Successful crown and bridge restorations rely on careful material selection and clear communication with the lab.
About the Guest Author
Dr Tran is a University of Sydney graduate with advanced training in orthodontics and cosmetic dentistry. He is also completing his diploma in Advanced Restorative and Aesthetic Dentistry through GDR. He is a member of both the Australian Dental Association and the International College of Oral Implantologists.
Material selection is one of the most important decisions in crown and bridge treatment planning, but it remains one of the most common causes of redos.
Inadequate strength, poor aesthetics, bonding failures, or excessive adjustment time are all frequent consequences of choosing the wrong material for the case. And while digital tools have made fabrication more consistent, the material selection matters – particularly when prep depth, stump colour, or load-bearing forces aren’t ideal.
So getting the restoration right begins with choosing the right material. But as Sydney-based general dentist Dr James Tran explains, many clinicians still fall into the habit of defaulting to a familiar material choice without checking whether it fits the case.
The problem often isn’t the material itself. Rather, it’s the mismatch between its requirements and the clinical reality that can result in a weak restoration, a rushed mid-treatment switch, or unnecessary chair time.
Another overlooked issue, says Dr Tran, is shade matching. This is particularly difficult when trying to match new crowns to older work, he explains.
“If the patient has a discoloured stump or an old metal-based crown, it can be really hard to get the shade right.”
Matching past restorations: The challenge of mixed-material cases
One of the more complex challenges in crown and bridge work is matching a new restoration to a patient’s existing dental work, especially when the original material is unknown or no longer available.
“It makes things much easier when you know what material the previous dentist used,” says Dr Tran. “Even better if you know which lab made it and exactly what the crown was milled from.”
But in many cases, patients don’t have access to those details, and dentists are left trying to match colour, translucency, and shape with limited information. Dr Tran says this is particularly difficult with older porcelain fused to metal (PFM) crowns.
“If a patient has an old metal ceramic crown or PFM, it’s pretty difficult,” he says. “Not many labs do those anymore, and most patients don’t want metal inside their crown. They want something pure white.”
In these situations, shade matching becomes less about replicating the exact material and more about understanding how to manipulate modern options to approximate the appearance. This may involve choosing a base material like zirconia or e.max, and relying on staining and glazing to match tone and translucency.
“If you’re working with a good lab, they can stain and glaze the restoration to match the adjacent teeth,” says Dr Tran.
He also notes that even subtle changes to the base material can help. Some labs may start with a greyish zirconia or add characterisation to simulate older restorations. But this relies on close communication from the start.
“The best thing you can do is talk to the lab about what they’re capable of,” he says. “Every lab is different.”
Understanding zirconia; Strengths, weaknesses, and evolution
Zirconia remains one of the most widely used materials in crown and bridge work, and Dr James Tran says that’s not without reason. It offers excellent strength, can tolerate thinner prep dimensions, and is well suited to posterior restorations under high load.
“Zirconia is extremely popular now,” he says. “It’s probably the most common material used for crowns and long span bridges. It’s more forgiving when the prep is shallow, and the strength is excellent.”
While strength is one of zirconia’s main advantages, Dr Tran explains that it can also be one of its limitations. He notes that zirconia can be too strong in some cases, which may result in wear on the opposing dentition if it has been glazed instead of polished.And depending on the type of zirconia used, it may not provide the level of translucency needed for anterior cases.
“Sometimes it’s too strong when glazed, especially if the patient is already grinding,” he says. “You’re putting a very hard material in, and aesthetically, it may not perform as well as e.max.”
He also points out that not all zirconia is created equal. There are now multiple generations of zirconia on the market, and each one balances strength and translucency differently. Some newer multilayer formulations offer improved aesthetics but may still not get the ideal result
“We now have high-translucency zirconia, which looks better, but may not be as strong. So it depends on the case.”
The e.max effect: Aesthetic performance and preparation
Lithium disilicate materials like e.max are often the go-to for aesthetic cases. But as Dr Tran explains, dentists need to be careful not to overuse them or expect them to compensate for dark stumps every time.
