Making the Right Choice

New instrument choices for initial periodontal therapy are now available due to the observations made possible by the dental endoscope.¹Perioscopy has confirmed that all clinicians regardless of level of experience leave some residual burnished calculus after initial scaling.^1,3Endoscopic analysis of the efficacy of various periodontal instruments has led to new techniques that target the removal of this residual calculus.

Recent dental hygiene literature has advocated instrumentation aimed primarily at disrupting and removing subgingival biofilm while minimizing the significance of calculus left on the root.^4,5Endoscopic observation is directly challenging this concept. Perioscopy consistently reveals persistent inflammation on the pocket wall adjacent to small pieces of residual calculus following extensive ultrasonic and hand instrumentation. Some clinicians believe that this burnished calculus does not harbor enough bacteria to cause problems so its complete removal is not essential to periodontal health. If we assume that most of the bacteria and endotoxin have been removed from the surface of this calculus, then what is causing the inflammation? Maybe even small amounts of bacteria and their byproducts provoke inflammation. Perhaps the rapid recolonization of bacteria on the residual calculus is the source. Is there something else associated with the calculus that promotes inflammation?

Observations on Instrumentation

A recent study conducted at the Eastman Dental Institute in London by Calabrese, Mordan, and Galgut found that periodontal pathogens (A. Actinomycetemcomitans, P. gingivalis, and T. denticola) and cytokines (IL-1 and IL-6) are harbored in calculus.⁶ Using immunogold labeling and transmission electron microscopy (TEM), they found that calculus is a porous entity with pathogens and cytokines localized in the covering plaque and the lacunae of the studied samples. Cytokines are biologic mediators that are released during the inflammatory process; they permeate the biofilm that initiated the inflammation and the calculus beneath it. Cytokines are chemical substances, such as interleukins and tumor necrosis factor, that stimulate the production of prostaglandins. In turn, these substances provoke an immune response that triggers the destruction of periodontal tissues. The presence of pathogens and these cytokines on and within burnished calculus may account for the persistence of inflammation even after instrumentation has removed most of the biofilm and the outer superficial layers of the calculus.

Clinical endoscopic observations following instrumentation include:

1. Some residual burnished calculus is always present on root surfaces scaled by hand and/or ultrasonic instrumentation even when performed by experienced clinicians.^3,7,8
2. In every instance of bleeding upon probing at evaluation, residual calculus on the root surfaces has been observed.
3. Small pieces of burnished residual calculus as small as 0.5 mm have been consistently observed with inflamed, bleeding spots on the inner aspect of the overlying tissue.
4. Recolonization of subgingival biofilm on residual burnished calculus occurs rapidly within 24-48 hours following instrumentation.
5. Bleeding upon probing is a clinical sign that residual calculus is present on the root surface. The dental literature supports the observation that bleeding on probing is a marker for residual calculus.^9,10
6. Once the residual calculus is removed, resolution of inflammation and healing by formation of a long junctional epithelium are more likely to occur.
7. Thorough calculus removal is important for the success of periodontal therapy.
8. The goal of periodontal instrumentation should be to remove all calculus and plaque wherever possible.

Additional clinical observations of instrumentation in deep pockets, depressions, and furcations are:

1. Hirschfeld files are very efficient in breaking up heavy calculus or sheet-like burnished calculus.
2. Mini-bladed curets are able to access and remove calculus from line angles, developmental depressions, and interradicular surfaces of furcations.¹¹
3. No form of instrumentation—hand-activated or powered—is capable of completely and reliably removing calculus from the inner depressions of any furcation without the aid of endoscopy.
4. Furcation curets remove calculus more effectively than any other hand or ultrasonic instruments from the floor or ceiling of the furcation.
5. Diamond coated files used with light pressure can remove biofilm and thin calculus efficiently from root surfaces and furcations with minimal removal of tooth structure.
6. Diamond coated files can achieve a clean, even, smooth, highly polished root surface.
7. Thin ultrasonic tips on low power do not remove hard calculus efficiently whether they are magnetostrictive or piezoelectric.
8. Ultrasonic instrumentation should always be followed by or combined with hand instrumentation to ensure complete removal of calculus.

Selecting the Best Instruments

During initial periodontal therapy, instrument selection is one of the most important factors in achieving complete debridement. Regardless of the instrument, the width and thickness of the blade or tip, as well as the length and angulation of the shank, are critical to the clinician’s ability to reach, engage, and remove subgingival deposits.

Thorough root debridement cannot be accomplished if the blade/tip size is inappropriate for the type of tissue or area being instrumented. Selection of blade/tip size is determined by pocket depth, tissue consistency, amount of calculus, root morphology, furcation invasions, and accessibility of the area.

