Case Details
Introduction
Class II (interproximal) decay and/or a failing restoration that involves a posterior proximal surface is still a common problem in daily practice. Many of these problems can be corrected utilizing directly placed restorative materials. The challenge with Class II restorations 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. 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 laborious at best.
Anatomically, the posterior proximal surface is convex occlusally and concave gingivally. The proximal contact is elliptical in the bucco-lingual direction and located approximately one millimeter apical to the height of the marginal ridge. As the surface of the tooth progresses gingivally from the contact point toward the cementoenamel junction, a concavity exists that houses the interdental papilla. Conventional matrix systems are made of thin, flat metallic strips that are placed circumferentially around the tooth to be restored and affixed with some sort of retaining device. While contact with the adjacent tooth can be made with a circumferential matrix band, it is practically impossible to recreate the natural convex/concave anatomy of the posterior proximal surface because of the inherent limitations of these systems. Attempts to “shape” or “burnish” matrix bands with elliptical instrumentation may help create non-anatomic contact, but only “distorts”, or “indents” the band and does not recreate complete natural interproximal contours.
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. Direct Class II composite restorations can present even more of a challenge to place for the dentist because of the inability of resin materials to be compressed against a matrix to the same degree as amalgam, as well as the shrinkage factor of most composite materials. This article will describe the use of an innovative sectional matrix system (Composi-Tight Gold: Garrison Dental Solutions) and instrumentation designed to facilitate placement of the matrix to assure maximum results, both in physiological tight contact and in anatomic form. When utilizing this system with the latest in composite resin technology, direct Class II tooth colored restorations can be placed that exhibit natural anatomic proximal form and have predictable proximal contact.
Tooth Preparation and Matrix Armamentarium
Class II preparations that need a matrix band for restoration will require rebuilding of the marginal ridge, proximal contact, and often a large portion of the interproximal surface. The goal of composite placement is to do so in such a way that the amount of rotary instrumentation for contouring and finishing is limited. This is especially true for the interproximal surface. Because of the constraints of clinical access to the proximal area, it is extremely difficult to sculpt and contour correctly this surface of the restoration. Proper reconstitution of this surface is largely due to the shape of the matrix band and the accuracy of its placement. After removal of caries and old restorative material, the outline form of the cavity preparation is assessed. If any portion of the proximal contact remains, it does not necessarily need to be removed. Conserve as much healthy, unaffected tooth structure as possible. If the matrix band cannot be easily positioned through the remaining contact, the contact can be lightened using a Gateway 50-µm diamond strip (Brasseler USA).
A sectional matrix system, such as Composi-Tight Gold (Garrison Dental Solutions), is an excellent choice for class II composite restorations for many reasons. First, the matrix band is anatomically correct. Rather than being flat like conventional matrix bands, the sectional matrix band is kidney-bean shaped with a concave inner surface. This allows for the proper restoration of interproximal anatomy as described above. Secondly, the G-Ring, which holds the sectional matrix in place, also causes a slight separation of the affected tooth and the adjacent surface by compression of the periodontal ligament. When the G-Ring is in place and the matrix touches the adjacent tooth surface, proximal contact is assured.
Also, some instrumentation has been developed to aid in accurate placement of the sectional matrix to maximize the restorative result. Sectional matrix pliers known as Dryer-Pliers (DryerPliers, Inc) were developed specifically for use with sectional matrix systems to aid in the accurate placement and positioning of the matrix band. There is one plier for placement of the mesial sectional matrix and one for the distal. Since the sectional matrix band is extremely thin, it can be difficult to place with a hemostat or cotton pliers without deforming the band. The DryerPliers maintain the shape of the band while positively holding the matrix in the proper position for placement. After positioning of the matrix band, initial stabilization is secured through the use of a proximal wedge.
Wedge Wands (Garrison Dental Solutions) were developed as an adjunct to the Composi-Tight system to stabilize the matrix band and help create a gingival seal. The wedge is plastic, so it is bendable and able to conform better to the convex root (tooth) surface when pressure is exerted on it by the G-Ring. The delivery is unique, since the wedge is on a plastic handle and can be bent to the desired angle for placement prior to being placed in the oral cavity. Once positioned, a twist of the handle releases the wedge, and the handle is discarded. This delivery system avoids awkward placement using cotton pliers, where many times wedges are hard to angle into place and often dropped or mishandled.
Case Study
A technique has been described utilizing a sectional matrix system and associated armamentarium (Composi-Tight Gold, WedgeWands: Garrison Dental Solutions), DryerPliers, and a nanofilled microhybrid composite (Premise: Kerr Corporation) to create an anatomically precise Class II posterior composite restoration. Using this armamentarium, the interproximal surface has also been recreated with natural anatomic contour and has a predictable, elliptical contact with the adjacent tooth, with very little rotary finishing necessary. With proper occlusal and proximal form, this “invisible” direct composite restoration will service the patient for many years to come.
