From Diamonds to Transducers

Q. From an evidence-based perspective, is there a difference between ultrasonic and hand scalers on clinical parameters?

A. Calculus removal and clinical success can be achieved with either ultrasonic or hand instruments.¹ The surface of the root is slightly different after the use of an ultrasonic instrument vs a hand instrument but this does not seem to affect clinical outcomes.

Q Anecdotally, what has been your experience with hand vs ultrasonic scalers?

A. I have been using ultrasonic scalers for a long time, starting with the old tube style and presently with piezo scalers. I could not practice periodontics without an ultrasonic scaler, however, I feel the same way about hand instruments. There are some situations where one is better than the other but I really need both to successfully remove calculus from the root surface. I believe that removal of calculus from the root surface is mandatory to achieving clinical success. My colleagues and I just had an article accepted for publication by the Journal of Periodontology that indicates that calculus is associated with the majority of pocket wall inflammation when observed in vivo with the endoscope.² This means that calculus cannot be left on the root surface, and in order to achieve this goal, dental hygienists need to use any and all of the tools available.

ULTRASONIC TIP DESIGN

Q. When looking at ultrasonic tip design, what is the most important consideration in choosing the appropriate tip?

A. The most important consideration in choosing any instrument, either hand or ultrasonic, is access to the root surface. If the instrument cannot gain access to the portion of the root surface with the calculus, it won’t do what needs to be done. Unfortunately, one of the factors in the design of all ultrasonic tips, no matter what type of transducer drives it, is the need for an adequate bulk of metal to prevent breakage. The transducer is the device that causes the tip to vibrate ultrasonically. Some dental professionals prefer a very thin tip in order to gain access to difficult areas, but to prevent breakage, these instruments must be used at a very low power setting. Low power settings may not completely remove tenacious calculus and they are more likely to burnish the calculus. Again, the calculus needs to be removed from the tooth to eliminate inflammation and gain clinical success.

DIAMOND-COATED TIPS

Q. Diamond-coated ultrasonic tips were recently introduced to the market. Are they appropriate for dental hygiene therapy?
A. Interestingly, very similar diamond coated ultrasonic tips are sold for root planing, endodontic surgical reshaping of the root canal, and, in Europe, for cutting restorative preparations. Unless used very carefully and with direct vision, fully coated diamond coated tips can be very dangerous and should not be used for root planing. Using a fully coated diamond tip designed for root planing at medium power, I was able to drill a hole completely through the root of an extracted molar in less than a minute. On the plus side, diamond-coated tips are extremely efficient for removing calculus. Because the diamond abrasive sands the calculus off of the tooth, diamond-coated tips really don’t have to ultrasonically vibrate the calculus. This means that the instrument is active at areas other than the very end of the ultrasonic tip. This gives the operator much more flexibility in accessing calculus on the root surface. I designed an ultrasonic tip* that contains the diamond abrasive in grooves on a smooth ultrasonic tip. The recessed diamond will rapidly abrade any rough calculus on the root. Once the calculus has been removed, the root surface is not touched by diamond abrasive and the tip acts just like a smooth tip without diamond coating.

Q. What is the technique for using diamond-coated inserts and how is it different from the technique for traditional ultrasonic inserts?

A. The fully coated diamond inserts should only be used with direct visualization of the tip and they should only be used by a very skilled operator. Basically, the fully coated diamond tip should not be used for root planing without the use of an endoscope. A highly skilled clinician can use a very small, fully coated-diamond ultrasonic tip to remove isolated calculus when performing endoscope-assisted root planing but an inexperienced clinician could easily damage the root and/or break the very small ultrasonic tip. For the average therapist, the fully coated diamond tip should be used only for supragingival scaling or root scaling during surgery.

WHAT LIES AHEAD

Q. What new advances in ultrasonic tip design do you see for dental hygiene therapy?

A. Many exciting changes are occurring in ultrasonic transducer and tip design. The traditional transducer is magnetostrictive. More recently, the popularity of the piezoelectric transducer has increased. The ultrasonic engineers tell me that they are working on new transducers that use rare earths, ferroceramics, and other materials that will allow more power and less breakage. Currently, the piezoelectric transducer seems to cause less breakage with narrow and small tip design, which has allowed the successful use of differently shaped tips. The use of recessed abrasive will allow for designs resembling a hand file similar to an Orban file, where the tip is vibrated by the transducer but does not have to reach ultrasonic levels to be effective. In the next 10 years, we will see transducer and tip designs that will allow for a completely new range of dental hygiene treatment options.

REFERENCES

1. Tunkel J, Heinecke A, Flemmig TF. A systematic review of efficacy of machine-driven and manual subgingival debridement in the treatment of chronic periodontitis. J Clin Periodontol. 2002; 29(Suppl):72-81.
2. Wilson TG, Harrel SK, Nunn ME, Francis B, Webb K. The relationship between the presence of tooth-borne subgingival deposits and inflammation found with a dental endoscope. J Perio. In press.

From Dimensions of Dental Hygiene. October 2008; 6(10):36.