Without the support of tooth contour, the interdental papilla may not completely fill the gingival embrasure, leading to potential food traps and areas for excess plaque accumulation. Attempts to “shape” or “burnish” matrix bands with elliptical instrumentation may help create nonanatomic contact, but only distorts or indents the band and does not recreate complete, natural interproximal contours. While contact with the adjacent tooth can be made with a circumferential matrix band, it is practically impossible to re-create the natural convex/concave anatomy of the posterior proximal surface because of the inherent limitations of these systems. Conventional matrix systems are made of thin, flat, metallic strips that are placed circumferentially around the tooth to be restored and affixed with some type of retaining device. As the surface of the tooth progresses gingivally from the contact point toward the cemento-enamel junction, a concavity exists that houses the interdental papilla. The proximal contact is elliptical in the buccolingual direction and located approximately 1 mm apical to the height of the marginal ridge. The thickness of the matrix band and the ability to compress the periodontal ligaments of the tooth being restored and the one adjacent to it can sometimes make the restoration of proximal tooth contact arduous at best.Īnatomically, the posterior proximal surface is convex occlusally and concave gingivally. The challenge for the dentist has always been to recreate contact to the adjacent tooth and at the same time restore proper interproximal anatomic form given the limitations of conventional matrix systems. Many of these problems can be handled utilizing directly placed restorative materials. Class II (interproximal) decay and/or a failing restoration that involves a posterior proximal surface is still a common finding in most dental patients.
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