Which fluoride is contraindicated for use with porcelain restorations?

Acidulated phosphate fluoride is contraindicated for use with porcelain restorations primarily due to its acidic pH. This acid can etch or damage the surface of porcelain, which is a common material used in dental restorations. Porcelain has a glass-like composition that can be adversely affected by acidic environments, leading to a breakdown of the material or diminishing its aesthetic qualities.

In contrast, other types of fluoride, such as stannous fluoride, neutral sodium fluoride, and sodium fluoride varnish, do not have the same acidic properties and therefore are safer options for use around porcelain restorations. Stannous fluoride and neutral sodium fluoride are pH neutral and do not pose a risk of etching or damaging such surfaces. Sodium fluoride varnish is also formulated to be safe for various dental materials, making it an appropriate choice when treating patients with porcelain restorations.