The words dental, dentil sound the same but have different meanings and spellings. Why do dental, dentil sound the same even though they are completely different words?
The answer is simple: dental, dentil are homophones of the English language.
Of, relating to, or for the teeth: dental caps.
Of, relating to, or intended for dentistry: dental work; dental bills.
Linguistics Articulated with the tip of the tongue near or against the upper front teeth: the English dental consonants t and d.
Linguistics A dental consonant.
Architecture One of a series of small rectangular blocks projecting like teeth from a molding or beneath a cornice.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.