**Core Concept**
Periodontal problems during fixed appliance therapy can be managed through preventive and therapeutic measures that aim to reduce the risk of gingivitis and periodontitis. This involves maintaining good oral hygiene, reducing plaque accumulation, and promoting periodontal health.

**Why the Correct Answer is Right**
The correct answer involves measures that address the primary causes of periodontal problems during orthodontic treatment, such as increased plaque accumulation and gingival inflammation. These measures include:

* **Regular professional dental cleaning**: This is essential for removing plaque and calculus that can accumulate around orthodontic appliances and contribute to periodontal disease.
* **Interdental brushing**: This helps to remove plaque and food particles from between teeth and around orthodontic brackets, reducing the risk of gingivitis and periodontitis.
* **Use of fluoride mouthwash**: Fluoride has antibacterial properties that can help to reduce plaque and prevent gingivitis.
* **Adjustment of orthodontic appliances**: Regular adjustments to orthodontic appliances can help to reduce pressure on the gingiva and prevent irritation.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not address the primary causes of periodontal problems during orthodontic treatment. It may even exacerbate the problem by introducing additional irritants into the oral cavity.
* **Option B:** This option is incorrect because it is not a standard preventive or therapeutic measure for periodontal problems during orthodontic treatment. While diet may play a role in oral health, it is not a direct solution to periodontal problems.
* **Option C:** This option is incorrect because it is not a typical preventive or therapeutic measure for periodontal problems during orthodontic treatment. Antibiotics may be used in some cases, but they are not a standard treatment for periodontal disease.

**Clinical Pearl / High-Yield Fact**
Regular professional dental cleaning and interdental brushing are essential for maintaining periodontal health during orthodontic treatment. These measures can help to reduce the risk of gingivitis and periodontitis, and promote a healthy periodontal environment.

**Correct Answer:** D.