The Mini Revolution

Root instrumentation is one of the most difficult and critical nonsurgical periodontal therapies. During all phases of nonsurgical periodontal treatment, including initial and periodontal maintenance therapy, root instrumentation—scaling, root planing, and deplaquing—is the determining factor in achieving a favorable tissue response. Complete periodontal debridement by removing hard and soft deposits from root surfaces requires a range of instruments as diverse as the surfaces treated. The mini-bladed Gracey curets capably address this diversity.

The beneficial effects of scaling and root planing combined with personal plaque control in the treatment of chronic periodontitis are substantiated by the American Academy of Peridontology.¹ Benefits include reduction of clinical inflammation, microbial shifts to a less pathogenic subgingival flora, decreased probing depth, gain of clinical attachment, and less disease progression.² Additional factors affecting therapy outcomes include pocket probing depths, pocket accessibility/location, and furcation involvement.² Subgingival root surfaces at greater than 4 mm below the cemento-enamel junction (CEJ) have concavities, depressions, and furcation entrances. These more varied root surfaces warrant a more diverse armamentarium. Instruments have been modified in recent years to facilitate improved access, adaptation, and a variety of activation techniques to address the complicating factors resulting from increased loss of attachment.

Figure 1. A comparison between a standard Gracey curet blade and a shortened Gracey curet blade. Figure 2. Without shortened blades, the blade has to be inserted sideways.

SHORTENED BLADES

The Gracey curet series is the standard for achieving positive outcomes in difficult instrumentation areas. Shortening the blade is the one modification to the standard Gracey curets that has had the greatest impact on the efficacy of scaling and root planing. Figure 1 compares a standard Gracey curet blade to a shortened Gracey curet blade. Prior to shortened blades, clinicians had to turn the instrument sideways, insert the blade with the toe directed apically, and use a horizontal stroke to reach into pockets more than 4 mm deep, as the length of blade would not allow complete access and adaptation (Figure 2). Shortening the blade by 50% and lengthening the terminal shank allowed access to root surfaces at greater depths (Figure 3).³

	Figure 3. Shortened blades allow easier access to root surfaces at greater depths. Figure 4. Mini-Five® Curet 11/12
	Figure 5. Anatomy of a curet.

When using Gracey curets, only the end third of the blade or the toe, as shown in Figure 1, touches the tooth surface. The toe third of the blade touches the tooth with the rest of the instrument following behind. The standard blade length is necessary to reach across the entire mesial and distal interproximal surfaces and to complete buccal and lingual surface instrumentation above furcation entrances and in areas with minimal levels of attachment loss. However, the standard instrument blade length is too great to adapt around the line-angles and much too long for adaptation to labial and lingual surfaces of mandibular anterior teeth and lingual surfaces of maxillary anterior teeth (Figures 6-7).

Figure 6. Vision Curvette®Sub-O on the left, traditional 5.6 Gracey curet on the right. Figure 7. Vision Curvette®Sub-O adapted to lingual surface of maxillary lateral incisor.

THE ROLE OF ULTRASONICS

Ultrasonic and sonic power instrumentation alone are not completely effective on the varied root surfaces at increased pocket depths.^4,5 An in vitro research project compared curets with a small blade to slim ultrasonic inserts on their efficacy in removing deposits (paint) from the root trunk and furcation entrance areas of mandibular molar dentiform teeth. Results revealed that the curets were significantly more efficient than the ultrasonic inserts in removing paint from both root trunks and furcation entrances.⁴ This study indicates the potential value of mini-bladed curets in debriding furcations during initial therapy and periodontal maintenance therapy.⁵

Power instruments are difficult to adapt in deep pockets, eg, the power tips have a straighter profile and do not conform to the highly variable curved surfaces of deeper root anatomy. Calculus may be burnished into concavities, depressions, and the concave portions of the furca. They are a useful instrumentation modality but require follow-up manual instrumentation to completely access and instrument the varied root surfaces at pocket depths greater than 4 mm below the CEJ.

Using a variety of vertical strokes with the instrument of choice is imperative. With manual instruments, there are a variety of techniques available to complete instrumentation, including extra-oral fulcrums, reinforced instrumentation techniques, stroke length, and increased lateral pressure. By varying the stroke angle on the tooth surface, a variety of crisscross directions can be utilized for thoroughness.

