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20

Yes you are right. It is the dentin. Enamel has got no nerves. So when the dentist use his/her instrument, initially there is no pain (if the enamel is intact). The next layer is dentin. As you said, dentin has got dentinal tubules containing dentinal fluid. Whenever there is any stimulus which has not yet reached the pulp, but may have reached the dentin, ...


13

The chemical mechanism by which fluoride protects teeth is the remineralization of hydroxyapatite $\ce{Ca5(PO4)3(OH)}$ in the tooth enamel into fluorapatite $\ce{Ca5(PO4)3F}$: $$\ce{Ca5(PO4)3(OH) \ (s) + F- \ (aq) -> Ca5(PO4)3F \ (s) + OH- \ (aq)}$$ This reaction occurs at the surface of the enamel, i.e. directly within the mouth. The fluoride ions ...


10

The evolutionary biologist in me would argue that, on average, teeth are exactly as strong as they need to be. In other words, the fitness cost of producing and maintaining teeth is balanced with the the fitness benefits of having teeth. To address your questions from an evolutionary lens: Why haven't humans evolved in the past tens of thousands of years ...


10

The outer shell of a tooth is enamel, which is hard and dense so that not much can penetrate it. Under that is dentin (or dentine), which is bony but has microscopic channels running through it to the center of the tooth where the pulp and nerve reside. If the enamel is breached, as with a cavity, crack, or wear, the dentin is exposed to the environment of ...


10

But I always assumed that plaque is formed by food remains in the mouth It's not surprising that you'd have this assumption. The clinical term, dental plaque, refers to soft deposits on the teeth. While is often described to the lay public in connection to eating (without brushing), it is not food, or the remains of food, it is a biofilm. Biofilms are ...


8

There are legitimate case reports in credited journals of hyperdontia, or the condition of having supernumerary teeth. Such cases are often associated with congenital syndromes-- cleft lip and palate, trichorhinophalangeal syndrome, cleidocranial dysplasia, and Gardner's syndrome. I included a case report and a comprehensive review for you below. Case ...


8

Because your teeth evolved as a sensory organ. The material teeth are made of evolved first in placoderms, it existed to sense the electrical current in the water around it, so it has to form around a nerve. in modern animals the nerve mostly functions in sensing stress and thermal stress on the tooth. And because mammals are weird. Teeth did not evolve to ...


7

This is a skull of a child of around 5 plus years; based on the eruption status and is an example of classic development and eruption pattern of of the teeth at that age. everyone goes through it. It probably looks scary to persons unfamiliar with normal anatomy and because the outer cortical plate has been removed to show the developing tooth germs. This ...


7

From different sources, I think that it can be safely assumed that fluoride stays in the mouth and is absorbed by the teeth while brushing unless ingested (reference). Most dental doctors agree that the fluoride is not absorbed in the mouth and that it may be retained on the surface of your oral mucosa, where it is then available to help re-mineralize your ...


7

Upper teeth: maxillary teeth Lower teeth: mandibular teeth The term, "maxillary", is given to teeth in the upper jaw and "mandibular" to those in the lower jaw. If you search these terms you will find many references. You can start with wikipedia which has many cross references.


5

Fluoride is absorbed mostly in the stomach and small intestine. Several aspects of fluoride metabolism - including gastric absorption, distribution and renal excretion - are pH-dependent because the coefficient of permeability of lipid bilayer membranes to hydrogen fluoride (HF) is 1 million times higher than that of F(-). This means that fluoride readily ...


5

Your understanding is correct to some extent. Tooth enamel mostly consists of a mineral called hydroxyapatite ($\ce{Ca_{10}(PO4)6(OH)2}$) (Staines et al, 1981). Though this makes enamel the strongest material in the body, it is susceptible to degradation. In acidic environment, hyrdoxyapatite gets dissolved and leads to cavities (Brown, p. 688). The ...


5

The answer is a simple no. Cavities in the teeth caused by dental decay cannot heal. Enamel which is affected by dental decay cannot heal as they are fully formed at the time of eruption and then on only deteriorates. The deeper part of the tooth which has dentin cannot heal the cavity formation, however it can produce a protective barrier between the ...


