In cases of mandibular fractures, which symptom is typically indicative of a fracture?

In cases of mandibular fractures, deviation on opening is a symptom that typically indicates a fracture. This occurs because a fracture can disrupt the normal mechanics of the jaw movement, leading to an asymmetrical motion when the patient tries to open their mouth. This abnormal deviation can often be observed as the mandible moves toward the side of the fracture when the mouth is opened.

Understanding the underlying anatomy and biomechanics of the jaw is essential, as when the mandible is fractured, the muscular control is compromised due to the pain and instability, resulting in this characteristic deviation upon opening.

Other symptoms, such as decreased mobility or pain while biting, can occur with various dental and jaw conditions and are not exclusively indicative of a fracture. Increased salivation might occur due to stress or pain but is not a reliable sign of a mandibular fracture specifically. Thus, the symptom of deviation on opening is a clear marker to suspect a fracture in the mandible.