I received a text last week from a woman in Makurdi, Benue State. She has three children aged 9, 7 and 41/2 years. She has had three teeth extracted by dentists, and still counting. She wanted me to educate her on teeth, since she had suffered much dental disorders, she did not want her children to suffer the same fate.
“Go to a dentist” I replied. “You know you doctors hardly have time, to explain anything in details to anybody. I like the way you break down and discuss difficult diseases”, she blackmailed me. So here I am leaving the second part of “Ageing-10 ways to fight brain damage”, to discuss teeth. She also wanted me to use ordinary language(whatever that means). This was despite my concern for the catastrophic flood that has just ravaged Benue State and my worry for the attendant flood water born diseases on her family and Benue State
How do we describe the teeth?
• Teeth are hard structures set in bony sockets in the upper and lower jaws. Their main function is to chew and prepare food for swallowing.
• Teeth also help in the articulation of sounds in speech.
• In humans, there are 3 types of teeth 1) Incisors. 2) Canines and 3) Molars.
1) Incisors; are sharp, chisel-like-teeth at the front of the corners of the mouth, used for cutting into food.
2) Canines; are round pointed teeth at the corners of the mouth, used for tearing and gripping food.
3) Molars; are square teeth with small cusps, which grind food at the back of the mouth.
• A tooth consists of two parts a) root – is embedded in the jaw and b) crown – projects out of the jaw. Where the root and the crown meet is called the neck.
• Each tooth is made up of a) enamel b) dentine c) pulp and d) cementum.
a) enamel – is the hardest tissue in the body, and it protects the sensitive crown of the tooth.
b) dentine – is a slightly elastic material which forms the bulk of the tooth under the enamel. It is sensitive to heat and chemical.
c) pulp – is the soft tissue inside the dentine and contains nerves and blood vessels, which enter the root of the tooth by a small canal.
d) cementum – is a thin layer of material which covers the root of the tooth and protects the underlying dentine. It also helps attach fibres from gum to the tooth
Note – whenever the enamel and dentine are eroded our dental problems have just begun. Cold water, hot water, all chewables become a tug of war. I shall tell you what I told the Benue woman to do, to either prevent dental disorders in her children, or arrest her own from further deterioration.
When do teeth appear in humans?
In humans, there are two successive sets of teeth – 1) Primary or milk teeth and 2) permanent teeth.
1) Primary teeth – arrive 6 to 24 months after birth. Please note upper limit. A woman once rushed her son to my hospital, crying that her son was yet to erupt a tooth after 12 months. I assured her that her son was normal. Two months later the first tooth erupted. The primary teeth, gradually fall out, from the age of 6 years , and the permanent teeth replace them.
2) Permanent teeth – These start to replace milk teeth, from the age of 6 and most of them are out by the age of 13, but the 3rd molar or “wisdom tooth” can erupt as late as the age of 25 or never.
• Human teeth do not keep growing, but reach a certain size then stop. Also, when the permanent teeth fall out, they are not replaced by a new set.
• But in some animals, such as the rabbit, the Incisors keep growing, as they are worn down by use, while the shark grows set after set of teeth – to its great advantage!
At what age does each tooth appear?
Under listed, are average figures only, dates of teeth eruption vary greatly from child to child.
Primary teeth – 1) Central Incisors – 6 to 10 months(one tooth). 2) Lateral Incisors – 9 to 11 months ( 2 teeth). 3) Eye teeth – 18 to 20 months (4 teeth). 4) First molars – 14 to 17 months (3 teeth). 5) Second molars – 24 to 26 months (5 teeth).
Permanent or Adult teeth. 1) Central Incisors – 7 to 8 years (2 teeth) . 2) Lateral Incisors – 8 to 9 years (3 teeth). 3) Canines – 12 to 14 years (6 teeth). 4) First Pre-molars – 10 to 12 years (4 teeth). 5) 2nd Pre- molars – 10 to 12 years (5 teeth). 6) First molars – 6 to 7 years (one tooth). 7) 2nd molars – 12 to 16 years (7 teeth) . 8) 3rd molar – 17 to 21 years (8 teeth).
Next week we shall discuss dental disorders. Meanwhile rinse your teeth and mouth after taking any food especially sugary things, and brush your teeth last thing before you sleep.
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