Oral Anatomy 2 Flashcards
How many teeth in each arch ? Primary
10 each arch
Eruption date - Primary teeth
- A- 6months
B- 9 months
C- 18 months
D- 12 months
E- 24 months
When root formation completed?
- Root formation complete approx 1-1.5 years after eruption
Tooth development at Birth (Crown formation )
A - 1/2
B- 1/2
C- 1/3
D- cusp
E- TIp
6- Just
When Root formation complete for secondary dentition?
2-3 years after eruption
Supernumeries teeth
- Extra teeth
- 1-2 % population.
- Most common - Upper anterior
- Present delay eruption
- often diagnosed in radiographs
Hypodontia
- Missing teeth
- 6.4 % population ( not 8s’)
- 2% - missing lateral incisors
-L5 > U2 > U5 > L1 > others
Stages of Odomtogenesis?
- Initiation - Thickening
- Bud - Morphogenesis
- Cap- Differentiation
- Bell - mineralisation
- Erupted tooth - Eruption root formation
How are enamel , dentine, cementum and bone similar but different?
- Development origin
- Cells
- Process and degree of mineralisation
- Organic and inorganic content
Define Enamel
- Cell- Ameloblast
- origin - Epithelial
- Present through out life ? No
Enamel composition?
- 95-96 % calcium Hydroxyapatite crystals (inorganic component)
- 1-2 % Non - amelogenin protein ( Organic protein)
- water - 2%
Dentine
- Cell- Odontoblast
- Origin - Mesenchymal
- Present through out life- Yes
Dentine composition?
- 70 %Calcium hydroxyapatite crystals (inorganic)
- 20 % Collagen types 1, 3, 5 non collagenous proteins
- 10% water
Cementum define?
- Cell - Cementoblast
- Origin - HERS (controversial)
- Present throughout life : yes
Cementum composition ?
- 65 % hydroxypetite crystals
- 23% collagen type 3,5,6,12.
- 12% water
Define Pulp
- Cell - Fibroblast
-Origin - Mesenchymal - Present thougout life? Yes
Pulp composition?
- 0 % in organic
- 75% fibres + semi fluid gel. organic component
- 25% water
Periodontal ligament
- Cell - Majority Fibroblasts
- Mesenchymal
- Present through out life? Yes
Periodontal ligament Composition?
- > 90% collagen fibre
- <10% oxytalan and reticulin fibres
Types of bones
- Cortical Bone ( compact bone) strong
- Cancellous ( Spongy or trabecular bone) weaker
- Woven bone - Weak
- Lamellar Bone - strong
Alveolar Bone anatomy
- Interdental septa - Between teeth present
- Interradicular septa- Between root present
- lamina dura and bundle bone
Defects of development
- Teeth provide good record of development disturbances.
- Defects of number - Anodontia / hypodontia or supernumeraries
- Complicated dental malformations - Odontomes
- Defects of size - micro/ macrodontia
- Defect of amelogenesis - Hypoplasia / Hypo-calcification
Suernumeries between midline called?
- Mesiodens
Define Hypoplasia
- Enamel defect characterised thin or absent enamel
Hypomineralisation
- Severely ill childhood , traumatic birth , high fevers can cause disturbance in tooth formation
Caries
- The breakdown of tooth surface from acid produced by bacteria.
What cause caries ?
-Time
- Substrate (carbohydrates sugar)
- Susceptible tooth surface
- Bacteria
Caries
- Risk of developing caries lesion around bracket is high
- 50% of patients - Caries
- first sign of caries - white spot lesion
- Remineralisation - OHI + Flouride
- GDP can carry out cosmetic tx- Microabrasion and bleaching
If you see caries what should you do?
- Don’t use sharp probe in region
- Ask orthodontist to check
- Document in notes
- Referral to GDP for filling
If you see caries what should you do?