“e.max works really well in aesthetic areas,” he says. “Especially when the tooth underneath is nice and white. But if the veneer prep isn’t done properly and too much enamel is removed, the strength drops off. That’s when you’ll need to switch to a crown prep for retention. .”
He notes that while some clinicians prefer to default to e.max for its appearance, this only works if the prep depth is sufficient and the underlying tooth colour supports it due to the thicker material requirements of e.max.
The success of e.max depends heavily on how well the case is prepared. Prep depth is especially critical. If the reduction is too shallow, the material may not be thick enough to mask the underlying stump colour, particularly in darker teeth or when matching adjacent work. That compromises both aesthetics and strength.
“If the prep is too shallow and the material is too thin, you won’t get the strength or coverage,” Dr Tran says. “In those cases, zirconia becomes the fallback.”
Isolation and bonding conditions also matter. e.max performs well when cleanly bonded in ideal conditions, but failure risk increases with contaminated fields or short, heavily restored teeth. These cases may be better suited to zirconia crowns and luting. And because ceramics are less forgiving of shade mismatches, clear prep photos and stump shade communication to the lab are essential.
“Bonding to to enamel is a real strength of dilithium silicates such as e.max,” says Dr Tran. “If the lab gives you a good restoration and you’ve got clean isolation, it’ll bond really well. That makes it a good choice. But if the prep is compromised or you can’t bond properly, zirconia crowns are usually safer.”
Hybrid ceramics on the rise: A flexible alternative for single units
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Hybrid ceramics promise to combine the best of both worlds. They offer ceramic-like aesthetics with resin-like flexibility.
Hybrid ceramics are also typically easier to mill and adjust, and they are gentler on opposing enamel. Because they cut more like composite, they are often easier to polish and handle chairside. But this does not remove the need for precision. The margin still needs to be clearly defined. If it is not, the fit can be poor.
Dr Tran says there are limits to where hybrid ceramics are appropriate. He sees them mostly used for single unit posterior crowns, and budget veneer cases.
“They are mostly chosen for single onlays,” he says. “I’ve seen hybrid ceramics used for one or two units at most, not for larger or more complex cases for posteriors. The future of hybrids will be for veneer cases where the patient can’t afford full ceramic but still want lab made detail.”
Although hybrid ceramics may be slightly more forgiving in cases with minor undercuts or uneven preps, they may not be as suitable for short preps or areas of high occlusal load posteriorly. Their lower strength makes them better suited for conservative preparations in non-load-bearing areas such as veneers.
Another key factor is bonding. While hybrid ceramics are easier to work with, they still rely on clean and dry bonding conditions. Contaminated preps can lead to bond failure, which limits their reliability in more complex cases.
“For me, I still prefer zirconia or e.max,” says Dr Tran. “Hybrid ceramics can be useful in the right situation, but I want to see more long-term data before I make hybrid ceramics my first choice.”
PFM crowns: Proven, predictable, and still relevant
PFM crowns continue to deliver consistent, high-quality results. For Dr Tran, they remain a dependable option in the right clinical situations.
“PFMs are incredibly reliable,” he says. “They have been used for decades, and their outcomes are very predictable.”
Their metal substructure gives them strength and durability in the case that we can make thin metal occlusion. That makes them ideal in cases with heavy functional load. PFMs are also well suited to second molars or bruxism cases where metal occlusion can be made as thin as 0.4mm and aesthetics are not the main concern.
PFMs are more forgiving than many modern materials and tend to seat more predictably when the prep taper or path is not ideal. That margin for error can be useful in complex or compromised cases.
That said, PFMs still benefit from clean, well-defined margins. A clear shoulder or chamfer supports the porcelain and reduces the risk of fracture. Tissue control remains important to ensure a dry field and an accurate fit.
