Slide 1: LABORATORY PROCEDURES
INFABRICATION OFCOMPLETEDENTURE Complete Denture : Complete Denture A dental prosthesis that replaces all of the natural dentition and associated structures of maxilla and mandible. It may be supported by mucosa or sometimes by dental implants. Slide 3: Esthetic.
Function without interferences.
Preservation of oral structures.
Maintenance of health & comfort. Objectives of complete denture Slide 4: STEPS IN FABRICATION OFCOMPLETE DENTURE Slide 6: Types of impression Primary impression : Primary impression Negative replica of the oral tissues
Done for the purpose of diagnosis or
construction of tray Slide 8: Stiff to prevent distortion.
Workable thickness must be 4mm.
Altered in areas hindering the ridge.
Borders - 2mm short of vestibule. HOW A TRAY SHOULD BE? Tray selection : Tray selection Slide 10: Perforated tray Non- perforated tray. Impression materials Conditioning the impression : Conditioning the impression Sprinkle dental stone on impression
- immersing in disinfectants for
trimming excess with BP blade Primary cast : Primary cast Pour the plaster in the impression in 3 steps.
Done within 15min after impression making.
Base should have 10mm thickness.
Pouring should be done from distal end.
Trimming Requirement of cast : Requirement of cast Free of voids.
Record the details accurately .
Extend 3 to 4mm beyond retromolar pad .
Moisture free. Special tray : Special tray A custom made device prepared for the particular patient which is used to carry , confine and control an impression material while making an impression. Why is it needed? : Why is it needed? Overview Of Border Moulding .
To Support Green Stick Compound.
To Make Out Final Impression .
To Provide Even Thickness Of The Impression Material. Requirements : Requirements Well adapted to the primary cast .
2mm thick in the palate area and lingual flange for rigidity.
2mm relief near the sulcus.
Free of voids & projections in the tissue surface. Slide 17: shellac Cold cure resin polystyrene Materials for custom tray
fabrication Polystyrene Trays : Polystyrene Trays Slide 19: Soak in water
Draw the outline on the cast.
Block out the undercuts using wax.
Place the wax spacer on the cast. Conditioning the
primary cast Slide 20: record tissues in a state of anatomical rest.
Stability during impression making.
Relief the non stress bearing areas .
modelling wax , non asbestos & casting liner. Spacer: Why is a spacer needed? Fabrication of custom tray (cold cure resin) : Fabrication of custom tray (cold cure resin) Sets by chemical reaction
Two techniques Slide 22: L/P ratio – 1 : 3
After mixing monomer & polymer undergoes six stages
- wet sandy
- early stingy
- late stingy
- stiff Dough technique Slide 23: Manipulate in dough stage.
Knead to achieve a homogenous mix.
Adapt the rolled sheet from centre to periphery.
Remove excess with BP blade.
After cutting hold in position to prevent shrinkage & warpage during polymerisation.
Monomer is sprinkled on the groove for chemical bonding . Handle : Handle Place anteriorly.
Should be parallel to the long axis of the teeth. Soak the tray in water to prevent warpage Slide 26: Negative likeness made for the purpose of fabricating a prosthesis.
It should have the finer details of denture bearing area at rest .
border moulding / peripheral tracing
make wash out impression
postdamming Secondary impression Steps: Slide 27: Techniques in making secondary impression Slide 28: The shaping of an impression material by manipulation or action of tissues adjacent to the borders of impression
simultaneous border moulding
incremental border moulding Techniques involved Border moulding/ peripheral tracing Tray preparation before imp. making : Tray preparation before imp. making Wax spacer should be removed.
Remove 0.5 – 1mm of tracing material but not in post. palatal seal.
Flanges and the border should be 2.5 to 3mm thick.
Drill holes in tray to prevent tissue displacement during imp.making. Slide 30: Tracing material enhances post palatal seal.
Serves as guide for positioning the tray .
Prevents aspiration of imp. Material. Why is post palatal seal preserved? Materials for secondary imp making : Materials for secondary imp making Slide 32: Imp. must be free of voids which is rectified by wax.
Disinfect with iodophor or 2% glutaraldehyde for 10 mins. Requirements Slide 34: Prevents the width and height of the sulcus
Mainly preserves mucobuccal and mucolingual borders.
beading utility wax
boxing plaster with pumice , paddle boxing and caulking compound . Beading & boxing Slide 35: Replica of the tooth structures , residual ridge areas and other parts of the dental arch or facial structures used to fabricate a dental restoration or prosthesis. Master cast Record base : Record base Base of denture .
Support wax occlusal rims.
Well adapted to the final cast .
1mm thick on the crest and facial slope of the ridge .
2mm thick in the palatal and lingual flange.
Smooth and rounded borders. : Record base Slide 38: ZnOE.
Elastomeric impression materials .
