teeth Flashcards
4 types of teeth
incisor, canine, premolar, molar
incisor
located in the front part of the jaw, for biting + cutting food chisel-shaped, sharp edge
canine
for tearing food, pointed
premolar
(can have 1-2 roots) for crushing / grinding food broad chewing surface w/ cusps
molar
(can have 2-3 roots) for crushing / grinding the food, has a broader chewing surface than premolar + has more cusps, largest in size
purpose of cusps / broader chewing surface on molars / premolars
helps to generate more force to crush / grind the food
what differentiates the roots of molars from premolars
the roots are more separated
3 parts of a tooth
crown (exposed)
neck (surrounded by the gum)
root (embedded inside the jawbone)
enamel
highly abundant in calcium salts –> enamel is tough, non-living tissue, hardest tissue in the human body
dentine
still mainly made of calcium, bone-like living tissue, not as hard as enamel (as there are less enamel salts)
contains living cytoplasm strands
pulp cavity
centre of tooth, contains blood vessels (supply oxygen and nutrients to teeth) + nerves (detects temp / pressure changes)
cementum
(covers the root of all teeth)
attaches the roots to jawbone through the periodontal membrane
periodontal membrane
connects tooth to jawbone, acts as shock absorber, allows slight movement
why are milk teeth smaller
to accommodate the size of a child’s jaw
when do milk teeth appear and when are they replaced
appear during first 2 years of life, and replaced during the ages of 6-12 by permanent teeth
what is the dental formula and its purpose
how many of each teeth we have on each side of upper / lower jaw (aids dentists)
how many teeth do adults have
32 permanent teeth
why may some people have less teeth
some people may have less than 32 teeth because their wisdom teeth have not come out (possible for it to never come out)
what does saliva contain and how does the substance help in the mouth cavity? + pH
saliva contains sodium hydrogencarbonate –> helps to neutralise the acids created by bacteria in sugar (pH. 7.3)
takes ab 30 min after eating for pH value in our mouth to return to normal
2 oral diseases
periodontal disease
tooth decay
what is tooth decay caused by
caused by action of bacteria in mouth
process of tooth decay
after eating, bacteria + food debris forms a sticky + invisible layer called plaque on the surface of the teeth. bacteria in plaque act on sugars in the food debris to produce acid, which dissolves the calcium salts in the enamel of the teeth, beginning tooth decay
when the tooth decay reaches the pulp cavity, the acid irritates the nerve endings in the pulp cavity and causes toothache
development of tooth decay
- bacteria act on sugar to produce acid, damaging the enamel and making a hole. tooth decay begins
- tooth decay spreads to the dentine, making the hole larger and deeper
- tooth decay reaches the pulp cavity and irritates the nerve, causing toothache
why does the pH in the mouth decrease after eating and eventually increase
pH in mouth decreases after eating bc of the increasing volume of acids produced by bacteria which acts on the sugar in the food
pH in mouth will eventually increase bc salivary glands secrete an increasing amount of saliva, which is slightly alkaline and can neutralise the acids in the mouth cavity
in what cases would one’s teeth require surgical intervention
if wisdom teeth is in wrong orientation –> requires surgical intervention
periodontal disease cause
caused by accumulation of plaque between the teeth (bc of improper brushing of teeth) eventually hardening to form calculus (of which the rough surface leads to the buildup of more plaque)
periodontal disease stages
- plaque accumulates between the tooth and the gums, hardening to form calculus. bacteria in the plaque secretes toxins, causing the gums to become red and swollen
- the calculus spreads downwards and pushes the gums away from the tooth
- (in serious cases, where it is left untreated) the periodontal membrane and the jawbone are destroyed –> tooth becomes loose and falls out
ways to protect teeth / gums
- brushing teeth twice a day
- using toothpaste that contains fluoride –> strengthens enamel
- using dental floss –> remove plaque
- chewing sugar-free gum after meals –> stimulate secretion of saliva
- balanced diet w/ sufficient calcium + vit d to maintain strong teeth
- avoid frequent snacking (as it creates an acidic environment in the mouth, which increases the risk of tooth decay occurring)
- dental checkups at least once a year
effects of soft drinks have on pig’s teeth exp: iv / dv / cv?
IV: concentration of soft drinks (10%-30%)
DV: change in mass of tooth
CV: volume of soft drink / brand of soft drink / type of teeth (as different types of teeth may vary in surface area)
effects of soft drinks have on pig’s teeth exp: effects
colour changes from white to brown (bc of the food colouring in the soft drink staining the tooth)
texture changes from smooth to rough + hard to soft (as the enamel is dissolved) // mass decreases
