Ibn Abbas (Radiallahu anhu) says:
"The front teeth of Rasulullah (Sallallahu alaihe wasallam) were a bit wide (spread out). They were spaced out and not close together. When Rasulullah (Sallallahu alaihe wasallam) talked, an illumination emitting from his teeth could be seen." (ES)
English reference (ES): Book 1, Hadith 14 (ES)
Arabic reference (ES): Book 1, Hadith 15 (ES)