Prosthetic Importance of Extra-oral Landmarks

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Questions and Answers

What is the primary purpose of recontouring the thin and sharp mylohyoid ridge?

To improve flange placement and border seal (correct)

To enhance food mastication

To facilitate better speech clarity

To increase the strength of the ridge

What do the genial tubercles attach to on the mandible?

Sternocleidomastoid muscle

Masseter muscle

Genioglossus and geniohyoid muscles (correct)

Temporomandibular joint

How does the position of the tongue change after teeth extraction?

The tongue shrinks in size

The tongue spreads laterally (correct)

The tongue becomes less active

The tongue moves backward

What is the purpose of the inter-pupillary line in dental prosthetics?

To assist in the orientation of the anterior occlusal plane Signup and view all the answers

What structural consideration should be taken when setting teeth after extraction?

The teeth should be set on the crest of the ridge Signup and view all the answers

Which line is used for the orientation of the posterior occlusal plane?

Ala-tragus line Signup and view all the answers

What effect does aging have on the naso-labial sulcus?

It becomes deeper and more prominent Signup and view all the answers

What is the role of the labial frenum in denture design?

It allows for lip movement without denture displacement Signup and view all the answers

How does the loss of teeth affect the vermillion border?

It results in the border becoming less visible Signup and view all the answers

What occurs to genial tubercles in cases of extreme alveolar bone resorption?

They migrate close to the crest of the ridge Signup and view all the answers

Where does the canthus-tragus line run?

From the outer canthus of the eye to the tragus of the ear Signup and view all the answers

What anatomical feature should be considered in the design of a denture for optimal fit?

Genioglossus muscle attachment points Signup and view all the answers

What does the mento-labial sulcus indicate?

The maxillo-mandibular relationship Signup and view all the answers

What type of muscle is the tongue classified as?

Skeletal muscle Signup and view all the answers

What is the significance of properly positioning the anterior teeth in relation to the naso-labial sulcus?

It restores proper appearance of the sulcus Signup and view all the answers

Which line indicates an arbitrary location of the condyles or rotational axis?

Canthus-tragus line Signup and view all the answers

What is the significance of the labial vestibule in denture construction?

It reflects the mucosa of the lip to the alveolar ridge. Signup and view all the answers

What muscle primarily limits the length of the labial flange of a denture?

Orbicularis oris muscle Signup and view all the answers

Why is it important to create a buccal notch in the denture flange?

To facilitate functional movement of the buccal frenum. Signup and view all the answers

Which area does the buccinator muscle relate to in denture construction?

Buccal vestibule Signup and view all the answers

What anatomical landmark is located superior to the first and second molar teeth?

Root of the zygomatic process Signup and view all the answers

What is the pterygo-maxillary notch frequently associated with?

A band of dense connective tissue Signup and view all the answers

What can inadequate clearance in the buccal flange lead to?

Dislodgment of the denture Signup and view all the answers

Which structure is NOT directly related to the denture flange in the buccal vestibule?

Orbicularis oris muscle Signup and view all the answers

What is one purpose of copying the rugae on the palatal surface of a denture?

To enhance comfort and reduce difficulty with taste and speech Signup and view all the answers

When dealing with a small torus palatinus, what should be done with the denture base?

The denture base should be relieved over this area. Signup and view all the answers

What is the location of the fovea palatinae in relation to the palate?

On each side of the midline, posterior to the junction of hard and soft palate Signup and view all the answers

What is the composition of the residual alveolar ridge?

Cancellous bone covered by soft tissue Signup and view all the answers

Why should the lower denture not extend beyond the external oblique ridge?

To avoid denture displacement by the masseter muscle Signup and view all the answers

What is the function of the buccal shelf of bone?

It serves as a base for denture retention. Signup and view all the answers

What occurs in cases of severely resorbed residual ridges?

It may appear as a cord-like soft tissue requiring intervention. Signup and view all the answers

What surgical action is typically required for a torus palatinus if it is large?

It needs to be surgically removed. Signup and view all the answers

What is the function of the vibrating line in dentural anatomy?

It indicates the posterior extension of the maxillary denture. Signup and view all the answers

How should the labial frenum be accommodated in denture design?

It should be opposed with a labial notch in the denture border. Signup and view all the answers

What is the significance of the buccal frenum in denture design?

It requires clearance to prevent denture dislodgement. Signup and view all the answers

What primary function does the buccal shelf serve in relation to dentures?

It is a primary stress bearing area. Signup and view all the answers

Which structure does the posterior palatal seal extend between?

One hamular notch to the other hamular notch. Signup and view all the answers

What will happen if the buccal flange of the denture does not have adequate clearance for movement?

Displacement of the denture may occur. Signup and view all the answers

Where is the mental foramen typically located?

In the premolar region of the buccal surface. Signup and view all the answers

What is the significance of the retromolar pad in denture design?

It helps with denture support and provides a soft tissue seal. Signup and view all the answers

What characterizes the relationship between the labial mucous membrane reflection area and the denture flange?

It influences the thickness and length of the labial flange. Signup and view all the answers

What is the function of the hamular notch in denture support?

It marks the extension area for posterior palatal seal. Signup and view all the answers

Which statement about the torus mandibularis is correct?

It varies in size and shape, sometimes requiring surgical intervention. Signup and view all the answers

What anatomical feature does the mylohyoid ridge represent?

