I'm 22. At 13, I had root canal on right front tooth after infection (tooth had been previously damaged from an accident so had prior reconstruction). Because my teeth weren't straight, that tooth was rebuilt shorter to look even. Now that my teeth are straightened, that tooth looks shorter. Also, the tooth is darker than the others since the treatment. I've been given several options: Internal bleaching and bonding; veneer; or crown (porcelain-metal composite). Which option is favourable?