- Don’t use sharp probe in region
- Ask orthodontist to check
- Document in notes
- Referral to GDP for filling
How to prevent caries
- Diet advice
- OHI
- Fluoride
How can you get Fluoride?
- Toothpaste 1350 to 1500 ppm
- Mouthwash 225ppm sodium fluoride
- Fluoride varnish
- Fluoridated water
- Fluoride supplements
- Naturally food substance : Spinach, black tea, raisins, grapes
What does fluoride do?
- It is used to help to reduce decalcification and remineralise enamel
Flouride - Mechanism of action
- Enamel crystals undergo demineralisation on acid exposure.
- When fluoride is present in saliva , FLUORAPATITE rather than hydroxyapatite, forms during remineralisation .
- Fluroapatite is less soluble than hydroxyapatite making it more resistance to demineralisation during future acid attacks.
How does fluoride work?
- Swallowed fluoride - become part of developing permanent teeth in children.
- Applied fluoride - helps to speed remineralisation
- High concentration fluoride disrupt production of acids by bacteria
Oral hygiene instruction for remineralisation
- Brush 2 a day
- Brush 2 minutes (manual / electric toothbrush)
- Spit ! Do not rinse with water
- Use mouthwash at different time to brushing
Diet advice
- Three main meals per day with one other snack
- Limit sugar containing food and drinks with meal time
- Snack should be teeth friendly food
- Only water between meals
- Diet diaries are useful
Tooth Mousse
- contains Casein protein
- No fluoride
- Aids remineralisation
- useful for removing white spot which develop during ortho tx.
- Reduce sensitivity
Position of oral cavity
Anterior border - lip
Posterior border- Oropharynx
Superior border- Hard palate
Inferior border- floor of the mouth
Oral cavity divided into ?
- Vestibules ( Space between lips and teeth)
- Oral cavity ( The cavity between teeth and pharynx )
Structure of vestibules
1- Lip
2- cheeks
3- Gingiva
4- Fraenum
5- Maxillary tuberosity
6- Retromolar area / triangle
Lips
- Orbicularis oris muscle
- Externally covered with Skin
- Internally covered with mucous membrane
Cheeks
-Buccinator muscles
- Form side of face
- Opening parotid gland visible opposite maxillary second molar
Gingiva
- Alveolar mucosa
- Mucogingival junction
- Attached Gingiva
- Free gingival groove
- Margina Gingiva
Frenum
- Eithelium fold of mucosa
- Superior labial frenum
- Inferior labial frenum
- lingual frenum
Maxillary tuberiosity
-Rounded prominence of bone behind the last maxillary molar tooth
Retromolar area/ triangle
- Area behind last mandibular molar
Structures of Oral cavity
1- Palate
2- palatoglossal arch (fold)
3- Palatopharybgeal arch (fold)
4- Palatine tonsils
5- Uvula
6- Pharynx
7- Tongue
8- Floor of mouth
Palate
- Hard palate - dense mucous membrane and covers palatal processes of maxilla and horizontal plates of palatine bones
- Soft palate - Mobile muscular attachment posterior to hard palate
Feature of palate
1- Incisive papilla
2- Palatine Raphe
3- Rugae (Transverse palatal folds)
Palatoglossal arch (fold)
- Fold of mucosa between palate and tongue covering muscle
Palatopharyngeal arch (fold)
- Fold of mucosa between palate and. Pharynx covering muscle
Palatine tonsils
- Lymphatic tissue located between palatoglossal and palatopharyngeal arches.
Uvula
- Midline projection of mucous membrane from free border of the soft palate
Pharynx
- Area behind nasal and oral cavities and larynx.
- 3 divided
1- Nasopharynx
2- Oropharynx
3- Laryngopharynx
7- Tongue
- Muscular organ
- Dorsal surface covered with papillae
- Consists of intrinsic and extrinsic muscles, salivary glands, taste buds
8- Floor of mouth
- Mucosa covering the mylohyois muscle
Caries
- Substrate
- Time
- bacteria
- Suspect able surface
