Theory of dentures 1 Flashcards
edentuolous
no natural teeth
facts of edentulism
The number of people with no natural teeth has gradually reduced
- Estimated 20% of US and UK population over 65 years of age wear complete dentures
But many edentulous do not attend regularly
Doesn’t matter where you live, racial background or ethnicity
edentulism mainly seen in
elderly
- Teeth lost at any age/ dental neglect
- Many patients are elderly and present with additional problems
additional problems when treating elderly pts
- Limited Mobility
- Communication
- Impaired vision
- Impaired hearing – masks add
- Cognitive function
- Ageing of oro-facial tissues – lack of flexibility/mobility
- Multiple medications – dry mouth
- Many domestic arrangements
Treat the patient not just the mouth
- You may be the patients only social contact.
- Older people generally work at a slower pace.
- They have lots to tell
Good rapport with you = better chance of denture wearing success
10 anatomical landmarks for upper dentures
- labial frenum
- incisive papilla
- labial sulcus
- palatine raphe
- tuberoisty
- vibrating line
- palatine fovea
- hamular notch
- rugae
- buccal sulcus
7 anatomical landmarks for lower dentures
- retromolar pads
- mylohyoid ridge
- buccal sulcus
- labial sulcus
- lingual sulcus
- buccal shelf
- lingual frenum
labial frenum
lip attached onto alveolar process in maxilla
incisive papilla
positon varies with
if teeth present
very near alveolar process if no natural teeth (there is resorption), otherise well behind upper incisors
lingual frenum
attached the tongue to the alveolar process in the mandible
1
incisive papilla
on ridge crest
2
tuberosity
appears larger in edentulous pts
1
shallow maxillary ridge offereing limited support
support in upper Vs lower
Support from hard palate and lateral aspect of the alveolar ridge in upper
Lower always has less area for support than upper
2
post dam indentation
what is this highlighting
Hamular Notch – imp for upper denture
- Between distal surface of tuberosity and the hamular process of the medial pterygoid plate.
- Ideal site for distal border of the denture and helps with the posterior seal.
overextension of upper denture (beyond hamular notch)
pain or looseness
under extension of upper denture (before hamular notch)
poor retention
ridge features for good support
good height and width
Narrow and shallow ridge offers less support (and is often soft tissue / mobile) – any stability = hard
retromolar pad
- triangular soft pad of tissue.
- posterior end of edentulous ridge.
- anterior 2/3 for denture coverage - aim
- Provides support
retromylohyoid space
- distal end of lingual sulcus.
- posterior to the mylohyoid muscle.
-
aids retention and stability if able to extend denture into
- 2 reasons – cannot get sideways movement as it impinges onto the ramus of mandible and often a small undercut which you can use for retention
quality and height of ridges assessed using
Cawood and Howell Classification of ridges
- Dentate
- Post extraction
- Broad alveolar process (after some resorption – aim for most pt)
- Knife edge (loading goes on point of ridge – uncomfortable for pts)
- Flat ridge (no alveolar process)
- Submerged ridge (loss of basal bone
Cawood and Howell Classification of ridges
1
dentate
Cawood and Howell Classification of ridges
2
post extraction
Cawood and Howell Classification of ridges
3
broad alveolar process (after some resorption - aim for most pt)
Cawood and Howell Classification of ridges
4
knife edge
loading goes on point of ridge - uncomfortable for pts
Cawood and Howell Classification of ridges
5
flat ridge (no alveolar process)
Cawood and Howell Classification of ridges
6
submerged ridge (loss of basal bone)
intra-oral change to bone if all teeth lost
- No remaining teeth or roots
- No remaining periodontium…therefore…
- No means of retaining the alveolar bone around teeth
Maximum rate of bone loss in the first 3 months post extractions
- (leave 3-6 month for definitive bridge, and denture will need relined or remade)
Bone loss continues over the lifetime of the patient
Tissues not created to withstand load from dentures
intra oral changes in alveolar ridge if all teeth lost
- Changes in the maxilla
- Distal resorption
- Changes in the mandible
- More vertical resoption
- Changes between the jaws
- Upper reduces in ridge – width of the area covering the denture narrows
- Lower increases in ridge
- Upper gets narrower, lower gets wider - Make dentures with crossbite in upper and lower
- Changes under dentures
describe
The sockets can still be seen following extraction. The ridge is bulbous and irregular
describe
This ridge has undergone more resorption. You can see that the arch is narrow and the height of the ridge much reduced
radiographic appearnce of edentulous
panoramic radiograph
maintain more anterior
buccal area narrow – liable to fracture
extra oral changes if all teeth lost
- Changes in the upper lip – less support
- Changes in the lower lip
- Change in lower facial height – greatly reduced
- Change in profile
- Almost in class II relationship – as mandible closes it becomes more anteriorly
Hopefully successfully designed dentures will help resolve these issues
Bone resorption reduces the support for the muscles/ soft tissue.
