WEEK 1- Skull and teeth Flashcards
Fontanelles
close after birth
Where are the 4 different fontanelles
- anterior- top front (9-18months)
- Posterior- back- fuses between 1-2 months
- Sphenoidal- side
- Mastoid- mastoid process at back- allow folding at birth canal
How can age be seen
By whether the fontanelles are closed- babies
What are formed when fontanelles close
Sutures
How many bones are there from newborns to adults?
28 bones vs 22 bones in an adult
8 cranial, 14 facial
How long do the bones remain separate?
12-18 months
What are the different types of sutures? and where are they?
Metopic suture- top down face coronal sutures- top of skull to each side squamosal suture- sides sagittal suture- down midline lambdoid suture- posterior
What is craniostenosis
problem with fusing of skull
1-2000 births
What are the 2 types of craniostenosis?
- sagittal cranostenosis
- sagittal fused too early
- bone cant carry on growing out width wards= long and narrow - left coronal craniostenosis
- unilateral fusion, difference in both sides of face
- impacts on orbits (difference in eyes)
- right side= no fusion= normal eye, left side= elevated eye= fuses too early
Remodelling the maxilla and mandible during maturity
- most growing of skull takes place before birth= cranium growth
- brain might grow up to a year
neural connections happen by 1 year
but length of mandible and maxilla increase after birth- elongate and move forward
How does the mouth change after birth?
Babies don’t have teeth
breathing different
mouth gets bigger
When does the skull stop growing?
CT scans of 100 men and women show bones in the human skull continue to grow as people age
- forehead move forward
- cheeks move back
- secondary marker of ageing
What happens to the face as the bones move?
Overlying skin and muscle also move
subtly change shape of face
Osteometric points
Defined set of points on the skull used to aid osteology often key landmarks or sutures
osteometic points (16)
- Glabella
- Gnathion
- Gonion
- Labrelle inferious
- mentolabial sulcus
- menton
- mid- nasal
- mid-philtrum
- mid ramus
- naison
- pogonion
- prosthion
- rhinion
- subnasale
- vertex
- Zygion
Glabella
Small depression medial to supraorbital ridges and superior to nasal bones (middle above eyebrows)
Gnathion
The most anterior-inferior, mid-sagittal point on the border of the mandible ( bum Chin)
Gonion
the most inferior, posterior and lateral point of the angle of the mandible (jaw side)
Labrale inferiorus
the point where the superior vermillion border (coloured edge of the upper lip) meets the midsagittal (median) plane (middle of bottom lip)
Mentolabial sulcus
sulcus between the lower lip and chin (indent before chin)
menton
Most posterior inferior, mid sagittal border of the mandible (underneath chin jaw bone)
Mid nasal
mid point between superior and inferior border of the nasal bone in the mid sagittal (median) plane (bump in nose)
Mid- philtrum
mid point between 2 vertical grooves (philtrum) under nose (middle of bottom of nose and upper lip)
Mid ramus
mid point between condyle and angle of the mandible (jaw joint)
Nasion
intersection between frontonasal suture and mid sagittal (median plane) (between eyebrows)
Pogonion
The most projecting point in the mid-sagittal (median) plane of the chin. (point of chin)
Prosthion
The most anterior point on the maxillary alveolar process in the midsagittal plane.(top of upper teeth)
Rhinion
Free border of nasal bone and mid-sagittal plane.(tip of nose)
Subnasale
Point where nasal septum and upper lip merge in the mid-sagittal plane. (Mid nostrils, septum)
Vertex
Meeting point of 4 cranial bones (occipital, frontal and 2x parietal bones). (top of skull)
Zygion
Most lateral point of the zygomatic arch. (cheek bone- lateral )
Number of bones of the skull
8 neurocranium bones
14 bones of viscerocranium
Bones of the neurocranium
- Frontal- forehead
- sphenoid- temples
- ethmoid- inside nose
- occipital -inside at back
5/6. temporal x2- side of head
7/8. parietal- x2- back of head k
Bones of viscerocranium
- mandible- jaw
- vomer- septum
3/4. nasal bones x2- sides of nose
5/6. lacrimal bones x2- corner of eye
7/8. inferior nasal conchae x2- nostrils
9/10. palatine bones x2- mouth palate
11/12- maxilla- above lip all around nose
13/14- zygomatic x2- cheeks
What is forensic odontology?
