Denture Anatomy

Question 1

limiting structures of maxilla

Answer 1

labial frenum
labial sulcus
buccal frenum
buccal sulcus
hamular notch
vibrating line

Question 2

labial frenum maxilla

Answer 2

fibrous band covered by mucous membrane
extends from labial aspect of residual ridge to lip
passive frenum with no active muscle fibres
v shaped notch should be cut at front of denture

Question 3

labial sulcus maxilla

Answer 3

bounded on one side by teeth, gingiva, residual alveolar ridge and on other side by lips
runs from one side of buccal frenum to the other; dividing in 2 compartments left and right by labial frenum

Question 4

buccal frenum maxilla

Answer 4

fibrous band covered by mucous membrane
has attachment of - levator anguli oris, orbicularis oris and buccinator
requires greater clearance on buccal flange of denture (shallow and wider) than labial frenum

Question 5

buccal sulcus maxilla

Answer 5

extends from buccal frenum anteriorly to hamular notch posteriorly
size of vestibule is dependent on:
- contraction of buccinator
- position of mandible
- amount of bone loss in maxilla

Question 6

hamular notch

Answer 6

depression between the maxillary tuberosity and the hamulus of the medial pterygoid plate; it is a soft area of loose CT
houses the distolateral termination of the denture
aids in achieving posterior palatal seal
overextension causes soreness
under extension results in poor retention

Question 7

vibrating line

Answer 7

imaginary line drawn across posterior part of palate that marks division between moveable and immoveable tissues of soft palate which can be identified by asking patient to say ‘ah’
it extends from 1 hamular notch to another; usually about 2mm in front of palatine fovea

Question 8

supporting structures of maxilla

Answer 8

these are the load bearing areas
support is resistance to displacement towards underlying structures
1. posterior palate
2. tuberosity
3. rugae

Question 9

relief areas of maxillary denture

Answer 9

incisive papilla
palatine raphe
crest of alveolar ridge
palatine fovea

Question 10

incisive papilla

Answer 10

midline structure behind central incisors
exit point of nasopalatine nerves & vessels
should be relieved as if not denture will compress nerves and vessels leading to necrosis of distributing areas & paraesthesia of anterior palate

Question 11

palatine raphe

Answer 11

extends from incisive papilla to distal end of hard palate
median suture areas covered by thin submucosa
relief to be provided as it is supposed to be most sensitive part of palate to pressure

Question 12

limiting structures of the mandible

Answer 12

lingual frenum
labial frenum
labial sulcus
buccal frenum
buccal sulcus
alveolingual sulcus
retromolar pads

Question 13

lingual frenum mandible

Answer 13

in anterior region of lingual flange

Question 14

labial frenum mandible

Answer 14

fibrous band extending from labial aspect of alveolar ridge to the lip containing CT which helps in attachment of orbicularis oris muscle
sensitive so denture should have appropriate labial notch

Question 15

labial sulcus mandible

Answer 15

runs from labial frenum to buccal frenum on each side
mentalis muscle quite active in this region

Question 16

buccal frenum mandible

Answer 16

fibres of buccinator are attached to buccal frenum
should be relieved to prevent displacement of denture during function

Question 17

buccal sulcus mandible

Answer 17

extends posteriorly from buccal frenum to outside back corner of retromolar region
area maximisation can be safely done here as fibres of buccinator run parallel to the border hence displacing action due to buccinator during its contraction is slight
impression is at its widest within this region

Question 18

alveolingual sulcus

Answer 18

between lingual frenum to retro mylohyoid curtain
can be divided into 3 parts
1. anterior = from lingual frenum to mylohyoid ridge, shallowest portion of lingual flange
2. middle = from premylohoid fossa to the distal end of the mylohyoid region
3. posterior = from end of mylohyoid ridge to the retromylohyoid curtain, provides valuable undercut area so important for retention

Question 19

retromolar pads mandible

Answer 19

pear shaped triangular soft pad of tissue at the distal end of the lower ridge
important structure that forms posterior seal of mandibular denture
denture base should extend up to 2/3s of the retromolar pad triangle

Question 20

supporting structures of mandible

Answer 20

1. residual alveolar ridge
2. buccal shelf - extends from buccal frenum to retromolar pad, between external oblique ridge and crest of alveolar ridge; boundaries are:
   - medially -> crest of ridge
   - laterally -> external oblique ridge
   - distally -> retromolar pad
   - mesially -> buccal frenum
   width of this area increases as alveolar resorption continues

Question 21

relief areas of mandible

Answer 21

genial tubercle
torus mandibularis
mylohyoid ridge

Question 22

genial tubercle

Answer 22

area of muscle attachment (genioglossus & geniohyoid)
lies away from crest of ridge
prominent in resorbed ridges so adequate relief to be provided

Question 23

torus mandibularis

Answer 23

abnormal bony prominence
bilaterally on lingual side near premolar area
covered by thin mucosa so should be relieved

Question 24

mylohyoid ridge

Answer 24

attachment for mylohyoid muscle
running along lingual surface of mandible
anteriorly ridge lies close to the inferior border of mandible
posteriorly it lies close to residual ridge
covered by thin mucosa which may be traumatised by denture base hence it should be relieved
extension of lingual flange is to be beyond palpable position of mylohyoid ridge but not in the undercut