Soft and hard curing resins. Stabilising materials Occlusal rims : Occlusal rims Occluding surfaces built on temporary or permanent denture bases for the purpose of making maxillo-mandibular relation records and arranging teeth.
Primarily serves as gingiva
Done mainly to arrange teeth Slide 41: Rolled wax technique
Pre-formed occlusal rim
Metal occlusal rim former Occlusal rim techniques Slide 42: 22mm high from the depth of the sulcus.
Ant region should be 8mm away from incisive papilla .
4 – 6 mm wide in ant region.
Occlusal table should be 18mm high from the depth of sulcus.
Occlusal table should be 8 – 12 mm wide posterior.
Occlusal table should be 10 – 12 mm above the crest of alveolar ridge anteriorly. Maxillary occlusal rim Slide 43: Thermoplastic material
Adapt from centre to periphery using Bunsen flame.
Overheat may lead to leaching.
Adapt by applying pressure with a wet cotton swab .
Borders are adapted upto sulcus using a blunt spatula . shellac Adaptation: Mandibular occlusal rim : Mandibular occlusal rim 6 -8mm high from the crest of the ridge anteriorly
18mm high from depth of the sulcus in the canine eminence region
3 – 6mm high from the crest of the ridge posteriorly
The occlusal plate should extend to 2/3rd ht of the retromolar pad posteriorly
anteriorly 4 – 6mm
posteriorly 8 – 12mm Centric occlusion: : Centric occlusion: Term used to describe the position of the lower jaw when the teeth are fully occluded together.
It is the mandibular jaw relation in which the head of the condyle is situated as far superior and posterior as it can. Slide 48: A Device Used To Record The Positional Relations Of The Maxillary Arch To The Tempromandibular Joints And To Orient Dental Casts In This Same Relationship To The Opening Axis Of The Articulator . Facebow Slide 49: Articulator A device that may be adjusted to permit movement of the casts into various recorded eccentric relationships Slide 50: The procedure of attaching the maxillary and mandibular casts to the articulator in the recorded jaw relations.
Zeroing the articulator.
Mounting the maxillary cast.
Mounting the mandibular cast. Articulation Mounting procedure: Slide 51: MOUNTING Bennett angle –30
Incisal pin position should be at zero point to the incisal table.
Maxillary cast – face bow transfer records.
Mandibular cast – centric relation records. Slide 52: Maxilla: Teeth setting Mandible: : Mandible: Slide 54: A malocclusion of the teeth in which the front upper incisor and canine teeth project over the lower.
vertical overlap. overbite Slide 55: Increased projection of the upper teeth in front of the lower teeth, usually measured parallel to the occlusal plane.
Horizontal overlap. overjet Slide 56: The contouring of a pattern in wax generally to shaping in wax of the contours of a trial denture. Wax Up Requirements : Requirements Aesthetics.
Functions of denture.
Prior to try -in for better treatment outcome .
Imitate the tissues around the natural teeth.
Proper thickness. procedure : procedure A softened rolled baseplate wax is kneaded and adapted over the cervical area of the teeth.
Wax width-6mm, 5mm long
Depression should be created between the central incisor and canine. Slide 59: . Should give convex contour to the dental flange.
Concave flange contour to molar regions.
Prominent bucco-gingival margins. Festooning : : Festooning : By creating depressions interdentally.
Wax should be carved around the neck of the tooth with wax spatula.
Posteriors – 45 degree.
Thin down near neck of the teeth for free gingiva. Carving : Slide 62: Stippling is produced interdentally with a tooth brush or bristle brush in the region of attached gingiva.
Effective in regions of interproximal areas. Slide 63: Polish by flaming and wiping with cotton.
Polish with damp nylon stocking in rough areas.
Normal thickness – 2mm -2.5mm. Polishing Slide 64: DENTURE
PROCESSING Slide 65: Involves Replacing The Base Of Waxed Portions With Final Denture Materials Denture processing Slide 66: Separation of cast Flasking Dewaxing Curing Denture processing Packing Slide 67: Sealing:
The Denture Is Sealed To The Cast At Its Borders With Molten Wax.
Cast Separation. Cast Preparation Why sealing is done ? : Why sealing is done ? It Helps To Maintain Position Of The Denture.
Mainly Prevents Plaster From Getting Under The Denture. Slide 69: Process by which trial denture is surrounded by stone / plaster in a metal flask .
It basically creates a mould for acrylic denture. Flasking / Investing Flasking Techniques : Flasking Techniques Two Pour
Ideal Material For Investing - Stone Three Pour Technique : Three Pour Technique Flask- Hanau flask .
Soak the cast in slurry water.
Checking the fit .
Excess height is trimmed off.
Lubricate using petroleum jelly .
Reduces the possibility of distortion and fracture.
Deflasking is easier. Advantage: Slide 73: Separating media is applied at base of sides.
Stone filled in the lowest portion.
Allowed to set for 20mins.
Apply separating media over 1st pour .
