Polishing Interproximal Restorations with Limited Space

Occasionally, dentists will detect damage resulting from previous restorative procedures to interproximal surfaces. Regardless of how the damage occurred and whenever possible, the interproximal surface(s) should be recontoured (and highly polished, if indicated) to improve the future contact prior to placement of a new direct restoration or the making of a definitive impression for an indirect restoration. When reconstructing proximal surfaces, two issues are of primary concern: contact tightness and surface contour.¹ Creating tight proximal contacts between natural tooth-supported and implant-supported restorations should be a principal goal of the restorative dentist.²

An optimal contact area provides stability for the teeth as well as an appropriately contoured gingival embrasure, which is necessary for adequate hygiene and to promote a healthy environment for the gingival papilla.¹ Ideal proximal contacts between adjacent teeth contribute to the overall stability of dental arches and healthy interdental periodontal tissues^3,4 and play an important role in protecting the periodontium against damage caused by food impaction.^3,5 Light or lose contacts may result in food impaction, potentially setting up a chain of events that can lead to decay, periodontal destruction, and pain.⁶ In addition, the contour of the proximal contacts should be convex to allow for adequate removal of interdental plaque.¹ If the normal anatomical interproximal convexity has been substantially damaged, consideration should be given to replacing the restoration. Fortunately, in most circumstances, recontouring and repolishing the adjacent interproximal restoration will provide an acceptable surface for the new restoration to be built against.

When the preparation is finished, it is critical to examine the opposing interproximal surface for the appropriate anatomical form and for any roughness or irregularities. Although tungsten carbide or diamond finishing burs, interproximal polishing strips, and finishing disks traditionally have been used to accomplish recontouring, there are situations in which the interproximal space is limited, hindering the practitioner's ability to access these proximal surfaces. If polishing points are selected as part of the polishing armamentarium, they also must be able to fit within the interproximal space in order to provide the desired result. Finishing burs used for recontouring come in a variety of different sizes and shapes, so they do not typically present a problem in terms of access. Similarly, finishing disks are thin, therefore they do not usually present a problem when used interproximally. However, if used too aggressively, they can result in a flat interproximal contour. Polishing points can provide a suitable alternative, but are often manufactured in sizes that are too large in diameter to fit within tight interproximal spaces. Modifying them can help to overcome this obstacle.

The following technique can be used to facilitate adequate contouring and polishing of tight interproximal restorations:

Step 1:Recontour the adjacent interproximal restoration as best as possible using preferred tungsten carbide or fine/extra fine diamond rotary instrument finishing burs (Figure 1 and Figure 2).

Step 2: Insert a friction grip “brownie” metal polisher (9608M FG 030; Komet USA) into a highspeed handpiece (a slow speed, latch grip brownie polishing point can also be selected, based on the practitioner's preference).

Step 3:While holding a coarse, large diameter diamond rotary instrument (6856 FG 021, Komet USA) still in one hand, run the brownie metal polishing point against it at a medium speed and in a vertical fashion (Figure 3 and Figure 4) until the desired final diameter is achieved (Figure 5). To prevent the polishing point from accidentally dislodging from the shank, use caution to avoid exceeding a safe speed with the handpiece (eg, 6,000 to 15,000 RPM, per manufacturer recommendations). Also, if instrument reshaping is performed chairside, it is advised that the clinician, staff, and patient wear safety glasses for eye protection. Alternatively, multiple points can be recontoured in advance during non-clinical time and stored for use as needed. This task can even be delegated to staff.

Step 4:Using the reshaped polishing point, polish the interproximal restoration to achieve the desired result (Figure 6 and Figure 7). When using a friction grip polisher, it is recommended that practitioners use an accompanying water spray (via handpiece or air/water syringe) to reduce frictional heat. To achieve the highest polish and shine, the practitioner can follow up with a “greenie” polisher (9618F FG 030; Komet USA), which can also be modified using the above technique if necessary.

Properly contoured and highly polished interproximal surfaces (coupled with a good clinical restorative technique) provide better interproximal contacts that improve hygiene and facilitate optimal gingival health of the interdental papilla. Clinicians should take great care in establishing the surface contours necessary to prevent food impaction, eliminate plaque retention, and facilitate easy flossing by the patient.¹This technique and the recommended polisher can be used to polish amalgam, composite, and gold restorations with predictable results. By employing intraoral porcelain polishers, the same technique could be utilized to polish interproximal ceramic restorations. However, because these porcelain polishers are more expensive, it may be prudent to minimize the amount of instrument reshaping to avoid decreasing the life span of the polisher. Using the technique described in this article can assist practitioners in the development of the desired surface contour and polish, thereby yielding a more ideal interproximal contact that will help maintain interarch tooth stability and better sustain interproximal tissue health.

Barry D. Hammond, DMD
Professor and Director of Dental Continuing Education
Department of General Dentistry
The Dental College of Georgia at Augusta University
Augusta, Georgia

Nancy B. Young, DMD
Assistant Professor
Department of General Dentistry
The Dental College of Georgia at Augusta University
Augusta, Georgia