from your question, I assume that you're referring to getting Porcelain Veneers in a Smile Makeover procedure.
Filing your teeth down is an irreversible procedure and should not be taken lightly. I am glad you did your homework to understand the issues and steps involved.
I understand how your front teeth are affecting you. If done properly, removing the surface layer of the teeth by 0.5-1mm should not result in permanent sensitivity. It should be transitional, lasting up to a 3 months in rare cases. These are very technical procedures that requires a very experienced dental team.
Decay will only occur when there're gaps in between your teeth or that you practice poor dental hygiene. It will not be caused by the porcelain veneers directly.
In order to minimise the amount of filling, I usually encourage my patients to align their teeth first so that they are not too crooked. If you use veneers to straighten crooked teeth, we would have to trim a lot of the tooth/teeth. Sometimes, this causes the tooth/teeth to lose its vitality. When this happens, a root canal treatment may be required.
Personally, I would strongly advise my patients to consider aligning their teeth first before doing porcelain veneers. Sometimes, after aligning the teeth, porcelain veneers may not be needed anymore because they're already satisfied with their smile. And if veneers are still needed, they can be done in a minimally invasive manner. That keeps all the trimming within the safe first layer of the teeth. I hope this helps!
