Getting a Crown, Appointment by Appointment: What Actually Happens

Most people agree to a crown without much idea of what the appointments involve, which is a shame, because the sequence is straightforward and knowing it removes almost all of the worry. It also explains why we do certain things in a certain order, and why some of those steps are not negotiable here.

A crown at Whitehorse Dental takes two appointments about two weeks apart, plus the assessment beforehand. We do not do same-day crowns. That is a deliberate choice: the restoration is made in a dental laboratory by a technician, and the extra fortnight buys a level of fit and finish that a chairside milling unit does not match on the cases we tend to be crowning.

Here is the whole thing, in order.

Before anything: the assessment, and the order of operations

The crown is not the first thing that happens. First we work out whether the tooth needs one at all, and whether anything has to happen before it.

We examine the tooth, take a bitewing and often an OPG, look at the crack or the failing filling under the intraoral camera, and check your bite. If the gums around that tooth bleed on probing, we chart the pockets and treat the gum disease before we touch the tooth. This is the step most often skipped elsewhere and it is the one that decides how long the crown lasts. A crown margin sits at the gum line. If that tissue is inflamed, it bleeds during the preparation, contaminates the field at the moment we are trying to bond, and swells or recedes afterwards so the margin ends up in the wrong place. Healthy gums first, restoration second, always in that order.

Two other things get decided before the tooth is prepared.

If you are planning to whiten, whiten first. A crown’s colour is fixed by the laboratory and it does not respond to bleach afterwards. Whiten first, let the shade settle for a couple of weeks, then match the crown to the teeth you have ended up with. Our take-home kits are Opalescence, and a custom kit is $199. Do it the other way around and you get a crown that no longer matches the tooth beside it.

If you grind, we talk about a splint now. Not as an upsell after the crown chips, but as part of the same plan.

Appointment one: preparing the tooth

Allow around an hour and a half. Numbing comes first, and it is thorough. If dental anaesthetic has not worked well for you in the past, tell us before we start rather than during, because there are several ways around it.

Shade first, before anything else. We take the colour at the beginning of the appointment, before the tooth dries out. Teeth become noticeably lighter and more opaque as they dehydrate under isolation, so a shade taken at the end of an appointment is a shade taken from a tooth that is not its normal colour. This is a small thing that causes a lot of crowns to come back looking wrong.

Removing what is failing. The old filling comes out, along with any decay, and only then can I see what I am actually working with. Occasionally what looks like a straightforward crown turns into a conversation about a core build-up or a root canal, because the crack runs deeper than the X-ray suggested. If that happens, we stop and discuss it rather than pressing on.

The core build-up, under rubber dam. If a lot of the tooth is gone, we rebuild a foundation in composite for the crown to sit on. This gets done under rubber dam. A build-up is a bonded restoration, and the bond is only as good as the dryness of the field. Saliva on an etched surface for a couple of seconds is enough to compromise it. The rubber dam is not for your comfort, though most people find it more comfortable than they expect; it is there because it is the only reliable way to keep the tooth dry.

Shaping the tooth. The tooth gets reduced by roughly a millimetre or two on each surface, which is the space the crown has to occupy. Different materials need different amounts, which is one of the reasons the material choice matters clinically and not just cosmetically. Zirconia can be made thinner than porcelain-fused-to-metal. Gold thinner again, which is why a gold crown removes the least tooth of any option we offer.

The margin. Where the edge of the crown finishes is the single most important line in the whole procedure. Wherever the tooth allows it, I keep that margin at or above the gum, because a margin you can see is a margin you can clean and a margin I can inspect at every check-up. Margins hidden deep under the gum are harder to clean, harder to bond, and are where cement gets left behind.

Scanning, not impressions. We use a Medit intraoral scanner. A small wand goes over the teeth and builds the model on the screen. There is no tray of setting material, nothing to hold still and breathe through, and nothing that triggers a gag reflex. We scan the prepared tooth, the opposing teeth and your bite. If you have historically dreaded impressions, this is the part of modern crown work that has changed most.

