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Concepts and techniques
of impression making
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentala...
Contents:
Introduction
Selection of impression material:
Examination
Selection of impression technique
Selection of impres...
The journey towards successful denture
fabrication begins with making accurate
impressions.
Therefore a good impression wi...
• Examination and conditioning of the
patient and the mouth.
• Complete case history
• Clinical examination
• Identifying ...
• Selection of impression technique:
1. Clinical findings.
2. Experience of the dentist.
3. Availability of materials.
4. ...
Selection of impression material:
• Prelimnary impression materials:
impression compound
alginate.
• Final impression mate...
• Modelling compound:
• Easily correctable.
• Can be border molded.
• Not influenced by saliva
• Can be used as impression...
• Alginate:
• Elastic
• Primary and final impression
• Records good details
• Not correctable but easily remade
• Not dime...
• Elastomeric impression materials:
• Elastic
• Fine details
• Hydrophobic
• Adhesive required.
• Available in different v...
• Zinc oxide eugenol impression paste:
• Rigid and inelastic.
• Adheres to tray
• Flows readily and records fine details.
...
• Tissue conditioners:
• Functional impression.
www.indiandentalacademy.com
• Impression plaster:
• Minimal pressure technique.
• Flows readily and records fine details.
• Rigid
• Wash impression
• ...
• Waxes:
• Flow at mouth temperature.
• Exert pressure
• Fine details not recorded.
• Corrections made.
www.indiandentalac...
Selection of impression trays:
• A device that is used to carry ,confine
and control impression material while
making an i...
Stock trays
• Caulk’s edentulous rimlock trays.
• Mc Gowen’s winkler trays-useful for
flat lower ridge
• STOKtrays-designe...
• Usually stock trays though supplied
in different sizes ,donot fit the
edentulous mouth with desired
accuracy.
• To produ...
• Custom trays:
• Close fitting or spaced trays
• Shellac
• Acylic resin
• Thermoformed polymer sheet
www.indiandentalacad...
• Seating of the patient:
maxillary mandibular
www.indiandentalacademy.com
• Prelimnary impression:
a negative likeliness made for the
purpose of diagnosis or the
fabrication of the impression tray...
using alginate
using impression compound.
For Primary impression high viscosity
material is preffered as it allows
to comp...
• Selection of stock tray:
• Tray extensions checked
• Defficiencies corrected.
• Lingual border of mandibular tray
• maxi...
Primary Impression in
alginate.
Tray should be adjusted by
bending .
Selection of stock tray. . Position borders at hamula...
Border of ray should be
short of tissue reflection.
Adequate clearance in frenal
areas.
Tray should be
smoothened.
www.ind...
Deficient borders corrected by
adding utility wax.
Tray extension in buccal space
and tissue side of posterior
border.
www...
Location of hamular notches. Mark the vibrating line.
Some alginate to be placed
in vestibule.
Alginate to be placed in
de...
Tray to be rotated into the mouth
and seated first at the back of
the mouth.
Upper lip elevated.
Tray is held in the mouth...
Completed maxillary Primary Impression with
rounded and molded peripheries.
www.indiandentalacademy.com
Mandibular alginate impression.
Tray should cover retromolar
pad.
metal edentulous tray. Retromolar pad should be
identifi...
Bending and cutting the tray for
adjustment.
Adding utility
was to extend
lingual border.
www.indiandentalacademy.com
Patient told to do tongue
movements.
Patient told to raise the tongue
and tray is rotated in the
mouth.
Gently mold the la...
• Completed Mandibular Primary Impression.
www.indiandentalacademy.com
Prelimnary impression with
impression compound.
Compound placed in
the tray.
Modelling compund. Softenend in water
bath an...
Should cover mylohyoid ridge
and external oblique ridge.
Molded with fingers to ridge
form.
Gently warmed over a flame. Be...
Patient instructed for
Tongue movements.
Tray should be gently
seated and border moulding
done.
Any short areas can be
rem...
Common faults
Mandibular
• Insufficient depth in
posterior lingual pouch:
• Insufficient depth in
lingual,labial and bucca...
Alginate wash impression technique:
• Resorbed mandibular
ridges.
• Using impression
compound has the
benefit of pushing a...
Preperation for Secondary
Impression
• Denture
outline
marked on
the
primary
impression
.Completed
preliminary
casts.
www....
Denture outline accentuated. Posterior border of tray marked.distal
to denture border.
Wax added for relief. Special tray....
Checking for tray extensions:
• Visual examination
• The diagnostic impression
• Correction of overextension
• Correction ...
Borders should be beveled. Vibrating line marked.
Tray inserted in mouth. Overextensions trimmed.
www.indiandentalacademy....