Middle portion of flask is assembled and pour the 2nd mix till the occlusal surfaces of teeth and allow to set for 20mins.
Excess stone is removed to expose cusp tips . First pour: Second pour: Slide 74: Separating Media Is Applied Again.
Stone Mix Is Poured Filling The Remainder Of Flask.
Allow To Set For 20mins. Third pour: Slide 75: Similar To 3 Pour Technique.
A Stone Core Is Built Over The Wax Surface
Thickness – 2-4mm
Height - 2-3mm Below Occlusal Surfaces. Four Pour Technique Slide 76: First Pour
Cast Is Flasked In Lower Half.
Rest Of The Flask Is Filled.
Difficult To Deflask
Risk Of Fracture
Risk Of Distortion Two Pour Technique Disadvantages: Slide 77: Eliminates the wax and temporary denture base for mould space.
Place in boiling water for 5mins.
Excess time in boiling water causes wax liquify and soak in stone.
Opened flask is flushed with boiling water to remove remaining wax. Dewaxing Separating Media : Separating Media Separating Media Is Applied To The Dewaxed Mold Space Prior To Packing The Acrylic Resin
Prevent Water From Mold Entering Into Resin Which May Affect The Rate Of Polymerisation.
Prevent Monomer Penetrating Into Mold Material , causing Plaster To Adhere To The Resin And Producing A Rough Surface. Types of separating medias : Types of separating medias Tin foil
Solution of alginated compounds
Most commonly used separating medium is sodium alginate solution which is also called as ‘cold mould seal’. Slide 80: Apply separating media on to the stone surface excluding the teeth.
Mixed acrylic dough is formed into a roll and adapt into mould space.
A plastic separating sheet is placed over the dough and 2 halves are closed with pressure. Packing Slide 81: The Flask Is Separated And Excess Is Trimmed Off.
In Final Closure Remove The Separating Sheet.
Flask Is Transferred To Clamp And Resin Is Allowed To Expand.
Flasks Are Secured In Clamp And Placed Aside For 30mins. WHY? : WHY? Permits equilization of pressure.
Allows time for uniform dispersion of monomer.
Helps in better bonding of tooth with base material. Slide 83: Polymerisation.
It Is Defined As Forming Of A Compound By Joining Together Of Molecules Of Small Mol.Wt Into A Compound Of Large Mol.Wt. Curing Slide 84: Methods Equipment Spl Electrical Curing Chambers : Equipment Spl Electrical Curing Chambers Short Curing Cycle
Flask Is Kept In Water At Room Temp. Is Raised For 74 Degree And Maintain For 2hrs.
Boil For 1hr. Long Curing Cycle : Long Curing Cycle Slow.
Cure At Low Temperature For Long Time For Thick Dentures.
Less Prone To Porosity.
Temp – 74 Degree.
Time – 8hrs.
No Need To Boil. : Less Risk Of Porosity.
Less Residual Monomer.
Indicated For Thick Acrylic Appliances. Advantages Slide 88: Slow Cooling
Bench Cooling For 30mins And Placing It Under Running Tap Water For 30mins. Cooling Slide 89: Removal of denture from flask using a wedge instrument.
Hanau flask is stabilised in a hydraulic press. DEFLASKING TRIMMING : TRIMMING Excess should be trimmed off to reproduce the accurate details.
Used for polishing and finishing irregular surfaces. Lathes Used For Trimming : Lathes Used For Trimming Types: : Types: Pumice:
Siliceous Material Of Volcanic Origin.
Used As Both Abrasive/Polishing Agent Depending On Particular Size. Carbides: : Carbides: Silicon carbide , boron carbide - abrading agents.
si/boron + C carbides of the high temp respective forms. Slide 95: The silicon carbide is sintered / pressed with binder into grinding wheels/ disks.
Eg: most of the stone burs are made of SiC. Trimming: : Trimming: For trimming borders:
lathe mounted arbor band.
laboratory sized carbide burs.
For deeper frenum notches:
fissure bur mounted on lathe.
To remove stone in betn. Teeth/ to remove acrylic nodules from denture:
pointed chisel/ fissure bur Slide 99: To finish lingual border of denture:
small sized carbide bur.
To reduce thickness of palate:
large egg shaped bur. Slide 100: Coarse abrasives Slide 101: FINE abrasives Slide 102: A slurry of fine flour of pumice with water is made.
The rag wheel is wetted using the slurry and polished at low speed.
In case of less accessible areas a brush/ prophy cup with slurry is used for polishing.
High shine is produced using no.341 TiGleam . PUMICING PROCEDURES Slide 103: Finally the denture is brushed with green soap to remove all traces of polishing material.
Storage - water. Slide 107: tHANK yoU B Y Radeep.
radeepa. 2nd yr BDS.,
TNGDC, chennai. P Slide 108: Questions? ?
Questions? Questions? Questions?