Dental crowns on front teeth and molars can last between five and fifteen years, though some can get damaged within two months, while others can last 40 years or even a lifetime. This is a huge range because there are many factors involved, most of which depend on the dental hygiene and habits of the patient getting the crown, as well as the position and type of material used on the crown.
Dental crowns refer to tooth-shaped “caps” placed over teeth to restore their shape, size, and strength, and enhance their appearance. When cemented in place, crowns fully encase the whole portion of a tooth that is above the gum line.
But how long can a dental crown last? This will depend on the material it’s made from and its position/location in the mouth.
1. Metal crowns
These caps are made from an all-metal alloy that may include palladium or gold, or a base-metal alloy like nickel or chromium. They are very strong and durable, but are not aesthetically pleasing. So, they are mostly used at the back of the mouth.
All-metal crowns are typically used for applications that require great strength without necessarily being interested in aesthetic appeal.
Advantages of metal crowns
- Great strength – it is extremely rare to see a metal crown break
- Excellent durability – does not break or fracture under stress, providing you lasting service
- Good biocompatibility – does not cause extreme wear on dental restorations or opposing teeth
- Superior fit – the crown-to-tooth fit construction is very accurate compared to other materials
- Minimal tooth reduction – fairly less tooth grinding is necessary for all-metal crowns as compared to the other materials
Disadvantages of all-metal crowns
- Absence of tooth color – the crown maintains its metallic look
- Likely to irritate sensitive teeth – metal conducts heat and cold
- High cost – requires laboratory services and a minimum of two office visits
2. Gold crowns
The caps are made of cast gold, and have been in use for more than a century. Gold crowns are the most successful, and should last for decades. In some cases, they can last for more than 50 years. Gold crowns are unmatched in terms of minimal wear to opposing teeth and long-term service. However, they may ultimately fail due to wear of the metal through to the underlying tooth structure, and also because of recurrent caries or decay.
Characteristics of gold dental crowns include:
- Workability – the physical properties of gold make it very easy to work with, which increases the likelihood of attaining a precise crown fit.
- Strength – using metal through-and-through means that the crown can withstand chewing and biting forces very well. They do not chip or break, which makes them the most durable among all dental crown materials
- Compatible with enamel – while gold is very strong, its wear rate is similar to that of tooth enamel, which implies that a gold crown would not cause excessive wear on the opposing teeth.
One drawback for using metallic crowns is their unappealing colour, which is why they are mostly placed on the back teeth where they won’t be overly visible when the person smiles, like the molars.
3. All porcelain crowns
The combination of recent breakthroughs in adhesives with the development of stronger porcelain materials has allowed dentists to make crowns entirely out of porcelain.
All porcelain crowns are preferred by patients because of their aesthetics, allowing amazing real-life appearance. While they blend in well with natural teeth, they are characterized by brittleness, lack of strength, and their potential damage to opposing teeth against which they bite.
Basically, all dental porcelains are ceramics – glass variations fired in an oven at extremely high temperatures so the components can fuse together. Like glass, any damage to porcelain crowns is catastrophic and impossible to repair, which makes it hard to predict their longevity. That said, porcelain crowns are expected to last between 10 – 15 years, though it is not unusual for them to last up to 30 or more years.
All-porcelain crowns are characterized by a transparency that makes them hard to distinguish from natural teeth. Since there’s no metal used, there is no dark line at the edge of the gums, as is the case with PFM crowns. As such, the edge of the crown can be easily placed above the gum-line, which is also healthier for your teeth and gums.
Porcelain crowns are typically used in cases where the tooth’s aesthetics is a key factor, like for the front teeth.
Advantages of all-porcelain crowns
- Outstanding aesthetics – provide a lifelike appearance for cosmetic purposes
- Good biocompatibility – they have the same abrasive properties as dental enamel, which means that it will not wear opposing teeth and dental restorations
- Accurate fit – gives it good resistance to leakage and further decay
- Material does not cause tooth sensitivity
- Single-visit placement – for dentists with programmed milling units to grind the crown in 20-30 minutes
Disadvantages of all-porcelain crowns
- Longevity and durability issues – the brittle material can break under biting forces
- Milled ceramic crowns do not look as natural as the hand-constructed ones
4. Porcelain-fused-to-metal (PFM) crowns
They are fairly esthetic restorations that combine the properties of metal crowns (gold or platinum) and porcelain. PFM crowns are strong, fit precisely, and are bonded to the tooth, eliminating the brittleness of porcelain. They have a functional longevity of 20 years, or so, though they tend to seriously abrade opposing teeth, resulting in undue wear.
Advantages of PFM crowns
- Greater strength – offer long-lasting service
- Precise fit – offers a more exact fit compared to all-ceramic
- Good resistance to leakage and further decay
Disadvantages of PFM crowns
- Likely to wear down opposing teeth
- Porcelain may fracture or get separated from its underlying metal substructure
- More tooth may have to be reduced
5. Temporary crowns
These are short-term caps made in the dentist’s office (permanent crowns are manufactured in a dental laboratory). They are fabricated from stainless steel or acrylic, and are meant to be eventually replaced with a permanent crown.
Frequently Asked Questions
Crowns are permanent restorations, though most insurance companies accept to pay for crown replacements after 5-8 years, which implies that a well-made crown should last at least this long, regardless of the type of material used for fabrication. Most crowns last for more than 10 years.
Some factors that may reduce the durability of your crown include:
- Poor dental hygiene
- Grinding your teeth / clenching your jaws
- Eating hard, chewy, and sticky foods
- Skipping dental exams and professional cleanings
Dental crowns can be used to strengthen a tooth after root canal therapy, which can in turn significantly increase the durability of the tooth to between 11 and 20 years, especially if the tooth gets both a filling and a crown. If the dental crown was fabricated to the highest standards, correctly fitted to your bite, and properly cared for, it should last for decades or even your lifetime.
All porcelain crowns are not only attractive and natural looking, blending seamlessly with your smile, but also extremely durable with a lifespan of 10 to 15 years or more depending on factors discussed above, giving you the dual benefits of aesthetics and function.
Crown replacement can be done multiple times provided the crown and tooth are in good condition. In the event that decay forms under the tooth cap, then the tooth only needs to be treated and a new crown made to restore the tooth. That said, it is unusual for a crown to fail on its own, since gold and porcelain do not decay. However, crown failure may occur due to poor hygiene. In fact, the most common cause of crown failure is decay under poorly maintained crowns.
Bad habits, like removing bottle caps and biting finger nails can also compromise the integrity of crowns.