Dentures Flashcards
Neurocentric
Position: closest to the tongue as possible
Proportion: reduce Occlusal table by 40%
Pitch: parallel between ridges
Form: non-anatomic
Number: reduce posterior teeth from 8 to 6
Devan
Neil’s Lateral Throat form
Class I: 8-12mm of extension below the mylohyoid ridge (long, wide flange)
Class II: 4-6mm of extension below the mylohyoid ridge
Class III: 2-3mm of extension below the mylohyoid ridge; RARE
Kelly Combination syndrome
Papillary Hyperplasia
Max ant ridge resorption
Extrusion of mand ant teeth
Downgrowth of tuburosities
Resorption of mand post ridge
House palatal throat form
Class I: 5-12 mm post from hard palate
Class II: 3-5 mm post to hard palate
Class III: anterior to hard palate
The area in the mouth where the force of the tongue pushing out is neutralized by the forces of the cheeks and lips pressing inward so that normal muscle activity retains dentures rather than dislodges them.
Neutral Zone
Berersin Scheiser
Dentogentics
Frush and Fisher
Sex
Age
Personality
Balancing ramps
Nepola and Sears
PDI for edentulism
1) residual bone height
2) residual bone morphology
3) muscle attachments
4) maxillo-mandibular relationship
Pear shaped pad
Cradock
-6 factors of retention
adhesion: the physical attraction of unlike molecules
-cohesion: the physical attraction between like molecules
-interfacial surface tension: resistance to separation by the film of liquid between
the denture base and the supporting tissues (combines cohesion and adhesion).
-mechanical locking into undercuts
-peripheral seal and atmospheric pressure: *the most important factor
-orofacial musculature: correct position of denture teeth must be in the neutral zone
The quality of a prosthesis to resist displacement by functional horizontal or rotational stress. THIS IS THE MOST IMPT FACTOR. Occlusion that is not balanced in excursive movements will create instability of the denture, loss of retention and eventually frustration to the patient.
Stability
The quality inherent in the prosthesis that resists dislodgement along the path of insertion
Retention
6 purposes of posterior palatal seal
1. retention of max denture
2. firm contact with the palatal tissue reduces the gag reflex
3. it reduces food accumulation
4. the pressure on the tissue makes the distal border of the denture less noticeable to the dorsum of the tongue.
5. it compensates for dimensional change
6. the thickened area provides added strength across the denture
the arbitrary terminal hinge axis: measured out from the posterior margin of the tragus of the ear – 13mm on a line between the tragus of the ear and the outer canthus of the eye.
Beyrons point
Hanau’s formula
L = H/8 + 12
-H is the horizontal condylar inclination established by the protrusive record
-L is the lateral condylar inclination
Theilman’s formula
K(balance) = IG x CG / CH x OP x CC
Foundation area on which a dental prosthesis rests
Denture support
5 ways to improve denture support
1. surgical removal of pendulous tissue
2. use of tissue conditioning materials
3. surgical reduction of sharp/bony ridges
4. surgical enlargement of ridge
5. implants
6 advantages of a anatomic teeth
-1. Can establish mechanical and physiologic occlusion.
-2. Penetrates food more easily.
-3. Articulate in harmony with TMJ and masticatory muscles.
-4. Resists rotation of denture base through interdigitation with cusps.
-5. Better esthetics.
-6. Less trauma to underlying tissues.
What is Frenum composed of?
Non keratinized, unattached alveolar mucosa with an underlying fibrous attachment to bone. 35% of max frenum have small striated muscle; Gartner, 1991
Muscles of Mastication
●Temporalis
Origin: lateral surface of the skull (temporal fossa)
Insertion: Coronoid process, anterior border of ramus
Action: elevates mandible, posterior part retrudes jaw
●Masseter
Origin: zygomatic arch (process)
Insertion: lateral surface of ramus, coronoid process
Action: elevates mandible
●Medial Pterygoid
Origin: medial surface of lat pterygoid plate, pyramidal process of palatine and tuberosity
Insertion: medial surface of ramus
Action: elevated mandible
●Lateral Pterygoid:
Origin: lateral surface of lateral pterygoid plate
Insertion: neck of condyle and Disc and capsule of TMJ
Action: depresses, protrudes, moves mandible side to side
What is in retromolar pad?
•glandular tissue
•loose areolar tissue
•pterygomandibular raphe
Superior pharyngeal constrictor
Buccinator
•Tendon of the Temporalis
•Most impt: cortical bone underlying these structures
How long leave denture out?
48-72 hours
How to balance monoplane setup
Balancing ramp
Nepola and Sears
PDI Classification for edentulism
1) residual bone height
2) residual none morphology
3) muscle attachments
4) maxillo-mandibular relationship
How to mark PPS
Empirical method; visually marked the vibrating line (ah technique) with Thompson indicator stick which transfer mark to record base. Adjusted the record base to this line and transferred to master cast
Landmarks for setting teeth and occusal plane
Esthetics; parallel to the inter-pupilary line and ala tragus line
Neutral zone impression: Fish; Beresin, Scheiser; ant corresponds to the modiolus Mandibular first molar is 2/3 way up the retro-molar pad
What are some reasons for porosity in processing?
If rate of reaction is too high you will get porosity; heat slow
What is Passavants pad
A prominence on the posterior wall of the naso-pharynx formed by contraction of the superior constrictor of the pharynx during swallowing.
