Denture Midterm PDF

Denture midterm Gypsum products CaSO4*2H20 - Dihydrate calcium sulphate Type 1 Type 2 Type 3 and 4 Type 5 Impression plaster Articulation plaster Models (p and F) Die stone Investing investing C and B...

Denture midterm Gypsum products CaSO4*2H20 - Dihydrate calcium sulphate Type 1 Type 2 Type 3 and 4 Type 5 Impression plaster Articulation plaster Models (p and F) Die stone Investing investing C and B Models Orthodontics index Implant models models Index Impression Plaster type 1 Used to take impression Must be devoid of undercuts due to rigidity Used as luting (clay or cement to seal) agent for intraoral gothic arch pin tracer Gypsum is heated to lose 3 molecules of water - calcium sulfate hemihydrate (Ca2SO4·½ H2O) Water is driven off as steam ( exothermic) - Beta hemihydrate Model plaster type 2 Used for preliminary casts Rough particles Dental stone type 3 and 4 Contains modifiers which are added to regulate the setting time and setting expansion Colour distinguish from plaster Dehydrated in a solution of calcium chloride Smoother crystal Dental stone type 3 Used for master casts removable prosthodontics (dentures, implants) Orthodontics  Investing of dentures Dental gypsum type 5 Die stones High strength Very fine particle size Used investments May include binder addition to increase strength to withstand turbulent alloy Accelerators Potassium sulfate nacl(pinch of salt) Warm water Slurry water Retardants Borax Sodium citrate Increase of water Food Nacl (too much salt will become a binding agent) Setting expansion- between 0.1-0.3% If underwater, may expand 2 or more times- Hygroscopic expansion Models Negative into positive Preliminary impressions (stock trays)- Preliminary models Final impression (custom tray)- final model Types of impression materials Alginate- preliminary impression Polyvinyl siloxane (PVS)- final impression Bite registration impression material Alginate elastic , irreversible hydrocolloid Used for removable cases that require less accuracy Handling alginate 1. disinfects impression  2. Wrapped in moist paper towel 3. Placed in ziplock bag, put into box 4. Store in fridge for 12-72 hours Lab handling 1. Receiver disinfects impression (again) 2. Rinsed and inspected for distortions and voids 3. Poured with stone or plaster 4. trim Polyvinyl siloxane (PVS) Extra light, light-heavy body Hydrophilic material Used for reline rebase repair and tooth add-on Bite registration Special type of material used to register patient’s vertical dimensions Extremely ridgid Known as blue mousse In dentures, it is used by clinician to record (lock) patients vertical dimension of occlusal Terminology (edentulous landmarks) Maxillary: Residual ridge - often called alveolar ridge. Where teeth were Mid Palatine Raphe (midline)- goes down the center of the palate from anterior-posterior. Midline is line from incisive papilla to bisect palatine fovea Incisive papilla- small bump at the anterior of raphe, generally on crest of ridge Rugae- bumpy area on mouth Maxillary Tuberosity- rounded dome of bone at posterior of ridge Hamular notch- groove across the posterior of the maxilla. DISTAL to the tuberosity Palatine Fovea-Two small depressions on either side of the raphe at posterior of mouth. Frenum ○ Muscle attachments ○ Ridge to facial tissues  ○ Located on the buccal and labial Sulcus (vestibule) - deepest line of a groove. Located on the BUCCAL and LABIAL Posterior palatal seal area (vibrating line)- junction of the hard and soft palate. Where the maxillary denture ends Mandibular: Frenum ○ Ridge to lingual ○ Located on the LINGUAL and LABIAL Sulcus (vestibule) ○ Deepest line of a groove ○ Lingual ○ Buccal ○ Labial Retromolar pads- pear or triangular shaped pads on each side at posterior of ridge Buccal shelf- almost flat area. Buccal of ridge in posterior Retromylohyoid ridge- irregular bony ridge on the lingual surface of the mandible Set up Arranging artificial teeth on the arch Wax up is the process to simulate the tissue and palatal area Acrylization -process Position of occlusal plane is provided by clinician through occlusal rims ○ If fabricating one arch the other is used for plane ○ Midline can be established by opposing arch Canine line is provided, determines mould selection Tooth shade eg, A1 Mould selection is the size of teeth 1 mm of overjet and overbite, long axis tilted slightly Lateral 0.5 shorter than centrals Canines are straight (cornerstones of the mouth) ○ Necks of canine are more facial 3-3 refers to anterior set up, aesthetics of dentures is determined by anteriors Posteriors First premolars are set up first, then second, then first molar Premolars ○ Long axis is positioned perpendicular to the plane of occlusion ○ Lingual cusps are placed in the lingual fossa of the lower premolar ○ Buccal cusps is placed in the embrasure of the lower 5,6 Molars ○ Long axis is perpendicular to the plane of occlusion ○ Lingual cusps is in the lingual fossa ○ Mesial buccal cusps of 1st molar is placed in the buccal groove of the lower 6 ○ Mesial buccal cusps of 2nd molar is in the buccal groove of lower 7 Steps of denture fabrication De-articulate Investing (flasking) Wax elimination (boil-out) Packing (acrylic) Polymerization (processing) De-flask Trim Polish Deliver Result of tooth loss Mesial drift Bone resorption ○ Loss of alveolar ridge ○ Alveolar ridge has no more function, it will shrink ○ Resorption is immediate, then slows to become gradual ○ Maxilla appears narrower and shorter ○ Mandible appears wider and shorter Gum disease ○ Tilted pockets can lead to bacteria deposits Misalignment Overeruption Vertical dimension is gone after teeth are lost  ○ Bite block is required to recreate Bite registration Centric occlusion ○ Point of contact of occlusal surfaces on posterior teeth Centric relation ○ Position of mandibular condyle in the glenoid fossa Midline Cuspid line VDO ○ Vertical dimension of occlusal is the amount of vertical separation of the maxilla and mandible when the teeth are in occlusion, max intercuspation VDR ○ Vertical dimension of rest is the amount of separation when mandible is at rest, when teeth are not touching but lips are closed Terms Potsdam ○ Ridge of acrylic in the intaglio surface of the denture High lip line ○ Position of lip when patient is displaying a full smile Low line line ○ Position of lip when patient is at rest Full set up Set up plate ○ Cuspid line to cuspid line ○ Cuspid line to ridge ○ Measure 6mm from center of ridge line at mesial of retromolar pad Custom tray Position handle of maxilla at approx. 45 degree angle at the incisal papilla Position handle of mandible 90 degree at the center of ridge length - 18mm Width - 10 mm Thick 6mm Timer for 4 mins, place again for 1 min 2mm away from sulcus line  Final W 15 mm, L 10mm D 4mm