MINI-BLADED INSTRUMENTS

Curvettes, manufactured by Hu-Friedy, Chicago, were the first mini-bladed instruments developed and the patent was filed in 1990. Since then, many mini-bladed instruments have arrived on the market, including the MiniFive^® instrument series (Hu-Friedy, Chicago); Access Instruments (American Eagle Instruments Inc, Missoula, Mont); Mini-Extended Gracey (G Hartzell & Son Inc, Concord, Calif); Gracey OO and Gracey Extended Reach, (Paradise Dental Technologies, Missoula, Mont); In Site Mini Pocket Scalers (Premier Dental Products Co, Plymouth Meeting, Pa); Flexichange (Dentsply International Inc, York, Pa); Mini Longs (Brasseler USA, Savannah, Ga), and Gracey Short (A. Titan Instruments Inc, Hamburg, NY).

Following are descriptions of the two types of mini-bladed Gracey instruments available.

1. Mini-bladed Gracey curets (Figures 3, 4). The blade has been reduced by 50% and is thinned. The terminal shank is elongated 3 mm. They may aid in both initial and periodontal maintenance therapy.

2. Curvettes (Figures 5-8). The blade length has not only been reduced by 50%, but also the radius of curvature of the blade is reduced, resulting in a tipping-up of the toe end. The shortened blade improves instrumentation and the tipped up toe (a pseudo “spoon”) assists with removing the loosened deposits from within the pocket. Tipping up the toe end of the blade also results in a better fit in the sulcus on the narrow surfaces for which it was designed. The Curvette blade is not thinned.

The blade base is oriented at right angles to the terminal shank rather than slanted down like the Gracey curets. Figure 5 compares the Gracey curet to the Curvette blade. The straightened shank eases insertion into the sulcus and allows the terminal shank to be adapted parallel to the long axis of the tooth to follow the conventional principles of instrumentation.

The combination of the straightened terminal shank and decreased radius of curvature facilitates instrumentation on the narrower root surfaces. These unique features eliminate the need to turn the instrument sideways and use horizontal strokes in deep pockets and allow the Curvette blade to be used with strong vertical strokes.

The Vision^® Curvettes have a raised border on the instrument shank to visually determine depth within the pocket, the marking starts at 5 mm and ends at 10 mm. The Sub-O is used on the most anterior root surfaces—the labial and lingual surfaces of mandibular and maxillary anterior teeth.

Figure 8. Traditional Gracey 11/12 Curet maxillary molar (left) compared with the Vision Curvette®on the same molar (right).

MINI-BLADES AT WORK

Curvettes are recommended for initial therapy while the blade is full-sized and for periodontal maintenance therapy after the blade is reduced from sharpening and wear.

Initial therapy patients who exhibit poor tissue response generally have tenacious or burnished deposits remaining on root-surfaces that are difficult to access either with power or manual instrumentation. These deposits call for increased lateral pressure and a selection from the assortment of mini-bladed instruments may be required to achieve complete calculus removal. Mini-bladed instruments are effective for removing burnished deposits since their blade size permits vertical strokes and cross-hatching of strokes on the root surface while applying variable lateral pressure.

During periodontal maintenance therapy, patients who demonstrate minimal attachment loss may require the use of mini-blades to minimize tissue manipulation. This is achieved by using instruments with narrowed blades from sharpening. For periodontal maintenance therapy patients with moderate attachment loss, the mini-bladed Gracey curets with thinned, shorter blades and Curvettes, when thinned by use, can be used for smaller root circumference access (Figure 7). The variety of small bladed-instruments also provide improved access to furcations where the ultrasonic/sonic tips cannot be adapted to the concave portions of the furcation (Figure 4).⁵

Currently, manual instrumentation remains the necessary follow-up to ultrasonic/sonic treatment and the addition of mini-bladed instruments has greatly enhanced our proficiency in scaling, root planing, and deplaquing during initial and periodontal maintenance therapy.

References

1. Greenwell H. Position paper: Guidelines for periodontal therapy. J Periodontol. 2001;72(11):1624-1628.
2. Treatment of plaque-induced gingivitis, chronic periodontitis, and other clinical conditions. J Periodontol. 2001;72(12):1790-1800.
3. Singer DL, Long BA, Lozanoff S, Senthilselvan A. Evaluation of a new periodontal curet. An in vitro study. J Clin Periodontol. 1992;19(8):549-552.
4. Otero-Cagide FJ, Long BA. Comparative in vitro effectiveness of closed root debridement with fine instruments on specific areas of mandibular first molar furcations. I. Root trunk and furcation entrance. J Periodontol. 1997;68(11):1093-1097.
5. Otero-Cagide FJ, Long BA. Comparative in vitro effectiveness of closed root debridement with fine instruments on specific areas of mandibular first molar furcations. II. Furcation area. J Periodontol. 1997;68(11):1098-1101.

From Dimensions of Dental Hygiene. June / July 2003;1(3):28-29, 31.