Instrument selection for patients with loose, edematous tissue is relatively easy because insertion and adaptation are not a problem. However, if the patient has tight fibrotic tissue or had previous periodontal therapy, resolution of gingival inflammation results in a patient with firmer, tighter tissue. Residual calculus in deep pockets with tight tissue and/or furcation invasions requires the use of special instruments. Smaller, thinner instruments such as mini-bladed curets, Hirschfeld files, diamond coated files, or a variety of thin ultrasonic tips are essential for the finishing stages of instrumentation. Using large bladed universal or Gracey curets in such situations is difficult and can result in incomplete root debridement and excessive tissue trauma.

Also important in selecting instruments is the nature of the calculus. In addition to the amount of calculus, surface quality and tenacity must be considered. Surface quality can range from porous, rough, brittle, easily removable calculus to hard, smooth, sheets of very tenacious burnished calculus. Residual burnished calculus has been observed with the endoscope following scaling by hand and/or ultrasonic instrumentation.

Burnishing is common and occurs with hand instruments if the blade angulation is closed, the blade is dull or poorly adapted to the root morphology, or if insufficient lateral pressure is applied. Thin ultrasonic tips used on low power also tend to smooth and burnish calculus until it can no longer be felt. This calculus is difficult to detect and engage because the edges of the deposit are very thin and blend into the root surface. The best, most efficient instruments to remove these residual burnished deposits are Hirschfeld files followed by sharp, mini-bladed Gracey curets.

Figure 1. Hu-Friedy Hirschfeld 5/11 files.	Figure 2. Hartzell 204SD sickle scaler, Hu-Friedy IUFW 204SD sickle scaler.
Figure 3. Hu-Friedy Columbia 4R/4L, McCall’s 17/18, and Younger Good 7/8 universal curets.	Figure 4. Hartzell Langer Curets: Langer 5-6 (anterior teeth); Langer 1-2 (mandibular posterior teeth); Langer 3-4 (maxillary posterior teeth).

Pain Control

There are two distinct benefits to employing local anesthetic during initial therapy. Anesthetizing the area to be scaled provides patient comfort during the procedure, which can increase efficiency and reduce stress for the clinician. More importantly, local anesthetic permits maximum subgingival insertion and activation in the presence of inflammation. Because these areas are typically sensitive to instrumentation, anesthetic is often the only way possible to be thorough. Local anesthesia is also indicated when tooth sensitivity is a problem. If the dental hygienist cannot administer local anesthesia, the dentist should be asked to anesthetize the patient to allow for optimal instrumentation.

Hand-Activated Instrumentation

The evaluation of instruments during perioscopy has revealed a sequential order of use for maximum efficiency. Selecting instruments in order of increasing degrees of effectiveness will help produce a thoroughly clean root capable of sustaining health.

1. Standard ultrasonic inserts. Large piezoelectric or magnetostrictive tips on medium to high power should be used first if the calculus deposits are heavy or if there are large, thick, burnished sheets of calculus.

2. Hirschfeld files. They are very effective for initial scaling (Figure 1). The thin head of the Hirschfeld file consists of a series of tiny cutting edges that readily engage calculus to crush, fracture, and initially remove it. Using these periodontal files prior to scaling moderate to heavy deposits of subgingival calculus with curets can save the clinician time and fatigue while minimizing wear on curet blades. Files should be followed by curets to complete calculus removal. Precise adaptation and activation of the file will prevent the inadvertent creation of grooves in the root surface. Keeping strokes parallel with the shank of the file (perpendicular to the blades) will ensure safe, effective instrumentation.

3. Sickle scalers, universal curets, or Langer curets. After using ultrasonic tips on medium to high power or files, sickle scalers, universal curets, or Langer curets may be used to complete the initial removal of deposits. The 204 type sickles have curved backs with very sharp cutting edges that will readily bite into calculus (Figure 2). Universal curets such as the Columbia 4R/4L, McCall’s 17/18, and the Younger Good 7/8 are all effective curets for initial scaling (Figure 3). Langer curets combine universal-type blades with area specific, Gracey-type shanks (Figure 4). This set of three curets is available with either rigid or finishing shanks and can be obtained in extended shank and mini-bladed versions.

4. Gracey curets or extended shank Gracey curets. Standard Gracey curets or extended shank Gracey curets may be used to follow heavy ultrasonic tips, files, scalers, or curets (Figure 5). Rigid or extra rigid Gracey curets should be selected if calculus is very tenacious or burnished. A variety of stroke directions will facilitate complete instrumentation to the base of deep pockets. Short horizontal strokes with the toe of the Gracey blade directed apically are essential for line angles or deep buccal or lingual pockets and are also very effective in deep mesial and distal pockets anywhere in the mouth (Figure 6).

Extended shank Gracey curets are modifications of the standard Gracey curet design and are used with the same technique. The terminal shank is 3 mm longer, allowing extension into deeper pockets of 5 mm or more. These curets are most useful for deep pockets on maxillary and mandibular posterior teeth where the longer terminal shank and extraoral fulcrums allow better access and adaptation.