Tray should be short of 2
mm from base of sulcus Borders should be adjusted.
Extra clearence in frenal
areas
www.indianden...
External oblique ridge
marked.
Tray outline marked 2-3 mm
short of denture outline.
Custom tray fabricated.
Posterior bord...
Pencil mark
transferred to fitting
surface.
Anterior border of the tray adjusted .
Tray border should be resting
against t...
Tissue stops
• Prevent seating of the tray too superiorly or posteriorly.
• Stabilize the tray
• Uniform thickness of the ...
Finger rests:
• Keep fingers which stabilise the tray
and support the impression.
• Absence of these result in inaccuracie...
• Border molding:
The shaping of the border ares of
an impression material by functional
or manual manipulation of the siz...
Materials:
• Modelling compound sticks
• Autopolymerizing acrylic resin
• Metallic pastes
• Elastomeric materials
• Impres...
• Modelling compound sticks:
• Advantages:
• Soften easily but are quite hard at
mouth or room temperature so other
areas ...
• Isofunctional impression plastic
sticks.
• Soften easily and have much longer
working time .
• Softer at room temperatur...
• Autopolymerizing acrylic resins:
• Rimseal
• Flexacryl.
• Disadvantages:
• Irritating
• Strong odor
• Heat produced poly...
• Premixed self curing soft resins:
• Added to the periphery of an existing denture.
• Material gradually polymerizes to a...
• Elastomeric materials:
• Heavy body-border molding.
• Advantage-wide range of working and
setting time.
• Elastic recove...
• Impregum-Smith etal.polyether based
material.
• Simultaneous border molding.
Advantages:
1.Can be trimmed
with knife or ...
Impression waxes-adaptol
Advantages
• Simultaneous border
molding.
• Donot irritate
• Additions easy
• Cannot injure oral
...
• Segment by segment
• One step:
www.indiandentalacademy.com
• Simultaneous molding of all borders:
• Advantages:
• Time saving.
• Less discomfort to the patient.
• Less effort for th...
• Requirements:
• Have sufficient body
• Allow some preshaping of the borders
• Setting time3-5minutes
• Retain adequate f...
The tray rotated in mouth
and cheek gently
massaged.
Compound molded with
fingers.
Softened again with alcohol
torch.
Temp...
Appropriate molding will have mat
surface.
Compound added in buccal frenum
area.
www.indiandentalacademy.com
Recording the frenum.Molded buccal and labial
borders.
Excess compound on tissue
side trimmed.
Compound placed on
posterio...
Junction of tray and
compound smoothened.
Tray seated in mouth with firm
pressure.
Border molded
maxillary custom
tray.
ww...
Compound placed on posterior
border
Compound added on buccal
border
The tray gently seated in
place.
The border should be
...
Border molding continued in labial borders.
Border molding the lingual areas.
www.indiandentalacademy.com
Genial tubercles
should be
covered.
Border molded
mandibular tray
www.indiandentalacademy.com
TEST FOR RETENTION
mandibular
• Protrude the tongue
• Move tongue in lateral
direction
• Roll tongue back to
touch palate....
Preparing and instructing patient
• Preparing tray for impression:
removing the relief wax
Removing spacer wax
Escape hole...
The final impression:
• Mixing
• Loading
• Seating
• Removing the impression
• Inspecting
• Correcting
• remaking
www.indi...
Master impression with impression
plaster.
• Custom tray with2.5mm spacer.
• Tissue stops
• Pheripheral tracing.
• Impress...
The border molded compound tray
technique:
• Advantage:
• Same appointment.
• Impression should be accurate with
proper bo...
• Seperating the compound
• Trimming the compound tray
• Attaching handles
• Border molding
• Scraping the compound.
• Mak...
• Closed mouth technique:
www.indiandentalacademy.com
• Using old dentures as an impression
tray.
www.indiandentalacademy.com
Patients wearing upper complete
denture opposed by lower natural
teeth.
Chronic complete denture wearers
Maxillary anterio...
• Mucocompression without
displacement.
• Primary impression with alginate and
special tray with relief in that region.
• ...
• Mucocompression without displacement:
• Two stage technique designed to compress the
flabby tissue so that the compressi...
mucostatic ,openwindow technique-
Zafrulla khan technique.
– Special tray with a window cut in the
region of the displacea...
– Wash impression
with ZOE paste.
Border molding with
low fusing compound.
www.indiandentalacademy.com
– Tray re-inserted, impression plaster
syringed over displaceable tissue.
www.indiandentalacademy.com
Completed impression.
www.indiandentalacademy.com
• Composition compression technique:
• It is designed to take an impression of the
tissues underpressure so that ,under th...
