National Dental Assisting Examining Board (NDAEB) Practice Exam

What type of matrix is used for anterior CR or GI restorations?

1. Metal matrix

2. Clear plastic

3. Rubber matrix

4. Wooden matrix

The correct answer is: Clear plastic

The appropriate choice for anterior composite resin (CR) or glass ionomer (GI) restorations is a clear plastic matrix. This type of matrix is beneficial as it allows for excellent visibility during the placement of the restoration. Clear matrices typically conform well to the contours of the teeth, helping to achieve a more natural final appearance by allowing the clinician to see the positioning and adaptation of the material being placed. Using a clear plastic matrix is particularly important for anterior teeth where aesthetics are critical. The translucency of the plastic allows light to pass through, which can aid in the polymerization of light-cured materials. This helps ensure that the restoration bonds properly and achieves the desired strength and durability. Furthermore, clear plastic matrices are flexible and can easily be adapted to fit various tooth shapes, making them versatile for different clinical scenarios. In contrast, metal matrices are more commonly used for posterior restorations due to their strength and rigidity but do not provide the aesthetic quality needed for anterior restorations. Rubber and wooden matrices are typically not used in modern restorative dentistry for composite or glass ionomer materials in anterior cases, as they do not allow for adequate visibility and adaptation necessary for achieving high-quality results.