5.preliminary impressions

5. Preliminary Impressions5. Preliminary ImpressionsJohn Beumer III, DDS, MSJohn Beumer III, DDS, MS

Division of Advanced Prosthodontics, Division of Advanced Prosthodontics, Biomaterials and Hospital DentistryBiomaterials and Hospital Dentistry

UCLA School of DentistryUCLA School of Dentistryandand

Frank Lauciello DDSFrank Lauciello DDSIvoclar VivadentIvoclar Vivadent

This program of instruction is protected by copyright ©. No portion of This program of instruction is protected by copyright ©. No portion of this program of instruction may be reproduced, recorded or transferred this program of instruction may be reproduced, recorded or transferred by any means electronic, digital, photographic, mechanical etc., or by by any means electronic, digital, photographic, mechanical etc., or by any information storage or retrieval system, without prior permission.any information storage or retrieval system, without prior permission.

Preliminary ImpressionsPreliminary Impressions

Preliminary ImpressionsPreliminary ImpressionsPurpose:Purpose:

-for -for diagnosis and construction of custom impression traysdiagnosis and construction of custom impression trays..

Requirements:Requirements:

-must capture all intraoral landmarks, retromolar pads, -must capture all intraoral landmarks, retromolar pads, retromylohyoid space, hamular notches, etc.retromylohyoid space, hamular notches, etc.

-will be slightly overextended but must essentially capture -will be slightly overextended but must essentially capture the 3-D contours of the vestibular borders of the limiting the 3-D contours of the vestibular borders of the limiting structures.structures.

****An accurate preliminary cast that records all anatomic landmarks An accurate preliminary cast that records all anatomic landmarks that should be covered by a denture permits fabrication of properly that should be covered by a denture permits fabrication of properly extended custom trays that will expedite border molding and extended custom trays that will expedite border molding and facilitate a quality final impression.facilitate a quality final impression.

Preliminary Impressions - Armamentarium

-Alginate(reversable hydrocolloid)-Tray Adhesive-Edentulous metal stock trays-Plastic mixing bowl-Round edge spatula-Periphery wax-Water bath-Mouth mirror-2x2 gauge

Preliminary ImpressionsPreliminary ImpressionsSelect a stock tray

Extend tray only where necessary with soft periphery wax

Warm the periphery wax in a warm water bath, insert in patients mouth and mold the periphery wax to the intraoral contours

Spray with tray adhesive

Irreversible hydrocolloid impression

The preliminary impression should have no major pressure spots or voids and it should capture all peripheral extensions

Pour impressions in plaster with adequate bases including the central “tongue” area of the mandibular impression

Warm the periphery wax in a warm water bath, insert in patientsWarm the periphery wax in a warm water bath, insert in patientsmouth and mold the periphery wax to the intraoral contours.mouth and mold the periphery wax to the intraoral contours.

**Note: the pts existing denture can be used**Note: the pts existing denture can be usedto help select an appropriate size tray.to help select an appropriate size tray.


Preliminary Impressions Preliminary Impressions

Spray alginate adhesive onto traySpray alginate adhesive onto tray

Practice tray insertionPractice tray insertionMix the alginate with the Mix the alginate with the round edge spatularound edge spatula..

Mix in a vigorous manner using Mix in a vigorous manner using sweeping sweeping strokesstrokes against the walls of the mixing bowl. against the walls of the mixing bowl.

Mix to a Mix to a creamy consistencycreamy consistency..

It is often recommended to It is often recommended to use slightly less use slightly less waterwater than the directions specify to achieve a than the directions specify to achieve a thicker mix. This is especially true for the thicker mix. This is especially true for the maxillary impression to reduce the likelihood of maxillary impression to reduce the likelihood of gagging.gagging.

Use the mirror handle to retract the lipsUse the mirror handle to retract the lips as as you you rotate the tray into positionrotate the tray into position..

Message the lips and cheeks to border mold Message the lips and cheeks to border mold the peripheriesthe peripheries..

