Anterior Crowns — The Ultimate Guide for Dentists

Anterior Crowns — The Ultimate Guide for Dentists image

Anterior crowns can be useful for repairing tooth damage and correcting cosmetic issues with a single solution.

Anterior dental crowns are an important tool in every dentist’s arsenal. From fixing tooth damage and correcting occlusal issues to achieving excellent cosmetic outcomes, anterior crowns can restore the look and function of your patients’ teeth.

“There’s quite a lot you can achieve with anterior crowns,” explains Dr Hitesh Gupta, Principal of The Smile Factory in Newcastle. “We’ve really changed the shape of people’s faces. In some cases, their teeth have been really worn down. We’ve increased the length of the teeth by quite a bit, and you can see their smile and soft tissue completely changing.”

But Dr Gupta says the benefits of anterior crowns extend beyond cosmetic outcomes. He explains that while veneers are perhaps the better choice for purely cosmetic treatments, anterior dental crowns can be used to fix tooth damage and structure, and address any occlusal issues the patient may be experiencing.

“It’s pretty common to see patients who have broken or worn down their teeth over the years,” he says. “We can use anterior crowns to restore the shape of their teeth and give them their own anatomy back. And if a patient has issues with their bite, we can often fix those issues by changing the shape of their front teeth. This enables us to fix the way they interact with their bottom teeth, which is one of the major reasons the teeth were broken in the first place.”

A word on material selection

Selecting the right material for anterior crowns is critical. Traditionally, dentists had a choice between anterior porcelain crowns or lithium disilicate (e.max). However, some dental labs have introduced an anterior zirconia crown option in recent years.

Avant, for example, offers Aidite 3D Pro Zir as a zirconia anterior crown option. We use a gradient layering manufacturing process to achieve a virtually chip-proof construction that’s approximately 10-times the strength of traditional layered ceramic and wears at about the same rate as natural enamel.

Dr Gupta says anterior zirconia crowns have been a hit with his patients: “Traditionally, we’ve had anterior porcelain crowns which look the prettiest, and e.max which is a newer, harder ceramic. But over the last couple of years, Avant has brought out an aesthetic zirconia which we’ve found patients love. It’s made our material selection decisions a lot easier. In my mind, this new zirconia is amazing.”

Dr Gupta explains that zirconia is also often easier to use because it can be used in thinner layers.

“About 90 per cent of the anterior crowns I do now are zirconia,” he says. “When we have to reduce a bit of tooth to make space for the crown, the thinner the material is the less reduction we have to do. You can use zirconia in thinner layers and still get a good aesthetic result, which is better for the patient.

“Anterior zirconia crown prep is also a much easier process than an anterior emax crown prep or anterior porcelain crown prep. With a traditional porcelain material, you have to prepare the porcelain in a certain way, and prepare the tooth in a certain way. There’s about three different chemicals we use to prepare the tooth. But anterior zirconia crowns are simpler with fewer steps and less chance for operator error. Even if you’re having a bad day, you know you’re going to get a good result with zirconia crowns.”

How material selection impacts colour matching

However, there are still times when Dr Gupta chooses to use anterior e.max crowns. This is predominately to do with colour matching. He says that while zirconia is particularly good in the cosmetic shades, he finds e.max is better for A2+ shades.

“There are two important considerations in terms of the colour,” Dr Gupta explains. “One is the hue, or density, of the colour, and the other is the translucency. You can have two things that are the same colour, but because one is more opaque and one is more clear, they look different even though the colour underneath is the same. That will guide us to which material to use.

“For example, older people tend to have more translucent teeth, so for that we need a material that allows the light to pass through more — that’s when I’d go for an anterior e.max crown.”

5-step workflow for anterior crowns

The Smile Factory uses a five-step workflow for anterior dental crowns. It begins with proper patient assessment, and includes a critical diagnostic wax-up trial that Dr Gupta never skips.

Step 1: Patient assessment

Like all dental treatments, the anterior crown workflow begins with proper patient assessment. Dr Gupta says it’s important to identify exactly what you want to achieve, and whether anterior dental crowns or veneers are the better option for the patient.

“Anterior crowns are a really good way of restoring teeth that have been broken down over the years. Whereas veneers are really good if you’re only changing how the front of the teeth look,” he explains. “When we’re trying to change the thickness of the back of the tooth or change the length of the tooth, a dental crown is more appropriate.”

However, even if a patient comes to you with what seems like a cosmetic issue, it’s important to identify the root cause of the issue in order to determine whether anterior dental crowns or veneers are the better treatment option.

“If a patient says ‘I don’t like my slightly crooked front teeth and don’t want to get braces’, and all you’re trying to change is the front surface of the tooth, then you’ll go for veneers,” Dr Gupta explains. “But if a patient comes in saying ‘my teeth are too short and I want them to look better’, it could be because they’ve been grinding their teeth away. In that case, we need to use a hard material — like a zirconia anterior crown — that can handle what they’re going to throw at it.”

Dr Ben Van Veenendaal , a Dentist at The Smile Factory agrees. He says it’s important to spend time ensuring that anterior crowns are definitely the best treatment option for the patient.

“Underlying issues must be addressed because everything we do is permanent,” he says. “Once we remove the tooth structure to put in a crown, it’s done. If the issue is purely cosmetic, I’d recommend orthodontic work first.”

Dr Gupta says to simply remember that anterior dental crowns are for fixing damaged or broken teeth, while veneers are best for correcting cosmetic issues with healthy teeth.

“Crowns are for fixing teeth that are broken, have holes, or old fillings that are breaking. If someone has a completely healthy tooth, and just doesn’t like how it sits in their mouth, they are not a good candidate for crowns.”

