Ideas of what actually constituted the substance that made up our teeth have changed with time. From bones, to nail like material, it wasn’t until till more recently when advances in technology allowed us to make more powerful and accurate observations than before. What we saw was a little disturbing. On closer observations with newly made powerful microscopes, man was able to identify that his teeth were in fact full of holes, a porous material. At the same time, people such as Louis Pasteur (1822-1895) were discovering that bacteria and other organisms only visible with a microscope, were alive and thriving at the invisible level, and the idea was beginning to grow that these organisms could be responsible for disease and decay.
Soon, this new found destructive agent was associated with the decaying of teeth. Man, aghast at this discovery, has spent the intervening time trying figure ways of how to get stains out of this porous substance, all with varying levels of success. It has taken more modern advances to understand exactly what the enamel is made of.
Enamel is the most highly mineralized and hardest substance in the body. 96% of enamel is made up from the mineral hydroxylaptite, with water and natural material making up the rest. Dentin, which is less mineralized so less brittle than enamel, is used as a support structure in the mouth. Enamel’s strength, and its brittleness, comes from this high amount of mineral, and as the enamel is used by the body as a coating to protect teeth, the strength helps the teeth to chew a variety of different foods, and allows a varied and versatile diet to be consumed. Unlike dentin and bone, enamel does not contain collagen, and has instead different proteins, whose roles are not yet fully understood. The normal color of enamel varies from light yellow through to gray white, and can vary in its thickness over the tooth. The rate at which enamel wears down has been termed ‘attrition’ and the average rate is around eight micrometers a year, in normal conditions.
What Are the Roots Made From?
The roots are mostly made from dentin, and can have one or more pulp ‘canals’ in them, depending on where in the mouth the tooth is located. When a dentist is performing root canal treatment, he is aiming to save the tooth be clearing the pulp and any infection and debris out of these canals to make them as clean as possible.
Parts of the Tooth
The main parts of a tooth consist of:
Tooth development is a complex process and can be broken down into four main stages:
- The bud stage
- The cap
- The bell
An aggregate of cells, know as an initial part of the bud stage, eventually forms the basis and then goes on to grow into a functioning tooth. The act of the tooth braking through the gum and becoming visible is called erupting. Eruption begins to occur at around six months of age in humans, and is known as teething. This is clearly painful and upsetting for babies, and lasts until about two years old. As the child grows older, these teeth, which have been the only ones in the mouth, begin to fall out as the eruption of adult teeth begins. This stage is known as the ‘mixed stage’ where a person has a combination of both primary and secondary teeth. This lasts until the last primary tooth has fallen out, allowing the last of the adult teeth to erupt through.
There have been a few theories over the years as to the impetus for an erupting tooth, with one theory suggesting that the development of the tooth’s root forces it to erupt through the gum. Another theory was the ‘cushion hammock’ theory, which resulted from a microscopic study. This was later shown to be incorrect, and the most widely accepted theory today is that the periodontal ligament provides the drive needed to facilitate the tooth’s eruption.
When Do Teeth Stop Growing?
Teeth usually cease growing at the end of puberty, although many people experience their third molars, or wisdom teeth, growing until they are around twenty five years of age. A modest amount of people experience teeth erupting into their mouth incorrectly sized. This is a fairly common phenomenon. There are two medical conditions associated with incorrect teeth size:
Microdontia is when teeth grow smaller in size and macrodontia is where teeth grow bigger in size. The first condition usually only infect the front teeth, particularly the incisors, while all teeth in general can suffer from macrodentia.
What Is the Difference Between Teeth and Bones?
Both are hard, heavy, white and full of calcium. Both are extremely painful to break. So what then are the differences between teeth and bones? From the way that they can look, to the way they heal, teeth and bones have many differences. The main difference is the presence of collagen in bones, which is a living, growing tissue that allows the bones to maintain a flexibility about them that allows them to withstand pressure. The exterior of bones are made form periosteum, a smooth, dense and slippery membrane. This periosteum contains cells that manufacture new bone growth and repair. When a bone is fractured, new bone cells proceed to the site and begin the process of bone regeneration.
Contrast that with the broken tooth, which in most cases will need to be extracted, as it cannot repair itself. Bone marrow, the substance found inside bones, produces red and white blood cells, as the bones have their own blood supply, whereas teeth do not. The last difference is that the teeth are on display permanently, where as bones are comfortably hidden inside our bodies, which mean that while teeth are subject to discoloring, bones stay the same color throughout.
Strange Facts Regarding Teeth
Teeth have been treated differently by different cultures over the years. Some interesting facts about teeth:
- The Mayans, probably more famous for other ideas such as their calendars, used to etch some of the tooth away to make it look more interesting, or would place different shaped and colored jewels in small holes made into the tooth.
- Before the dental industry started, barbers and blacksmiths performed the majority of the dental work, as no one would have visited a dentist in between when not suffering pain. The introduction if licences soon prevented this practice, which then fell exclusively to the newly formed dental industry.
- A mini crisis was created in the Appalachian regions of the United States of America. Several factors contribute to the constant drinking of a brand of drink –Mountain Dew- by people of all ages, often in place of water. This rotted teeth in the regions, and gave rise to a condition known as ‘Mountain Dew Mouth’, where several of the teeth are in fact rotted stumps due to the beverages.
- Chinese researchers have previously attempted to grow a human tooth on a mouse. They got round the problem of obtaining normally difficult to acquire stem cells from human urine. They managed to grow some dental pulp and some beginnings of enamel. Mixed responses met the review of the experiment, and the possibly deficient source of urine was hinted at as the potential weak link. If better quality stem cells were available, theoretically a better grade of synthetic tooth can be grown. All in all most were in agreement that this was a step in the right direction toward growing synthetic teeth for human use.
- Weak teeth may be genetic, and can cause rapid and early tooth loss. Some cases have been noted where people who have healthy teeth on the surface suddenly succumb to sudden loss of teeth. One individual, in a family of people who all claimed to have weak teeth, had to have dentures fitted at thirty years of age, after half of his tooth fell out over night. Upon examination by his dentist, who had previously seen him five months before without an issue, was amazed to find cracks on twelve teeth. An attempt to save them was initiated, but to no avail.
- Some babies are born with teeth, known as Natal Teeth, which can be a sign of another underlying condition, but it is usually harmless. The teeth are removed in most cases anyway, as it can impeded breastfeeding for the baby as well as make it uncomfortable for the mother, and to prevent accidental swallowing of the tooth by the baby if it manages to work loose. In ancient times, babies born with teeth were considered a sign of evil.
Modern understanding of what parts constitute the make-up of the tooth, and how it is connected to the jaw, and the reasons that they decay, have all contributed to the advanced understanding of the properties of teeth, and the best methods with which to treat them. The oldest, and of course best advice, is establish a good routine, and stick to it.