Oral histology LO 3 part 2

After

The process of root development takes place ————— the crown has been completely shaped.

Cervical loop

The structure responsible for root development is the ——————— ————. The ——————— ———— is the most cervical part of the enamel organ, a bilayer rim that consists of only IEE and OEE.

Hertwigs epithelial root sheath (HERS)

The cervical loop begins to grow deeper into the surrounding ectomesenchyme of the dental sac, elongating and moving away from the newly completed crown area to enclose more of the dental papilla tissue and form:

Hertwigs epithelial root sheath (HERS)

The function of this is to shape the root(s) and induce dentin formation in the root area, so that it is continuous with coronal dentin.

Odontoblasts

Root dentin forms when the outer cells of the dental papilla undergo differentiation and become ————————. After the differentiation of ———————— in the root area, these cells undergo dentinogenesis and begin to secrete predentin.

Epithelial rests of Malassez (ERM)

When root dentin formation is complete, there is disintegration of the root sheath, its cells may become this. The remanence of the HERS when it doesn’t fully disintegrate.

Cementoid

The cementoblasts move to cover the root dentin area and undergo cementogenesis, laying down cementum matrix or ——————— (partially mineralized cementum).

Cementocytes

Many cementoblasts become entrapped by the cementum they produce and become mature:

Dentinocemental junction (DCJ)

As a result of the apposition of cementum over the dentin, the —.—.—. Is formed. Also at this time, central cells of the dental papilla are forming into the pulp. The pulp tissue is surrounded by the newly formed dentin.

Concresence

Excess cementum formation can rarely occur with this developmental anomaly. This is where the roots of 2 teeth join together by the cementum.

periodontal ligament (PDL)

The ectomesenchyme from the dental sac begins to form the —.—.—. This process involved forming collagen fibres that are immediately organized into the fibre bundles of the —.—.—. The ends of these fibres insert into the outer part of the cementum and the surrounding alveolar bone to support the tooth.

Cervical loop (made up of IEE and OEE)

The structure responsible for root formation is the:

Enamel pearl.

In some cases, misplaced ameloblasts can migrate to the root area, causing enamel to be abnormally formed over the root surface, which produces an:

Dilaceration

———————— results in either distorted root(s) or crown angulation in a formed tooth. It's caused by a distortion of HERS due to an injury or pressure; it can occur in any tooth or group of teeth during tooth development. This doesn't pose an issue unless an exo or RCT is indicated.

Root.

Eruption begins with the development of the:

Eruption causative factors

These are all ————— causative factors:

1. Root growth

2. Changes in vascularity

3. Increased cellular activity around the forming tooth

4. Endocrine factors (growth hormone)

5. Enzyme activity.

Reduced enamel epithelium (REE)

This is the 1st step in tooth eruption: After enamel apposition ceases in the crown area of each primary or permanent tooth, the ameloblasts place an acellular dental cuticle on the new enamel surface. AND, the layers of enamel organ (OEE, stellate reticulum, stratum intermedium, and IEE that are now differentiated into ameloblasts) are compressed, forming the:

Oral epithelium

This is the 2nd step in tooth eruption: To allow for the eruption process, the REE first has to fuse with the ———— ——————— lining the oral cavity.

Epithelial tunnel

This is the 3rd step in tooth eruption: the enzymes from the REE then disintegrate the central part of the fused tissue, leaving an ——————— ————— for the tooth to erupt through the surrounding oral epithelium into the oral cavity.

Junctional epithelium

As a primary tooth erupts, the coronal part of the fused epithelial tissue peels back off the crown, leaving the cervical part still attached to the neck of the tooth. This fused tissue that remains near the CEJ after the tooth erupts then serves as the initial ——————— ———————.

Lingual

When a primary tooth is lost, the succedaneous permanent tooth has developed ————— to it.

Osteoclasts

During the process of exfoliating primary teeth, these cells absorb the alveolar bone between the 2 teeth (primary and permanent).

Odontoclasts

In the process the exfoliation, these cells cause resorption or removal of parts of the primary tooth's root of dentin and cementum as well as small parts of the enamel crown.

Apical

As the primary incisors erupt, permanent successors are lingual to the ————— third of the primary tooth.

Underneath

Permanent premolars shift from locations near the occlusal area of primary molars to ——————— the primary molars between the roots. This causes lengthening of the face as we mature and increases the height of alveolar bone.

Dentigerous cyst (follicular cyst)

An odontogenic cyst that forms from the REE after the crown has completely formed and matured is the ———————— ————

Eruption cyst

If a dentigerous cyst appears on a partially erupted tooth, it is considered an ——————— ———— and appears as fluctuant, blue, vesicle-like gingival lesion.

Naysmith's membrane

A residue may form on newly erupted teeth of both dentitions that may leave the teeth extrinsically stained. This residue, ——————— ———————, consists of the fused tissue of the REE and oral epithelium as well as the dental cuticle placed by the ameloblasts on the new enamel surface.