Tray ready to insertTray ready to insert

Alginate Mixing Tips:Alginate Mixing Tips:


Mix alginate and load tray

Mandibular Alginate ImpressionMandibular Alginate Impression

Seat the tray and hold it firmly in position. Seat the tray and hold it firmly in position. Have the patient lift their tongue and displace it anteriorlyHave the patient lift their tongue and displace it anteriorly ..

Mandibular Alginate ImpressionMandibular Alginate Impression

Ideal impression should:Ideal impression should:Show no pressure spotsShow no pressure spotsRecord the ridge, peripheries, retromolar pad, and Record the ridge, peripheries, retromolar pad, and the retromylohyoid fossa.the retromylohyoid fossa.

Insert trayInsert traySeat posterior portionSeat posterior portionRotate the anterior portion into positionRotate the anterior portion into positionBorder mold the impressionBorder mold the impression

Completed impressionCompleted impression

Maxillary Alginate ImpressionMaxillary Alginate Impression

Dense mix of plasterAvoid entrapment of air bubblesPour the impression with adequate plaster to create a base

Note: The plaster Note: The plaster should capture the should capture the contours of the labial-contours of the labial-buccal borderbuccal border..

Pouring the Preliminary Casts

The preliminary impression should have no major pressure The preliminary impression should have no major pressure spots or voids and it should capture all peripheral extensions.spots or voids and it should capture all peripheral extensions.Pour impressions in plaster with adequate bases including the central “tongue” area of the mandibular impression.Pour impressions in plaster with adequate bases including the central “tongue” area of the mandibular impression.

Completed ImpressionsCompleted Impressions

Alternate Technique- Accu-dentAlternate Technique- Accu-dent

Accu-Dent System 1Accu-Dent System 1Irreversible hydrocolloid (hydrophilic)Irreversible hydrocolloid (hydrophilic)

Two viscositiesTwo viscosities

Non-slumpingNon-slumping

Premeasured sealed packagingPremeasured sealed packaging

Syringe delivery Syringe delivery

Temperature controlledTemperature controlled

Unique tray designUnique tray design

Single entry impression systemSingle entry impression system

Tray SelectionTray Selection

Post DamPost Dam

Locate the physiologic Locate the physiologic posterior palatal seal area posterior palatal seal area by having patient say “ah”by having patient say “ah”

Using an indelible stick, Using an indelible stick, mark the palate just distal mark the palate just distal to where the palate to where the palate vibrates.vibrates.

Palpate where the palatal Palpate where the palatal tissues are displaceable tissues are displaceable (glandular area) and mark. (glandular area) and mark.

Mix the Syringe Gel using Mix the Syringe Gel using 7070°F water measured to the °F water measured to the designated line on the vial. designated line on the vial.

Back load the syringeBack load the syringe

Replace the plunger and Replace the plunger and express out anyexpress out any air. Set air. Set asideaside

Syringe GelSyringe Gel

Mix the Tray Gel using 70Mix the Tray Gel using 70°F °F water measured to the water measured to the designated line on the vial. designated line on the vial.

The mix will appear dry at The mix will appear dry at first but first but do notdo not add additional add additional water.water.

Tray GelTray Gel

Accu-Dent Maxillary ImpressionAccu-Dent Maxillary Impression

Make sure a small amount of Tray Gel Make sure a small amount of Tray Gel is pushed through the large holes in the is pushed through the large holes in the tray for retention.tray for retention.

Hold the tray under cold running water Hold the tray under cold running water and smooth the surface with your and smooth the surface with your fingers.fingers.

The proper shape of the Tray Gel The proper shape of the Tray Gel material is very important: most of the material is very important: most of the material should be in the front sloping material should be in the front sloping to very little in the back.to very little in the back.

Loading the trayLoading the tray

Wipe dry the vestibules and palate Wipe dry the vestibules and palate with a 2x2 gauge.with a 2x2 gauge.

Express a line of the Syringe Gel into Express a line of the Syringe Gel into the vestibule from the hamular notch the vestibule from the hamular notch to the midline.to the midline.

