Permanent Posterior Teeth Flashcards

Flashcards reviewing key concepts about permanent posterior teeth, including their properties, features, and clinical considerations.

What two types of teeth are included in permanent posteriors?

Premolars and molars. These teeth are located towards the back of the mouth and are designed for grinding food. Premolars have cusps for tearing and grinding, while molars have a larger, flatter surface for efficient grinding.

What is the masticatory surface of a posterior tooth called?

Occlusal surface. This is the surface that comes into contact with opposing teeth during chewing. It features various anatomical landmarks such as cusps, fossae, and grooves that contribute to the grinding action.

What borders the occlusal surface of posterior teeth?

Marginal ridges on the distal and mesial surfaces. These are elevated crests of enamel that form the boundaries of the occlusal surface. The distal marginal ridge is located on the side away from the midline, and the mesial marginal ridge is on the side towards the midline.

What is the inner portion of the occlusal surface of permanent posteriors called?

Inner occlusal table. This area is defined by the cusp tips and the network of ridges and grooves within the marginal ridges. It's the primary functional area where food is crushed during mastication.

What are the four cusp ridges that descend from each cusp tip?

Outer incline (facial or lingual ridge), inner incline (triangular ridge), mesial cusp ridge, and distal cusp ridge. These ridges are critical for directing forces during chewing and contribute to the overall efficiency of the tooth.

What are the sloping areas between cusp ridges on posteriors called?

Four inclined cuspal planes. These planes are formed by the convergence of cusp ridges and determine the direction of food movement during chewing.

What is the term for cusp ridges that descend from the cusp tips toward the central part of the occlusal table?

Triangular ridges. Named because they are roughly triangular in cross-section, these ridges play a crucial role in the initial breakdown of food particles.

What is the term for the joining of two triangular ridges crossing the occlusal table transversely?

Transverse ridge. This ridge runs from the buccal to the lingual side, adding strength to the tooth and improving grinding efficiency.

What is the term for shallow, wide depressions on the occlusal table?

Fossa(e). These depressions accommodate the cusps of opposing teeth, allowing for a more effective bite and grinding action. They are critical in the distribution of occlusal forces.

Where is the central fossa located?

At the convergence of the cusp ridges in a central point where the grooves meet. This is a significant area as it's often the deepest part of the occlusal surface and a common site for caries due to its complex anatomy.

Where do triangular fossae form?

At the convergence of cusp ridges and termination of triangular grooves. They are smaller than the central fossa and are located near the marginal ridges, contributing to the intricate occlusal pattern.

What are pinpoint depressions where two or more grooves meet?

Occlusal pits. These are the deepest points on the occlusal surface and are particularly susceptible to decay due to their depth and narrowness, making them difficult to clean.

What is another term for developmental grooves?

Primary grooves. These grooves are formed during tooth development and mark the primary divisions between the lobes of the tooth. They define the major cusps and ridges.

Which developmental groove generally travels mesiodistally and separates the occlusal table buccolingually?

Central groove. This groove is a key feature of the occlusal surface, running along the length of the tooth and separating the buccal and lingual cusps. It aids in the efficient breakdown of food.

What do marginal grooves do?

Cross the marginal ridges and serve as spillways for food during mastication. These grooves allow food to escape from the occlusal surface during chewing, reducing the risk of excessive force on the teeth.

What type of grooves separate a marginal ridge from the triangular ridge of a cusp?

Triangular grooves. These grooves define the triangular ridges and help in directing food particles towards the fossae, optimizing the chewing process.

What is another term for supplemental grooves?

Secondary grooves. These are less distinct than primary grooves but still contribute to the overall complexity of the occlusal surface, enhancing its grinding capacity.

What is the function of supplemental grooves?

Widen pathways for opposing cusp movement. By widening these pathways, supplemental grooves allow for a more fluid and efficient chewing motion.

Where is the buccal height of contour on a posterior tooth?

Cervical third. This contour protects the gingival tissue by deflecting food away from the gumline, maintaining periodontal health.

Where is the lingual height of contour on a posterior tooth?

Middle third. Similar to the buccal contour, the lingual height of contour supports gingival health by promoting natural cleaning during mastication.

What is the root trunk?

The part of multirooted premolars and molars where the root originates as a single root on the base of the crown. This section is crucial for the tooth's stability and attachment to the alveolar bone.

What term describes a tooth with two roots?

Bifurcated. Maxillary first premolars and mandibular molars are examples of bifurcated teeth, which require specialized care due to the furcation areas.

What term describes a tooth with three roots?

Trifurcated. Maxillary molars are trifurcated, featuring three roots that enhance stability and resistance to occlusal forces.

What is the area between two or more root branches before they divide from the root trunk called?

Furcation. This area is a common site for periodontal disease due to its complex anatomy and difficulty in cleaning. Proper oral hygiene is essential to prevent infection.

Why are posteriors at increased risk of caries?

Complex and deepened pit and groove patterns on the occlusal surface. These areas can trap bacteria and food particles, leading to decay if not properly cleaned. Sealants are often recommended to protect these vulnerable surfaces.

What is the function of premolars?

Assist the molars in grinding food during mastication. Prem