Why Are Sensitive Teeth Prone to Pain?

06 September, 2020
Sensitive teeth can be a pain in the behind as they're rather important structures that allow us to chew and speak. 

Dental structures are very important for our speech, for chewing food, and for the formation of food bolus. Of course, they’re also aesthetically pleasing. This is why sensitive teeth can not only be painful but can also affect us in many other ways.

We’ve all had a toothache at some point throughout our lives. It’s a warning sign that something harmful is happening to our teeth. Stick around, in today’s article we’ll explain the reasons why teeth are so sensitive to pain.

Tooth layers and sensitive teeth

Teeth have three basic parts:

  • Root. This is the part inside the dental cavity – the non-visible part of the tooth buried in the alveolar bone. The root would be part of the end of a tooth that’s been extracted
  • Crown. This is the protruding part of the alveolar bone; it’s visible
  • Neck. This is what joins the root and the crown

There’s a hole through which the vessels and nerves that nourish the teeth enter at the base of the root, forming what’s referred to as the pulp cavity. A layer of dentin covers and protects this pulp cavity.

Dentin is made from a mineral matrix, specifically calcium hydroxyapatite. As a result, this structure can protect the entry of harmful agents into the vessels and nerves of a given tooth.

A woman with a toothache.
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Dentin, the protective layer

Dentin forms by cells called odontoblasts located between the exterior and the pulp cavity. Furthermore, they have extensions that work their way through the dentin.

When any alteration in the tooth, such as cavities, affects or destroys the dentin, the odontoblasts are able to repair it, and thus the pulp cavity is well protected.

However, dentin isn’t enough to protect the teeth. It requires an even harder substance to prevent breakage every time we chew or speak. This substance is enamel.

Enamel, the hardest layer

Enamel is a very hard layer, composed entirely of hydroxyapatite. Dentin is also made of this mineral but to a lesser extent and concentration. In addition, cavities, made by the extensions of the odontoblasts, make it less resistant.

The enamel is white, hard, and with a composition of 96% hydroxyapatite. The remaining 4% contains protein and water. Its composition is made of cells called ameloblasts that create enamel before the tooth erupts.

Once a tooth surfaces, the ameloblasts degenerate and the enamel never regenerates again. As you can see, we have a limited amount of it for life, so its important to care for it.

Cement, the anchor layer

This substance lives around the root of the tooth, right above the dentin. Also, this layer is softer than enamel, as it only contains 65% hydroxyapatite.

The cement has two layers. One of them doesn’t contain cells and forms before the tooth comes up. Similarly, cement contains cementum cells and these produce a mineral matrix that forms after the eruption of the tooth due to functional requirements.

The main function of cement is to anchor the fibers of the periosteum — the layer that covers the bone around the tooth. It’s just like the glue that holds the tooth attached to the cavity.

A woman smiling.
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Why are teeth sensitive to pain?

We can answer this question if we know a bit about tooth anatomy. As you can see, the dentin has extensions of the osteoblast within it. That is, there’s communication between the dentin and the pulp cavity, where the nerve endings are.

Enamel doesn’t regenerate, so it stops protecting the dentin when it wears out or when tooth decay finally destroys it. Thus, it’s more susceptible to external factors. The cavities of the dentin remain open and external stimuli can reach the nerve endings, leading to pain.

So to keep this from happening, you must exercise proper dental hygiene; consult your dentist often, and maintain a healthy diet. This is the only way to preserve and protect your enamel and dentin.

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  • Guerra Álvarez, Pamela Alexandra. Reabsorción radicular después del tratamiento ortodóncico. BS thesis. Quito, 2017.
  • Sensibilidad Dental: Origen, Causas y Diagnóstico – DENTAID. Expertos en Salud Bucal. (n.d.). Retrieved May 17, 2020, from https://www.dentaid.es/salud-bucal/sensibilidad-dental
  • Pécora, Jesús Djalma, and M. D. Sousa. “Uma breve história dos métodos de estudo de anatomia interna dos dentes humanos.” Endodontics. São Paulo 24 (2011).