Ultrasonics—A New Perspective

Have you ever re-evaluated a patient after periodontal quadrant scaling or maintenance debridement and wondered about the source of residual inflammation and bleeding? Is the source just recolonized subgingival plaque or is there residual calculus on the root? Imagine being able to actually look down into those bleeding pockets to find the answer to such questions.

THE INFLUENCE OF PERIOSCOPY

The dental endoscope has enabled us to do just this. We have been among the first of hundreds of clinicians using perioscopy to examine and treat thousands of periodontal pockets. We feel as Galileo must have when he described his first observations of the Milky Way with the newly invented telescope. He said, “The Milky Way itself…with the aid of the spyglass [telescope], may be observed so well that all the disputes that for so many generations have vexed philosophers are destroyed by visible certainty, and we are liberated from wordy arguments.”¹ The clarity of endoscopic observation eliminates all of the speculation about what happens subgingivally during instrumentation. Endoscopic observations have made us reassess our instrumentation concepts.

In every instance of bleeding upon probing at evaluation, we have observed residual calculus on the root surfaces and inflammation in the pocket wall overlying this burnished calculus. We now question any periodontal debridement technique that emphasizes only the removal of subgingival plaque while minimizing the importance of complete calculus removal. Instead, regardless of the method of instrumentation, the goal should be to remove all calculus and biofilm wherever possible.^2,3

Using perioscopy, we have analyzed the action and effectiveness of a variety of ultrasonic and manual instruments while watching them perform in deep pockets. These observations have changed our selection of instruments.

Using perioscopy, we have observed the following:

1. Thorough calculus removal is important for the success of periodontal therapy.
2. Recolonization of pathogens on residual burnished calculus occurs rapidly enough to sustain inflammation in these areas.
3. Bleeding upon probing is a clinical sign that residual calculus is present on the root surface.
4. When residual calculus is removed, resolution of inflammation and healing is more likely to occur.
5. Thin tips on low power do not remove hard calculus efficiently whether they are magnetostrictive or piezoelectric.
6. Piezoelectric thin tips are able to withstand high power.
7. Tips with bevels or blades remove calculus more efficiently than smooth tips that are round in cross section.
8. Plastic or carbon composite tips are excellent for implants and restorative margins because they debride biofilm without damaging the restorative material.
9. Ultra thin diamond coated tips on low power can remove biofilm and thin or light calculus efficiently with minimal removal of tooth structure.
10. Diamond coated tips that are larger than a periodontal probe can potentially cause damage by removing root structure even if used on low power.

Figure 1: Thin magnetostrictive tip on palatal root of maxillary molar.	Figure 2: Thin magnetostrictive tip in buccal furcation of mandibular molar.

ASSESMENT

Proper ultrasonic instrument selection is of primary importance in achieving complete periodontal debridement. A variety of tips can be used when performing periodontal instrumentation. Features, such as the length, shape, thickness, and angulation of the tip, are critical for gaining access to remove subgingival deposits.

Proper ultrasonic instrument selection begins with accurate patient assessment. After evaluating examination data, determine whether a single maintenance appointment or a series of periodontal scaling and root planing appointments are necessary. Determine the number of appointments, the need for local anesthesia, and then the type of ultrasonic tip to be used.

Loose, edematous tissue will accommodate larger tips. Tight fibrotic tissue inhibits insertion into deep pockets. Deep pockets with tight tissue and/or furcation invasions require the use of thinner tips (Figures 1 and 2). Using only a large tip in such situations is difficult and can result in incomplete root debridement and patient discomfort.

The type, amount, surface topography, and tenacity of the calculus must be considered for proper tip selection. Hard, heavy calculus should be removed with larger tips on medium to high power. Light calculus or soft, new calculus can be removed with thinner tips on medium to high power.

Figure 3. Piezo tips, from left to right: a) ProDenTec straight slim tip; b) Satelec #10 tip; and c) EMSPS tip. Magnetostrictive tips: d) Parkell Burnett Power tip; e) Dentsply Cavitron FSI #10 tip; and f) Hu-Friedy Satin Swivel #10 universal tip.	Figure 4. Satelec Piezoelectric bladed scaling tips, from left to right: #1-Universal tip; H4R-Right angled mini-tip for premolars and molars; H3-Anterior mini-tip; and H4L-Left angled mini-tip for premolars and molars.

ULTRASONIC BASICS

Ultrasonic devices are available in either magnetostrictive or piezoelectric technology. Piezoelectric units are predominately used in Europe and Asia . Magnetostrictive devices are more widely used in the United States. They are distinguished primarily by the direction and pattern of movement at the tip. Distance of tip movement (amplitude) and speed of movement (frequency) also differ. Depending on the manufacturer, average frequencies range from 27,000 to 31,000 cycles per second. Since amplitude is a measure of power output, this factor will determine suitability to the task at hand. Among piezoelectric units there is a wider range of amplitude compared to magnetostrictive units.^3-5

In magnetostrictive units, the pattern of tip movement is elliptical with all sides transferring energy. In contrast, piezoelectric units feature linear tip movement with the lateral edge transferring energy. This influences the positioning of the piezoelectric tip, since the lateral surfaces of the tip are most active during deposit removal.