- nasiolabial angle increases
- prominence of chin
physiological factors of edentulism
- Loss of proprioception
- Decreased masticatory efficiency – loading on teeth reduced
- Decreased incising efficiency
- Decreased swallowing efficiency (unsure as tongue still present)
- Problems with speech (rare)
short and long term effects of edenulism
- Phew what a relief no more teeth!? (less pain)
- Lost limb syndrome
- Embarrassment
- Denial (my husband/wife doesn’t know!)
- Depression
warning to all complete denture pts to set expectations relatistically
Dentures do not have same level of function as natural teeth – alike a prosthetic limb, prevents being gummy mouth or loss of limb but will not have the same function and feel as natural body
factors in design of complete dentures
- How are dentures retained within the mouth?
- Support, Retention and Stability are important
Aim is to provide well fitting dentures that are in harmony with the oral musculature
support
- Resistance to vertical movement of the denture (towards the tissues)
How well the underlying oral tissues, including mucosa, keeps the denture from moving vertically towards the arch and thus being excessively depressed and moving deeper into the arch
mandible support for complete dentures (3)
buccal shelf
residual ridge
retromolar pad
maxilla support for complete dentures (2)
hard palate
residual ridge
retention
Resistance to Displacement in a vertical direction (away from tissues)
accurate fit is
of the denture base to the mucosa so that the space between the two is as small as possible.
border seal
achieved by extending the denture flanges to the depth of the functional sulcus and incorporation of post dam on cutting
overextension impact on border seal
negative - should only be to functional depth
increasing bulk of flanges impact on border seal
negative - should only be to functional depth
borders of dentures should not interfere with
muscle or frenal attachments
testing retention
Pulling vertically on the anterior teeth
- Ensusre not movement of head without displacement of denture from upper incisor region
- Try not to tip denture – more force on palatal aspect of anterior teeth
stability
resistance to horizontal movement
testing stabilty
Place fingers on the occlusal surface and trying to rock the denture side to side
- Almost every case will be movement esp lower case as less retention
2 ways retention reduced
- is over extended and interferes with muscles or frenal attachments
- if the peripheries are under-extended
2 ways stability is reduced
- if the denture is under-extended
- if the occlusion is not balanced
6 tx options for edentulous pt
- Complete upper and lower dentures
- Complete upper or lower denture against natural teeth (more common upper against natural lower as lower against upper natural is unsatisfactory as poor retention, support and stability)
- Nothing
- Implant supported removable prosthesis esp lower
- Implant supported fixed prosthesis more complex, hard to keep clean
- Conventional or Replica dentures
8 stages in conventional complete dentures
- Assessment of patient and dentures
- Primary Impressions
- Master impressions (Definitive/Secondary)
- Registration Visit
- Trial Insertion visits (Tooth trial)
- Insertion (Delivery)
- Maintenance (Review)
- Aftercare
- Upper reduces in ridge – width of the area covering the denture narrows
- Lower increases in ridge
stages in replica construction
- Assessment of patient and dentures
- Replica impressions
- 2nd imps and occlusion
- Try-in (re-try)
- Finish
- Maintenance
- Aftercare
Fewer appointments as second master impression at same appointment as recording occlusion
