Final answer:
The radiograph indicating that the radiolucency at the apex is filling in after a root canal treatment points to the growth of healthy alveolar bone in the area, which is a good sign that the infection has been eradicated and the tooth is healing.
Step-by-step explanation:
The success of a root canal treatment (RCT) being confirmed by a radiograph that suggests the radiolucency at the apex is filling in indicates that C) healthy alveolar bone is now growing in the radiolucent area. During the healing process after RCT, the bone begins to regenerate, and the previously radiolucent area seen on the x-ray, which indicated the presence of an infection or a void, starts filling in. This is a positive sign that the RCT has been effective in removing the infection and that the tooth is healing properly.
Radiographs play an essential role in dental health care for the diagnosis and management of dental conditions. They help in the detection of decay, the assessment of the status of the pulp and surrounding bone, the planning of dental structures for the placement of implants and other restorations, and the monitoring of the success of treatments such as RCT. The absence of a growing infection and the growing in at the apex shown in the radiograph is a clear indication that the tooth does not require extraction, is not decaying further, nor is the infection spreading.