To understand why your dentist might prescribe antibiotics for a toothache, you must first understand how bacteria contribute to tooth decay and toothaches. Without regular, twice-daily brushing with proper technique, the bacteria in your mouth can grow and turn the foods you eat into acid that then gets deposited on your teeth. This promotes cavity formation and tooth decay. As the American Dental Association (ADA) explains, frequent sugar intake can especially fuel the bacteria that break down tooth structure. The type of bacteria that primarily cause cavities is Streptococcus mutans, as a study in PLOS ONE notes.

When bacteria break down a tooth's surface, forming a cavity, the inner chamber of the tooth becomes vulnerable. This inner chamber contains the nerves that supply your tooth with sensation. When bacteria reach this chamber, it can be painful and lead to more severe dental problems that may require antibiotic treatment.

There are many causes for a toothache, including cavities, inflamed pulp tissue and dental abscesses, according to Merck Manuals. Having a cavity in a tooth does not necessarily mean that you will need antibiotics. As the Mayo Clinic explains, cavities are often treated with fillings, or possibly crowns, based on how much of the tooth is infected. When a tooth infection reaches the nerve of the tooth, it may require a root canal and a protective cover to seal bacteria out of the tooth. Additionally, if a tooth is so broken down by a cavity that it can't be repaired, the dentist may need to extract the tooth.

When the dental infection is severe or impacts the gum around an erupting tooth, your dentist may recommend antibiotics. For instance, pericoronitis is an infection in the gum tissue that can develop around impacted wisdom teeth, as Merck Manuals explains. Patients with this condition may be given antibiotics as part of their treatment.

Additionally, if your dentist notices signs of a dental abscess, a tooth infection that can develop from an untreated cavity, they may recommend antibiotics.

For dental infections, dentists will often prescribe penicillin or amoxicillin, explains Merck Manuals. Clindamycin is also a commonly prescribed alternative for those allergic to penicillin. Your dentist will be sure to identify the right dose and duration of medication for your particular situation. Since over-prescription of antibiotics can sometimes lead to more resistant strains of bacteria, your dentist will also take antibiotic resistance into consideration when they prescribe your dose, as the ADA explains.

It's important to take the full course of pills exactly as your dentist prescribes for the best outcome. Just remember, even if the pain resolves, you'll likely still need further treatment to fully restore your tooth.

There are many ways to prevent a toothache, as the National Health Service explains. Following these steps can help you reduce your risk of cavities or a toothache:

• Limit your frequency and intake of sugary foods and drinks.
• Brush your teeth with fluoride toothpaste twice daily to decrease the sugar and bacteria accumulation on your teeth.
• Floss between your teeth to prevent cavities from forming where your teeth touch.
• Maintain regular checkup appointments so that your dentist can continue monitoring your risk of cavity formation.

You can take steps to help prevent cavities and tooth infections. However, if you already have one, know that your dentist has your best interests in mind if they prescribe you antibiotics for a toothache.

When is antibiotic treatment necessary for tooth pain?

If an abscess (pocket of pus) from bacteria affecting the pulp is the cause of your tooth pain, an antibiotic may be necessary to avoid the spread of infection. Serious infections require antibiotics because they can spread to the surrounding bones and become life-threatening. If the infection hasn't spread to nearby teeth, is contained and treatable, your dentist may decide not to prescribe antibiotics.

What are common signs that may indicate the need for antibiotics in tooth pain?

Common signs that may indicate antibiotics are needed to resolve your tooth pain include fever or feeling unwell, swelling of the jaw and neck (lymph nodes), fatigue and persistent pain that won’t go away. This is an indication the infection is spreading.   

Can antibiotics be used for all types of tooth pain?

Antibiotics are a last resort and should be taken only when necessary. Tooth pain isn’t always an infection. It may be a result of sensitivity from tooth whitening treatments, eating hot or cold foods, and grinding your teeth at night. This type of pain usually resolves on its own. If tooth pain is cavity related it may resolve after it is filled. Even deeper cavities can be treated by a root canal without antibiotics if the infection is contained.

How long does it take for antibiotics to relieve tooth pain?

It may take several days or a full week after starting antibiotics for tooth pain to go away, depending on the severity of the infection. Typically, a dentist will reassess your pain after three days and may discontinue antibiotic treatment 24 hours after your symptoms are fully resolved. Be sure to take the antibiotics as prescribed. 

What should I do if my tooth pain persists after taking antibiotics?

If your pain continues or gets worse, let your dentist know right away.

This article is intended to promote understanding of and knowledge about general oral health topics. It is not intended to be a substitute for professional advice, diagnosis or treatment. Always seek the advice of your dentist or other qualified healthcare provider with any questions you may have regarding a medical condition or treatment.