Wax Classification
Baseplate: Type I, soft; Type II, medium; Type III hard (75% Parafin)
Casting: Type I direct(medium hard), Type II indirect(soft)
Modeling plastic: Type I stick, Type II cake
What is compound wax
“modeling plastic”
Low thermal conductivity: it requires time for cooling to prevent distortion ADA Spec #3: Type I, stick; Type II, cake
Compound specifications
Flow at 98.6 F is >6%
Thermal Contraction is .3%
Softening temperature:
Green, 123F
Red, 132F
Green stick compound makeup
Rosin
Copal resin
Carnauba(filler)
Talc
Rouge(color)
Stearic Acid(fat
Ways to evaluation vertical dimension
Physiologic rest
Phonetics
Pre-treatment records
Closing forces
Ceph
Esthetics
Tactile
Swallowing
Wear
Closest speaking space clearance
Class I: 2-3mm
Class II: 3-6mm
Class III: 1mm
Frankfort horizontal plane
Lowest point on orbit to Highest point on external auditory meatus
Porion to orbitale
Why use blue mousse
Initially dead soft
Fast set
Sets rigid
Dimensionally stable
Unaffected y disinfectants
Can be trimmed
What are the four methods of obtaining CR
1) Static Recordings; Direct interocclusal records
2) Graphic recordings; started with Balkwill but Gysi first to record mandibular movement and
CR, pantograph, coble balancer (Hardy and Pleasure)
3) Functional Records: myomonitor, swallowing with compound cones, stereograph (TMJ-
articulator- Swanson and Swif); chew-in Myers
4) Cephlometrics- Atwood
What are 4 ways of guiding patient?
1) swallowing (.4mm error); Shannahan (static)
2) chin point guidance (.14 error); Gnathology (static)
3) chin point w/ ant jig (.07 error); Lucia (static)
4) bimanual manipulation (.05 error); Dawson (static
Define CR
A maxillomandibualr relationship in which the condyles articulate with the thinnest avascualr portion of the disc with the complex in an anterior superior relationship against the articular eminance
What bacteria are in caries
Strep mutans (8 serotypes): found in everyone; probably responsible for onset
Lactobacilli: probably responsible for progression of cavitated lesions
Strep has ability to adhere to tooth structure, and form sticky matrix
Fluoride level
Optimal in water 1ppm
>10 cause fluorosis
Saliva quantity
1000-1500 ml/day
Parotid - 26% - serous
Submandibular - 69%- mixed
Sublingual & palatine - 5% - mucous
Facial forms for denture teeth
Williams classification
Square
Tapering
Ovoid
Dentogenics
Frush & Fisher
Sex
Personality
Age
Muscles of masseteric notch
Buccinator and masseter
How to treat Candida Albicans
Nystatin rinse 5ml qid 10 days
Ketoconazole 200-400mg daily 1-4 weeks
Treatment for patients with xerostomia
Sialogogue therapy
Pilocaprine 5mg qid
Acrylic powder
Polymer-PMMA
Initiator - benzoyl Peroxide (decomposes after 60 degrees Celsius)
Pigments - mercuric sulfide, ferric oxide, carbon black
Dyes - leach out by oral fluids
Opacifiers - zinc or titanium oxide
Plasticizers - dibutyl phthalate
Acrylic liquid
Monomer - MMA
Inhibitor - hydroquinone; prevents premature polymerization
Accelerator - tertiary amine; dimethyl-para-toludine; used in auto polymerization to initiate peroxide decomposition
Plasticizer - dibutyl phthalate- creates plasticity
Cross linking - glycol dimethacylate - resists cracking and crazing
Steps of acrylic
Initiation: formation of free radicals; heat/amine +peroxide = free radicals
Propagation: free radical + monomer = growing polymer chain
Termination: hydroquinone + free radical = polymer chain
What is triad
Urethane dimethacrylate
initiated by light (400-500 nm) and camphoriquinone
3% shrinkage
What are high impact resins reinforced with?
Butadiene styrene rubber
Initial PMMA shrinkage
Volumetric 21%
Linear 7%
Pre-polymerized shrinkage
Volumetric 6%
Linear .5%
Types of Shrinkage
1) thermal- due to different CTE of stone and resin
2) polymerization Shrinkage- due to covalent bonds which occupy less vol than unbound mole.
Dentate vs. edentulous bite force
Dentate 200psi
Edentulous 50psi
Earl Pound concept for maxillary central incisor
The central incisor length = the face length / 16
the angle formed between the saggital plane and the average path of the advancing non-working side as viewed in the horizontal plane during lateral mandibular movements.
Bennett Angle
Fisher’s angle
The angle formed by the intersection of the protrusive and non-working side condylar paths as viewed in the saggital plane when recording of mandibular movement is made by using a device located lateral to the TMJ.
a plane that passes through the inferior border of the mandible.
Mandiblar plane
The space that occurs between opposing posterior teeth during mandibular protrusion.
Christensen phenomenon
Decrease percent of complete edentulism by 2050
2.6%
Decrease in edentulism but increase in population
3 Indications for pre-prosthetic tori removal
A torus that extends beyond the posterior palatal seal area
A torus with overlying traumatized tissue/mucosa
A torus that interferes with function (speech and deglutition)
Contra-indication- tori fills more than half the palate
Advatanges of lingualized occlusion
Reduces lateral forces on the denture bearing tissues
Vertical forces are centered upon the mandibular residual ridges
This scheme yields cross-arch, but not cross-tooth, balance