Nargiz I. Zadeh, DMD
General, Cosmetic, and Implant Dentistry
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Differences Between Crowns and Fillings

October 5, 2021
Posted By: Dr. Nargiz I. Zadeh, DMD

Dental terminology can be confusing, but it’s still important to know the difference between some of the most common terms. Let’s dive into the differences between the two types of restorations encountered most often — crowns and fillings. 


Tooth decay, or a cavity, is one of the most prevalent diseases in the mouth and often requires urgent intervention. Decay is caused by bacteria that use leftover food in the mouth to produce acids. These acids slowly eat away tooth enamel, and eventually create holes in the tooth. If tooth decay is neglected, it becomes painful and more costly to treat. 


One way to treat small areas of decay is with fillings. A filling is a soft, sculptable material that is used to fill the hole created by a cavity. Your dentist first cleans out the decayed part of the tooth, which is soft and flaky until only healthy, hard tooth structure remains. Then, the missing tooth structure is restored by layering a filling material and molding it into the shape of the tooth. The material is hardened by shining a blue light on it, allowing it to bond to the healthy tooth structure and become part of the tooth. Overall, a filling is completed in one appointment and typically, requires no follow-up. 


One common misconception, is that once a filling is placed it will never have decay again. Wrong!  Decay can eventually recur around the filling margins if the teeth are not properly brushed and flossed. Even with excellent hygiene, fillings have a lifespan before the material itself starts to break down and form gaps between it and the tooth. The lifespan depends on many factors including the type of material used, and the way it was placed. 



Related post: Dental Crowns Can Restore Your Teeth and Smile



So, what are the different types of fillings? There are several—gold, amalgam, and composite resin—but for the purposes of this post, we are only referring to composites since they are ubiquitously used. Composite fillings are tooth colored and do not contain mercury, making them a popular option in comparison to gold and amalgam. Regarding cost, fillings are more affordable than crowns. However, dental health should never be compromised to save a dollar; a small problem can lead to massive issues in the future, which may end up costing far more. 


A crown, sometimes called “a cap,” covers the entire tooth like a protective cap that covers an object. It extends to the gumline and mimics the shape of a tooth. A crown is used to treat advanced tooth decay that has consumed more than 50% of the tooth, making the tooth too weak to hold a filling long-term without breaking. Cracked and broken teeth are also conditions that require a crown. If a tooth cracks, meaning it splits down the middle, there is no way for it to repair itself. A crown is used to cover it up and prevent the crack from propagating into the nerve or roots.  Alternatively, some patients even request crowns for cosmetic improvements, such as to cover up discolored teeth with a brighter color. 



Related post: Dental Crowns: Ever Wondered What's in Them? 


A crown procedure requires two appointments. During the first appointment, the tooth is prepared to make room for the crown to fit; this requires removing any decay or sharp edges. An impression with putty, or a digital scan of the tooth is taken and sent to the lab. This gives the lab an exact replica of the prepared tooth so they can design a crown to fit perfectly over it. On the second visit, the dentist places the crown over the tooth and makes sure that the color, bite, and fit are ideal. If everything checks off, the crown is permanently cemented onto the tooth so it can’t fall off.  


Like fillings, crowns can be made of different materials including ceramic, metal, resin, or a combination of these materials. While dental crowns cost more than fillings, they should last between five and 15 years if properly cared for. However, as mentioned, both options are subject to wear-and-tear and eventually require replacement. 


To summarize, the main difference between crowns and fillings are that crowns protect the teeth, while fillings repair smaller areas of decay. Crowns are used when more than 50% of the tooth needs a filling, or if there is a crack. Only in rare circumstances, can a filling be used to repair a crack because it can act as a wedge when you chew, causing the crack to grow. Therefore, it’s important to thoroughly understand your options for restoring teeth, because something that may seem cheaper up front can end up costing more visits and money in the long run.  


The best person to discuss which solution is ideal for you is your dentist. She can carefully examine the severity of your tooth condition and suggest a solution based on your overall health, oral hygiene, social and financial situation. Every dentist will advise you to protect the health of your mouth by brushing and flossing daily, and scheduling routine dental appointments. If we can identify the problem early, you won’t have to endure pain and more expenses.


If you would like to more information about the differences between dental crowns and fillings or you're ready to book your appointment with our office, please get in touch with us today.