Bio Mechanics of Ede State 2
-
Upload
praveen-badwaik -
Category
Documents
-
view
215 -
download
0
Transcript of Bio Mechanics of Ede State 2
-
8/8/2019 Bio Mechanics of Ede State 2
1/14
-
8/8/2019 Bio Mechanics of Ede State 2
2/14
Causes of patients becoming edentulous
Caries
Periodontal disease
Non disease factors
Attitude
Behavior Dental attendance
Characteristics of health system
Low occupational levels
-
8/8/2019 Bio Mechanics of Ede State 2
3/14
Mechanism of tooth support
Teeth function properly only ifadequately supported--- Periodontium(PDM) -- 2 soft & 2 hard tissues
PDM attaches teeth to bone(resilient suspensory
apparatus resistant to functional forces)
Teeth adjust their position under stress Principal function
Support & positional adjustment
Hard tissues (cementum & bone) Soft tissues (periodontal ligament & lamina propria
of gingiva)
-
8/8/2019 Bio Mechanics of Ede State 2
4/14
Occlusal forces exerted are controlled byneuromuscular mechanisms of masticatory system
Reflex mechanisms with receptors in muscles,
tendons, joints & periodontal structures --- regulatemandibular movements
Greatest force produced mastication & deglutition,
short & vertical in direction Tongue & circumoral musculature longer duration
& horizontal in direction
-
8/8/2019 Bio Mechanics of Ede State 2
5/14
Calculation of forces applied on PDMCHEWING
Actual chewing time per meal 450 secFour meals per day 1800 sec
One chewing stroke per sec 1800 strokes
Duration of each stroke 0.3 sec
Total chewing forces per day 540 sec (9 min)
SWALLOWING
Meals
Duration of one deglutition 1 Sec
During chewing, 3 deglutition per min, 1/3 rd with occlusal
force
30 Sec (0.5 min)
BETWEEN MEALS
Daytime 25 / hr (16 hr) 400 sec (6.6 min)
Sleep : 10 / hr (8 hr) 80 sec (1.3 min)
TOTAL 1050 sec = 17.5 min
-
8/8/2019 Bio Mechanics of Ede State 2
6/14
Mechanisms of Complete denture Support
Approximate area of PDL support 45 cm2
Masticatory load (conscious effort) 44 lb (20 kg)
Maximum forces with CD - 13-16 lb (6 to 8 kg)(Selective food habits)
Mucosa support - denture bearing area Maxilla 22.96 cm2
Mandible 12.25 cm2
Residual ridge resorption, little tolerance, systemic diseases
anaemia, hypertension, diabetes, nutritional deficiencies
-
8/8/2019 Bio Mechanics of Ede State 2
7/14
Residual ridges
-
8/8/2019 Bio Mechanics of Ede State 2
8/14
Residual ridges
Mucosa, submucosa, periosteum & residualalveolar bone
-
8/8/2019 Bio Mechanics of Ede State 2
9/14
Dentures move -- resiliency of mucosa &
instability of CD can cause tissue damage
Factors affecting retention
Maximal extension of denture base Maximal intimate contact of denture base & itsbasal seat
Equilization of pressure Muscular factors, impression techniques, polished
surfaces
-
8/8/2019 Bio Mechanics of Ede State 2
10/14
Occlusion Primary components
1. Dentition
2. Neuromuscular system
3. Craniofacial structuresFORCE GENERATED
DIRECTION DURATION & MAGNITUDE
Mastication Mainly Vertical Intermittent & lightDiurnal only
Parafunction Frequently Horizontalas well as Vertical
Prolonged, possibly excessiveBoth diurnal & nocturnal
-
8/8/2019 Bio Mechanics of Ede State 2
11/14
Distribution of Stress
Mucosal health can be promoted
Hygienic measures Therapeutic measures
Tissue-conditioning techniques
OCCLUSAL LOAD can be reduced by Maximum extension
Reduction of area of occlusal table
Frequent rest periods (8 hours)
-
8/8/2019 Bio Mechanics of Ede State 2
12/14
Function ¶function
generate
Force Time
Pressure Controlled by Controlled partially by
Tissue damaged byoccluding local
circulation
1. Correct clinical technique2. Use of permanent soft liner
Nocturnal tissue rest
-
8/8/2019 Bio Mechanics of Ede State 2
13/14
Premature reduction occurs with Attrition /Abrasion of teeth
Reduction is more conspicuous in edentulous &CD wearers
Changes in Face Height
COSMETICCHANGES1. Deepening of Nasolabial groove2. Loss of Labiodental angle3. Decrease in horizontal labial angle
4. Narrowing of lips5. Increase in columella-philtral angle6. Prognathic appearance
-
8/8/2019 Bio Mechanics of Ede State 2
14/14
Adaptive & psychological responses CD requires adaptation of learning, muscular skill &
motivation Patients ability & willingness to accept & learn to use
dentures ---- success
Also Habituation gradual diminution of responses tocontinued or repeated stimuli
In old age Memory & Storage is difficult, soadaptation to CD becomes difficult
(as progressive atrophy of elements in cerebral cortex &consequent loss in facility of coordination occurs)
So Dentists role is to MOTIVATE the patients & makeunderstand their NEEDS has proven to be of greatest
clinical value