5. Mini-bladed Gracey curets or Gracey Curvettes. Mini-bladed Gracey curets are smaller and thinner than other hand instruments (Figure 7). Designed for superior adaptation to root contours, they feature a blade that is half the length of a regular Gracey curet and a shank that is 3 mm longer. Their small size and rounded backs allow easy insertion under firm tissue and into deep, narrow pockets. They are used for careful, focused removal of residual calculus in depressions, furcations, on line angles, and around the cemento-enamel junction.¹² These are the most common areas where burnished deposits are found with the endoscope requiring careful additional instrumentation with specialized instruments.

Gracey Curvettes are another series of mini-bladed curets with a blade that is 50% shorter than the standard Gracey curet with a very curved and blunted tip. This allows the Gracey Curvettes to adapt more closely to the tooth surface than any other curets, especially on anterior teeth, line angles, and in furcations (Figure 8).¹¹ Mini-bladed curets can be used on both walls of a furcation as well as the ceiling or floor of the furcation. Vertical, oblique, or horizontal strokes can be used on all aspects of the furcation with these small blades that adapt well to the root anatomy.

Figure 5. Hu-Friedy Rigid Gracey 13/14, Hu-Friedy Rigid After Five® Gracey 13/14.	Figure 6. Hu-Friedy Rigid Gracey 7/8 positioned for a horizontal stroke on the palatal surface of a maxillary molar.
Figure 7. Hu-Friedy Mini Five® Gracey Curets, 5/6,7/8,11/12,13/14.

6. Quetin furcation curets. The Quetin furcation curets are actually compact hoes with a shallow half-moon radius that fits perfectly into the ceiling or floor of the furcation. The curvature of the tip also fits into developmental depressions on the inner aspects of the roots. These instruments are available in two widths (Figure 9).

Although the toe of a standard curet or mini-bladed curet can be used on the ceiling or floor of a furcation in a horizontal pull stroke, most curets are too large and tend to gouge. The Quetin furcation curets will remove burnished calculus very effectively from the inner depressions of the furcations while conserving root structure.

7. Hirschfeld files. They are very efficient in breaking up heavy calculus or sheet-like burnished calculus as indicated earlier. Even after using ultrasonic tips and a variety of hand instruments, burnished calculus can still remain and be seen with the endoscope. Files readily crush and fracture burnished calculus that is otherwise impervious to removal. Hirschfeld files should always be followed by curets or other instruments to smooth and finish the root surface. If deep, tight, narrow pockets cannot be finished by mini-bladed curets or diamond files, thin-tipped ultrasonic inserts on medium power or thin diamond ultrasonic tips on low power should be used.

8. Thin ultrasonic inserts. These tips on low power are efficient and effective for removing biofilm and subgingival flushing of deposits but they are not effective for removal of hard calculus. Endoscopic observation consistently shows that low powered slim ultrasonic tips burnish the calculus and often only partially remove it. Therefore, these tips are only recommended for deplaqueing of the root surface. Do not assume that low powered thin ultrasonic tips are effectively removing calculus. When scaling subgingival calculus, ultrasonic instrumentation should always be followed by or combined with hand instrumentation.¹⁴

9. Diamond coated curets (files). These are actually files that are used as final finishing instruments (Figure 10). Instead of having cutting edges, these files are coated with a very fine diamond grit. They are used like an emery board with light pressure to avoid gouging or grooving the root surface. Light multidirectional strokes with these unique instruments will create a clean, highly polished root surface.

When viewing tactilely smooth root surfaces, the dental endoscope has revealed small remnants of calculus embedded in the root even after “final” ultrasonic or hand instrumentation has been completed. The diamond file is rubbed against the root surface to remove these last very small pieces of calculus while conserving as much root structure as possible.

For final instrumentation of furcations, light, “in and out” strokes in various directions with the diamond files are used to gently clean and smooth the roots. This technique allows thorough but conservative final removal of burnished calculus from all of the inner aspects of the furcation.

During initial scaling, all clinicians are essentially guessing where they are in the instrumentation process because tactile assessment is subjective and not consistently reliable. If endoscopy or a calculus detection device is not available, only careful re-evaluation of the tissues and bleeding upon probing will guide the clinician to areas of residual calculus.

Figure 8. Hu-Friedy Gracey Curvette Sub-0.	Figure 9. Hu-Friedy Quetin furcation curets: QBL 2, QBL 1 (buccal, lingual).
Figure 10. Brasseler diamond coated curets (files): F1and F2 (buccal and lingual root surfaces and furcations); F3 and F4 (mesial and distal root surfaces and furcations).

Clinicians are challenged daily to select the most efficient, effective instruments. Endoscopic observation is contributing new knowledge about the efficacy of hand instruments and will influence future instrument design. New categories of instruments will be developed for use with the dental endoscope. Hand instruments with miniature blades and tips that provide superior adaptation to root morphology and new diamond coated instruments are emerging. These innovative new instruments will be important tools for any clinician performing initial periodontal therapy.

References

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