• Impression technique for unemployed
mandibular ridge:
• Impression recorded mucostatic over the
crest of the ridge and m...
• IndicatedIndicated
– Unemployed lower alveolar ridge unable
to provide acceptable support against
vertical loads and pos...
• MethodMethod
– Primary impression made with alginate or
putty elastomer.
– Impression relieved over ridge crest area
and...
• Customized special tray with 2mm spacer
constructed.
• Spacer removed ; tray perforated in
crestal region .www.indianden...
• Low fusing compound used to obtain
impression of primary cast with special
tray. www.indiandentalacademy.com
• Impression reduced in the region of
buccal & lingual sulci ; border
molding refined in patient’s mouth.
• Painful areas ...
Denture spaceDenture space
The portion of the oral cavity that is or may be
occupied by the maxillary and / or mandibular
...
Neutral ZoneNeutral Zone
• That area in the mouth, where, duringThat area in the mouth, where, during
functions thefunctio...
• IndicationsIndications
– Past denture looseness
due to powerful lower lip
activity.
– Non-replacement of
missing teeth l...
•    Generally done for lower
•       Materials used-Waxes,ZnOE,rubber
base putty, self-cure acrylic, impression
compound,...
• On accurate master casts, stabilized
denture bases are constructed.
• Wire loops embedded over ridge
crest for retention...
• Low fusing compound rims attached
to bases.
• Patient trained to perform a range of
functional movements such as
smiling...
Recommended movementsRecommended movements
Smile
Swallow
‘ooh’
‘ah’
www.indiandentalacademy.com
www.indiandentalacademy.com
• Wash impression obtained with light –
bodied elastomer brushed on compound
rims.
• Functional movements repeated.www.ind...
• Plaster matrices constructed around
records.
• Matrices guide in arranging & waxing teeth
& polished surfaces in optimum...
www.indiandentalacademy.com
• PrecautionsPrecautions
– Stable record bases not interfering with muscle
activity.
– Patient to be trained in molding pr...
Functional impressionsFunctional impressions
• IndicationsIndications
– Reduced retentive forces ( Atrophic ridges )
– Hig...
• MethodMethod
– Tissue conditioning materials usually
employed for the procedures.
www.indiandentalacademy.com
• Impression surface & periphery of existing
denture reduced by 1.5-2mm to create
space.
• Fitting surface of denture clea...
• Denture seated in patients mouth;
patient instructed to close in centric
occlusion.
• Patient encourage to perform
funct...
• Denture removed after 5 – 6Denture removed after 5 – 6
minutes ; inspected and surplusminutes ; inspected and surplus
ma...
• Patient returns after few hours;Patient returns after few hours;
impression inspected & cast poured.impression inspected...
• Factors complicating impression
making:
• Uncooperative patients
• Excessive salivation.
• Hyperactive gag reflex.
www.i...
• Hyperactive gag reflex:
• Causes:
• Iatrogenic-physical and visual stimuli.
• Systemic problems
• Psychological factors
...
• Management:
• Reduction of amount and duration of
stimuli.
• Distraction maneuvers
• Prosgressive desensitization:
• Pha...
• John Osborne1964:Two impression
methods for mobile fibrous ridges.
www.indiandentalacademy.com
• Tryde et al 1965 “Dynamic impression
methods :”
• This is an impression procedure for patients
with advanced mandibular ...
• John D Walter 1973 “Composite impression
procedures” :
• These procedures allow the use of more than
one impression mate...
Shanath Shetty,P.Venkat 2007:the selective
pressure maxillary impression :a review of
techniques and presentation of alter...
• Conclusion:
Though there are many techniques and
procedures available for a dentist to make
an ideal impression, the pro...
References:
• Prosthetic treatment of the edentulous patient –
Basker and Davenport.4th
edition.
• Boucher’s prosthodontic...
• John Osborne-Two impression methods for mobile fibrous ridges :British
dental journal,november 3,1964,pg392-394
• Tryde ...
