Basic Dentistry

BASIC DENTAL
	Sturctures	Eruption	Types	Injuries	More
	Enamel	Permanent	Incisors	Evulsed	Pain
	Dentin:	Deciduous	Cuspids	Extruded	Funny Words
	Pulp:		Bicuspids	Fractures
	Cementum:		Molars	Soft Tissues	Dentures

The hardest human substance. It covers the visible or working part of a tooth and protects the body of the tooth. It is made from crystals of calcium and phosphate in a protein matrix. The crystal structure exchanges ions and minerals from the diet and can become even stronger. It has no connection with the blood stream or nerves, therefore it cannot repair itself as can other tissues. The crystal integrity withstands a wide temperature range, from hot coffee to ice cream. There is no such thing as "soft teeth".

Makes up the mass or bulk of a tooth. More yellow in color than enamel but not near as hard. It is more elastic and compressible, has less tensile strength and not brittle like enamel.

When exposed, it is more susceptible to decay and wear than enamel. It receives nourishment from the pulp and is considered alive. It is able to make some repair against trauma and adjacent to invading decay.

The pulp fills the root canal chamber. It contains blood vessels, nerves and lymph tissue. The pulp sends pain signals to your brain.

Cementum covers and protects the root of the tooth imbedded in bone similar to the way enamel protects the crown. Similar in structure to enamel but thinner and less wear resistant. Periodontal fibers anchor the cementum to the bone.

The human dentition consist of four types of teeth: Molars, Bicuspids, Cuspids, Incisors

Eight in number. Four uppers and four lowers. Two types: Central and lateral. Right and left.Almost flat to a knife edge, they look like little shovels. They are used to incise food. To take the first bite and separate a piece to chew.

Four in number. Two uppers and two lowers. Right and left. Also called canines because of the their prominence in the animal kingdom. The longest of all teeth, the uppers extending towards the eye, hence sometimes called Eye-Teeth. Their length and strength are well suited for tearing and ripping off tough foodstuff. New cuspids are very pointed which aids in the piercing action. They are the "fangs".

Eight in number. Four uppers and four lowers. Two types: First and Second. Right and left. Transitional tooth between a cuspid and a molar. They have properties of both. Pointed cusps for piercing but also a broader table surface for chewing. We use these teeth to titrate our mouthful of food, to inspect what's in our mouth.

Twelve in number. Six uppers and six lowers. Three types: First, Second and Third. right and left. Molars are large, multi-rooted, strong, broad teeth. They make up the bulk of the chewing table. We use the uppers and lowers together to capture our food and pulverize it between them.

The Third Molars are commonly called Wisdom Teeth, probably because they come into the mouth somewhere between 18 and 35 years of age, when your a little wiser. Many of us do not have enough room in the jawbone to accommodate this last set of molars.

Injuries to the mouth may include teeth that are knocked out (evulsed), forced out of position (extruded) or broken (fractured). Sometimes lips, gums or cheeks have cuts. Oral injuries are often painful, and should be treated by a dentist as soon as possible.

Evulsed teeth

Extruded teeth

If the tooth is pushed out of place (inward or outward), it should be repositioned to its normal alignment with very light finger pressure. Do not force the tooth into the socket. Hold the tooth in place with a moist tissue or gauze. Again, it is vital that the injured individual be seen by a dentist within 30 minutes.

How a fractured tooth is treated will depend on how badly it is broken. Regardless of the damage, treatment should always be determined by a dentist.

Minor fractures can be smoothed by your dentist with a sandpaper disc or simply left alone. Another option is to restore the tooth with a composite restoration. In either case, you should treat the tooth with care for several days.

Moderate fractures include damage to the enamel, dentin, and/or pulp. If the pulp is not permanently damaged, the tooth may be restored with a full permanent crown. If pulpal damage does occur further dental treatment will be required.

Injuries to soft tissues of the mouth

Injuries to the inside of the mouth include tears, puncture wounds and lacerations to the cheek, lips or tongue. The wound should be cleaned right away and the injured person taken to the emergency room for the necessary suturing and wound repair.

Bleeding from a tongue laceration can be reduced by pulling the tongue forward and using gauze to place pressure on the wound area.

Hot sensitive - More severe trouble, invasion of pulp, trauma, decay or other infection.

Since recorded history, man has been trying to find replacements for missing teeth. We have all heard the stories about George Washington and his wooden teeth. Not exactly true. He did have one set that were spring loaded, to force them against his upper and lower jaws, to help hold them in. You can see from his picture, he has his mouth clamped shut to counteract the springs.

1. Appearance. They must look like the teeth they are replacing. We got this part down fairly well. We can make them look good.

2. Function. They must work like the teeth they are replacing. This is where Dentures fail.

A denture is a collection or row of teeth mounted on a plastic or metal base. This base, usually replacing gum tissue is designed to "sit" on the persons gums. This arrangement works okay if you just want to Smile, but chewing is a different matter. Yours gums are attached to your jawbone, which is very hard. The denture base is very hard. The gums are in the middle. Application of more than a modest amount of pressure will "Squeeze" the gums between the dentures and the jawbone. Soon pressure becomes pain and you will back off. You just can't apply enough force to chew properly without hurting the gums. Real teeth, on the other hand do not get caught in the middle of anything. They are attached or anchored directly into the jawbone. Tremendous amounts of force can be transmitted from the teeth to the bone without squeezing the gums. This is why the best Denture in the world will never really function.

Many people will argue that they have dentures that work great and they can eat everything. I am sure they are comfortable and feel good. In reality they have modified their lifestyle to adapt to their new teeth. Humans typically have the ability to bite with a natural set of teeth at 150 to 250 psi. Those that grind or clench can approach 1000psi. The best set of dentures in the world limits the owner to about 50 psi when they are new. The longer you wear them, the less force you can generate. After 15 years the maximum force is less than 6 psi. Now in all fairness, I must add that most of the time Upper Dentures are rather stable and they work reliably. This is because your entire palate is supported by hard bone. The problem comes trying to negotiate that Lower Denture. This horseshoe shaped slippery device just doesn't have the geometry to be supported. It is not the fault of the denture but rather the changes that occur when a person loses their teeth. In the natural condition, the teeth generate forces that are transmitted to the bone and muscles. When the teeth are missing, these forces change. The jawbone is no longer required to support the teeth and it begins to shrink away and atrophy. As it changes, so does it's geometry, and unfortunately, in a way not conducive to support a denture.