The Reason Why Dentistry Expensive
Most practices will have at least three staff looking after a single patient. The dentist, a dental chairside assistant (DCA), and a receptionist. That's three wages to pay. It is near on impossible for a dentist to work without a DCA, and inconvenient to have to stop working on a patient to answer the phone. Large practices will often have multiple reception staff, a few dental hygienists/therapists, at least one DCA for every dentist, and a dedicated assistant just for sterilisation of instruments.
A dental practice basically contains a small operating theatre. The dental chair alone will cost from $30,000 upwards. You then need a setup for the drills and scalers, a compressor to run them, a bright overhead light, a suction unit, radiographic (x-ray) equipment. Other optional fancy machines like lasers, air abrasion units, and CAD/CAM machines easily run into the hundreds of thousands.
Keeping things clean costs an awful lot as well. The sterilisation of instruments requires the practice have an ultrasonic bath and an autoclave at bare minimum. There are specialised machines available for cleaning and lubrication of drills. Yep, the good old dental drill is pricey enough to warrant its own cleaning system, and each dental practice requires a bunch of drills so they can be clean for each patient.
Next time you visit the dentist you may also notice the amount of disposable items that are used to stop infection spreading from patient to patient. Plastic covers, disposable suction tips etc. I once heard the rough figure quoted of $30 per patient just on infection control. That's just for a patient to sit in the chair before any procedures have been done and any other materials used.
Suppliers of dental materials put a lot of research and development into their products, and they also know they have a niche market to supply to. Filling materials, adhesives, etchant, polishing paste, burs (drill-bits), impression materials… the list goes on.
They all cost money, and like any other product, you pay for better quality. Yes, there are filling materials on the market that are less advanced, meet Australian standards but may not be the best of the best, and so cost less than their more expensive competitors. There's a good chance that if your dentist charges at the upper end of the scale, they are using top quality materials.