They put stainless steel caps on 3 teeth of my 5 yo autistic son because we wanted no metal. will this leak?

Not sure of question: Stainless steel is highly resistant to a wide range of corrosive agents, so mouth acidity should not have an effect. It is iron with other compounds; so, even if there was some corrosion, which is extremely unlikely, it would not affect your child's health. Speak with your dentist for more details.

It depends: If he has pica ( craving & ingesting non-food items) & chews on hard or sticky objects, or has dental trauma, any crown can be jarred enough to allow entrance of bacteria. Stainless steel crowns are often used for deciduous teeth & don't impact their natural loss. Behavioral therapy, use of safe "chewies, " desensitization to toothbrushing, water only if he carries around a "sippy"cup also help.

Not likely: Stainless steel caps are strong and usually do not leak. However, the teeth can still abcess under the cap depending upon how badly decayed the tooth was before the dentist put the cap on the tooth. The goal is to save the tooth as long as possible to hold the space open for the developing permanent tooth. Stainless steel caps are very safe and have little to no complications.