For more details please visit
www.indiandentalacademy.com
www.indiandentalacademy.com
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Techniques of dental impression making/ dental education in india

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Techniques of dental impression making/ dental education in india

  1. 1. Concepts and techniques of impression making INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
  2. 2. Contents: Introduction Selection of impression material: Examination Selection of impression technique Selection of impression material selection of impression tray Prelimnary impression Custom tray Border molding Secondary impression impression for hypermobile ridges composite compression impression Impression for unemployed mandibilar ridge denture space determination functional impressions review of literature conclusion references www.indiandentalacademy.com
  3. 3. The journey towards successful denture fabrication begins with making accurate impressions. Therefore a good impression will help to insure that complete denture is stable, retentive and comfortable. So, the knowledge of different impression techniques are very important for us to achieve a good impression. www.indiandentalacademy.com
  4. 4. • Examination and conditioning of the patient and the mouth. • Complete case history • Clinical examination • Identifying and correcting adverse conditions • Factors that complicate impression making • Old denture wearer. www.indiandentalacademy.com
  5. 5. • Selection of impression technique: 1. Clinical findings. 2. Experience of the dentist. 3. Availability of materials. 4. Patient related factors. Time Undercuts Old denture wearer www.indiandentalacademy.com
  6. 6. Selection of impression material: • Prelimnary impression materials: impression compound alginate. • Final impression materials: Alginate Elastomers Zincoxide eugenol impression paste. Impression plaster Tissue conditioners waxes www.indiandentalacademy.com
  7. 7. • Modelling compound: • Easily correctable. • Can be border molded. • Not influenced by saliva • Can be used as impression tray. • Can be scraped easily to provide relief. • Viscous. • Cannot record fine details. • Compound sticks used for border molding. • Inelastic www.indiandentalacademy.com
  8. 8. • Alginate: • Elastic • Primary and final impression • Records good details • Not correctable but easily remade • Not dimensionally stable. • Donot adhere to tray. www.indiandentalacademy.com
  9. 9. • Elastomeric impression materials: • Elastic • Fine details • Hydrophobic • Adhesive required. • Available in different viscosities • Dimensionally stable. • Cannot be adjusted after set. • Prolonged setting time. www.indiandentalacademy.com
  10. 10. • Zinc oxide eugenol impression paste: • Rigid and inelastic. • Adheres to tray • Flows readily and records fine details. • Burning sensation and tissue irritation. • Dimensionally stable. • bulk of the impression is minimal. • Flaking or breaking during trimming. www.indiandentalacademy.com
  11. 11. • Tissue conditioners: • Functional impression. www.indiandentalacademy.com
  12. 12. • Impression plaster: • Minimal pressure technique. • Flows readily and records fine details. • Rigid • Wash impression • Absorbs saliva. • Dimensionally accurate with anti expansion solution. www.indiandentalacademy.com
  13. 13. • Waxes: • Flow at mouth temperature. • Exert pressure • Fine details not recorded. • Corrections made. www.indiandentalacademy.com
  14. 14. Selection of impression trays: • A device that is used to carry ,confine and control impression material while making an impression. Stock trays. Custom trays Perforated Non perforated. Dentulous edentulous www.indiandentalacademy.com
  15. 15. Stock trays • Caulk’s edentulous rimlock trays. • Mc Gowen’s winkler trays-useful for flat lower ridge • STOKtrays-designed by Arthur Krol available in Square,round,tapering shapes www.indiandentalacademy.com
  16. 16. • Usually stock trays though supplied in different sizes ,donot fit the edentulous mouth with desired accuracy. • To produce satisfactory impression and avoid variations in transmitted pressure, there must be a reasonably even thickness of impression material over the entire fitting surface and flanges of the tray almost reach the functional position of the sulci and frena and yet not displace them. tray www.indiandentalacademy.com
  17. 17. • Custom trays: • Close fitting or spaced trays • Shellac • Acylic resin • Thermoformed polymer sheet www.indiandentalacademy.com
  18. 18. • Seating of the patient: maxillary mandibular www.indiandentalacademy.com
  19. 19. • Prelimnary impression: a negative likeliness made for the purpose of diagnosis or the fabrication of the impression tray. www.indiandentalacademy.com
  20. 20. using alginate using impression compound. For Primary impression high viscosity material is preffered as it allows to compensate better for the shortcomings in the fit and extension of the stock tray. www.indiandentalacademy.com
  21. 21. • Selection of stock tray: • Tray extensions checked • Defficiencies corrected. • Lingual border of mandibular tray • maxillary tray for Deep palate www.indiandentalacademy.com
