WAX DEPARTMENT
OBJECTIVE
To make morphology / structure of tooth
UTENSILS:
-
Electronic carver/ wax carver
Lence with lamp
Carver
Wax pot
Waxes with different density
Pico- sep(wax separator)
Scalpel (B P blade)
Smoothing brush
Caliper
Fleximeter
Procedure:
Barcode Scanning, Job card & instruction slip verification.
Work starts from the wax department. We use German Adenta wax because of its less
expansion, shrinkage, capacity, and dynamical stability (Thermoplastic material).
Mainly we have three types of wax work in our lab. They are,
1. Metal Ceramic (Dent care Nova, Magna, Facing ceramic)
2. Full Metal (Dentcare Nova Metal , precious & N P G, Titanium )
3. E-max work
We have 4 types of wax
1.
2.
3.
4.
Dipping Wax
Body wax
Sticky Wax
Cervical wax
–
–
Melts always in 990C in wax pot
To make anatomy of tooth
Gives joint in case of bridge & joint crown.
Cervical area /to make margin
Make the correct occlusion for posteriors and midline for anteriors. A Wax separator
(Picocep) is applied over the stump. Dip the stump in the dipping wax. Next by using the body
wax is make copying or anatomy of the tooth and 1.5 to 2mm clearance should be there for
copying. Cervical wax is used in the cervical area. Sticky wax is used to connect the work in
case of bridge/ joint crown.
Caliper is used to measure thickness. Thickness of crown - 4mm,
Bridge - .5mm.
Scalpel & smoothening carver is used (electronic carver) to takeout the extra part
or thickness.
Wax works in our lab
Full metal with full morphology, Acrylic facing, Inlay, Onlay, Post & Core, Space
maintainer, Non Precious Gold Full metal, Titanium full metal,
E-max works, Metal ceramic.
Wax mock up
White wax is used to make a full morphology. Wax trial to doctor for perfection
in final work.
E-max work
Lithium disilicate pressable glass-ceramic material is used.
Five types of work are
i)
Crown
ii) Bridge iii) Inlay iv) Onlay
v) Veneer
Three methods are
1. Staining: Full anatomical work, no body build-up
2. Layering: Ingot frame + Ceramic body
3. Cut Back technique: Enamel apply on labio -Incisal tip area.
Job details are to be entered and send to the next section INVESTING.
EVALUATION
1. Which are the Different types of waxes
2. What are the Steps involved in the wax-up process.
INVESTING
Objective:
Make the wax work for dewaxing and to convert as metallic form
Tools
Procedure:
Barcode Scanning, Job card, instruction slip verification.
Cast is checked under a microscope (Cropping frame) to check irregularities, folding in
margins, rocking, etc.
Three steps involved in investing are,
i)
Spruing
ii) Base molding
iii) Investing
1. Spruing
Different sizes and shapes of sprues are available. Sprue is placed on work at
450 angles –.3mm thickness for crown and .4mm thickness for the bridge. For bridge
and bigger works, big balloon suppliers are used.
“ L ” shaped cooling sprue is used for pontic.
2. Base molding
Weigh the crucible former (base). Mount the sprued work on base center 3
mm gap to be maintained with work & work. Between the ring and work 5mm.
Weigh the total i.e., (base + work). Subtract the weight of base from the total
weight.
Total weight – base weight = Wax weight
Wax weight x 8.3 (density) = Metal weight
This is the weight of metal required for work. Work is inserted in a ring.
3. Investing (Refractory mound)
Picocep is sprayed to avoid air bubbles. Vaseline is applied inside the ring and
on-base as a separating medium. Heat-provided phosphate bonded Adentavest
powder is mixed with Adenta tech liquid and distilled water in correct ratio 30-seconds
hand mix + I minute vacuum mixing). This mixture is poured into the ring and sprue
placed in the ring by placing on the vibrator. Setting time 30 minutes.
Job details are to be entered and sent to Casting.
Evaluation
1. Write any two features of investment material.
CASTING
Objective
Tools
Procedure:
Barcode Scanning, Job card , Instruction slip verification.
Casting is the process by which wax work is dewaxed and replaced by metal
frame.
Types of casting are:
1.
2.
3.
4.
5.
Induction casting –
Pressure casting Vacuum casting –
Titanium casting –
E-max Pressing –
Centrifugal force
Argon force
Vacuum casting
Argon force
Pressing Force
For Co Cr, Precious gold, and non-precious gold, the Ring is to be placed in a
pre-heating furnace at 9000 C for an hour. In the meantime, wax is burnt off & space remains.
Metal to be placed in the crucible such that the mouth of the crucible and ring are face to
face for 2-3 minutes. So that metal gets melted & fill the empty space left by the wax. For
Titanium, preheating time is 7.30 – 8 hours at 9000 C decreased to 4000 C & last one hour
4000 C.
For E- max pressing, 1.15 hours is the pre-heating furnace duration at 8500 C.
