Dentists don't routinely provide anaesthetic when drilling into a tooth to place a cavity. You might wonder what's the point of the actual drilling. Tooth decay has already created a hole in the tooth, so isn't it just a case of filling the hole? In fact, the decay has to be removed to stop it from spreading, so a dentist can't just fill a cavity without preparing the tooth. It's all quite simple. What might not be so simple is the fact that you've been delaying seeking treatment for a suspected cavity because of a fear of the dental drill.
You probably already know, but delaying treatment for tooth decay is extremely unwise. It's inevitably going to get worse as the decay corrodes more of the tooth's structure. The decay will permit bacterial contaminants to enter the tooth, where it may reach the tooth's nerve. This nerve (also called the dental pulp) will become infected, and you will need a root canal. Ultimately, the tooth may need to be extracted. This is why repairing a cavity shouldn't be delayed.
You're aware of the relative urgency of the situation, but this doesn't help much with the initial problem—your reaction to the dental drill. As mentioned, a dentist won't routinely anaesthetise a patient for a basic filling, as the drill only makes contact with hard tissues without nerve endings of their own, which is the tooth. But you will undoubtedly feel the vibrations emanating from your tooth, and for some patients, this sensation is unbearable.
Talk to your dentist about your concerns, allowing you to work out a solution that permits comprehensive treatment. Your dentist can provide you with an anaesthetic, numbing your jaw to the same level as a patient undergoing minor oral surgery. This dulls the senses in proximity to the injection site, and you won't feel a thing. Other forms of anaesthetic are possible, such as nitrous oxide (or laughing gas, to use its more common name). This invokes a sense of tranquillity, making you far less concerned about all aspects of the procedure—including the drill.
Some dental clinics have another option, which doesn't involve medication. An increasing number of dental procedures are carried out using lasers. Laser is a catch-all term for the technology, and there are a number of different lasers being used in dentistry. Your dentist may operate an erbium-doped yttrium aluminium garnet laser (Er:YAG). The Er:YAG is ideal for teeth and bones, as it's readily absorbed by hydroxyapatite—a mineralised type of calcium that's found in teeth and bones. Your dentist may be able to prepare your cavity using a laser, with no drill involved.
Even though you're not elated at the idea of having your cavity filled, you know it has to happen. However, it can happen without you being too aware of the drill, or without a drill at all. Speak to a local dentist to find out more.