  22. 22. Primary Impression in alginate. Tray should be adjusted by bending . Selection of stock tray. . Position borders at hamular notches. Lift the tray anteriorly, 3-5 mm space for impression material. www.indiandentalacademy.com
  23. 23. Border of ray should be short of tissue reflection. Adequate clearance in frenal areas. Tray should be smoothened. www.indiandentalacademy.com
  24. 24. Deficient borders corrected by adding utility wax. Tray extension in buccal space and tissue side of posterior border. www.indiandentalacademy.com
  25. 25. Location of hamular notches. Mark the vibrating line. Some alginate to be placed in vestibule. Alginate to be placed in deepest part of palate.www.indiandentalacademy.com
  26. 26. Tray to be rotated into the mouth and seated first at the back of the mouth. Upper lip elevated. Tray is held in the mouth. Labial and buccal borders to be molded.www.indiandentalacademy.com
  27. 27. Completed maxillary Primary Impression with rounded and molded peripheries. www.indiandentalacademy.com
  28. 28. Mandibular alginate impression. Tray should cover retromolar pad. metal edentulous tray. Retromolar pad should be identified www.indiandentalacademy.com
  29. 29. Bending and cutting the tray for adjustment. Adding utility was to extend lingual border. www.indiandentalacademy.com
  30. 30. Patient told to do tongue movements. Patient told to raise the tongue and tray is rotated in the mouth. Gently mold the labial and buccal areas.www.indiandentalacademy.com
  31. 31. • Completed Mandibular Primary Impression. www.indiandentalacademy.com
  32. 32. Prelimnary impression with impression compound. Compound placed in the tray. Modelling compund. Softenend in water bath and kneaded. www.indiandentalacademy.com
  33. 33. Should cover mylohyoid ridge and external oblique ridge. Molded with fingers to ridge form. Gently warmed over a flame. Before insertion, tempering in warm water bath.www.indiandentalacademy.com
  34. 34. Patient instructed for Tongue movements. Tray should be gently seated and border moulding done. Any short areas can be remolded. Impression should cover all denture bearing area. www.indiandentalacademy.com
  35. 35. Common faults Mandibular • Insufficient depth in posterior lingual pouch: • Insufficient depth in lingual,labial and buccal sulci. Edge of the tray showing through the impression. An asymmetrical impression. Maxillary: • Defficiency in the midline of palatal vault. • Excess material extending beyond posterior palatal border of the tray. • Insufficient depth in one or more region of sulci • Tray flange exposure. www.indiandentalacademy.com
  36. 36. Alginate wash impression technique: • Resorbed mandibular ridges. • Using impression compound has the benefit of pushing aside the floor of the mouth and cheeks which tend to become trapped by the edge of the tray. www.indiandentalacademy.com
  37. 37. Preperation for Secondary Impression • Denture outline marked on the primary impression .Completed preliminary casts. www.indiandentalacademy.com
  38. 38. Denture outline accentuated. Posterior border of tray marked.distal to denture border. Wax added for relief. Special tray. custom tray 1mm from mucobuccal fold 2mm past the estimated border. 25mm from vestibule to the top of the handle,3-4mm thick www.indiandentalacademy.com
  39. 39. Checking for tray extensions: • Visual examination • The diagnostic impression • Correction of overextension • Correction of underextension. Impression material tray www.indiandentalacademy.com
  40. 40. Borders should be beveled. Vibrating line marked. Tray inserted in mouth. Overextensions trimmed. www.indiandentalacademy.com
  41. 41. Tray should be short of 2 mm from base of sulcus Borders should be adjusted. Extra clearence in frenal areas www.indiandentalacademy.com
  42. 42. External oblique ridge marked. Tray outline marked 2-3 mm short of denture outline. Custom tray fabricated. Posterior border of tray should cover anterior half of the pad. www.indiandentalacademy.com
  43. 43. Pencil mark transferred to fitting surface. Anterior border of the tray adjusted . Tray border should be resting against the ridge. Lingual border adjusted. www.indiandentalacademy.com
  44. 44. Tissue stops • Prevent seating of the tray too superiorly or posteriorly. • Stabilize the tray • Uniform thickness of the material. • Molar or cuspid areas. • Palatal aspect of the ridge till mucobuccal fold.-maxillary • Mucobuccal fold to the lingual floor –mandibular. • Ways to produce-inlab during construction of special tray. • Chair side in mouth • Chair side on cast. www.indiandentalacademy.com
  45. 45. Finger rests: • Keep fingers which stabilise the tray and support the impression. • Absence of these result in inaccuracies resulting from fingers restricting border molding movements of soft tissue. www.indiandentalacademy.com
  46. 46. • Border molding: The shaping of the border ares of an impression material by functional or manual manipulation of the size of the vestibule. www.indiandentalacademy.com