A small ring is chosen for smaller work and a big for bigger. Ingot to be placed and selected
as per shade. Plunger to be dipped in separating medium and load on Ingot (pressing take
place) here wax is replaced by wax. After cooling, the ring is broken ansandblastingng is done
with aluminum oxide 1100 C.
Work details are entered and passed to the next section.
EVALUATION
1. Write any two features of a dental alloy.
2. Different types of casting machines.
METAL FINISHING
Objective
Tools
Procedure:
Barcode Scanning, Job card, instruction slip verification.
The metal finishing department provides a proper and finishing to the metal.
Works from CAD-CAM and wax department after casting reach here. Two types of works are
DMLS and Metal Ceramic.
i) Insertion – Removal of metal extras, melt, and air bubbles with electric motor and bur.
Removes sprue, high point, correction, and marginal level is checked. Insertion of
metalwork on the stump and proper insertion is assured. Lipstick is applied to check
the seat. Lipstick visible portions are trimmed and perfect seating and insertion are
made.
ii) Finishing – Metal ceramic and facing ceramic works come to this section.
Doctors instruction and Job card to be read. Work type to be checked. Metal trial to
be provided if asked.
For full metal, a ceramic body is not required. For facing, a Ceramic body is required
on the facial side. Thickness is to be measured with a caliper. Disc and mantle are used
to soften and shape the work. Use carbide to smoothen in the same direction if it is to
be sent for glazing.
Metal thickness of Nova crown .3 mm and Bridge .4 mm.
For MLS CAD-CAM; crown .4 mm, Bridge. 5 mm.
Bite and high point to be checked with the articulator. Insertion is done after checking
and correcting of marginal level. Duplicate model to be also checked. Full metal and
facing ceramic is sent for Polishing and others to Opaque
iii) Metal polishing – Full metal works – full anatomy is cleared, Glazed, and sent to final
checking and dispatch.
Read Job card and check whether the work is done as per the instructions. Check
upper and lower occlusion, high point, contact, margin, etc. Insert and correct in case
of an air bubble or melting mark. Highpoints and movements to be checked with
Articulator. Check the morphology. Metal and facing ceramic work are polished mainly.
The inner side of the work is to be sandblasted with sandblasting machine. Sprue
to be sized, shaped, smoothened using disc without losing its morphology. Use carbide
to glaze the work. Highpoint to be removed with highpoint bur. Draw groove with
groove bur. Use brown wheel and blue wheel to polish the work. Check the work, use
polishing soap and polishing brush to buff the working buffing motor. Use a steam
cleaner and steam clean the work. If full metalwork, send it to final checking and to
dispatch.
Evaluation
Differentiate between the full metal crown and PFM
Dental alloys used in the dental lab for making core.
OPAQUE
Objective:
Materials & Tools:
Procedure:
Both MLS and Nova works reach here the five main stages of work in opaque
after checking metalwork.
1. Oxidation
2. Micro blasting
3. Apply to wash opaque
4. Apply first opaque
5. Apply second opaque
Nova work will be sent to oxidation to remove impurities of metal at 1100
program (Aluminum Oxide).
All works including Nova and DMLS are sent to micro blasting to gain bonding strength
for work. Steam cleaning to be done with a steam cleaner. Artery forceps are used to
hold micro-blasted and steam cleaned work to avoid air bubbles and dust. First coating
(Wash) after steam cleaning 3C bond to be mixed with distilled water. Use brush and
apply a thin layer and set 50 programs in the furnace. The second time is 20 minutes.
The second opaque is given A1- D4 a total of 16 opaque shades are available. Shade to
be verified in job card and shade tab (Ivoclar, 3D Master, and Vita shades are available).
Check the work- facial or full ceramic. IPS shade + IPS liquid is mixed with the
spatula on glass rode and a thin uniform shade is given so that the shade of stump is
not visible. For facial, only buccal or labial side and tip to be shaded, for a full ceramicfull tooth. Uniform thickness is given to avoid are bubbles and blackening. Placed in a
furnace in eleven programs, checked, and send to next section ceramic body.
Evaluation
What are the functions of opaque coating?
CERAMIC BODY
Objective
Tools
Procedure:
Barcode Scanning, Job card, instruction slip verification
i)
ii)
Body build-up: Works from Opaque & E-max reach here. Read the instruction
slip, Job card. Steam clean work before & after correction. Check shade and use
deep dentine, dentine, effect powder, enamel, and orange with body liquid and
mix in glass slab.
Work and powder should be wet. Apply deep dentine 1 mm ceramic brush in
the cervical area. Give dentine for the body in the same size and shape as the
original tooth. Orange is used for occlusal surfaces. Cut back body and apply
effect powder and enamel from incisal tip to middle, mesial and distal. Keep
work in firing tray and fire in a ceramic furnace.
