EMB ch16-17 Eruption Sequence

What are the four developmental lobes found on anterior teeth?

Three labial lobes (mesiolabial, middle labial, distolabial) and one lingual lobe

What are mamelons?

Rounded enamel extensions on the incisal ridge of newly erupted incisors, formed from the three labial developmental lobes

Why do mamelons appear translucent?

They are composed of enamel with no dentin layer underneath

What typically happens to mamelons over time?

They wear away through attrition as the teeth come into occlusion

What does it mean if mamelons are still present long after eruption?

The teeth are likely not in occlusion, such as with an anterior open bite

What is a labial developmental depression?

A vertical groove on the labial surface marking the division between labial developmental lobes

What is the cingulum?

A raised, rounded area on the cervical third of the lingual surface, corresponding to the lingual developmental lobe

Which permanent tooth has the largest, most prominent cingulum?

The maxillary canine

What is a tubercle?

A small extra projection or accessory cusp, often located on the cingulum

What is a talon cusp?

A sharp, small extra cusp projecting from the cingulum, shaped like a claw

Why are talon cusps clinically significant?

They can interfere with occlusion and often contain a pulp horn, increasing risk of pulpal exposure during odontoplasty

What is a fossa?

A shallow, wide depression on the tooth surface

What is a developmental pit?

A sharp pinpoint depression located at the deepest part of a fossa, marking where developmental grooves meet

What is a developmental (primary) groove?

A sharp, deep V-shaped linear depression marking the junction between developmental lobes

What is a supplemental (secondary) groove?

A shallower, more irregular linear depression that branches from a developmental groove

How does groove complexity change as you move posteriorly in the arch?

The further posterior the tooth, the more grooves and pits it has, and the more complex the surface becomes

What is a marginal ridge?

A rounded raised border on the mesial or distal edge of the lingual (anterior) or occlusal (posterior) surface

What is a cusp?

A pointed elevation on the occlusal or incisal surface of a tooth, shaped like a pyramid with sloping ridges

What are cusp ridges?

The sloping ridges that descend from a cusp tip, forming the sides of the cusp

What is a triangular ridge?

A ridge that runs from a cusp tip toward the center of the occlusal surface, named for its cusp of origin

What is a transverse ridge?

A ridge formed by the union of two triangular ridges from opposite sides of the tooth, crossing the occlusal table from buccal to lingual

What is an oblique ridge?

A ridge formed by the union of the triangular ridge of the distobuccal cusp and the distal cusp ridge of the mesiolingual cusp, crossing the occlusal table diagonally

Which teeth have an oblique ridge?

Maxillary first and second molars (not the third molar)

Do mandibular molars ever have an oblique ridge?

No, an oblique ridge is never present on mandibular molars

What is a central fossa?

A depression where several cusp ridges converge at a central point on the occlusal surface

What is a triangular fossa?

A depression formed where triangular grooves terminate, bordered by a marginal ridge

What is an occlusal pit?

A sharp pinpoint depression at the deepest point of a