Sectional matrix solutions: the distorted truth

Abstract

Sectional matrix techniques offer more predictable solutions to achieving contact areas when placing direct interproximal posterior composites than circumferential matrix techniques, resulting in reduced reported complaints of food packing from patients. Despite this, a large majority of UK dentists and therapists don't currently use them. Sectional matrix systems are technique-sensitive to use, which can be a barrier to implementation for inexperienced users. The matrices can easily distort during their placement and stabilisation and when placing the restorative material. This can result in unwanted, clinically relevant problems in the resulting restorations, some of which may not be discernible once they have occurred. This paper explores the advantages and disadvantages of sectional matrices and the processes and techniques involved in their use, before discussing the potential for distortion at each step. It offers solutions to some of the commonly seen problems which will provide more predictable outcomes for those already using these techniques and encourage non-users to add them to their armamentarium.

Current Strategies to Control Recurrent and Residual Caries with Resin Composite Restorations: Operator- and Material-Related Factors

“…Nevertheless, building effective tight contact requires compensating for the polymerization shrinkage and thickness of the metallic matrix [ 177 , 178 ]. Evidence-based reports recommend using pre-contoured sectional matrix systems with separation rings and wedges to produce more effective tight contacts and more anatomically shaped contours with class II direct resin composites than a circumferential matrix with wooden wedges [ 179 , 180 , 181 , 182 ].…”

“…This constitutes a possible additional challenge. Producing a concavity at proximal contact areas with more biofilm accumulation and difficult cleanability can occur upon using a sectional matrix, which is less likely to occur with circumferential matrices [ 179 ].…”

“…Regardless of the sectional matrix system used, the following criteria of a properly applied matrix are essential to ascertain the faithful restoration of physiological anatomical features of proximal contours, embrasures, and tight contacts [ 179 ]: An appropriately adapted matrix that contacts the greatest convexity point of the adjacent tooth surface. This is influenced by the cavity design, size, and configurations as well as by the operator skills of matrix selection, placement, and stabilization method in addition to the specific resin composite used and its insertion technique.…”

“…To assure the above-mentioned criteria, the matrix should extend cervically below the gingival margin of the preparation and about 0.5 mm above the level of the marginal ridge of the adjacent tooth [ 19 , 179 ]. It is worth emphasizing that rubber dam isolation is mandatory for facilitating proper bonding procedures and resin composite placement, and producing an effective tight proximal contact of resin composite restorations [ 19 ].…”

Sub-gingival posterior composites: How confident are you?

“…6,12,13 Improper matrix adaptation can also lead to ledge formation or deficient margins which can be difficult to access and adjust. 14,15 They can then provide sheltered areas for biofilm adherence and proliferation, with limited access to cleaning aids. Given that composite has also been shown to support and favour the growth of a cariogenic biofilm, 16,17 these factors all provide a rationale for the higher incidence of secondary caries around composite restorations than amalgam restorations 18 and help us to understand confidence levels seen in primary care clinicians when placing sub-gingival composite restorations.…”