Australian Dental Council (ADC) Practice Test

The application of the matrix band for an upper first premolar with a mesio-occlusal (MO) cavity is complicated by the mesial concavity of the root surface. This anatomical feature presents challenges because it can impede access and proper placement of the matrix band, which is essential for achieving a proper seal and contour during restoration. The concavity may make it difficult to adapt the matrix band tightly against the tooth structure, potentially leading to excess material flow or inadequate coverage of the cavity.

While the other factors mentioned may contribute to the overall complexity of treating such a tooth, they do not specifically hinder the placement of the matrix band as notably as the mesial concavity does. The small lingual pulp and high buccal pulp horn pertain more to the internal anatomy of the tooth, while the concavity of the distal root surface typically does not directly affect the matrix band application for the mesial aspect of the tooth. Thus, understanding the anatomical nuances of premolars is essential for effective restorative procedures.