common faults in impression making 2016
TRANSCRIPT
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COMMON FAULTSIN IMPRESSION MAKING
Hpone Kyaw Myint
Department of Prosthodontics
University of Dental Medicine, Mandalay
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Outline of the Presentation
• Introduction
• Common faults in lower impression
• Common faults in upper impression
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Introduction
• Very first step for good and successful
removable dental prosthesis
• If objectives of primary impression are
failed…
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Common faults in lower impression
• Five faults
• Order in frequency of fault
• Reasons as well as correction methods are
described
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• Fault #. 1 insufficient depth in the posterior
lingual pouch
• Most occurring one
Common faults in lower impression
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Proper Impression
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Fault #. 1 may be caused by
1. Tray flang is too short
2. Shortage of impression composition
3. In adequate force
4. Tongue trapped
Common faults in lower impression
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Corrections for fault #. 1 are
1. Use long flange
2. Get sufficient impression composition
3. Use due force
4. Instruct the patient to raise the tongue
Common faults in lower impression
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• Fault #. 2 insufficient depth in the lingual,
labial and buccal sulci
• Second most occurring one
Common faults in lower impression
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Proper Impression
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Fault #. 2 may be caused by
1. Lack of impression material
2. Using low pressure to seat tray
3. Material is too cold and can’t flow
Common faults in lower impression
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Corrections for fault #. 2 are
1. Use sufficient compo
2. Use proper pressure
3. Manipulate material properly and adequately
Common faults in lower impression
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• Fault #. 3 the presence of smooth hollow in
the buccal distal periphery
• Sometime occurs
Common faults in lower impression
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Proper Impression
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Fault #. 3 may be caused by
• Trapping of cheek
Common faults in lower impression
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Corrections for fault #. 3 are
1. Functional exercise
2. Retraction of cheek during pressing the
tray
Common faults in lower impression
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• Fault #. 4 edge of the tray showing through
the impression
• Occasionally occur
Common faults in lower impression
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Proper Impression
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Fault #. 4 may be caused by1. Incorrect centering of tray
2. No sufficient back ward pressure on tray
3. Improper size of tray
4. Long flanges of the tray
Common faults in lower impression
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Corrections for fault #. 4 are
1. Centre tray before pressing
2. Sure to give back ward pressure
3. Choose tray judiciously
Common faults in lower impression
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Fault #. 5 an asymmetrical impression
• Rarely occur
Common faults in lower impression
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Proper Impression
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Fault #. 5 may be caused by
• Unbalance loading of material
• Ignorance of operator
Common faults in lower impression
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• Corrections for fault #. 5 are
1. Load material smartly
2. Care to seat loaded tray
Common faults in lower impression
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This is the end of the part I.
Part II will be continue on
March 25, 2016 at 1300 hour to 1400 hour.
Thank you for your kind attention!
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Common faults in upper impression
• Five faults
• Order in frequency of fault
• Reasons as well as correction methods are
described
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Fault #. 1 shortage of impression in one or
more regions of labial sulcus, esp around the
tuberosities or the labial sulcus
• Most commonly occur
Common faults in upper impression
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Proper Impression
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Fault #. 1 may be
caused by• Material shortage
• Failure to mold material
• fail;ure to pull upper lip
• Low pressure
• Cold material
Common faults in upper impression
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• Corrections for fault #. 1 are
1. Load material smartly
2. Care to seat loaded tray
Common faults in upper impression
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Fault #. 2 too much composition beyond the
posterior palatal border of the tray
• Frequently occur
Common faults in upper impression
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Proper Impression
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Fault #. 2 may be caused by
• Usage of undue force
• Retaining pressure for long time
• Loading too much composition in palatal area
Common faults in upper impression
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Corrections for fault #. 2
• Make sure of pressure
• Stop upward pressure on tray if app 1 cm
• Loading material properly
Common faults in upper impression
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Fault #. 3 exposed tray
• Occasionally occur
Common faults in upper impression
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Proper Impression
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Fault #. 3 may be caused by
• Poor tray selection
• Poor tray adaption
• Incorrect centring of tray
Common faults in upper impression
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Corrections for fault #. 3
• Good knowledge in tray selection
• Smartly prepared the tray
• Careful seating of tray
Common faults in upper impression
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Fault #. 4 many compo in labial sulcus
• Sometimes occur
Common faults in upper impression
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Proper Impression
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Fault #. 4 may be caused by
• Unrelated tray and ridge
• Too much material in front of the tray
Common faults in upper impression
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Corrections for fault #. 4
• Care in seating tray over the ridge
• Put only sufficient composition in front of
the tray
Common faults in upper impression
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Fault #. 5 void of material at the midline of
the palate
• Rarely occur
Common faults in upper impression
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Proper Impression
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Fault #. 5 may be
caused by
• Material shortage
• Low pressure
• Cold composition
• Trapped air
Common faults in upper impression
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Corrections for fault #. 5
• Use sufficient material
• Applied due force
• Use warm material
Common faults in upper impression
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Reference
• Fenn; Clinical Dental Prosthetic
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Thank you for your kind attention…