Continue from opposite posterior to Continue from opposite posterior to midline. Do not go all the way around midline. Do not go all the way around in a single pass.in a single pass.

Taking the ImpressionTaking the Impression


Taking the ImpressionTaking the Impression

Place a small amount of Syringe Gel Place a small amount of Syringe Gel in the anterior vault of the palate.in the anterior vault of the palate.

Seat the tray from front to back.Seat the tray from front to back.

Stop seating the tray when a small Stop seating the tray when a small amount of Syringe Gel appears in the amount of Syringe Gel appears in the distal edge of the tray.distal edge of the tray.


Pull straight down once on the filtrum Pull straight down once on the filtrum at the vermilion border.at the vermilion border.

Massage the cheeks very lightly Massage the cheeks very lightly downward with the fingers.downward with the fingers.

Have the patient open wideHave the patient open wide

Border MoldingBorder Molding


Tray RemovalTray Removal

When set, break the seal at the When set, break the seal at the distal buccal periphery and distal buccal periphery and carefully remove the carefully remove the impression. Using the handle impression. Using the handle alone to remove the impression alone to remove the impression might dislodge the material.might dislodge the material.

Disinfect according to OSHA Disinfect according to OSHA guidelines and immediately pour guidelines and immediately pour the model the model


Impression tray acts Impression tray acts only as a method of only as a method of delivering the delivering the impression materialimpression material


Accu-Dent Mandibular ImpressionAccu-Dent Mandibular Impression

The lower Accu-Tray selection is accomplished in two steps, 1) tray type and 2) tray size

Chose the tray that best suits either a normal ridge, or a highly resorbed ridge. Trays # 26-30 are designed with a moderate distal rise to accommodate the moderately resorbed ridge.

Trays #20-24 are designed with a high distal rise to help accommodate the severely resorbed ridge .


Tray TypeTray Type

Tray SelectionTray Selection

Use the supplied calipers to measure the width of the residual ridge in the first molar region. This can be done on the existing denture, as shown, or in the patients mouth.

Use this measurement to select the correct size lower tray. The caliper measurement should line up with the large holes in the first molar region of the lower tray. When in doubt use a smaller tray.

Accu-Dent Mandibular ImpressionAccu-Dent Mandibular ImpressionTray SizeTray Size Tray SelectionTray Selection

Mix the Syringe Gel using 70Mix the Syringe Gel using 70°F °F water measured to the water measured to the designated line on the vial. designated line on the vial.

Back load the syringeBack load the syringe

Replace the plunger and Replace the plunger and express out any air. Set asideexpress out any air. Set aside

Syringe GelSyringe Gel

Mix the Tray Gel using 70Mix the Tray Gel using 70°F °F water measured to the water measured to the designated line on the vial. designated line on the vial.

The mix will appear dry at first The mix will appear dry at first but but do notdo not add additional water. add additional water.

Tray GelTray Gel

Mix the Tray Gel and place half on each side Mix the Tray Gel and place half on each side of the tray. Make sure that some of the tray of the tray. Make sure that some of the tray material is pushed through the holes.material is pushed through the holes.

This is the correct shape of the loaded tray. This is the correct shape of the loaded tray. More material should be in the posterior of the More material should be in the posterior of the tray.tray.

Give the Tray Gel a surface wash and rub Give the Tray Gel a surface wash and rub smooth under cold running water with your smooth under cold running water with your fingers.fingers.

Accu-Dent Mandibular ImpressionAccu-Dent Mandibular ImpressionLoading the TrayLoading the Tray

Express Syringe Gel from the retromolar pad forward to the midline.

Repeat on the other side of the arch. It is not necessary to place Syringe Gel into the lingual vestibules.

Place tray front to back until Syringe Gel appears in the posterior of the tray. Have the patient bring their tongue forward as you rotate the tray backward into position. When the Tray Gel rises up in the distal, Stop.

Accu-Dent Mandibular ImpressionAccu-Dent Mandibular ImpressionTaking the ImpressionTaking the Impression

Completed lower impressionCompleted lower impression


5.preliminary impressions

Technology

Transcript of 5.preliminary impressions