1/10: Edentulous Anatomy Flashcards
What are three types of mucosa?
Masticatory
Lining
Specialized
What kind of mucosa is highly keratinized, best denture support?
Masticatory
What kind of mucosa is thin, non-keratinized mucosa of lips and cheek. Forms seal against denture, but does not resist stress?
Lining
What kind of mucosa is on the dorsal surface of tongue. Is keratinized, contains taste buds?
Specialized
What are characteristics of the ideal denture-bearing tissue?
1- firmly bound, keratinized masticatory mucosa
2- a zone of connective tissue and submucosa
3- underlying cortical bone
4- muscle attachments nearby (enhance resistance to bone resorption)
What is centripetal resorption?
Routine resorption pattern following extraction of teeth results in a smaller maxilla when compared to dentate arch
What doesn’t the labial frenum contain?
Muscle fibers
Where does the labial frenum insert?
In vertical direction
Describe the movement of the labial frenum?
Little lateral movement in function
Describe the notch on the labial frenum on a denture
Should be narrow
What is the labial vestibule?
Space between labial frenum and buccal frenum
*contains no muscle fibers
What may the buccal frenum contain?
Few fibers of caninus muscle
What should the notch on the buccal frenum look like?
Broad since movement of frenum is affected by buccinator and orbicularis oris muscle
Where is the notch in denture broader?
At buccal frenum than labial frenum
Where is the corono-maxillary space?
Between buccal frenum and hamular notch
Describe the space of a corono-maxillary space on the buccal vestibule
Varies in size
Must be filled vertically and laterally by denture flange to prevent ingress of air and loss of retention of maxillary denture
Where should you palpate for the retrozygomatic process?
In buccal vestibule just buccal to first maxillary molar
Vestibular space psoterior to zygoma
What are characteristics of complete denture retention?
Adhesion
Cohesion
Interfacial surface tension
Intimate tissue contact
Border seal - prevent ingress of air
Neuromuscular control by patient
What is the hamular notch?
Narrow cleft between tuberosity and pterygoid hamulus
What are the three characteristics of the maxillary tuberosities?
Oversized
Resorbed
Undercut
Where is the location of the vibrating line?
On the soft palate - not the junction of the hard and soft palate
It’s the junction of movable and immovable tissues of the soft palate
What does the vibrating line mark?
The junction of the movable and the immovable portion of the soft palate
What is unique to humans?
Fovea palatini
What is the coalescence of mucous glands?
Fovea palatini
Where are the fovea palatini located?
One on each side of the midline
In the general area of the vibtaing line. Much individual variation. Only a guide
What is in the area of the “vibrating line”?
Fovea palatini
What is the median palatine raphe?
Bony midline structure, no cushioning effect
*may require relief when covered by a denture
What is the maxillary secondary denture support area?
Rugae
What resists anterior displacement of maxillary denture?
Rugae
What is the landmark for the setting of anterior teeth?
Incisive papilla
What is the incisive papila?
Pad of connective tissue overlying nasopalatine canal opening
What is not tolerant of pressure from denture?
Incisive papilla
What is the ideal depth for the palatal vault form?
Medium depth with well-defined rugae in anterior
What should you do if ridges are severely resorbed?
Inform patient
- U shape
- V shape
What is the primary support area of the hard palate?
Horizontal anterio- and posterolateral hard palate
What is the secondary support area of the hard palate?
Ridge crest
What part of the hard palate should require relief?
Midline suture
What in the maxilla may require removal?
Torus palatinus
Where is the posterior palatal seal?
Distal to junction of hard and soft palates
What is the palatal seal?
Glandular and fibrous connective tissue which may be slightly compressed without harm
What is the purpose of the posterior palatal seal?
Retention of maxillary CD
What are the 4 functions of the posterior palatal seal?
- Complete border seal of max. CD
- Compensates for dimensional changes in processed resin
- Gives firm contact with tissue of s. palate which reduces gagging
- presses into tissue making posterior border less conspicuous to tongue
What are the 3 House’s. classifications of soft palates?
Class 1 - >5mm tissue available (ideal)
Class 2 - 1-5mm tissue available (adequate)
Class 3 - <1mm tissue available (poor)
What house classification is easiest to tolerate, broadest range, and hardest to locate?
Class I
What house classification is most common?
Class II
What classification is easiest to locate, hardest to tolerate?
Class III
What three things make up the anatomy of the mandibular arch?
Labial frenum
Labial vestibule
Buccal frenum
What may the buccal frenum contain?
Fibers which attach to “modiolus”
What is the modiolus?
Structure at corners of mouth where 8 muscles converge
Where is the buccal shelf?
Area posterior to buccal frenum
What is the primary support area for mandibular CDs?
Buccal shelf
What should the base of the denture cover?
Buccal shelf
Where is the buccal shelf located?
Between height of the ridge and external oblique ridge
How does the buccal shelf resorb?
More slowly
What is the primary support area of the mandibular denture?
buccal shelf and pear shaped pad
What is the secondary support area of the mandibular denture?
Ridge crest and area of genial tubercles
What areas of the mandibular denture are relieved or noncontributing?
Lingual and labial ridge inclines
What is the pterygomandibular raphe?
Narrow, ligamentous band extending from pterygoid hamulus to posterior part of mylohyloid line
What enters at the pterygomandibular raphe?
Buccinator m. and superior pharyngeal constrictor m.
What does the pterygomandibular raphe limit?
Length of max. and mandib. CD
Where does the pterygomandibular raphe connect?
Hamulus to the mylohyoid ridge
What happens if the pterygomandibular raphe is prominent?
Can cause pain or loosening
Requires relief “groove”
What is an important landmark in removable pros.?
Retromolar pad
What is the retromolar pad?
Triangular pad of soft tissue at posterior end of mandibular residual ridge
What contains glandular tissue?
Retromolar pad
What is the shape of the retromolar pad?
Inverted pear
Posterior border
What is the retromolar pad created from?
Scarring after extractions
What are the 5 contents of the retromolar pad?
- Loose submucosa
- Glandular tissue
- fibers of buccinator and sup. pharyngeal constrictor muscles
- pterygomandibular raphe
- Temporalis m. tendon fibers
What must be covered by the base of a denture?
Retromolar pads
What occurs if the retromolar pad isnt covered?
Excessive resorption of residual ridge
What is the anterior attachment of tongue?
Lingual frenum
What muscle does the lingual frenum overly?
Genioglossus muscle
What does the mylohyoid muscle influence?
Length of lingual flange
What is the alveolingual sulcus?
Space from lingual frenum to retromylohyoid curtain in posterior
What is the distal end of lingual sulcus?
Retromylohyoid space
What is the area psoterior to the mylohyoid muscle?
Retromylohyoid space
What does a good seal in the Retromylohyoid space aid in?
Retention and stability
What is the secondary support area of a mandibular denture?
Residual ridge
What happens to the size of the residual ridge over time?
Decreases
What happens when there is pressure on the residual ridge?
Blood supply interrupted –> bone resorption
What do we want to do if there is pressure on the redidual ridge?
Minimize pressure and spread out the pressure onto a wider support base
Where is residual ridge resorption more severe?
On mandibular arch than on max
How to reduce the pressure on residual ridges?
- Remove dentures from mouth 8 hours/day to allow tissues to rest
- Proper impression techniques
- Clincial remount and occlusal refinement at delivery of dentures to patients
- No contact of opposing anterior teeth in centric relation
What are proper impression techniques?
Record tissues at rest
Denture base extensions using maximum support area
place pressure on those areas that can withstand pressure
