How far is it possible for you drill a tooth down without crowning it?

Why Is it Drilled: It depends why the tooth is being drilled. If the bite is off, an adjustment of the tooth usually takes off a small fraction of a millimeter of the enamel outer coating. Small areas of decay can be drilled out & a simple filling placed. When decay is deep, the tooth is fracture or more and 1/2 to 2/3 of the tooth needs restoring then a crown is needed.

Difficult to say...: It depends on which part of the tooth is missing (due to drilling, decay, fracture, etc) and the circumstances. If a part of the tooth is a part required to support a filling, then a crown will be required. If you have concerns with your how much your dentist is drilling, get a second opinion.If anything this will either reinforce what your dentist has been doing or you find out alternatives.

Crown: A crown is recommended when there is not sufficient tooth structure remaining for predictable function. So when there are cracks or a large part of the tooth is missing a crown will protect the rest of the tooth from fracture.

Depends: Depends on what's wrong with crown of tooth or the tooth's function. When you drill, tooth structure is removed. Simple bite adjustment may remove a minuscule amount of tooth material, not requiring restoration. If tooth is fractured, badly decayed, or infected, large amount of tooth material may need to be removed requiring a cap. And there can be anything in between. See Dentist for evaluation.