Which class of cavity preparations requires the use of a matrix system?

Cavity preparations that fall under Class II, III, or IV require the use of a matrix system to properly restore the tooth structure. A matrix system is essential when a cavity extends into the interproximal areas or involves the incisal edge, as these preparations often result in a loss of tooth structure that needs firm support during the restoration process. The matrix helps maintain the shape and contour of the filling material while it sets, especially in areas where direct access and visibility are limited.

Class II cavities affect posterior teeth and typically involve proximal surfaces, making the use of a matrix essential to ensure that the restoration is properly formed and in contact with adjacent teeth. Class III and IV cavities, which involve anterior teeth, also necessitate a matrix system to achieve a natural appearance, supporting composite or other materials as they cure.

In contrast, Class I cavities affect the pits and fissures of the teeth and do not typically require matrix support because they can be easily accessed without needing to recreate smooth contours associated with adjacent teeth. Additionally, Class V cavities, located on the gingival third of the facial or lingual surface of any tooth, also do not usually necessitate the use of a matrix system, as their location allows for straightforward restoration techniques without the need for