Exam 22: Eruption and Shedding of Teeth

Each of the following has a role in tooth eruption EXCEPT for one. Which one is the EXCEPTION?

If a root is damaged during formation, which of the following would occur?

The reduced enamel epithelium and the oral epithelium fuse into the united oral epithelium.

The united epithelium is broken down by enzymatic action of Hertwig's root sheath. Upon breakdown of this epithelium the tooth emerges into the oral cavity.

Which structure acts as a "shock absorber" during the eruption process?

Tooth eruption is dependent upon the dental sac because this structure plays a role in the formation of cementum, the periodontal ligament, and alveolar bone.

As the permanent teeth become surrounded by bone, the successional lamina forms small openings in the alveolar bone, known as

In eccentric growth the crown of a tooth grows in a perfectly symmetrical pattern because all areas grow proportionately as the crown enlarges.

It is possible for a child to have a deciduous tooth and its permanent counterpart at the same time. This can occur when the permanent teeth erupt labially.

Each of the following typically occur with retained root tips EXCEPT one. Which one is the EXCEPTION?

If Hertwig's root sheath is destroyed the tooth will not erupt.

In spatial movement, the crown develops while the tooth socket fills in with bone.

Supra-eruption is

The primary tooth is able to erupt because the gubernacular canal breaks down the bone between the tooth and the surface oral epithelium.

The eruptive movement that pushes the crown of the tooth directly toward the surface is called eccentric movement. Excentric movement occurs during the eruptive stage.

Vascular pressures in the periodontium seem to disrupt eruption because the pulsating blood pressures interfere with cellular activity.

A fully formed impacted third molar is technically in the posteruptive stage because the roots are formed and this tooth would erupt if not impeded by another tooth.

Deciduous ankylosis occurs when

During the pre-eruptive stage bone is in a U-shaped crypt. When the root forms, osteoclasts may deepen the crypt.

Which of the following are necessary for the tooth eruption to occur (select all that apply)?