Ceramic insertion: Seating and marginal level are checked. Blue artifole paper is
used to check proximal clearance. Excess portions are removed and perfect
seating is assured.
Evaluation
List out powder materials for body build up.
CERAMIC FINISHING
Objective
:
Tools
Procedure :
Barcode Scanning, Job card, instruction slip verification
Check the gender of patient and opposite is checked for shape. Proximal
contact is checked with blue artifole paper and side is made convex with diamond bur.
Caliper is used to measure thickness and bur is used to make the tooth identical to the
adjacent and opposite.
a) Anterior finishing
Model to be checked and impurities to be removed. Check the
Gender and mark the contact by drawing line and point angle. Aesthetics is given
importance for anteriors. Mamalons, tubercles, contacts, anatomy, High point, bite,
primary plane, mesial and distal anatomy are priority. Mesial should be straight and
distal to be convex Lingual side should be ‘V’ shaped and separation is given with a
pencil. Contacts to be rounded. Disc bur is used for grinding. Uniform thickness to
be given. High point to be checked. Length of tooth is checked with a glass slab.
Grooves are given with air router. Check rocking and to seat tooth on model and
duplicate
b) Posterior finishing
Function and occlusion are the main concern on the posterior aspect. Seating,
correction, high point, full anatomy and morphology, occlusion, bite, contact,
movement, cusp, ridge, groove, fissure,
Sulcus, etc. are to be taken care incorporated point angle and line angle to be
drawn and shaped accordingly. Margin adaption, High point and seating to be
checked both in model and duplicate.
Evaluation
What are the major steps involved in ceramic finishing?
GLAZING AND STAINING
Objective
Tools and Materials:
Procedure:
Barcode Scanning, Job card, instruction slip verification
Steam cleaned work is polished with stain liquid and then with shade. The
shade on instruction slip is cross checked with given shade and polished with glazing paste
and then shaded. Stain liquid also can be applied prior to shading. Furnace the work and
shade to be matched. Apply the glazing paste and reapply the same shade. For pressable
ceramic work. Work to be cleaned under running water and steam cleaned after glazing.
The shades of the tooth are given by Value, Hue, and Chroma. These factors affect the depth
and perfection of shade.
1. Value: White has more value than black. Value decreases from A1-A4
2. Chroma: Intensity of color. Intensity increases from A1-A4
3. Hue: Determines the color. A1-A4: Reddish, B1-B4: yellowish, C1-C4: grayish, D2-D4: red
grayish.
The depth of the shade depends 70% on value, 20% on chroma, and 10% on hue. When the
value increases, chroma decreases. So increase value.
EVALUATION
1.Why do we glaze a work before sending it?
2.Difference between shade tab and shade tab.
FINAL CHECKING
Objective:
Tools:
Duropolish, knife-edge, white wheel, rose wheel, blue wheel, blue artifol
Procedure:
Microblasting is done for the work in presence of Aluminum Oxide at 1100c to
eliminate the green color attached to the material during staining.
Steam cleaning to be done.
Final checking includes through checking of various parameters such as….
Shade, sharpness, roughness, porosity, air bubble, black spot, glazing,
metal polish, crack, sandblasting & cleaning, fitting, open margin, overextension, margin
short, proximal contact, metal expose, rocking, stains, morphology, the height of contour,
embrasure, size & shape, not within arch, function, canine guidance & all movements,
occlusal high point, under occlusion, bulkiness in metal, collar, pontic type, opaque inside
coping.
Evaluation
What are the steps involved in the final checking process.?
FINAL QUALITY CHECKING
Objective:
Tools: Caliper, Articulator, Blue artifol paper
Procedure:
Quality of product is ensured here by our quality analyzing team. The major areas of concern
here are




Rocking in model and duplicate
Margin shortage and adaptation
Perfection in ceramic finishing
Shade perfection/ Stain/ Glaze/ Translucency






Proximal contact and seating
Occlusion, under occlusion and high point
Movements
Sandblasting inside
Opaque inside coping
Articulator checking
Evaluation
Parameters used to check a work finally before dispatch.
DISPATCH
Objective:
Tools:
Procedure:
The work is to be removed from the model, wrap in cotton, insert in polythene cover, place
on the model and to be wrapped in air bubble paper, and to be kept in the box. Warranty
cards and bills are inserted into the box. Address sticker and name including job number are
pasted on the top of the box and packed tightly with a rubber band over it.
Boxes are loaded into corresponding area boxes and passed over either to the logistics dept.
for distribution or through courier services and respective executives collects the work and
distribute to their clients.
Evaluation
List out the packaging materials and mention their importance.