Dental OSCE (Objective Structured Clinical Examination) Practice Exam

Which muscle is commonly impinged by an overextended flange in a full lower denture?

1. Temporalis

2. Masseter

3. Buccinator

4. Orbicularis oris

The correct answer is: Masseter

The masseter muscle is commonly impinged by an overextended flange in a full lower denture because it plays a crucial role in the chewing process and is located in the posterior area of the jaw. When a lower denture flange extends too far, it can interfere with the functioning of the masseter muscle, leading to discomfort and potentially impacting the efficiency of mastication. This muscle is a powerful elevator of the jaw, and its location makes it particularly susceptible to pressure or irritation from poorly fitting dentures. An ill-fitting denture can cause the masseter to become overworked or stressed, leading to pain or dysfunction in that area. In contrast, while the other muscles listed—temporalis, buccinator, and orbicularis oris—are important in various functions of mastication and facial expressions, their implications with overextended flanges are not as immediate or direct as those with the masseter muscle. The temporalis contributes to jaw elevation but is less likely to be affected directly by the denture's position. The buccinator is involved in maintaining food within the mouth rather than heavy chewing forces, and the orbicularis oris is primarily responsible for movements of the lips and may not experience the same level of impingement