Tooth Eruption & Exfoliation (Exam III) Flashcards
The primary & permanent dentition develop _____ as the jaws increase in size from infancy to adolescence
Simultaneously
Jaws of the infant accommodate development of:
20 deciduous teeth
At 4-5 years of age, the haws accommodate:
20 erupted teeth & 20 developing
The mixed dentition stage occurs at ____ years of age
8-12 years
Involves the concomitant exfoliation of deciduous teeth and eruption of permanent teeth
mixed dentition stage
Defined as the movement of a tooth from its site of development within the alveolar process to its functional position in the oral cavity:
Tooth eruption
What three stages is tooth eruption divided into?
- Pre-eruptive phase
- Pre-functional eruptive phase
- Functional phase (post-eruptive phase)
Pre-eruptive tooth movement results from: (3)
- Growth of jaws
- Growth of tooth buds
- Remodeling of the walls of the bony crypt
Results when there is resorption of the mesial wall with concomitant apposition of bone on the distal wall
Mesial migration
In the pre-eruptive phase, overtime the jaws increase in (4):
- Length of jaw (anterior-posterior)
- With of jaw (coronal plane)
- Alveolar ridge height
- Buccal-lingual with of the alveolus
In the pre-eruptive phase, what region does crowding occur due to the tooth germs rapid growth?
Anterior region
In the pre-eruptive phase, as the jaws increase in length, the crowding is alleviated by migration of the teeth _____ which allows a more even distribution
Distally
In the pre-eruptive phase, with an increased jaw size, the developing teeth move:
Outward (facially) & towards the oral cavity (upward or downward)
In pre-eruptive phase, because of the jaw length, the permanent developing molars have _____ prior to and during eruption and achieve ____ only when the jaw length is sufficient to allow
Angled inclination; vertical alignment
What are the five components to the theories of tooth eruption?
- Root growth
- Vascular pressure
- Selective bone deposition & resorption
- Pulpal pressure
- Periodontal & gingilla fiber ligaments
Theories of tooth eruption:
Elongation of the roots in relation to stability of the fundus of the socket
Root growth
Theories of tooth eruption:
Increased hydrostatic pressures in the apical dental sac or periodontal ligament
Vascular pressure
Theories of tooth eruption:
Coronal bone resorption concomitant with bone apposition in the fundus area
Selective bone deposition & resorption
Theories of tooth eruption:
Tissue pressure differential in the pulp compared to the PDL
Pulpal pressure
Theories of tooth eruption:
Cells (myofibroblasts) exert traction on the tooth through the collagen network and cell-to-cell contacts
Periodontal & gingival fiber ligaments
Theories of tooth eruption:
Of the numerous causes of tooth eruption, the most frequently cited are:
- Root growth
- Alveolar bone remodeling
- PDL formation
Other factors that influence tooth eruption:
- PTH
- MMPs produced by fibroblasts, osteoclasts & macrophages
The gubernacular canal plays a role in:
Eruptive phase
A strand of connective tissue that contains remnants of dental lamina epithelium (derived from the successional lamina)
Gubernacular canal
During the eruptive phase, the rate of eruption is not constant but bet described as a “burst of eruption” that averages about:
3mm every 3 months
During the functional phase of tooth eruption & exfoliation we see what two types of wear?
- Occlusal surface wear
- Proximal wear (mesial drift)
Occurs during the functional phase and is caused by oblique fiber groups of the PDL continually pulling the tooth into occlusion as enamel is abraded
Occlusal surface wear
Apical cementum deposition also serves as a compensatory eruptive mechanism to continual:
Occlusal abrasion
Mesial inclination of teeth in full contact will yield an anterior force vector and when coupled with the pull of the transseptal fibers result in:
Mesial drift
Cell mediated tooth resorption involves the:
Odontoclasts
The odontoblasts involved cell mediated tooth resorption during exfoliation are derived from monocytes that exit capillaries to become connective tissue _____ which, in turn, fuse together to form a syncytium of large multinucleate giant cells that functions like an osteoclast
macrophages
Odontoclasts degrade both the collagenous and non-collagenous matrix of ____ & ____ (lysosomal enzymes) and the hydroxyapatite mineral phase (acids)
Cementum & dentin
Specialized fibroblast-like cells that are thought to destroy the collagen fibers of the PDL associated with the resorbing tooth root
Fibroclasts
Fibroblasts are thought to destroy the:
Collagen fibers of the PDL
The finding of apoptotic cell death in the resorbing PDL suggests that shedding of teeth is:
A programmed event
