the teeth- pages 473-475. function of teeth digestive: via mastication (chewing) teeth aid in...
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Ch 5. Skeletal SystemThe Teeth- pages 473-475
Function of TeethDigestive: via mastication (chewing)
Teeth aid in mechanical digestion, in conjunction with the tongue, by breaking food into smaller piecesThis speeds up the chemical digestive process
Arrangement and DentitionLocation: located in sockets called alveoli
Mandible (lower)Maxilla (upper)
Deciduous Teeth (milk teeth) : primary dentitionAppear at 6 monthsCompleted by 2 years (20 teeth)Fall out between 6-12 years
Permanent teeth get larger causing resorption Resorption of roots causes teeth to loosen
Permanent and Wisdom TeethPermanent:
Established at the end of adolescenceFull set is 32 teeth
Wisdom (third molars):Emerge between 17-25 years oldCan be absent in some individualsImpacted wisdom teeth:
Wisdom teeth remain embedded and push on the roots of other teeth Causes pressure and pain
Classification of Teeth:Classification by
shape and function:Incisors: to snip off
foodCanines: to tear
and piercePremolars
(bicuspids): 2-cusp grinders
Molars: 4-5 cusps; best grinders
Deciduous vs. Permanent Teeth
Numbers of Teeth (expressed as only half of the mouth)
Deciduous Teeth = 20 total• On each layer:
• 2I, 1C, 2M = 5• 2I, 1C, 2M = 5
• 10 x 2 = 20
Permanent Teeth = 32 total
• On each layer:
• 2I, 1C, 2P, 3M = 8 • 2I, 1C, 2P, 3M = 8
• 16 x 2 = 32
Tooth Structure:Teeth have 2 main regions:
Crown: (exposed part): Covered by enamel (hardest substance in the body) Dentin underlies enamel – comprises bulk of tooth
Similar to bone in mineral and collagen components Pulp: makes up the middle part of the tooth
Loose connective tissueRoot:
An extension of the pulp cavity, which contains the blood and nerve supply
Surrounded by cementum – a calcified connective tissue
Nerve/Arterial Supply & DisordersThe trigeminal nerve is the main nerve
supplying teethThe arterial supply comes from branches of the
carotid
Disorders:Gingivitis: inflammation of the gingiva
Caused by increased deposits of plaque which increase bacterial populations
Periodontitis: when gingivitis causes infection of the bone and the teeth fall out
Lesson Learned:Brush your teeth after
you eatDon’t let sugar sit on
your teethFloss dailyGo to the dentist at
least 2x/year to get cleanings
ONLY TAKE CARE OF THE TEETH YOU WANT TO KEEP!