Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates that there was a slight gap between the two front teeth of the Messenger of Allah (peace and blessings be upon him). When he ((peace and blessings be upon him)) spoke, something like light could be seen shining between those teeth.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12129