  47. 47. Materials: • Modelling compound sticks • Autopolymerizing acrylic resin • Metallic pastes • Elastomeric materials • Impression waxes www.indiandentalacademy.com
  48. 48. • Modelling compound sticks: • Advantages: • Soften easily but are quite hard at mouth or room temperature so other areas of periphery can be molded with least possible distortion to the previously completed section. • Corrections easily accomplished. www.indiandentalacademy.com
  49. 49. • Isofunctional impression plastic sticks. • Soften easily and have much longer working time . • Softer at room temperature compared to compound sticks. www.indiandentalacademy.com
  50. 50. • Autopolymerizing acrylic resins: • Rimseal • Flexacryl. • Disadvantages: • Irritating • Strong odor • Heat produced polymerization. www.indiandentalacademy.com
  51. 51. • Premixed self curing soft resins: • Added to the periphery of an existing denture. • Material gradually polymerizes to a semisolid state in few hours-functional border molding. • Advantages: • Less irritating • Easy to use. • Disadvantage: • Consistency changes each time the container is opened. • If denture border is grossly defficient the material will slump as it cannot flow into the vestibule that is 6mm away from the border. www.indiandentalacademy.com
  52. 52. • Elastomeric materials: • Heavy body-border molding. • Advantage-wide range of working and setting time. • Elastic recovery good. • Disadvantage: • Borders difficult to trim • Addition requires time consuming mix of new materials. www.indiandentalacademy.com
  53. 53. • Impregum-Smith etal.polyether based material. • Simultaneous border molding. Advantages: 1.Can be trimmed with knife or burr 2.Corrected with modelling compound or wax. Disadvantages; 1.Skill and great care required. Good prelimnary impressions are important as underextensions cannot be detected. www.indiandentalacademy.com
  54. 54. Impression waxes-adaptol Advantages • Simultaneous border molding. • Donot irritate • Additions easy • Cannot injure oral tissues if correct temperature is applied Disadvantages • Distorts easily and must be handled carefully • Insertion not to be delayed • Chilled wax subjected to flaking and breaking while trimming • Not strong enough to correct underextensions. www.indiandentalacademy.com
  55. 55. • Segment by segment • One step: www.indiandentalacademy.com
  56. 56. • Simultaneous molding of all borders: • Advantages: • Time saving. • Less discomfort to the patient. • Less effort for the dentist. www.indiandentalacademy.com
  57. 57. • Requirements: • Have sufficient body • Allow some preshaping of the borders • Setting time3-5minutes • Retain adequate flow when seating in the mouth. • Allow finger placement of the material in to defficient parts after seating of tray. • Not cause excessive displacement of tissues • Readily trimmed and carved so that excess material can be carved and borders shaped before the final impression is made www.indiandentalacademy.com
  58. 58. The tray rotated in mouth and cheek gently massaged. Compound molded with fingers. Softened again with alcohol torch. Tempered in warm water bath. www.indiandentalacademy.com
  59. 59. Appropriate molding will have mat surface. Compound added in buccal frenum area. www.indiandentalacademy.com
  60. 60. Recording the frenum.Molded buccal and labial borders. Excess compound on tissue side trimmed. Compound placed on posterior border. www.indiandentalacademy.com
  61. 61. Junction of tray and compound smoothened. Tray seated in mouth with firm pressure. Border molded maxillary custom tray. www.indiandentalacademy.com
  62. 62. Compound placed on posterior border Compound added on buccal border The tray gently seated in place. The border should be smooth,round and convex. www.indiandentalacademy.com
  63. 63. Border molding continued in labial borders. Border molding the lingual areas. www.indiandentalacademy.com
  64. 64. Genial tubercles should be covered. Border molded mandibular tray www.indiandentalacademy.com
  65. 65. TEST FOR RETENTION mandibular • Protrude the tongue • Move tongue in lateral direction • Roll tongue back to touch palate. • Open the mouth. • Exerting vertical pull on handle • Forward pressure on distal aspect of the handle. maxillary • Upward and outward pressure in the incisor region. • Upward and outward pressure in the premolar region. • Pulling the upper lip downward. www.indiandentalacademy.com
  66. 66. Preparing and instructing patient • Preparing tray for impression: removing the relief wax Removing spacer wax Escape holes Reducing the borders Applying adhesive Protecting the mouth Drying the mouth. www.indiandentalacademy.com
  67. 67. The final impression: • Mixing • Loading • Seating • Removing the impression • Inspecting • Correcting • remaking www.indiandentalacademy.com
  68. 68. Master impression with impression plaster. • Custom tray with2.5mm spacer. • Tissue stops • Pheripheral tracing. • Impression. www.indiandentalacademy.com
  69. 69. The border molded compound tray technique: • Advantage: • Same appointment. • Impression should be accurate with proper border molding. • Even thickness of compound in the tray must be maintained. www.indiandentalacademy.com
