**Question:** Rats are administered with 1PPM NaF and ALF3, all of the following will happen, except?

A. Increase in bone mineralization
B. Decrease in bone resorption
C. Increase in tooth erosion
D. Increase in renal calcium excretion

**Core Concept:**

Fluoride (F-) is an essential element for human health and has been widely used in drinking water and toothpaste to prevent dental caries. When ingested, fluoride ions (F-) combine with hydrochloric acid (HCl) to form hydrofluoric acid (HF), which is the active form responsible for its effects on bone and tooth mineralization.

**Why the Correct Answer is Right:**

In this multiple-choice question, the correct answer (C) is "Increase in tooth erosion," because fluoride ions (F-) primarily affect tooth enamel by inhibiting the activity of enzymes involved in demineralization (e.g., enamel-degrading enzymes) without affecting the remineralization process. This leads to a decrease in tooth erosion.

**Why Each Wrong Option is Incorrect:**

A. Fluoride ions (F-) actually increase bone mineralization by enhancing the formation of hydroxyapatite crystals in bone tissue and teeth, making them more resistant to dissolution.

B. Fluoride ions (F-) inhibit the activity of enzymes involved in the resorption of bone and tooth tissues, resulting in a decrease in bone resorption.

D. Fluoride ions (F-) contribute to the formation of hydrofluoric acid (HF) which increases renal calcium excretion, thereby preventing the development of hypercalcemia and osteoporosis.

**Clinical Pearl:**

Fluoride therapy, when administered appropriately, can significantly reduce dental caries and increase bone density. However, overexposure to fluoride can lead to dental fluorosis (discoloration of teeth) and skeletal fluorosis (bone pain, deformity, and joint pain). When administering fluoride, it's crucial to consider the dose, duration, and route of administration to avoid these complications.