HESI General Chairside Assisting Practice Exam

Which material requires a cavity with minor to prevent irritation to the pulp of the tooth?

1. Composite resin

2. Amalgam

3. Zinc phosphate

4. Glass ionomer

The correct answer is: Zinc phosphate

Zinc phosphate cement is specifically formulated to provide a protective barrier for the pulp of the tooth while also ensuring good adhesion to the tooth structure. When a cavity preparation is made, it is crucial that the pulp chamber remains undisturbed, and the material used to fill the cavity should not cause irritation to the pulp. Zinc phosphate has a low pH when initially mixed, which can irritate the pulp if it comes into direct contact. Therefore, it is important that the cavity is prepared with a minor depth to create a suitable barrier between the zinc phosphate and the pulp. This minor cavity depth allows the material to effectively fill the space while minimizing any risk of damage or sensitivity to the pulp tissue. In contrast, other materials like composite resin, amalgam, and glass ionomer may have different properties that allow for direct application against the pulp without the same level of concern for irritation, or they may not require as precise cavity depth management to prevent pulp irritation.