  70. 70. • Seperating the compound • Trimming the compound tray • Attaching handles • Border molding • Scraping the compound. • Making the final impression. www.indiandentalacademy.com
  71. 71. • Closed mouth technique: www.indiandentalacademy.com
  72. 72. • Using old dentures as an impression tray. www.indiandentalacademy.com
  73. 73. Patients wearing upper complete denture opposed by lower natural teeth. Chronic complete denture wearers Maxillary anterior ridge replaced by fibrous tissue; reduced support for dentures. Patient complains of loose dentures Impression techniques to avoid undue tissue displacement. Impression technique for hypermobile ridges www.indiandentalacademy.com
  74. 74. • Mucocompression without displacement. • Primary impression with alginate and special tray with relief in that region. • Hobrik technique • mucostatic ,openwindow technique- Zafrulla khan technique. www.indiandentalacademy.com
  75. 75. • Mucocompression without displacement: • Two stage technique designed to compress the flabby tissue so that the compression through out the whole of the maxillary denture bearing area is as uniform as possible. www.indiandentalacademy.com
  76. 76. mucostatic ,openwindow technique- Zafrulla khan technique. – Special tray with a window cut in the region of the displaceable tissue. www.indiandentalacademy.com
  77. 77. – Wash impression with ZOE paste. Border molding with low fusing compound. www.indiandentalacademy.com
  78. 78. – Tray re-inserted, impression plaster syringed over displaceable tissue. www.indiandentalacademy.com
  79. 79. Completed impression. www.indiandentalacademy.com
  80. 80. • Composition compression technique: • It is designed to take an impression of the tissues underpressure so that ,under the stresses of mastication ,the pressure transmitted through the entire mucosa to the underlying bone is approximately equal over its whole surface. www.indiandentalacademy.com
  81. 81. • Impression technique for unemployed mandibular ridge: • Impression recorded mucostatic over the crest of the ridge and mucocompressive on the peripheral parts and prevents any load being placed on unemployed part of the ridge. • Increased bulk and surface area of denture. www.indiandentalacademy.com
  82. 82. • IndicatedIndicated – Unemployed lower alveolar ridge unable to provide acceptable support against vertical loads and positive stability against lateral forces.www.indiandentalacademy.com
  83. 83. • MethodMethod – Primary impression made with alginate or putty elastomer. – Impression relieved over ridge crest area and wash impression obtained with low viscosity material.www.indiandentalacademy.com
  84. 84. • Customized special tray with 2mm spacer constructed. • Spacer removed ; tray perforated in crestal region .www.indiandentalacademy.com
  85. 85. • Low fusing compound used to obtain impression of primary cast with special tray. www.indiandentalacademy.com
  86. 86. • Impression reduced in the region of buccal & lingual sulci ; border molding refined in patient’s mouth. • Painful areas relieved. • Tray re-insertion should not result in pain. • Impression completed with light – bodied elastomer. www.indiandentalacademy.com
  87. 87. Denture spaceDenture space The portion of the oral cavity that is or may be occupied by the maxillary and / or mandibular denture (s).www.indiandentalacademy.com
  88. 88. Neutral ZoneNeutral Zone • That area in the mouth, where, duringThat area in the mouth, where, during functions thefunctions the forcesforces of the tongueof the tongue pressingpressing outwardoutward areare neutralizedneutralized by theby the forcesforces of the cheeks and lips pressingof the cheeks and lips pressing inwardinward.. • Hence a possible zone of equilibriumwww.indiandentalacademy.com
  89. 89. • IndicationsIndications – Past denture looseness due to powerful lower lip activity. – Non-replacement of missing teeth leading to tongue / cheeks / lips partially occupying the usual denture space. – Enlarged tongue, E.g. Down’s Syndrome. – Abnormal anatomy, E.g. Hemimandiblectomy. – Inability to wear a lower denture www.indiandentalacademy.com
  90. 90. •    Generally done for lower •       Materials used-Waxes,ZnOE,rubber base putty, self-cure acrylic, impression compound,tissue conditioners. www.indiandentalacademy.com
  91. 91. • On accurate master casts, stabilized denture bases are constructed. • Wire loops embedded over ridge crest for retention. Denture spaceDenture space determinationdetermination www.indiandentalacademy.com
  92. 92. • Low fusing compound rims attached to bases. • Patient trained to perform a range of functional movements such as smiling, swallowing, speaking, etc. • Compound rims softened and denture bases inserted ; functional movements carried out. www.indiandentalacademy.com
  93. 93. Recommended movementsRecommended movements Smile Swallow ‘ooh’ ‘ah’ www.indiandentalacademy.com
  94. 94. www.indiandentalacademy.com
  95. 95. • Wash impression obtained with light – bodied elastomer brushed on compound rims. • Functional movements repeated.www.indiandentalacademy.com