With both types of tips, the contact area between the tip and the curved root surface is very small. Therefore, a careful technique of closely placed, light, overlapping strokes using the terminal few millimeters of the tip is essential to successfully covering every square millimeter of the entire root.⁵

LOCAL ANESTHESIA

Ultrasonic instrumentation for periodontal patients with hard subgingival calculus should follow a rational sequence. Begin with standard large ultrasonic tips on high power using local anesthesia whenever necessary. In most cases, attempting to treat this type of patient without local anesthesia will result in inadequate calculus removal. After using larger tips to remove calculus, follow up with manual instruments for removal of residual calculus. Finally, thin tips on low power may be used to remove more biofilm and to flush out bacteria and debris.

Starting with thin tips on lower power for patient comfort in order to avoid local anesthesia is a common strategy among dental hygienists who cannot administer local anesthesia by state law. This is problematic because thin tips on low power do not remove hard calculus effectively and should be reserved for biofilm removal only. Perioscopy reveals that low powered thin tips burnish hard calculus into smooth, thin veneers or small pieces embedded in the root surface. These deposits cannot be detected with skillful exploring and are visible only with the intense fiberoptic light and magnification of the endoscope.

Although periodontal pathogens may be removed from the root surfaces, residual calculus is left behind providing a breeding ground for recolonization of bacteria. If thin tips are used to remove hard calculus they must be turned up to high power. This is only possible with a limited number of thin tips and still requires local anesthesia. If the dental hygienist cannot administer local anesthesia, the dentist should be asked to anesthetize the patient to allow optimal use of heavier ultrasonic tips.

For periodontal maintenance patients who have little or no new calculus, thin tips can be used on low power for removal of subgingival biofilm that has recolonized previously well instrumented root surfaces.

Figure 5. Thin tips from left to right: Piezo tips: ProDenTec UltraSlim®Right Curve tip; Satelec PerioFine PFR Right tip; EMSPL2 Right perio slim tip. Magnetostrictive tips: Hu-Friedy After Five®PLUS™ Right tip and Dentsply Cavitron SlimLine™ right tip.	Figure 6: Piezoelectric Diamond Coated mini tips, from left to right: a) EMS HPL3 Perio Diamond tip for rough cleaning and odontoplasty; b) EMS DPL3 Perio Diamond tip for polishing; c) Satelec H2R for premolars and molars; d) Satelec H1 for anterior teeth and premolars; and e) Satelec H2L for premolars and molars.

Figure 7: Implant tips, from left to right: a) EMS Piezon®implant cleaning tip; b) Tony Riso magnetostrictive plastic implant tip; and c) Satelec PerioSoft carbon composite mini-tips: PH2R, PH1, PH2L.

ULTRASONIC TIP OPTIONS

1. Standard magnetostrictive tips (Figure 3). Standard large magnetostrictive tips on medium to high power should be used for heavy calculus or burnished sheets of calculus. They effectively fracture tenacious subgingival as well as supragingival deposits. Standard tips are available in a variety of sizes and shapes, ranging from a broad flat beaver-tail design to a curet shape with bevels.

Ledges, rings, or tenacious sheets of calculus should be removed by pointing the tip in an apical direction and “tapping” against the coronal-most portion of the deposit with the point of the large tip to break it up. Stroking with the side of a standard cylindrical magnetostrictive tip has the potential to burnish hard calculus because it often removes the calculus in incremental layers with each stroke.

2. Standard piezoelectric tips (Figures 3 and 4). Piezoelectric units have a large selection of tips. The large scaling tips and bladed tips achieve excellent calculus removal even on very tenacious calculus when used on medium to high power. Light to moderately mineralized calculus is easily removed on medium power with any of these tips.

Although bladed tips have the potential to cause root damage, when used properly on the recommended low to medium power with light pressure, these tips are able to produce a smooth root surface without damage.⁶

3. Additional instrumentation after the use of standard ultrasonic tips. After using standard ultrasonic tips on medium to high power, a variety of manual instruments may be used. If tight, narrow pockets or furcations cannot be accessed and finished by manual instruments, thin-tipped ultrasonic inserts on medium power or thin diamond ultrasonic tips on low power should be used.

4. Thin magnetostrictive tips (Figures 3 and 5). Endoscopic evaluation has revealed that thin magnetostrictive tips on low power are excellent for removal of biofilm and loosely adherent plaque. While these tips allow improved access, they can break when power settings move beyond medium toward a higher power. Therefore, manufacturers recommend their use be limited to low-to-medium power settings only. This is a major disadvantage because these tips do not remove hard calculus at these settings and tend to burnish it. This residual calculus is difficult or impossible to detect tactilely and is also difficult to remove. Therefore, thin tips are only recommended for deplaquing of previously well scaled root surfaces. Do not assume that low powered thin ultrasonic tips are removing calculus—even when the surface feels smooth.

