Enamel does not grow back. That single fact governs every decision here, and it turns the question at each tooth into an arithmetic one: how much tooth structure does this option take, and is there a smaller one that will still hold? The differences are not marginal. Preparing a front tooth for a full ceramic or metal-ceramic crown removes about 63 to 72 percent of its natural crown by weight, while bonded veneer preparations on the same teeth remove roughly 3 to 30 percent.[1] At the back of the mouth the same comparison runs from about 67 to 76 percent for a full crown, against roughly 5 to 27 percent for adhesive and inlay designs.[2]
So the sequence runs from the smallest upward. Can the tooth be watched rather than restored? If not, will a bonded filling do? If not, will a partial restoration covering only the damaged part and the cusp at risk do? A full crown is proposed when too little sound wall is left to carry anything smaller, and that is a finding shown to you on the images rather than a preference.
The same logic governs deep decay. The older habit was to keep cutting until every discoloured layer was gone, and the recurring consequence of that was an exposed nerve. A Cochrane review of deep lesions in permanent teeth found higher odds of failure after complete removal than after stepwise removal, an odds ratio of 2.06 with a 95 percent confidence interval of 1.34 to 3.17, where failure counted pulp exposure, root canal treatment, extraction and restorative complications together.[3] Stopping at the right layer is not leaving a job half done. It is the option the evidence supports.
And when the nerve is already inflamed, a root canal is no longer the only answer. A 2024 systematic review and meta-analysis of mature permanent teeth with irreversible pulpitis reported a pooled clinical success rate of 92.9 percent for pulpotomy beyond twenty-four months, with no significant difference from root canal treatment.[4] It does not suit every tooth, and the judgement is made once the tooth is open rather than before. But where it suits, the inside of the tooth stays alive.
What all of that means for you is simple enough. The smallest option is put on the table first, you are told why anything larger is being proposed, and the larger option stays available later if it turns out to be needed. The reverse is not available. What has been removed does not come back.