  96. 96. • Plaster matrices constructed around records. • Matrices guide in arranging & waxing teeth & polished surfaces in optimum denture space. www.indiandentalacademy.com
  97. 97. www.indiandentalacademy.com
  98. 98. • PrecautionsPrecautions – Stable record bases not interfering with muscle activity. – Patient to be trained in molding procedure prior to insertion of loaded tray. – Excessive volume of molded material to be avoided – causes distortion of potential denture space. – External impression may be totally unlike the shape of a “normal” denture, hence laboratory staff must be instructed about reproduction of the recorded contours. www.indiandentalacademy.com
  99. 99. Functional impressionsFunctional impressions • IndicationsIndications – Reduced retentive forces ( Atrophic ridges ) – High displacing forces ( Uncontrolled muscle activity) • Peripheral form molded by peri–denture musculature. • Existing denture utilized for the procedure. www.indiandentalacademy.com
  100. 100. • MethodMethod – Tissue conditioning materials usually employed for the procedures. www.indiandentalacademy.com
  101. 101. • Impression surface & periphery of existing denture reduced by 1.5-2mm to create space. • Fitting surface of denture cleaned & dried. • Material mixed & spread over fitting surface.www.indiandentalacademy.com
  102. 102. • Denture seated in patients mouth; patient instructed to close in centric occlusion. • Patient encourage to perform functional movements such as talking, swallowing, smiling, to obtain a functionally generated impression. www.indiandentalacademy.com
  103. 103. • Denture removed after 5 – 6Denture removed after 5 – 6 minutes ; inspected and surplusminutes ; inspected and surplus material trimmed.material trimmed.www.indiandentalacademy.com
  104. 104. • Patient returns after few hours;Patient returns after few hours; impression inspected & cast poured.impression inspected & cast poured. www.indiandentalacademy.com
  105. 105. • Factors complicating impression making: • Uncooperative patients • Excessive salivation. • Hyperactive gag reflex. www.indiandentalacademy.com
  106. 106. • Hyperactive gag reflex: • Causes: • Iatrogenic-physical and visual stimuli. • Systemic problems • Psychological factors • Problems in existing prosthesis. www.indiandentalacademy.com
  107. 107. • Management: • Reduction of amount and duration of stimuli. • Distraction maneuvers • Prosgressive desensitization: • Pharmacologic management. www.indiandentalacademy.com
  108. 108. • John Osborne1964:Two impression methods for mobile fibrous ridges. www.indiandentalacademy.com
  109. 109. • Tryde et al 1965 “Dynamic impression methods :” • This is an impression procedure for patients with advanced mandibular residual ridge resorption. • The advantages of dynamic impressions are • Avoidance of the dislocating effect of the muscles on improperly formed denture borders. • Complete utilization of the possibilities of active and passive tissue fixation of the denture www.indiandentalacademy.com
  110. 110. • John D Walter 1973 “Composite impression procedures” : • These procedures allow the use of more than one impression material according to local indications. Such techniques may also be employed for large impressions which are difficult or impossible to obtain with a single tray. Techniques: • The edentulous fibrous ridge : • Impression technique for restricted access to the oral cavity: www.indiandentalacademy.com
  111. 111. Shanath Shetty,P.Venkat 2007:the selective pressure maxillary impression :a review of techniques and presentation of alternate custom tray design www.indiandentalacademy.com
  112. 112. • Conclusion: Though there are many techniques and procedures available for a dentist to make an ideal impression, the procedures that follows should be based on sound biological principles, depending on patients oral and systemic conditions, by understanding the concept of function of oral tissues. www.indiandentalacademy.com
  113. 113. References: • Prosthetic treatment of the edentulous patient – Basker and Davenport.4th edition. • Boucher’s prosthodontic treatment for edentulous patient -9th edition. • Impression for complete dentures-Bernard Levin • Fenn Clinical dental prosthetics-3rd edition. • Complete denture prosthodontics-3rd edition John .J.Sharry. • Syllabus of complete dentures-fourth edition – Charles M Heartwell. • Essentials of complete denture prosthodontics- second edition-Sheldon Winkler. www.indiandentalacademy.com
  114. 114. • John Osborne-Two impression methods for mobile fibrous ridges :British dental journal,november 3,1964,pg392-394 • Tryde et al “Dynamic impression methods :”journal of prosthetic dentistry,1965,volume15,issue 6,pg1023. • John D Walter “Composite impression procedures” journal of prosthetic dentistry,1973,volume30,issue 4,pg385. • Shanath Shetty,P.Venkat :the selective pressure maxillary impression :a review of techniques and presentation of alternate custom tray design .journal of indian prosthodontic society,march 2007,volume 7,issue 1.page8-12. • www.indiandentalacademy.com
  115. 115. For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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