Dental Hygiene – Molar Anatomy

Vocabulary flashcards covering anatomy, morphology, and unique features of mandibular and maxillary molars for dental hygiene review.

Molars

Posterior teeth specialized for grinding food; typically have 3–5 cusps and are wider mesiodistally than occlusocervically.

Functions of Molars

Include mastication (grinding), maintaining vertical dimension of the face, preserving arch continuity and alignment, and supporting the cheeks for esthetics.

Mastication

The process of grinding food; the primary chewing function performed by molars.

Vertical Dimension of Face

The facial height maintained by proper molar eruption and position, preventing over-closure of the jaws.

Arch Continuity

The uninterrupted alignment of teeth within the dental arch, aided by molars acting as posterior stops.

Molar Class Traits

General features of all molars: 3–5 lobes and cusps, crowns wider than tall, distal marginal ridge more cervical, buccal HOC in cervical third, lingual HOC in middle third, mesial contacts at occlusal/middle junction, distal contacts in middle third.

Buccal Height of Contour (HOC)

Greatest bulge on the buccal surface of molars, located in the cervical third of the crown.

Lingual Height of Contour

Greatest bulge on the lingual surface of molars, positioned in the middle third of the crown.

Mesial Contact Area (Molars)

Point of proximal contact located at the junction of occlusal and middle thirds.

Distal Contact Area (Molars)

Proximal contact situated in the middle third of the crown, more cervical than the mesial contact.

Embrasure Space (Posterior)

V-shaped area around the contact; on molars the contact is more facial, creating a larger lingual embrasure.

Root Trunk

Part of a multirooted tooth between CEJ and furcation; shorter in first molars, longer in second molars.

Furcation

Area where a multirooted tooth divides; bifurcation in mandibular molars, trifurcation in maxillary molars.

Lingual Crown Tilt (Mandibular Molars)

Characteristic inclination of the mandibular molar crowns toward the tongue.

Mandibular Molar Arch Traits

Two roots (mesial & distal), crowns wider mesiodistally, lingual cusps taller, buccal pits, and CEJ curving occlusally on mesial surface.

Buccal Pit

Small depression at the end of a buccal groove on mandibular molars; common site for caries.

Mandibular First Molar

Five-cusped molar (MB, DB, D, ML, DL) with short root trunk, widely spread roots and pentagon-shaped occlusal outline.

Mandibular Second Molar

Four-cusped molar with longer root trunk, straighter roots, rectangular occlusal outline, and central, buccal, and lingual grooves forming a ‘+’ pattern.

Pentagon Occlusal Shape

Five-sided outline seen on mandibular first molars due to their three buccal and two lingual cusps.

Rectangle Occlusal Shape

Outline form typical of mandibular second molars with two buccal and two lingual cusps.

Trifurcation

Three-root division found in maxillary molars (one palatal, two buccal).

Maxillary Molar Arch Traits

Three roots, crowns centered over roots, buccolingual dimension greater than mesiodistal, presence of an oblique ridge (ML to DB).

Rhomboid Shape (Maxillary First Molar)

Parallelogram-like occlusal outline created by unequal side lengths; wider buccolingually.

Heart-Shaped Molar

Maxillary second molar lacking a DL cusp, creating a three-cusp heart appearance occlusally.

Oblique Ridge

Prominent ridge running from mesiolingual to distobuccal cusp on maxillary molars; absent on heart-shaped variant.

Cusp of Carabelli

Accessory cusp/depression on the lingual surface of the ML cusp of maxillary first molars; present in ~70 % of cases.

Palatal (Lingual) Root

Largest and broadest root of maxillary molars, often banana-shaped, providing strong anchorage.

Mesiobuccal Root

Buccal root of maxillary molars located mesially; often shows a mesial surface depression.

Distobuccal Root

Smaller buccal root on the distal side of maxillary molars; usually no distal depression.

Buccal Cervical Ridge

Prominent ridge on the mesiobuccal cusp of mandibular second molars used for identification.

Root Concavity

Longitudinal depression on root surfaces; especially deep on inner surfaces between mandibular mesial and distal roots.

CEJ Curvature on Molars

Cemento-enamel junction curves more occlusally on the mesial surface than on distal, buccal, or lingual surfaces.

Marginal Ridge Groove

Developmental groove crossing a marginal ridge; common on mesial of mandibular molars and distal oblique of maxillary molars.

Central Fossa

Large depression in the center of molar occlusal surfaces where major grooves converge.

Mesial Triangular Fossa

Small triangular depression just inside the mesial marginal ridge of a molar.

Distal Triangular Fossa

Triangular depression adjacent to the distal marginal ridge of a molar.

Distal (Cigar-Shaped) Fossa

Elongated fossa along the distal oblique groove of 4-cusped maxillary molars; absent in 3-cusp form.

Supplemental Grooves

Extra, unnamed grooves branching from primary developmental grooves, adding complexity to occlusal anatomy.

Enamel Extension

Projection of enamel toward or into the furcation area, sometimes complicating periodontal instrumentation.