Branch of forensic medicine that deals with the proper examination, handling and presentation of dental evidence in a court of law
What does forensic odontology include?
identification of human remains through dental records, age, estimation on the living and diseased.
- Analysis of weapon marks and bite analysis
- helps reconstruction of social environment
2 main areas of the oral cavity
- Vestibule- space between teeth and inner mucosal lining of lips and checks
- oral cavity proper- within the 2 arcades- behind teeth
What are the upper and lower arches called?
Maxilla and mandible
How many teeth are there and what are they called?
An individual can have up to 32 teeth
incisors, canines, molars and premolars
Why do we have different teeth? function of teeth?
different function of grinding and cutting
work together in act of mastication and speech
One set of 8 teeth from medial to lateral
- Central incisor
- lateral incisor
- cuspid
- 1st bicuspid
- 2nd bicuspid
- 1st molar
- 2nd molar
- 3rd molar (wisdom tooth)
What is part of the oral cavity proper?
palatine tonsil uvula soft palate- rough of mouth body of tongue submandibular ducts- underneath tongue
What are the different surfaces of the teeth?
Incisal, occlusal, mesial, distal, buccal, palatal, linguinal, labial, cervical
What is incisal and occlusal surface?
incisal-biting edge of the incisors and canines
occlusal- biting surface of the premolars and molars
Surfaces of the sides of the teeth?
Mesial- surface of tooth nearest the mid-line of the arch
Distal- the surface of the tooth furthest away from the mid-line of the arch
labial- the surface facing the lips
Buccal- surface facing the cheeks (molars and premolars)
Surface of teeth facing the inside?
palatal-surface facing the
palate- upper teeth
lingual- surface facing the tongue- lower teeth
4 main dental tissues
- Enamel
- dentine
- cementum
- Pulp
What is enamel?
hardest substance
white tissue- visable
no blood or nerve supply
formed before tooth erupts- made of minerals (96% hydroxylapatite)
- Damage to the enamel cant be repaired
- damaged by wear, acid erosion, fracture
What is dentine?
lies below enamel
70% mineralised, rest structures and water
yellow appearance
brittle and differs in growth throughout life
- contains dentine tubules- radiate from centre of tooth (pulp)
- tubules full of fluid- carry sensation
What is cementum?
Similar to dentine
50% mineralised
surface covering root - link between periodontal ligament that holds tooth to bone
What is pulp?
Centre of tooth shape and size varies but like a canal - keeps tooth supplied with moisture and nutrients - contains nerves - pulp inflamed= pulpitis
How are teeth divided in a dental chart?
midline divide and by the oral cavity- left right and upper and lower
8 teeth each section
1. central, 2. lateral. 3. cuspid. 4/5. bicuspid 6/7. molars 8. premolar
How does tooth decay happen?
Presence of acid in food
mixture of food debris and bacteria form a film over the teeth= plaque- bacterial waste (acid)- tooth decay
Symptoms of tooth decay
Discolouration
sharp, long lasting pain- when eating/drinking
dull long-lasting throbbing toothache
infected or damaged
Deciduous teeth (baby/ milk teeth) - takes 6 months until 20 to lose teeth
- pulp chambers are wider and more vascularised
- deciduous teeth are smaller and enamel is whiter/ more opaque
- these teeth are more bulbus and the cervical junction is more pronounced
- roots are shooter and narrower and they feature resortion of the roots
the first primary teeth erupt at what age?
6 months
- often lower teeth erupt first
First permanent teeth?
6 years
When do most kids have all their primary teeth?
2 1/2 years
What is teething?
Eruption of teeth - often not painless
don’t cut through gums- gums melt and tooth emerges
What are dental materials?
Presence of a restoration in a tooth gives a unique picture of an individual
What are the commonly used materials for tooth restorations?
amalgams- lead based
composities- tooth coloured restorations
Temporary fillings, gold crowns, bridges
How do we look at dental materials
X Ray
similar radiography of the antemortem and post-mortem
Key stages of development of human dentition
seen prenatal- not erupted
- first erupt 6 months
- 6 years all primary teeth through- start to fall out
- 12 years- all adult teeth except 2nd molars and pre molars through
- 21 years pre molar comes through- wisdom teeth
