Teeth.

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Prepared by group (D)

Mahmoud KhalilDlnia Khalifa

Dunya TahseenFarhang Ismat

Hanna MohammadHazher Mawlwd

Hemn JamilKazhin Hamid

Dr.Hiwa Balisane

Introduction

Humans grow two sets of teeth during their lives. The first set has 20 teeth baby teeth. When a child is about 6 years old, these teeth become loose and fall out. Over the next few years 28 permanent teeth replace the baby teeth. When a person is around 20, four more back teeth, called wisdom teeth grow in. We have different types of teeth in our mouth. Each one has a different function.

Types of the teeth

The adult human mouth contains 32 permanent teeth. There are four layers to a tooth. The pulp is the middle of the tooth made up of soft connective tissue, blood vessels and nerves. The cementum, made of minerals, covers the pulp and helps to anchor the tooth. The majority of the tooth is made up of dentin which gives the tooth its shape. The shiny outer surface of the tooth is made of enamel, the hardest substance in the human body according to the Dental Health Site. There are four types of teeth that work together to help to tear and chew food needed for nutrition.

Types of the teeth

• Incisors

• Canine Teeth

• Pre-Molars

• Molars

Incisors

Incisors, also called cutting teeth, have flat surfaces with a straight, sharp edge. The front 4 top and bottom teeth are incisors, making 8 total incisors in the human mouth. These teeth work to cut and bite food into small pieces that can be chewed by the other teeth. Incisors have one long conical root that anchors it into the jaw bone.

The primary (also known as baby teeth) incisors are the first teeth to erupt. The bottom incisors usually begin to appear between 6 and 10 months of age, according to The Online Knowledge Magazine, while the top incisors appear between 8 and 12 months of age.

Pre-Molars

Behind each canine tooth are two pre-molar teeth, also known as bicuspids. This makes a total of 8 pre-molar teeth in the adult human mouth. The pre-molars have a flat upper surface with at least 2 cusps and are used for chewing and crushing food. The pre-molar teeth have either 1 or 2 roots.

Canine Teeth

The canine teeth are the strong, pointed teeth found in the corners of the mouth. There are 4 canine teeth, two on top and two on bottom. The canine teeth surround the incisors. These teeth are used to shred and tear food.

The top canine teeth are often also called the eyeteeth. The canine teeth are the longest teeth in the mouth and extend beyond the other teeth. Like the incisors, the canine teeth have one single root. In addition, the canine teeth are the only teeth with a single cusp (a rounded projection on the chewing surface of a tooth).

Molars

The teeth found furthest back in the mouth are the molars. There are 12 molars in the adult human body, 3 in each quadrant. The molars have the largest upper surface providing for the maximum chewing and grinding of the food. This is important since the molars are the final teeth food meet before swallowing. Molars have between 2 and 4 roots to anchor them into the jaw bone.

The third molars are also known as the wisdom teeth. These molars are the last to appear, erupting in the late teens to the twenties. The wisdom teeth are often removed due to lack of space in the jaw or because of a partial eruption that can lead to infection.

Teeth Whitening

Teeth whitening is a highly effective way of lightening the natural colour of your teeth without removing any of the tooth surface.

How long will my teeth stay whiter?

The effects of whitening normally last for many years, although thiswill vary from person to person. Inevitably with time the teeth willstart to darken again due to drinks and food (and more rapidly if youare a smoker). Most people like to maintain their whitening effectby using the gel for one or two nights every three to six months.