vertical crack lines on front tooth

i have 3 vertical crack lines that show up when i put a flashlight up to my teeth on one of my top front teeth. it doesnt hurt, but im scared. the lines go 1/3 up to the gum line. how much would this cost to fix if they are infact cracks and not craze lines? what method do they use to fix that?

[Jerome Tsang, DDS]

I would imagine they're craze lines so no treatment is necessary.  If it is indeed a crack, then they could do either bonding if its not deep or they can do a veneer/crown on it if the fracture is severe. But from what you say, my initial guess is that its a craze line