Tooth Morph: Ch. 17 - Posterior Teeth

Comprehensive practice questions and answers covering posterior tooth anatomy, root and furcation measurements, developmental anomalies, and groove morphology.

On which tooth is the distal cusp the smallest with a sharp cusp?

Mandibular 1st Molar

What is the sharp, deep, V-shaped linear depression found on the occlusal table called?

Developmental/Primary Grooves

Which tooth has the greatest mesiodistal width of any tooth in the oral cavity?

Mandibular 1st Molar

Which cusp of the permanent maxillary second molar shows the most variability?

Distolingual Cusp

Which anatomical feature of the permanent maxillary first premolar resists torquing forces?

Mesial Root Concavity

What are the spaces between the roots called?

Furcation Crotches

Which furcation on the maxillary first molar is located 4mm apical to the CEJ?

Buccal Furcation

On which teeth is the mesiolingual cusp outline longer and large, but not as sharp as the distolingual cusp outline?

Maxillary 1st and 2nd molar

What is the disturbance in which a tooth does not follow its usual course and intercepts a primary tooth, causing premature loss and malposition of the permanent tooth?

Ectopic Eruption

What are the shallower, more irregular linear depressions on the table that branch from developmental grooves?

Supplemental/Secondary grooves

What structure borders the occlusal surface and is located on the mesial and distal surface?

Marginal Ridge

What feature is located in the deepest parts of the fossae?

Occlusal Pit

Which furcation is predisposed to develop periodontal disease due to its limited access and narrow furcation entrance?

Distal Furcation

What condition is characterized by a crown with an abnormally shaped occlusal surface displaying berry-like nodules or tubercles of enamel instead of cusps?

Mulberry Molars

On the permanent maxillary first molar, which furcation is located 2/3 of the way across the surface from the buccal aspect and 3mm from the CEJ?

Mesial Furcation

Which teeth feature a much smaller and nonfunctioning lingual cusp compared to the buccal cusp?

Mandibular 1st Premolar

What are the cusp ridges that descend from the cusp tip towards the central part of the occlusal table?

Triangular Ridge

Which tooth is wider buccolingually on the mesial than on the distal?

Mandibular 3rd Molar

What developmental disturbance is a deposit of enamel that is apical to the level of the CEJ, and is found on the buccal surface of the second molar?

Enamel Pearl

Which tooth is lingual and offset to the mesial?

Maxillary 2nd Premolar

Which furcation is located halfway between the buccal and lingual root on the distal surface 5mm from the CEJ?

Distal Furcation

What term describes a smaller crown with one cusp or a peg molar?

Microdontia

What is the union of the root structure of two or more teeth through the cementum only called?

Concrescent

Which permanent teeth can have a lingual pit that is at risk for caries?

Maxillary 1st Molars

Which tooth exhibits a longer mesial cusp slope than distal cusp slope, a deeper mesial CEJ curvature, a marginal groove, a developmental depression, and a deep mesial root concavity?

Maxillary 1st Premolar

What is the occlusal surface bordered by the marginal ridges called?

Occlusal Table

How many cusps do the occlusal surfaces of a premolar have?

2 or more

What do four cusp ridges descending from each cusp tip make?

Goth Pyramid

What is the joining of 2 triangular ridges that cross the occlusal table transversely called?

Transverse Ridge

What is each shallow and wide depression on the occlusal table considered?

Fossa

What groove is the most prominent developmental groove that travels mesiodistally separating the occlusal table buccolingually?

Central Groove

What crosses the marginal ridges and serves as a spillway?

Marginal Groove

What separates a marginal ridge from the triangular ridge of a cusp?

Triangular Groove

The HOC for a premolar is at the ____ on the buccal surface and at the ___ for the lingual surface.

Cervical 3rd, Middle 3rd

The CEJ for premolars are:

Less pronounced, quite straight

What is the single root on the base of the crown in which premolars/molars originate from called?

Root Trunk

Having 2 roots

Bifurcated

Having 3 roots

Trifurcated

What is the area between 2 or more root branches before they divide called?

Furcation

First maxillary premolars erupt at ages ___ and root completion is at age ___.

10, 11 and 12, 13

Second maxillary premolars erupt at ages ___ and root completion is at age ___.

10, 12 and 12, 14

First maxillary molars erupt at ages ___ and root completion is at age ___.

6,7 and 9, 10

Second maxillary molars erupt at ages ___ and root completion is at age ___.

12, 13 and 14, 16

First mandibular premolars erupt at ages ___ and root completion is at age ___.

10, 12 and 12, 13

Second mandibular premolars erupt at ages ___ and root completion is at age ___.

11, 12 and 13, 14

First mandibular molars erupt at ages ___ and root completion is at age ___.

6, 7 and 9, 10

Second mandibular molars erupt at ages ___ and root completion is at age ___.

11, 13 and 14, 15

All posterior teeth are wider labiolingually than mesiodistally except:

Mandibular Molars

What is the function of the premolars?

Assist molars in grinding food

A premolar crown’s outline is ___ shaped from the buccal and lingual view.

Pentagonal

A premolar’s buccal surface is rounder and has a prominent centrally placed vertical:

Buccal Ridge

True or False: Maxillary first premolars are larger than the maxillary second premolars.

True

A premolar’s crown outline is ___ shaped from the proximal aspect (view).

Trapezoidal

A maxillary premolar crown’s outline is ___ shaped from the incisal (occlusal) view. (2 cusps of equal size)

Hexagonal

True or False: Premolar roots are shorter than canine roots. (Premolars have slight lingual and distal inclination and it’s cervical cross section is elliptical)

True

The maxillary first premolar’s cervial cross section follow the crown form which is ___ shaped.

Kidney Bean

Which premolar’s crown is the widest mesiodistally of all the premolars? It is also the only teeth in the permanent dentition that has a buccal cusp with the mesial cusp slope longer than the distal cusp slope.

Maxillary 1st premolars

True or False: Both maxillary first and second premolars have a lingual cusp that is offset towards the mesial.

True

Which tooth has a mesial developmental depression located cervical to the contact area in the proximal view?

Maxillary 1st Premolars

True or False: Between cusp ridges or the maxillary premolars, there are 4 buccal-inclined cuspal planes - MB, ML, DB, and DL. ONLY the ML and DL cuspal planes function during occlusion.

True