November 2009 | Dental Products Report
Clinical 360°: COSMETIC/restorative technique

How to: Safely, efficiently
perform IPR

OS Discs allow clinicians to perform interproximal enamel reduction, with virtually no risk of injuring the soft tissue.

by Dr. Tamara L. Bailey
Information provided by KOMET USA.

With the ever-growing popularity of Align Technology Inc.’s Invisalign®, more general practitioners are offering orthodontic treatments to their patients, including orthodontic aligner treatments. Many of them are even offering traditional orthodontic bracketing as a cosmetic option for patients.

In cases of both cosmetic and orthodontic procedures, interproximal enamel reduction (IPR), also known as “stripping,” may be required. IPR may be indicated in some of the following situations: to correct minor tooth-size discrepancies; to eliminate crowding, allowing tooth movement; to broaden interproximal contact areas; and to improve orthodontic outcomes.

Traditionally IPR has been performed with diamond discs or very thin diamond burs. Discs also may be used to reduce the proximal areas of primary teeth allowing for proper eruption of adjacent permanent teeth. Diamond discs are difficult to manipulate in tight spaces and regularly jam when the speed is decreased during use. Diamond burs, while excellent for initiating IPR, are generally too large in diameter or are too tapered for optimal interproximal reduction.

While stripping is used for these procedures, there are other concerns when using diamond discs in the mouth. Diamond discs were not designed to be used in the oral cavity. There is the risk of soft-tissue damage and an obstructed view when using the disc guards.

• Refer to the slideshow for figures

For practitioners who need to perform IPR, KOMET USA has introduced an instrument designed specifically for this procedure—the OS Discs (oscillating segment discs) (Fig. 1). Developed in conjunction with Professor Dr. Paul-Georg Jost-Brinkmann of the Berlin Charité Dental Hospital in Germany, the OS Discs are safe and efficient for interproximal reduction. OS Discs are 60° segmented discs with a radius of only 1.4 cm and a pivoting angle of 30°. This allows clinicians to access tight spaces with excellent user control (Fig. 2).

The OS Discs were designed to be used in the oscillating KOMET handpiece OS30. When using the micro-motor at full capacity, an effective performance of 5,000 oscillations per minute is reached. It also is possible to use the OS30 with an air motor. At the motor’s maximum capacity, an effective performance of 2,500 oscillations per minute can be reached. Before using the OS Discs, KOMET recommends eliminating the interproximal contact by using a diamond strip with honeycomb design. Afterward, the user must guide the OS Discs from the occlusal edge through the contact point in a slow, but continuous movement for maximum efficiency.

KOMET USA developed 15 different OS Discs for the OS30 handpiece—nine with fine-grit diamonds and six with medium-grit diamonds. Out of the 15 discs, eight are one-sided and seven are two-sided. They come in various thicknesses (0.13 mm to 0.45 mm).

Case report

After determining the amount of interproximal enamel reduction necessary, the medium-grit OS Disc is inserted into the KOMET OS30.

01. The disc is placed at the incisal edge of the tooth to be reduced (Fig. 3). The disc is then guided from the incisal edge through the contact point, toward the gingival margin, with slow and continuous motion and copious amounts of spray coolant (Fig. 4).

02. A narrow, diamond flame-shaped bur is placed behind the space created by the OS Discs, demonstrating the instrument’s precision.

03. The bur in Fig. 5 also shows minimal tooth structure removal is possible when using these discs.

04. After using the discs (starting with a medium-grit followed by a fine-grit disc), the area of the tooth is polished and ready to be prepared for traditional orthodontic or aligner therapy (Fig. 6).

05. Choose from a variety of instruments for best results. For interproximal enamel polishing KOMET offers the IPR Kit 4598 with polishing discs in three different grit sizes (medium, fine and ultra-fine). The latest innovation is the IPR Kit 4594 (Fig. 7). It contains two diamond strips, 11 OS Discs and two rotary diamond instruments, and was developed with the expert advice of Dr. Thomas Drechsler of Germany, one of the most experienced Invisalign® system users in Europe. The kit is organized according to the most popular target sizes that shall be removed (i.e., 0.2, 0.3, 0.4 and 0.5 mm) during IPR.