The attachment of the mylohyoid muscle. Signup and view all the answers

Which of these muscles influences the labial flange of the denture?

Orbicularis oris Signup and view all the answers

What problem can arise from a large torus mandibularis relative to denture fitting?

Inability to fit the denture properly, necessitating relief or surgery. Signup and view all the answers

What is true about the location of the mental foramen in cases of severe ridge resorption?

It usually shifts to the crest of the ridge. Signup and view all the answers

Why is relief of the denture necessary near the mental foramen?

To avoid numbness of the lower lip. Signup and view all the answers

Study Notes

Extra-oral Landmarks of Prosthetic Importance

Inter-pupillary Line: An imaginary line running between the pupils of the eyes when a patient is looking straight ahead. Used to orient the anterior occlusal plane of artificial teeth.
Ala-Tragus Line (Camper's Line): An imaginary line stretching from the ala of the nose to the tragus of the ear. Used for orienting the posterior occlusal plane of artificial teeth.
Canthus-Tragus Line: An imaginary line from the outer corner of the eye (canthus) to the tragus of the ear. Used in determining the arbitrary location of the condyles (rotational axis).
Naso-labial Sulcus: A crease running from the ala of the nose downward and laterally to the corner of the mouth. Deepens with age, and proper positioning of the anterior teeth and contouring of the upper denture flange help recreate it and improve appearance
Vermillion Border: The transitional epithelium between the lip's mucous membrane and facial skin. Loss of teeth/alveolar bone resorption can cause the border to shrink inward.
Mento-labial Sulcus: A horizontal depression between the lower lip and chin. Its curvature indicates the relationship between the maxilla and mandible. Different angles indicate various jaw relationships (Class I, II, and III).
Philtrum: A diamond-shaped area at the center of the upper lip, beneath the nose.
Angle of the Mouth (Comissure): The point where the upper and lower lips meet. Inflammation and salivation from this area is known as angular cheilitis. This may result from prolonged edentulism, dentures with reduced jaw measurements, or Vitamin B12 deficiency.
Modiolus: The point of intersection of facial muscles. Located below and behind the mouth angle. Loss of teeth and alveolar bone resorption can cause the modiolus to recede. Proper denture construction rectifies this.

Intra-oral Landmarks of Prosthetic Importance

Residual Alveolar Ridge: The portion of the alveolar process remaining after tooth extraction, covered in soft tissue. The ridge's highest point is the crest. Dense connective tissue supports the denture.
Maxillary Tuberosity: A rounded bony prominence behind the distal end of the maxillary ridge. Contributes to retention and support of the maxillary denture.
Median Palatine Raphe: A thin mucoperiosteal ridge on the hard palate covering the median suture. Lack of relief in this area can lead to denture rocking.
Incisive Papilla: A pear-shaped elevation of soft tissue in the midline of the hard palate, behind the upper central incisors. It covers the incisive foramen and should be relieved in the denture to avoid pressure.
Palatine Rugae: Ridges of dense fibrous tissue radiating from the anterior one-third of the hard palate on both sides of the midline. Important for mastication and taste.
Torus Palatinus: A bony bulge in the midline of the hard palate. Can be surgically removed if necessary to create proper denture fit.
Fovea Palatinae: Two small pits on each side of the hard palate behind the meeting of hard and soft palate. Minor salivary glands open into these areas.
Mandible sections include various features, like the condyle, condyloid process, ramus, angle, external oblique line, lingual, buccal shelf, mental foramen, mandibular notch, mylohyoid line, genial tubercle, and Fovae.
Residual Alveolar Ridge (Crest): The remaining bone structure after tooth extraction. Soft tissue covering the crest can vary in density and is sometimes susceptible to tissue breakdown.
External Oblique Ridge: A distinct bony ridge descending from the ramus of the mandible and fading at the mental foramen.
Buccal Shelf (Buccal Plateau): A horizontal shelf of bone, found between the ridge crest and external oblique ridge (typically in the molar area) Dense compact bone, supporting the denture and acting as a primary stress bearing area.
Mental Foramen: Located on the buccal surface of the mandible between the first and second premolars. Mental nerves and vessels pass through it.
Retromolar Pad: A pear-shaped pad of soft tissue located at the distal end of the mandibular residual ridge.
Torus Mandibularis: A bony prominence on the inner surface of the mandible in the premolar region.
Internal Oblique Ridge (Mylohyoid Ridge): A bony ridge on the medial surface of the mandible, running from the third molar to the mandibular border, marking the attachment to muscle
Genial Tubercles (Mental Spine): Two small projections on the medial surface of the mandible that mark the attachment of the genioglossus and geniohyoid muscles.
Tongue: Muscular organ in the floor of the mouth. It shapes the mouth's cavity and supports the lower incisor teeth. Oral cavity anatomy and function are influenced by the position and form of the tongue during mastication, swallowing, and speech.
Limiting Structures of the Denture include various anatomical features like frenula, ridges, muscles, openings(foveae), and tissue that affect the denture's form and placement.

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Description

This quiz explores key extra-oral landmarks that hold significant importance in prosthetics. It covers various reference lines and anatomical features that help in the proper orientation and positioning of artificial teeth. Test your understanding of these essential concepts in prosthetic dentistry.