One specially designed thin magnetostrictive tip allows use on high power (Figure 3d). This thin tip is longer than other thin tips and is powerful because it has wider amplitude at the tip. This allows effective calculus removal from the roots in deeper pockets.

5. Thin piezoelectric tips (Figure 5). Piezoelectric technology allows higher power to be used with thinner tips without breakage. These very adaptable, thin piezoelectric tips can be used on high power to remove calculus effectively and efficiently from the root surfaces with less burnishing. The best designed piezoelectric tips are very long and are able to easily access deep pockets and furcations in the posterior areas of the mouth. The Perio Slim (PS) tip, which is long and thin with flat edges, provides outstanding interproximal and subgingival access (Figure 3c).⁴

6. Thin diamond coated tips (Figure 6). Diamond coated tips are only available with some piezoelectric units. The thinnest diamond-coated tips are designed for fine scaling and root planing in narrow furcations. These unique tips are used only on low power and provide unprecedented access to deep periodontal pockets even with tight tissue. They are ultra thin like the ODU 11/12 explorer. These tips are not designed for heavy deposit removal but are effective for removal of small residual burnished deposits (Figure 6c, e).

Two new diamond coated piezoelectric ultrasonic tips for use with direct vision on the root surface during periodontal surgery have recently been introduced. These tips can also be used subgingivally with the aid of the dental endoscope (Figure 6a, b).

7. Furcation ball tips. Ball-tipped furcation inserts are available for both magnetostrictive and piezoelectric units. A .8 mm ball tip conforms to the inner contours of furcations. On low power, these tips burnish the calculus very smoothly inside the furcation. If used on medium to high power, they remove calculus better but they also create grooves in the root surface. These tips should be followed by specialized manual instruments to remove residual calculus and smooth the root surface.

8. Plastic or carbon composite tips for implants (Figure 7). A blue plastic magnetostrictive tip is available for implants (Figure 7b). A set of piezo carbon composite tips designed for use on implants also polishes the root surfaces and restorative margins when scratching has occurred from instrumentation (Figure 7c). Another new piezoelectric implant tip has a stainless steel core and an outer coating made of a plastic material (Figure 7a).

This is the first of two articles on the influence of endoscopy on periodontal instrumentation. Part II will discuss manual instrumentation and will appear in a future issue.

SUMMARY

Perioscopy will continue to influence instrument design. Tips will become smaller to adapt better to root morphology. New technology will allow more effective calculus removal with thinner tips on higher power and enhanced abrasion with diamond coatings. Miniaturization of ultrasonic tips will allow simultaneous use with the dental endoscope. These innovations will raise the standard of instrumentation in education and practice and improve the success of nonsurgical therapy and maintenance.

Anna Matsuishi Pattison, RDH, MS, is associate professor in the Department of Dental Hygiene at the University of Southern California School of Dentistry, Los Angeles, and the editor in chief of Dimensions of Dental Hygiene. Stacy A. Matsuda, RDH, BS, is a clinical instructor, Department of Dental Hygiene, Oregon Health and Science University School of Dentistry, Portland. Gordon L. Pattison, DDS, is in private periodontal practice in Brentwood, Calif. The Pattisons are members of DentalView Inc’s Scientific Advisory Board.

For more information on the various ultrasonic units available and to see photos of the actual units, visit each manufacturer’s website.
Amadent	www.amadent.com
Biotrol International	www.biotrol.com
Colténe Whaledent	www.coltenewhaledent.com
Dentsply	www.professional.dentsply.com
EMS	www.ems-dent.com
Hu-Friedy	www.hu-friedy.com
Odontoson	www.odontoson.com
Parkell Inc	www.parkell.com
Pro-Dentec	www.prodentec.com
Satelec (ACTEON North America)	www.acteongroup.com
USI	www.usiultrasonic.com

REFERENCES

1. Galileo G. Sidereus Nuncius. 1610.
2. Greenstein G. Periodontal response to mechanical non-surgical therapy: a review. J Periodontol. 1992;63:118-130.
3. Drisko CL, Cochran DL, Blieden T, et al. Position paper: sonic and ultrasonic scalers in periodontics. Research, Science and Therapy Committee of the American Academy of Periodontology. J Periodontol. 2000;71:1792-1801.
4. Automated scalers (ultrasonic and sonic). Clinical Research Associates Newsletter. 1998;22:6.
5. Petersilka GJ, Flemmig TF. Sonic and ultrasonic instrumentation. In: Newman MG, Takei HH, Carranza FA, eds. Carranza’s Clinical Periodontology. Philadelphia: WB Saunders Co; 2002:607-608.
6. Himeno H. Evaluation of URM treatment in advanced periodontitis: a study on pocket elimination at initial preparation. HokkaidoShika Ishikai Shi. 1994;49:1.

From Dimensions of Dental Hygiene. June / July 2003;1(3):32, 34-35.