Final answer:
Patients who frequently miss dental appointments due to apprehension often demonstrate a lower pain reaction threshold, which means they have a low tolerance for pain.
Step-by-step explanation:
Patients who frequently miss dental appointments due to apprehension often demonstrate a lower pain reaction threshold, which means they have a low tolerance for pain. When someone has a lower pain reaction threshold, they are more sensitive to pain and may experience discomfort at a lower intensity compared to individuals with a higher pain reaction threshold.