Contact Perfect QEP
A direct contact approach to Class II dentistry.
Arnel Dental Products has reintroduced the Contact Perfect matrix system. Modified to simplify its use, Contact Perfect is essentially a Tofflemire-like band with a removable 0.001-in interproximal window (Figure 1) that, upon removal, allows for displaced uncured resin to directly contact the adjacent tooth.
By eliminating the matrix wall and its associated thickness, Contact Perfect produces absolutely predictable contacts that negate the need for aggressive tooth separation and potential periodontal ligament trauma. Contact Perfect’s operation is two-fold. After packing the preparation, the matrix wall is removed (Figure 2) to expose uncured interproximal resin.
Secondly, the uncured resin surface is tapped (poked) once (about 1 mm deep) with a condensing instrument (Figure 3). This action extrudes the resin through the open wall to create direct contact with the opposing tooth. As it traverses the opening, the composite resin’s fluid dynamic properties cause an expansive bulge. This creates ideal contact placement with natural and desirable contours.
Contact Perfect has universal quadrant compatibility and is oriented appropriately in a Tofflemire-style retainer to correlate with the prepared tooth’s quadrant. The band is then positioned around the tooth with the band’s window aspect positioned interproximally. Note: gentle wedging of tight opposite intact proximal areas will facilitate band insertion.
Contact Perfect works well with any universal non-sticky resin or packable posterior resin. To ensure deep-seated compaction and curing, a beveled axial ramp (1 mm to 2 mm) is created and photo-cured. Also, shallow preparations, at the operator’s discretion, may preclude the need for ramp build-up. The new generation of universal resins proclaims less polymerization shrinkage and permits a greater depth of cure. This allows for bulk packing the remainder of the preparation. To ease finishing, take time to create a well-rounded marginal ridge. Engage the wall’s eyelet with an explorer or condenser and extract the wall from the band with a rapid withdrawing motion. Do not photo-cure yet.
Tap for Contact
With the 0.001-in thick wall removed, the uncured resin is still 0.001 of an inch shy of contact with the abutting tooth. Taking advantage of resin’s fluid dynamics and its displacing rather than condensing properties, application of an external force results in bodily movement of the mass in a concentric fashion. The application of a condensing tip will cause the resin mass to move through the path of least resistance, which coincides with the area of the removed wall. The resin will flow through the window and touch the convexity of the abutting tooth, thereby creating positive contact at the ideal spot. Gently tap the occlusal surface of the resin about 1 mm deep only once with the tip of a condenser. Place the tap in the mid-area of the box 1.5 to 2 mm from the marginal ridge.
Tapping has established the contact, so now it is time to photo-cure. Note that the restoration may be cured occlusally and interproximally through the opened window area from a buccal and/or lingual approach. The tapping procedure may leave a dimpled depression in the occlusal surface. If necessary, fill the tap hole with resin and cure.
Remove the Band
Because direct contact has been formed, Contact Perfect has incorporated a means to remove the matrix without disturbing the contact area. Be certain that the band is secured in the retainer. Then simply increase the tension on the retainer until you feel the separation of the band at its gingival connection. The band may then be removed in an occlusal direction without disturbing the interproximal area. The restoration may then be adjusted and polished according to the clinician’s normal protocol. Because of the band’s close adaptation and aggressive compaction, the proximal wall of the restoration is left in a smooth condition requiring very little attention, even at the gingival margin. Adhesion to the enamel or resin surface of the abutting tooth also is not a concern, although the judicious application of a separating medium to that surface before band insertion can be done if so desired.
The Contact Perfect band represents a new direction in matrix technology while retaining the desirable utility of a Tofflemire system. Contact Perfect eliminates the major component of Class II unpredictability—the matrix wall. Rather than relying on aggressive tooth separation to overcome matrix thickness, Contact Perfect allows the matrix wall to be removed for predictable direct Class II contacts. Furthermore, composite resin’s fluid dynamics allow for expansive resin movement when establishing contact. The result is proper contact placement with desirable contours that eliminates the flat, high marginal ridge contact so strongly associated with Tofflemire-style matrices. The novelty of the system does present with an initial learning curve, which is anticipated through an online video tutorial. Contact Perfect is presently available in a universal MO/DO version.
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About the Author(s)
This article was written by Dominic A. Viscomi, DDS, who is the co-inventor and a consultant for Arnel Dental. He may be reached at firstname.lastname@example.org.