Have you ever visited your Rochester, NY dentist for a dental implant procedure and when it came time to give you a local anesthetic, you couldn’t get numb? This unfortunate situation could leave you feeling pain during a dental procedure and provide an overall bad experience at the dentist. So why can’t you get numb? The inability to get numb can be caused by a number of factors.

Why Does Lidocaine Not Work on Me?

A few surprising factors can interfere with the effectiveness of local anesthetics.

Vitamin C

One of the first factors that can prevent you from getting numb with dental anesthetic is vitamin C. When you consume vitamin C, it can have an effect on your body’s pH balance. The change in pH balance can actually counteract dental anesthetics. If possible, try to avoid taking vitamin C supplements or drinking large glasses of orange juice before your dental appointment. On the flip side, if you’re trying to wear off the numbing effects of the dental anesthetic, consume vitamin C after your appointment. Your consumption of vitamin C will rapidly expedite your body’s clearing of the local anesthetic.

Hot Tooth

If you have a particularly painful tooth and it won’t get numb, your dentist might refer to it as a “hot tooth.” When a tooth causes significant pain, it can change the nerves which can make them overactive. If it’s overactive, it will require more anesthetic than usual to calm it down. The nerves may also develop more pain receptors which would also require more local anesthetic. Continue to let your dentist know if your tooth does not get numb.

Movement During Administration

Another reason why you can’t get numb at the dentist is that you moved or flinched during the administration. If your dentist tries to inject the local anesthetic into the nerve and they miss it because you moved or flinched with the prick, you won’t get numb. Try to stay as still as possible when we administer the local anesthetic.

Your Metabolism is Too Fast

For some patients, the issue isn’t that the drug doesn’t work, but that it doesn’t last. Your body views local anesthesia as a foreign substance and immediately uses enzymes in the liver and blood to break it down. If you are a “fast metabolizer,” your body may dismantle the medication faster than the dentist can administer it. This often results in numbness that sets in for a brief window but vanishes before the procedure is complete. If you notice that other medications or alcohol wear off quickly for you, your high metabolic rate is likely the culprit.

It Could Be in Your Genetics

Your DNA plays a surprising role in how your body processes pain blockers. It is a well-documented phenomenon that people with the MC1R gene mutation (commonly associated with natural red hair) often require up to 20% more anesthesia to achieve the same level of numbness as the general population. Additionally, genetic conditions like Ehlers-Danlos Syndrome (EDS) affect how connective tissue is structured, which can physically prevent the anesthetic solution from spreading correctly to reach the nerve. If you have red hair or joint hypermobility, mention it to your dentist beforehand.

Previous Trauma and Anxiety

The connection between your mind and your nerves is powerful. If you have a history of dental trauma or severe anxiety, your body likely enters a “fight or flight” mode the moment you sit in the chair. This response triggers a massive release of adrenaline, which increases your heart rate and alters your blood chemistry. This surge can cause the anesthetic to be swept away from the injection site and into your bloodstream much faster than usual. Essentially, your body’s survival instinct overrides the medication, making it difficult to get—and stay—numb.

Your Dentist Missed

You can’t expect your dentist to hit the bullseye 100% of the time. There is always the slightest chance for error. If your dentist doesn’t hit the nerve, you likely won’t feel numb. Let your dentist know you don’t feel numb, and they will inject you again.

Anatomy

Not all mouths are made the same. Your teeth, bones, blood vessels, and nerves might be in a different location than someone else. Your dentist might place a local anesthetic in an area that works for 9 other patients but doesn’t work for you. Aside from having anatomy in a different location than other patients, you might also have longer roots on certain teeth. This is where 3D x-rays come in handy. Just know that if you don’t get numb on your first shot, a second one will probably help.

Infection

If you have an infection in your tooth, it can also affect the pH of your mouth just like vitamin C. Infections cause the mouth to become more acidic. In order for local anesthetics to work correctly, they need a neutral pH. This is why dentists often prescribe antibiotics before root canals or other procedures when an infection is present. In some cases, a nerve block is a better option when a patient can’t get numb.

Anxiety

If you generally feel anxious when you visit the dentist, it can also affect your ability to get numb. Anxiety can cause you to move when we’re trying to inject the local anesthetic and it can also make you interpret the lightest touch as pain. If you feel anxious simply getting a local anesthetic, that’s okay. We offer several solutions that can help. We offer three different types of sedation dentistry.

First, we offer nitrous oxide which you might know as “laughing gas.” During your appointment, you will inhale the nitrous oxide and immediately feel relaxed. Once you’re relaxed, we will inject the local anesthetic. The effects of the nitrous oxide will wear off within minutes of stopping the inhalation.

Another option for sedation dentistry is oral sedation. This involves taking a pill before your appointment. We can also prescribe one for the night before your appointment if you tend to experience anxiety before bed for your upcoming appointment. The pill will help you stay relaxed throughout your entire appointment and especially during your local anesthesia injection.

The last type of sedation dentistry we offer is IV sedation. We recommend IV sedation for patients who need a much deeper level of sedation. After the IV sedation begins to take effect, we’ll apply the local anesthetic.

Talk to one of our dentists in Rochester about sedation dentistry to learn if it’s right for you.

Struggling To Get Numb? Visit Our Rochester Dentists

If you’ve struggled to get numb when visiting the dentist, consider visiting Contemporary Dentistry on South Clinton Ave between Elmwood and Westfall in Brighton. We take our time to get to know a patient, their anatomy, and specific circumstances to ensure we provide you with a comfortable and pain-free experience every time. Please call us at (585) 244-3337 to book your next appointment.