When it comes to getting a cavity filled, patients often wonder which dental filling material is the strongest and will last the longest. With many types of fillings available, including metal amalgam, composite resin, porcelain, and gold, it can be difficult to know which is the best choice.
What are the Different Types of Dental Fillings?
There are four main types of dental fillings:
- Amalgam – Also known as “silver fillings,” amalgam is a mixture of metals including silver, tin, copper, and mercury. Amalgam fillings are strong, durable, and inexpensive.
- Composite Resin – Also known as “tooth-colored fillings,” composite resin is made from plastic and glass materials. It matches the color of natural teeth but is less durable than metal fillings.
- Porcelain – Porcelain fillings, also called ceramic, are made of porcelain and bonded to the tooth. Porcelain mimics the look of natural teeth but may not be as strong.
- Gold – Gold fillings involve gold being molded into place in the cavity. Gold is very durable but more expensive than other filling options.
How are the Strength and Durability of Fillings Measured?
When determining the strongest filling material, dentists look at two key factors – compressive strength and tensile strength. Compressive strength refers to how well the filling withstands chewing forces. Tensile strength measures how resistant the material is to cracking or fracturing. Fillings also need to hold up well to abrasion and corrosion over time.
In addition to lab testing, clinical studies observe how long fillings last before needing replacement. Longevity depends on proper placement by the dentist, good oral hygiene by the patient, and the durability of the material itself.
How Strong are Amalgam Fillings?
Amalgam fillings have high compressive strength, meaning they can withstand heavy biting forces. The various metals in amalgam bond together to form a strong, stable filling. However, amalgam scores lower in tensile strength, so it is more prone to cracking over time.
Clinical studies show amalgam fillings have an average lifespan of 10-15 years. With good placement and care, they may last 20 years or longer before needing replacement. Amalgam is resistant to abrasion and corrosion which contributes to its longevity.
How Strong are Composite Fillings?
Composite resin fillings have good compressive strength, though not quite as high as amalgam. Their tensile strength is also lower. However, modern composites are made from improved materials and can rival amalgam for durability.
Well-placed composite fillings can last 7-10 years on average. Their longevity depends on factors like location in the mouth and biting forces. They are more prone to staining and chipping over time if not cared for properly.
How Strong are Porcelain Fillings?
Porcelain has excellent compressive strength, surpassing both amalgam and composite. It can withstand heavy chewing forces without fracture or deformation. Porcelain also scores highly in tensile strength and resistance to abrasion.
Due to its strength, porcelain can be used for fillings in the back teeth and in larger cavities. Clinical studies show porcelain fillings last at least 10-15 years before needing replacement. With good placement and care they may serve 20 years or longer.
How Strong are Gold Fillings?
Gold is one of the strongest dental filling materials in terms of both compressive and tensile strength. It performs well under biting forces and is highly resistant to fracture or cracking. Gold is also non-corrosive and resists abrasion over decades of use.
Gold fillings have remarkable longevity, with clinical studies showing they can last 30 years or longer. Some gold fillings serve 50 years or more. This lifespan makes gold a popular choice when a very durable filling is needed.
How do the Strengths Compare?
This table summarizes how the four main types of dental fillings compare in strength and longevity:
| Filling Material | Compressive Strength | Tensile Strength | Average Lifespan |
|---|---|---|---|
| Amalgam | High | Moderate | 10-15 years |
| Composite | Good | Moderate | 7-10 years |
| Porcelain | Excellent | Excellent | 10-15+ years |
| Gold | Excellent | Excellent | 30+ years |
In summary, gold and porcelain fillings have the highest strength and durability. Composite resin is moderately strong while amalgam fillings, though very durable, have some risk of cracking over time.
What are the Pros and Cons of each Filling Type?
Beyond strength, there are other factors to weigh when choosing a filling material:
Amalgam Fillings
Pros:
- Very durable and long-lasting
- Wears well over time
- Bonds tightly to tooth
- Less sensitive to moisture during placement
- Low cost compared to other materials
Cons:
- Silver color – not tooth-colored
- May darken as it corrodes over time
- Requires removal of more healthy tooth during prep
- Contains mercury which causes some health concerns
Composite Resin Fillings
Pros:
- Matches color of natural teeth
- Bonds adhesively to the tooth
- Versatile – can be matched to shade of individual tooth
- Doesn’t require removal of as much healthy tooth
Cons:
- Costs more than amalgam
- Less durable than other materials
- More technique sensitive to place well
- May stain, chip or wear over time
Porcelain Fillings
Pros:
- Very strong and durable
- Mimics natural tooth shade and translucency
- Resists staining, abrasion, and corrosion
- Biocompatible material
Cons:
- Higher cost than amalgam or composite
- May not be suitable for large fillings
- Requires at least two dental visits to place
Gold Fillings
Pros:
- Extremely durable – lasts “forever”
- Doesn’t corrode or cause corrosion
- Kind to surrounding teeth – seals well
- Doesn’t expand or contract with temperature
Cons:
- High cost – most expensive filling option
- Not tooth colored – metallic yellow appearance
- May need to remove more natural tooth structure
Which Filling is Right for You?
When deciding on the best type of dental filling, be sure to discuss the options with your dentist. They will consider the location of the cavity, size of the filling needed, cost concerns, insurance coverage, and your restoration goals. Amalgam and porcelain provide the greatest longevity, while composite and gold offer excellent aesthetics. With good care, regular dental cleanings, and checkups, your dental fillings should serve you well for many years.