Cavity Basics

Cavity Basics

Dental cavities are an infection caused by a combination of carbohydrate-containing foods and bacteria that live in our mouths.

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Cavities attack the teeth in two main ways. The first is through the pits and fissures, which are grooves that are visible on the top biting surfaces of the back teeth (molars and premolars). The pits and fissures are thin areas of enamel that contain recesses that can trap food and plaque to form a cavity. The cavity starts from a small point of attack, and spreads widely to invade the underlying dentin

The second route of acid attack is from a smooth surface, which is between, or on the front or back of teeth. In a smooth surface cavity, the acid must travel through the entire thickness of the enamel.

How Will I Know if I Have a Cavity?

The large majority of cavities are completely painless. This is because the outer enamel has no nerves. It is only when the cavity enters the underlying dentin that the cavity may begin to feel sensitive. The most common symptoms are an increased sensation to cold and/or sweet foods or beverages. A cavity is often responsible for a tooth that breaks. The cavity weakens the tooth, especially when it forms under a filling or a tooth cusp, and can easily cause a fracture when biting down.

It is far better to treat a small cavity than to wait until they have symptoms (like pain). By the time there are symptoms, the cavity may have spread to infect the dental pulp, necessitating a root canal procedure or an extraction to eliminate the infection. Regular dental examinations, at least twice a year, will greatly reduce the likelihood that a dental cavity will go undetected and spread, causing pain and infecting the dental pulp.

How Fillings Work

Most cavities discovered during a dental examination will need to be treated.

The goal of treating cavities involves two basic steps: removing the decayed portion of the tooth, and rebuilding the missing tooth structure with a filling material. The dentist usually begins the procedure with an injection of local anesthetic (xylocaine in most cases). The tooth is isolated from the rest of the mouth, and in most cases, a high-speed dental drill is needed to remove the decay and prepare the tooth for the filling. Depending on which material is used, the dentist will vary the tooth preparation accordingly. After the tooth has been prepared, a liner is often used to reduce tooth sensitivity.. Dycal is a compound containing calcium hydroxide, and is used in deep cavities to stimulate the dentin to regenerate and protect the dental pulp. The dentist and patient can then choose a number of different materials to fill the tooth, but the most common is a white resin. These materials are layered on top of the liner or base to finish the process of rebuilding the tooth.

After a tooth has been filled, it is not unusual for the tooth to be sensitive for a day or two. In general, the deeper the filling, the more likely the tooth will have prolonged sensitivity, especially to cold food or beverages.

Most fillings should be completely comfortable within two weeks. In some cases, the filling will be built up too high, and a second appointment is needed to shave down the filling to a comfortable level. If sensitivity lasts more than two weeks, it may indicate that there is a void under the filling. Prolonged discomfort may also indicate a tooth that has an infected pulp, and requires root canal therapy.

How to Prevent Cavities

People who have reduced saliva flow are more likely to develop cavities. Saliva is important in fighting cavities because it can rinse away plaque and food debris, and help neutralize acid.

People who have limited manual dexterity and have difficulty removing plaque from their teeth may also have a higher risk of forming cavities. Some people have naturally lower oral PH, which makes them more likely to have cavities.

The easiest way to prevent cavities is by brushing your teeth and removing plaque at least three times a day, especially after eating and before bed. Flossing at least once a day is important to remove plaque between your teeth. You should brush with a soft bristled toothbrush (Sensodyne 3.5), and angle the bristles about 45 degrees toward the gum-line. Brush for about the length of one song on the radio (3 minutes). It’s a good idea to ask your dentist or hygienist to help you with proper brushing methods and for your dentist to give  a comprehensive Oral Hygiene instruction during examination.

Reducing the amount and frequency of eating sugary foods can reduce the risk of forming cavities. If you are going to drink a can of lemonade, for instance, it is better to drink it in one sitting, than sip it throughout the day. Better yet, drink it through a straw in one sitting, to bypass the teeth altogether.

Getting to the dentist at least twice a year is critical for examinations and professional cleanings.

To reduce the incidence of cavities, use toothpaste and mouthwash that contain fluoride. Fluoride is a compound that is added to most tap water supplies, toothpastes, and mouth rinses to reduce cavities. Fluoride becomes incorporated into our teeth as they develop and makes them more resistant to decay. After our teeth are formed, fluoride can reverse the progress of early cavities, and sometimes prevent the need for corrective dental treatment.

A dental procedure called sealants can also help reduce cavities on the top and sides of back teeth (occlusal, buccal and lingual surfaces).

A sealant is a white resin material that blankets the tooth, protecting the vulnerable pits and fissures of the tooth. Sealants are routinely placed on children’s teeth to prevent cavities on their newly developing molars. The use of sealants to prevent cavities is also a cost-effective way to reduce the incidence of cavities on adults as well. Sealants are generally not used on teeth that already have fillings.