The objective of this article was to present two nonodontogenic conditions that may mimic odontogenic toothache: trigeminal neuralgia and burning mouth syndrome. Two cases are presented in which one is related to the upper left second premolar and the other is related to the upper left first molar. Both showed pain when chewing. These two cases highlight the complexities involved in diagnosing nonodontogenic toothache. This article demonstrates the importance of having a thorough knowledge of both odontogenic and nonodontogenic toothache, as well as the need for careful evaluation of the nature of the pain and history, clinical and radiographic examinations.

When we use the total-etch dentin adhesive system for composite resin restorations, gel or liquid acid etchant such as 37% phosphoric acid is commonly used. Thirty seven percentage phosphoric acid is very powerful erosive agent, and can cause severe harmful effects when it contacts with an oral mucosa and facial skin.

This case describes iatrogenic chemical burn on facial skin caused by phosphoric acid which was happened during composite resin restorative procedure.

Chemical burn by acid etchant can be evoked by careless handling of remnant and syringe. In order to prevent these iatrogenic injuries, we should check the complete removal of the etching agent both in intra and extra-oral environments after etching and rinsing procedure and it is necessary to use of the rubber dam or isolation instruments.

If accidental burn were occurred, immediate wash with copious water. And bring the patient to the dermatologist as soon as possible.