The temporary. You leave with a temporary crown cemented on. It is there to protect the prepared tooth, stop it drifting, keep the gum shaped correctly and let you chew and smile normally in the meantime. Treat it gently, avoid anything sticky on that side, and floss by pulling the floss out sideways rather than snapping it up. If the temporary comes off, ring us; it is a quick fix and not something to leave for a fortnight.

In between: what the laboratory does

Your scan goes to a dental technician who builds the crown to the design we specified: material, shade, contact points with the neighbouring teeth, and how it meets the opposing tooth. This is skilled handwork and it is where the aesthetics of a front crown are actually won or lost. For a front tooth we will sometimes send photographs alongside the scan, and for more complex cases design the shape digitally and try it in your mouth as a mock-up before committing.

The material was chosen at the planning stage:

e.max (lithium disilicate) for front teeth and premolars, and for onlays. It bonds adhesively to the tooth, which means the restoration and the tooth support each other, and it is the most natural-looking of the tooth-coloured options.
Zirconia where strength matters most, typically molars and heavy grinders. Very difficult to break. Slightly less lifelike than e.max, though modern translucent versions have narrowed the gap.
Gold for lower back teeth in people who do not mind the colour. It needs the least tooth removed, wears at a rate close to natural enamel so it is kind to the opposing tooth, and the marginal fit is the best of any material.
Porcelain fused to metal where a specific case calls for it, usually as part of a bridge.

Appointment two: fitting it

Around an hour, two weeks later.

Off comes the temporary, and the prepared tooth gets cleaned properly. This is where air abrasion comes in. A fine stream of aluminium oxide particles is directed at the prepared surface to strip off temporary cement residue and the smear layer left by the drill. It sounds like a detail. It is not. Bonding to a surface with temporary cement residue on it produces a substantially weaker bond than bonding to a freshly abraded one, and residual cement is invisible to the eye. We air-abrade the fitting surface of the crown as well where the material calls for it.

Try-in before cementation. The crown goes on unbonded and we check four things: that it seats fully, that the margins are sealed all the way round (checked with a probe and with floss), that the contacts with the neighbouring teeth are correct, and that it looks right. If anything is off, it goes back to the laboratory. A crown that is not right does not get cemented because it is inconvenient to send it back.

The bite. Articulating paper, and not just tapping straight up and down. I check the tooth in side-to-side and forward movements as well, because a crown that is fine in a straight bite but catches when you slide sideways is a crown that will chip, or crack the tooth beneath it. Complex bite problems are the part of dentistry I find most interesting, and this is where that pays off for the patient.

Cementing or bonding. Isolation again, moisture control again, then the crown is either adhesively bonded (e.max) or cemented (zirconia, gold, PFM) depending on the material and how much retention the preparation gives.

Cleaning out the excess. Every trace of cement has to come out from around the margin, including from between the teeth. Cement left under the gum is one of the more common causes of chronic gum inflammation around an otherwise well-made crown, and it can go unnoticed for years. Floss goes through every contact before you get up.

Final bite check once the anaesthetic has worn off enough for you to feel it. And a standing instruction: if it feels high over the next few days, come back. Do not wait it out. A high crown makes the tooth ache, then the muscles ache, and left long enough it can crack the tooth.

If you find dental appointments difficult

The preparation appointment is the longer one, and it is the one people are most likely to be anxious about. There is a ceiling TV above the chair, so you can pick a show and watch it through the whole thing, or bring your own music. Happy gas is available, and oral anti-anxiety premedication if you would prefer that. Dr Annie Tong sees many of our more anxious patients and they tend to stay with her.

Tell us what specifically bothers you rather than just that you are nervous. Some people need everything slowed down and narrated. Others want no narration at all. Those are different problems with different solutions.

Practicalities

We are at 129A Canterbury Road, Blackburn, with on-site parking, and both Blackburn and Laburnum stations are a short walk. Wednesday and Friday we open at 8:00 if you want the preparation appointment done before work, and we run Saturday mornings from 9:00 to 1:00. Consultations and treatment discussions are available in Mandarin, Cantonese, Teochew and Shanghainese.

To book an assessment, call (03) 8838 8820 or book online.