The ulcer site appears white and hardened.

Whitening and hardening of oral ulcers may be caused by physiological factors, or by pathological conditions such as residual roots or crowns, oral leukoplakia, etc. Different treatments should be selected based on the underlying cause. Specific analysis is as follows:

1. Physiological Factors

In the initial stage, the mucosa surrounding the ulcer appears red. As the lesion heals, the surrounding mucosa gradually turns white and feels firm upon touch. This is generally a normal phenomenon and does not require special treatment.

2. Pathological Factors

1) Residual Roots or Crowns

When broken tooth roots or crowns are present, they may continuously irritate the surface of the wound, leading to fibrous scar tissue formation, making the area feel particularly hard. This results in hardened, whitened oral ulcers. Most cases require root canal treatment at the affected site; tooth extraction may be necessary in some cases.

2) Oral Leukoplakia

In patients with oral leukoplakia, the mucosa at the ulcer site undergoes keratinization. Under inflammatory stimulation, epithelial tissue may proliferate abnormally, causing the aforementioned symptoms. Patients can use medications such as tretinoin cream or vitamin E soft capsules under medical supervision.

Besides the above causes, conditions such as oral thrush, tuberculous ulcers, or mucoceles may also lead to similar symptoms. It is important to seek timely medical evaluation at a hospital and follow the doctor's instructions for appropriate treatment.