How to make canine substitution better? Will teeth bonding fix the problem?

This simple answer is yes, bonding composite or porcelain to the canines can help mask your missing Lateral Incisors, but a Canine will NEVER be mistaken for a Lateral Incisor. The problem here is that a Canine tooth is widest as it emerges from the gumline. The Lateral on the otherhand is the narrowest tooth at the gumline and gets wider as you move toward the biting edge of the tooth. We call this the emergence profile. Canines and laterals could not be more different in that regard. This leads the newly restored canines to be MUCH wider than a natural Lateral Incisor would be. Beauty is about symmetry and proportion. The proportion between the Central and Lateral Incisors will be off when trying to convert canines in this situation. The Central Incisors need to be the dominant teeth in the smile. What you will have as a result of the conversion will be 4 roughly equal incisors. It may look Ok, but it will never look 100% right. A skilled cosmetic dentist working closely with the orthodontist may have prevented this situation, but now you are looking at a compromise. 

Hello,This can easily be done by bonding ,or a porcelain veneer. Bonding can  be considered initially, however over time they will discolor, or need to be repaired. Please consult with a experienced cosmetic dentist as doing a single porcelain veneer will need custom shade matching.Dr. Mazaheri