Article
Matrix technique challenges
Matrix technique has been demonstrated to be the most important determinant in the restoration of tight, anatomically correct proximal contacts and contours.1 Unfortunately a high percentage of dentists complain of regular problems with open Class II posterior composite contacts. This primarily results from reliance on out-moded matrices designed for amalgam, such as the notoriously unsuitable Siqveland matrix system. Common errors are illustrated in Figure 1.
To combat this, a range of specialized matrices, wedges and contact forming instruments are available that are designed to:
Matrix options
Sectional matrices, wedges and separation rings have been demonstrated to produce optimal restorative contacts, but are not suitable for all clinical situations or for amalgam restorations.1 In larger cavities and those with wider proximal boxes, specialized circumferential matrices, such as AutoMatrix (DentsplySirona, Weybridge, UK) and SuperMat (Kerr, Orange County, CA, USA) (Figure 2) are recommended because they confer a number of advantages (Table 1).1
| Creates tight, optimally positioned contact points |
| Creates anatomically correct embrasure contours |
| Easy to use |
| Offers improved instrument access and clearer view of the operative field |
| Versatile/reversible positioning options |
| Retainerless design does not impede wedge placement |
| Minimizes cusp flexion |
| Helps to hold rubber dam in place |
| Minimizes interproximal restorative finishing |
| Suitable for composite and amalgam restorations |
| Greater patient comfort |
| Cost effective |
| Single use eliminates cross-infection risk |
These matrices are applied to the tooth and tightened with a matched instrument. Only metal matrices are recommended for posterior restorations because transparent versions are thick, difficult to insert and stabilize, and cannot be burnished.1 In extensive cavities with limited residual coronal tissue, freehand build-up of missing cusps may be carried out to facilitate circumferential matrix retention and stabilization.
New Palodent 360
Launched in January 2021, the Palodent 360 is the latest single-use circumferential matrix system from DentsplySirona. As well as the advantages listed in Table 1, the Palodent 360 does not require a separate tightening instrument and is used according to the following step-by-step guide (Figure 4):
