Unit 11 Flashcards
Active Eruption
Toot entry to oral cavity to contact w/ antagonist
Passive Eruption
Continuing process of adaptation of the tooth.
No antagonist = supraerupt
Nasmyth’s Membrane
When tooth erupts, keratinous membrane-like enamel cuticle surrounds the crown
-abbraded away
Time lag btwn eruption and root ocompletion for deciduous teeth is….?
1 year
Position of developing permanent teeth
- Perm teeth lingual to succedaneous teeth
- Premolars are in the root furcations of molars
- Perm molars are not succedaneous teeth - buds develop from dental lamina in the alv process, distal to deciduous dentition
Growth causes extra space between teeth (anterior segment of arches), this is known as….
diastemas
What is the first permanent tooth to emerge, and at what age?
Mandibular First Molar, age 6
What are the cornerstones of occlusion in the permanent dentition
4 First molars
Serve as guide for eruption
Loosing deciduous teeth prematurely may cause a tilt/drift mesially - reducing space for canines and premolars
What does changing the space available in the mouth possibly lead to..
Changing first molars relationship w/ antagonist, possible impaction, crowding, or malocclusion
Process by which root of tooth is “melted away”
Resorption
Where does resorption begin
Apex then towards cervical, begins at least 1 year prior to exfoliation
Exfoliation
When root structure is absorbed, crown becomes loosened and is lost
- occurs symmetrically (L/R)
- Mandib teeth precede the same max teeth in exfoliation - exception = 2nd molars (all are lost simultaneously)
Ankylosis
When eruption ceases, tooth becomes fixed, and resorption cannot progress naturally
- when root structure fuses w/ bone
- remove as soon as its diagnosed
Stages of tooth development (alternative)
Initiation Proliferation Histodifferentiation Morphodifferentiation Apposition - laying enamel and dentin
Initiation
Includes dental lamina and bud stages
Affects presence/absence of tooth buds
Proliferation
During bud/ca/bell sages
Influences size and proportions of tooth
Histodiff
Advanced cap stage through bell stage
Formation of potential enamel and dentin forming cells
Morphodiff
Shape and size of tooth, takes place during bud/cap/bell stages
No effect on enamel and dentin forming process
Which dentition is more prone to abnormaliites?
Permanent
Abnormal number of teeth
Anodontia
Supernumerary Teeth
Anodontia
“complete lack of teeth” - missing any teeth
Should be hypodontia
Total or Partial Anodontia
Partial Anodontia
Hereditary Factors Dental lamina may be below threshold ~5% Permanent Max and Mandib 3rd molars > max lat incisor > man 2nd premol In deciduous = man central incisor
Supernumerary
Extra tooth buds diff from dental lam = Genetic Both decid and perm teeth 1. Mesiodens - btwn max central incisors 2. Distodens - 3rd molar region ~1-2%
Abnormal Size of Teeth
Macrodontia
Microdontia
Macrodontia
(Gigantism)
- True macrodontia - pituitary gigantism - all teeth
- False Macrodontia - individual teeth - incisors, canines, man 3rd molars
Microdontia
(Dwarfism)
- True Microdontia - pituitary dwarfs - all teeth
- Individual teeth - max lat incisor (PEG LATERALS), and max 3rd molars
Abnormal Shape of Teeth
- during morphodiff and appositional stages*
1. Taurodontism
2. Dilaceration
3. Flexion
4. Germination
5. Fusion
6. Concrescence
7. Segmented Root
8. Dwarfed roots
9. Hypercementosis
10. Accessory Cusps and Roots
11. Missing Cusps
12. Enamel Pearls
13. Hutchinson’s Teeth
14. Dens in dente
15. Odontoma
Taurodontism
Premolars and Molars Crown occupies greater proportion of the tooth bulk than normal -No CEJ constriction -Furcation - apical half of tooth - Hereditary - w/ other syndromes
Dilaceration
Distortion of the root and crown
- Trauma, injury, pressure
Flexion
Distortion of root portion only
Sharp Bends
Germination
Incomplete splitting of single tooth germ
Wide MD, usually incisor (twinning)
Fusion
Union of two adjacent tooth buds
- Enamel & dentin
- 2 identifiable pulp cav’s
- only the crowns
- ANT teeth
- Deciduous
Concrescence
Unions of root structure through cementum only
- Permanent molars (max)
- After eruption, never involves dentin or enamel
Segmented root
disturbance during root development, seperated root segment
-Break in hertwig’s sheath?
Dwarfed Roots
Root = dwarfed
Crowns = abnormal contour –> great incisocerv convexity on labial surace
- Max Central (bilateral)
- Hereditary?
Hypercementosis
XS cementum
- Perm Molars
- Trauma, metabolic disturb, CHRNOIC INFLAM of PULP
Accessory Cusps
3rd Molars or if anterior - talon cusp (phillips screwdriver)
Accessory Roots
Trauma, pressure, metabolic disease
3rd Molars
Missing Cusps
Usually dimunitive
Enamel Pearls
aka Enamelomas
B/L of Man Molars
M/D on Max Molars
~2%
Hutchinson’s teeth
Hypoplastic Defects (enamel dysplasia)
Prenatal Syphilis
Screwdriver shape w/ deep notch, mulberry appearance w/ gnarled enamel
Dens in Dente
Small tooth w/in tooth
Perm Max Lat Incisor
Lingual Pit–> leads to enamel and dentin in the pulp caivty
Odontoma
Benign Tumor
Complex Odontoma - no dental form - calcified dental tissues
Compound Odontoma - arranged in shape that resembles tooth
Abnormal Calcification and Apposition
Enamel Dysplasia
Dentinal Dysplasia
Enamel Dysplasia
Catchall label - all enamel developmental abnormalities
- Enamel Hypoplasia - during enamel matrix formation
- Enamel hypocalcification - time of disturbance is later than for hypoplasia (during enamel matrix maturation)
Types of Enamel Dysplsia
Amelogenesis Imperfeca
Dental Fluorsis
Focal Hypomaturation
Turner’s Teeth
Dentinal Dysplasia
Tetracycline Staining
Dentinogenesis Imperfecta
Amelogenesis Imperfecta
- Hereditary
- Range: almost no enamel, to depositied to immature enamel
- rampant caries, excessive attrition
- rough surface
Dental Flurosis
XS fluoride
- Hypocalcification problem
- Chalky white bands, pigmented w/ brown or yellow
- resistant to caries
Focal Hypomaturation
- similar to enamel dysplasias
- chalky white and opaque area (circular)
- susceptible to caries
Turner’s Teeth
Individual Teeth
- injury to dev perm tooth follicle
- assymetrical
Tetracycline Staining
Admin of wide-spec antibiotic tetracyclines to mother during prenatal periods or to an infant
- intrinsic color change of dentin
- primary and perm teeth
- yellowing cast, may be gray or purple
Dentinogenesis Imperfecta
Genetic disturbance of dentin formation
- bluish-brown crown = Opalescent dentin
- normal enamel, but fractures easily