Step 2: Patient consultation

Once the patient has been identified as a good candidate for anterior crowns, Dr Van Veenendaal moves on to the consultation stage. He starts with some photos of the patient’s teeth and smile as a reference guide for a conversation with the patient.

“We want to show what’s happening in the patient’s mouth now,” he says. “Photos lets us talk to the patient about what bothers them about their smile, so we can get on the same page.”

Then digital scans are taken of the patients teeth, and a leaf gauge may be used to determine the length of the anterior crowns.

“If we’re trying to change their occlusion, we simulate the new length and thickness of their teeth with a leaf gauge,” explains Dr Gupta. “In that new position, we take another scan, and send it all off to Avant to make the diagnostic wax-up.”

Step 3: Anterior crown preparation

Avant’s technicians use the photos, scans and other notes provided by the dentist to design a diagnostic wax-up of the anterior crowns. This is essentially a resin model of the patient’s new anterior crowns, and Dr Gupta says it’s a critical step in the process.

“It’s a physical model that the patient can hold and move around, so it makes it easy to review the design with the patient,” he says. “The quality of Avant’s wax-up models is the best I’ve seen. In my opinion, it’s what pushes the patient over the edge. They can suddenly visualise how their teeth are going to look and the quality that is coming back from the lab.”

But before the diagnostic wax-up is fitted, the anterior crown prep must be completed. The patient is anesthetised, and broken teeth, holes, decay and old fillings are removed. The teeth may also need to be reduced to make room for the anterior crowns.

“The ceramic needs to be a certain thickness for it to work, so we need to reduce the tooth. Avant provides us with a clear template which we can put over the patient’s teeth,” says Dr Gupta. “We can visually see through the template to the patient’s natural teeth underneath. This allows us to see how much of the tooth we need to adjust.”

Step 4: Diagnostic wax-up

The diagnostic wax-up is then fitted over the patient’s existing teeth, so the patient can see exactly how their new anterior crowns will look. At The Smile Factory, Dr Gupta and Dr Van Veenendaal send their patients home for three days with the temporary wax-up in place.

“The wax-up gives the patient an idea of the new tooth length and how the crowns will look and feel,” says Dr Van Veenendaal. “Often there will be a new occlusion and a new colour, so the patient gets some time to ensure they are comfortable.”

Dr Gupta says the wax-up trial should never be skipped. He believes it’s one of the key reasons why he hasn’t been asked to do a single re-do out of the 300 to 400 anterior crown treatments he’s provided since implementing the wax-up trial.

“In my experience, usually when you put the wax-up in, the patient is a bit shocked. They often think it’s too big, or it’s too white. The patient goes home, shows their partner and their friends, and has some time to live with it. Then, in the vast majority of cases, by the time the patient comes back in, they are in love with the wax-up.”

In the rare case a patient does want a change made to the wax-up, Dr Gupta says he can quickly do so without sending the wax-up back to the lab.

“It’s made of resin, so if a patient wants one of the teeth slightly rounded, we can do that while they are in the chair. Or if they’re finding that the bite doesn’t feel even, we can make it thicker on one side,” he explains.

Once any adjustments are made to the wax-up, another digital scan is taken of the adjusted wax-up and sent back to Avant.

“Avant makes the crown exactly in the shape of that wax-up,” says Dr Gupta. “As a result, none of our patients has ever been unhappy with the final outcome because they know what they are getting. It’s not a surprise to them. They’ve shown everyone, and they’ve come back and consented that this is the shape and colour they want. It’s a critical step in the process.”

Step 5: Final crowns are fitted

Dr Gupta approves the design of the permanent crowns before manufacture begins, and the patient keeps the wax-up in for about two weeks leading up to the final fitting.

“When the patient comes back in, it’s a simple process of taking off the temporaries and putting the permanent ones on,” says Dr Gupta.

Dr Gupta explains that two key factors tend to determine the ease of the final fitting — the hygiene of the patient, and the accuracy of the crowns.

“The patient has had the temporary wax-up in, and we leave a little gap at the gum they can clean through. If they’ve done that and their gums are quite healthy, it’s quite easy for us to put the crowns in.

“It also depends on your lab. If you’ve taken a good scan and the lab has made quality crowns, then they should go in quite easily. I’ve found zirconia usually provides a particularly accurate fit.”

Following the final fitting, patients are brought back a week later for a post treatment check-up and, in most cases, to have occlusal splints fitted.

“If there was damage to the tooth, there’s something that’s caused it, so you’ve got to prevent that from happening in the future. So most patients who have anterior crowns will need splints,” says Dr Gupta. “Then they should be coming back every six months for recall checkups. We’re checking the margins of the crowns — which is the weakest area — and we’re making sure no bacteria has leaked in, that they’re flossing, and their gums are healthy.”

Dr Gupta and Dr Van Veenendaal agree that communication through the early stages of the process is critical. It’s also vital not to skip any steps — particularly the diagnostic wax-up.

“The only times I’ve had problems is when patients have rushed me to get a result,” says Dr Van Veenendaal. “They’ll want it done in two weeks, so we’re rushing and not following the process as we normally would.”

“Never skip the wax-up, no matter how much pressure the patient is putting on to get it done in a shorter time frame,” Dr Gupta agrees. “Since we’ve implemented this process and have been using the high quality wax-up from Avant, re-dos have gone out the window. I can’t remember the last time a patient wasn’t happy with the end result.”

Want to find out more about partnering with Avant for all your anterior crown needs? Please email [email protected]
or phone 1800 287 336.

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