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Harbour Bridge - Sydney - Australia

The Harbour Bridge is a steel arch bridge that allows trains, cars and pedestrians to cross the Sydney Harbour. With the Opera House, the Harbour Bridge is an icon of both the city Sydney and Australia.

Pink Flamingo - Galápagos - Ecuador

These birds with long and curved necks, are the only birds to be tall and pink. They are found not only in the Galápagos Islands, but also on some islands in Central America and some parts of Africa and Asia.

Kylemore Abbey - Connemara - Ireland

This Neo-Gothic castle is located in the region of Connemara. It was built by Henry Mitchell who later offered it to his wife. Today the monastery became a school for girls and is run by nuns.

Zambezi River - Zimbabwe

The Zambezi River has its origins in the low-lying floodplains where Zambia, Zaire and Angola meet, an area from which water flows both northwest into the Congo system and the Atlantic, and southwest into the Zambezi system and the Indian Ocean.

Primary Teeth

Primary teeth (baby teeth or deciduous teeth) are teeth that appear in the mouth of a child and stay there for some years before falling and leaving their place to permanent teeth. There are 20 deciduous teeth including eight incisors, four canines, and eight molars.

They begin to come out from the gums around the age of 6 to 7 months, normally starting with the two lower central incisors. The second primary molars emerge between 24 and 30 months. The set of deciduous teeth should therefore have completed full eruption around the age of 3 years and any delay of more than one year of this chronology is to be regarded as pathological.

Primary teeth have anatomical and physiological differences when compared to permanent teeth. The enamel is thinner and more translucent, making teeth look paler. The enamel is also less mineralized, whereas dental cavities and baby bottle tooth decay become more common. The pulp chamber is larger; therefore if an aggressive cavity is to form, dental abscesses arise more easily.

Eruption Pattern of Primary Teeth
Upper Teeth	Eruption Time	Age of Loss of Tooth
Central Incisor	8 to 12 months	6 to 7 years old
Lateral Incisor	9 to 13 months	7 to 8 years old
Cuspid	16 to 22 months	10 to 12 years old
First Molar	13 to 19 months	9 to 11 years old
Second Molar	25 to 33 months	10 to 12 years old

Lower Teeth	Eruption Time	Age of Loss of Tooth
Central Incisor	6 to 10 months	6 to 7 years old
Lateral Incisor	10 to 16 months	7 to 8 years old
Cuspid	17 to 23 months	9 to 12 years old
First Molar	14 to 18 months	9 to 11 years old
Second Molar	23 to 31 months	10 to 12 years old

Dental Classification

References

Naudin C., Grumbach N., Larousse Médical, 3ième édition, Paris, 2003.
Marcovitch H., Black's Medical Dictionary, 41st edition, London, 2005.
Leikin J. B., Lipsky M. S., Complete Medical Encyclopedia, First edition, New York, 2003.
Wikipedia, the free encyclopedia (www.wikipedia.org).
Last update: 9th of March 2008.