handle as well - the Satin Steel. Satin Steel instruments feature a maximum-diameter, stainless-steel handle, which gradually tapers between the handle and the tip; it weighs approximately 20 grams. This feature reduces pressure points during instrumentation and enhances comfort. American Eagle offers the EagleLite line of instruments with a handle made of a composite, plastic material that weighs 12 grams. It can be heat sterilized, but cannot be sterilized in a cold solution containing phenol. All of these designs are comfortable to use and easily attainable.

Although the handle is a crucial part of the instrument, the vital part consists of the working end. The working end is considered to be the "high tech," more costly component. In high-quality instruments, a high-carbon stainless steel is used, which ensures a longer-lasting sharp edge. The working ends are handcrafted and offer a consistent quality and value. Lower cost, economy instrument blades are not as hard and, therefore, do not hold the desired level of sharpness as long. This increases the need to sharpen and reduces the life of the instrument.

Maintenance program

Dental practices should understand how and why decisions are made regarding the selection, replacement policy, and care of instruments. It is also important to understand the options available to determine what will work best for the practice. Starting an instrument program within a practice setting requires planning and flexibility. The first step is to select which instrument designs will be included in each setup.

In a practice with more than one hygienist, agreeing on a setup will help simplify the need for replacements and reduce costs. The best way to approach this situation is to make a group decision on the basic instruments to include in each setup. Everyone usually will agree on sickle scalers and curettes. A sample setup may include an H6/7 sickle scaler, a posterior sickle scaler (204), and Graceys 1-2, 11-12, and 13-14. Many times, hygienists will have a favorite instrument that must be included in every setup. To complete the set, the remaining instrument could include that "favorite" instrument. Each setup can then be color-coded for identification purposes.

Establishing the correct number of setups for each hygienist also is useful when ordering instruments. At a minimum, a good "rule of thumb" is to have a setup to a patient ratio of .8. For example, if a dental hygienist has 10 patients scheduled per day, a minimum of eight complete setups is needed. With this ratio, instruments should last approximately 12 months.

A commitment to a maintenance program is the second step in prolonging the longevity of an instrument's life. Sharp instruments decrease the number of strokes needed to remove deposits, reducing operator time. Fatigue will also be reduced due to less pressure being applied.

At the first sign of dullness, instruments should be sharpened. A blunter edge increases the possibility of burnishing calculus, rather than removing it in its entirety. Fine ceramic stones are recommended instead of the Arkansas stone when sharpening, because less material is removed.

Postponing sharpening is not advised. Additional sharpening time will be required, and more material is removed to attain the sharp edge desired. As the sharpening procedure is performed, inspect the work frequently to notice if a proper angulation is being achieved.

Sharpening procedures require skill and patience. More often, instruments are worn out due to improper sharpening techniques rather than from use. If proper results are not accomplished, seek assistance - refer to a dental-hygiene instrumentation book, attend a seminar on sharpening instruments, or ask an associate for help.

Another option is to send the instruments to an outside professional sharpening service. They will be able to reestablish the original factory blade angles and complement the program established within the dental practice.


Another alternative to ordering new instruments is to have them retipped. This option is often chosen because of cost. The price of retipping a double-ended instrument is approximately $10, half the cost of a new instrument. Although instrument manufacturers do not offer retipping services, some independent companies do.

The retipping process requires the handle to be heated and the tips removed, possibly making the handle more susceptible to cracking and premature failure. If cracks occur, the instruments weaken and an opportunity for contamination is possible. Once the original tips are removed, new tips are inserted with an adhesive that is activated by heat. As a result, a structural defect may occur during this assembly process, causing the new tips to become loose. Also, by replacing tips, the lower-cost component, the handle, is being saved and the higher-cost component, the tip, is being replaced - sometimes with varying quality.

Most instrument manufacturers do not offer their tips for the retipping process. The tips are handcrafted by the retipping company. Also, note that not all instruments can be retipped.

Most high-quality manufacturers do not recommend retipping and, as an alternative, offer instrument recycling programs. In addition, warranties from the manufacturers are void if their instruments have been retipped.

By focusing on the proper selection, sharpness, and care of instruments, productivity will increase accompanied by a decrease in fatigue, time, and tissue trauma. Patient satisfaction will increase as well.

With some planning, ordering instruments can be done with minimal work. Order high-quality and appropriate instruments for the specific task. If wide-handled instruments are selected for ergonomic purposes, keep in mind that using them in a setup with smaller handled instruments is still recommended. Use of varying sizes of handles helps prevent repetitive-strain disorders such as carpal tunnel syndrome. Also, sharpen instruments when indicated.

All of these recommendations will assist the comfort of the clinician and patient, and, in turn, extend the life of the instruments.

Mary D. Cooper, RDH, MSEd, is a professor of dental hygiene at Indiana University-Purdue University at Fort Wayne, Ind.

References available upon request.

Making room in the budget for instruments

It is best to purchase the highest quality instruments for use. The real value of a high-quality instrument can be measured beyond the initial cost with reduced maintenance and superior performance.

The minimum life span of a high-quality instrument is 450 uses and the maximum is approximately one thousand. If the average cost of an instrument is $20 and 450 uses are achieved, the cost per use is four cents. If five instruments are included in a setup, then the average cost for high quality instruments per patient is 20 cents. This equals the approximate cost of a pair of latex gloves.

In addition to purchasing instruments, replacement instruments must be determined. Many practices purchase instruments only once a year.

It is best to design a replacement policy which includes a yearly budget for instrument purchases and maintenance. Practices can reduce instrument expenditures if replacements for old, worn instruments are replaced with new ones throughout the year rather than at once.

This helps dental practices reduce instrument expenditures and avoids replacements being made all at one time, which is more economically feasible.