Final answer:
True. There have been incidences of acute or chronic fluoride toxicity using fluoride varnish documented.
Step-by-step explanation:
**True**. There have been incidences of acute or chronic fluoride toxicity using fluoride varnish documented. Fluoride varnish is a dental treatment that is applied to the teeth to prevent cavities. While it is generally considered safe when used according to guidelines, excessive or improper use can lead to fluoride toxicity.
For example, a study published in the British Dental Journal reported on a case of acute fluoride toxicity in a child after the application of fluoride varnish. The child experienced symptoms such as nausea, vomiting, and abdominal pain.
It's important to note that such incidences are rare when fluoride varnish is used correctly. However, it is essential to follow the recommended guidelines and consult with a healthcare professional if any adverse effects are experienced.