Actually, the rules/regulations are very clear on this issue. Dental instruments and especially the handpieces are always sterilized between patients. Things that aren't sterilized are disposable.
The process goes like this......finish the procedure and the assistant debrides the instruments by hand and replaced in the sterilization cassette. That cassette is then placed in an ultrasonic cleaner which has a solution specifically designed to aid in removing the bio burden. Once this cassette comes out of the ultrasonic, it's then wrapped for sterization with a indicator in the middle of the pack which confirms the unit has been sterilized. Packaging will also have either indicators printed on the package which will change color once exposed to the sterilizer heat or the wrap will be sealed with an indicator tape which changes colors. After proper packaging/wrapping, the kits are then placed in an autoclave. There are several types but the most popular are steam autoclaves. After the kit comes out of the autoclave, it's properly stored for the next patient/procedure. If the packaging gets wet or somehow perforated, it's no longer considered "sterile" and must be reprocessed.
Most of the modern, high tech practices use the Lisa autoclave which uses medical grade type B cycles. It's a phenomenal unit but costly as heck. Worth it as it dries much better than the old style autoclaves which really helps preserve that high tech practices electric handpiece inventory.
Most practices that are on the cutting edge will also have a Statim. Hygienists love it as the cycle times are much shorter.
Also, another thing to give you peace of mind is that offices will have their autoclaves tested using a monitoring service. Of course, those high tech guys have their own spore tests and incubators in the office while those less modern guys mail theirs out.
If the unit kills those spores, it kills any and everything you could worry about.....everything. Should the test come back positive, the dentist will pull every kit sterilized since the last negative test and re-wrap and re-sterilize using a replacement autoclave. Many of the high tech guys have one on standby for just such an incident.
In short, find yourself a progressive office that's on the cutting edge of technology. Ask to see their sterilization area. Most quality practices will absolutely LOVE the opportunity to "show off". Just once, I'd love to see folks who complain about the cost of dental care sit down and go through the overhead numbers and spend a couple of weeks trying to digest CDC guidelines(which are mandatory btw) and the OSHA regs. It would put things in an ENTIRELY different light.