“They might not be the most aesthetic option, but they function well,” adds Dr Tran. “Especially for second molars where appearance is not a priority.”
While patient preferences have shifted towards metal-free options, when dentists explain the structural benefits, PFMs are often viewed more favourably.
“If the prep is less than ideal or you are concerned about strength, PFMs are often the safer and more reliable option,” Dr Tran notes.
Full metal crowns: Minimal prep and maximum durability
While full metal crowns may no longer be the go-to for some dentists, Dr Tran says there are still situations where they remain the best choice.
“If the patient is a heavy grinder or there is very limited space, full metal is still a great option,” he says. “You get strength, you get reliability, and you do not have to reduce as much.”
These cases often include second molars or function-first situations where aesthetics are not the priority. Minimal occlusal reduction can be as thin as 0.4mm, which can be a major advantage when space is limited. Less aggressive reduction also means more natural tooth structure is preserved.
Full metal crowns are also more forgiving from a technical perspective. They also adapt well in cases with restricted space or tilted teeth, where other materials might struggle, and can be seated reliably when access is limited or the prep angle is less than ideal.
“You can still get a good fit, even if the taper is not perfect,” says Dr Tran. “That gives you more margin for error in tricky situations.”
Dr Tran notes that patient communication is key. Explaining the benefits in terms of function, strength, and reduced chair time can help overcome aesthetic hesitation.
“If you explain that it will last longer and cause fewer problems, patients are usually fine with it. “I still use full metal when the situation calls for it and the patient just wants something that will last.”
Getting temporaries right: Why they matter more than you may think
Temporary crowns are more than placeholders. For Dr Tran, they are an essential part of the crown and bridge workflow. They give patients comfort and function, but they also protect the prep and help shape the final outcome.
“Provisionals are really important,” he says. “They allow the tooth and the gum to settle, and they give the patient a sense of what the final crown will feel like.”
Temporaries also give dentists an opportunity to refine the prep if needed. Poor margins or over-reduction may only become obvious after cementing the provisional. They also help assess occlusion, phonetics, and aesthetics before finalising the restoration.
“Sometimes you realise that the bite is off, or that the crown is a bit bulky,” Dr Tran explains. “That is your chance to adjust before the lab makes the final one. It might add more time to your appointment but it will save a lot of headache on insert.”
Material selection plays a key role in how well the temporary performs. Dr Tran previously used acrylic, but found it had limitations. “In the past I used acrylic for temps but they would often crack or stain, especially if the patient had to wear them for a while.”
He now prefers 3D-printed or milled provisionals, which offer better accuracy and longevity: “They are more accurate, they last longer, and the patients are happier with the look.”
In longer cases, the right material becomes even more important. “If you are waiting on a final crown for a few weeks, you do not want the temp falling off or changing shape. You can consider asking your lab for an interim PMMA temporary to hold for longer, especially for those veneer cases..”
Dr Tran adds that for bridges or long-term provisionals, strength is even more critical. “If it is a bridge or a long-term case, you have to make sure the temp is strong enough and retentive enough”.”
Treating the provisional as part of the case – not a temporary afterthought – helps prevent redos and supports a smoother final fit.
The final word: Fewer redoes start with better decisions
For Dr Tran, consistent crown and bridge outcomes come down to one key habit: stop defaulting to the same material every time.
“Just because e.max or zirconia worked well last time doesn’t mean it’s right for this case,” he says. “You have to work backwards from the clinical conditions and choose the material that will give the best result.”
That means taking into account prep reduction, stump shade, load-bearing position, and the patient’s expectations. It also means recognising that no material is perfect, but that each has strengths when used in the right situation.
“There’s no magic crown material. They all have pros and cons,” Dr Tran confirms. “Your job is to know them, and use them accordingly.”
Above all, Dr Tran encourages dentists to slow down, ask questions, and involve their lab in material selection.
“Crown and bridge isn’t about shortcuts,” he concludes. “It’s about understanding what you’re doing, and making decisions that hold up long term.”
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