5

While I can't find any specific sources regarding bacteria eating enamel, I highly doubt this is what's happening in our mouths. I doubt this because your point is likely true - minerals in enamel provide no added benefit to the bacteria. I would ask a dentist about this to be sure though. However, what is certainly true is that the acid produced by the ...


4

Humans are diphyodont animals, which means we are having two sets of teeth cycles, on contrast, the polyphyodont animals which are having multiple tooth cycles. The first deciduous teeth(milk teeth,baby teeth or primary teeth) then followed by the permanent teeth. Milk teeth develop from the embryonic stage and continue to develop for 6-7 years and gradually ...


4

The incisal and occlusal edges of teeth are more translucent since there is only enamel in this area and the dentin core is deeper inside. The dentin is more opaque and reflect the light back and it looks lighter whereas the enamel is translucent and allow more light to pass through and less light is reflected back so it looks darker. Many human teeth the ...


4

Unfortunately, the answer to your question isn't as well researched as other areas, I believe...let's add some complexity into this. You're correct, teeth does "grow" in the gums. And it does start off surrounded by cells (look up: tooth bud, cap, bell stage)! The tooth originates from an interaction between the ectomesenchyme (likely originating from the ...


4

Human teeth and animal teeth are not fragile. It is meant to last a life time, barring physical injury. If anything makes it fragile it is ourselves. The main two causes of tooth loss is dental decay and gum disease. Both are cause by the soft tenacious bacteria filled biofilm called 'Plaque". If there is no plaque then there is no dental caries(cavities) ...


3

Chandra's Textbook of Dental and Oral Histology and Embryology with MCQs p40-42 explains the complexity of enamel, and provides diagrams and images of real enamel. What I didn't know before was that the hydroxyapatite is in the form of very small crystallites packed inside the key-like structure of the rods. The rods are packed together with a cement-like ...


3

There is an interesting historical story of fluoride use in prevention of dental caries. Interestingly the journey started with a "mysterious disorder-fluorosis." In 1909 Dr. McKay (r) persuaded the Colorado State Dental Association to invite Dr. Green Vardiman Black (l), one of the nation's most eminent dental researchers, to attend 1909 ...


3

Its definitely not a marine mammal, just based on size and general configuration. those convoluted ever growing teeth are pretty diagnostic of non-cetacean ungulates. Just based on the pattern I would say bovidae, but that does not narrow it down much in turkey, the H shaped central portion is fairly diagnostic of bovidae. However you have several antelope ...


2

Because teeth first evolved to be disposable not permanent... then mammals lost the ability to replace them. There are two questions here, one about regrowth of teeth the other about tooth composition. Tooth regrowth The norm for vertebrates is to keep growing new teeth forever, mammals have lost this ability, the current reasoning is that the ancestor of ...


2

For more than 70 years calcium hydroxide has played a major role in endodontic therapy, although many of its functions are now being taken over by the recently introduced material MTA. Calcium hydroxide may be used to preserve the vital pulp if infection and bleeding are controlled; to repair root fractures, perforations, open apices and root resorptions [1]....


2

Xylitol does not kill any bacteria. Xylitol is a sugar alcohol that bacteria happen to not be able to use as an energy source. In the absence of other sugars, bacterial growth slows. Therefore, its antimicrobial mechanism is bacteriostatic rather than bactericidal. No antibiotic exists, or will ever exist, that kills or inhibits all kinds of bacteria. One ...


2

I think your daily pattern has made your brain associate brushing your teeth as a precursor of your breakfast. Skipping this step will confuse your brain into thinking it's not time for breakfast yet. Same goes for chewing gum, the toothpaste smell will trigger your brain's association of brushing teeth with the breakfast to come.


2

See, since it was a simple drilling followed by restoration or filling, that means the infection was superficial, not involving the pulp where the nerves and blood vessels are situated. Ok, so now to remove the superficial infection the dentist might have used an airotor. It's an instrument which rotates at high speed, has a hole for water spray to cool the ...


2

Teeth first: The vast majority of people have no problems with their wisdom teeth, whether they emerge or not. Impacted wisdom teeth are very common and are usually painless. They do, however, sometimes mess around with other teeth and throw off our bites (which will always readjust, not necessarily in a cosmetically pleasing manner, but the bite will ...


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