Part III Study Guide Flashcards
Ways to determine Vertical dimension
Pre tx records
Physiologic rest
Phonetics
Ceph
Closing force
Esthetics
Tactile
Swallowing
Wear
Interocclusal rest space average
2-4mm
Closest speaking space averages
Class I: 1.5-3mm
Class II: 3-6mm
Class III: 1mm
Who determined correct incisal edge position
Vig, Frush&Fisher
Who talked about F
Pound - hit wet/dry line
What info do you get from provisionals (3)
Incisal edge length
incisal palatal contours
vertical dimension
what is golden proportion
Who spoke about it
It is a repeated ratio that had its origins in ancient Greece and produced esthetically pleasing architecture due to the repetition of the 1:1.618 proportion.
LOMBARDI
Why did you choose articulator
It’s an arcon semiadjustable articulator so it accepts a facebow and allows me to program the condylar inclination and immediate mandibular lateral translation. This information allowed me to develop anterior guidance with mutually protected occlusion
What is an arcon semiadjustable articulator
Arcon refers to an articulator containing the condylar path elements in the upper member and the condylar elements on the lower member. A semiadjustable articulator has condylar pathways simulated by averages and accepts a facebow
How is an arcon different than a nonarcon articulator
An arcon has the condylar element on the lower member and a nonarcon has the condylar element on the upper member. With an arcon articulator the condylar inclincation remains in the same relationship the occlusal plane when opening or closing the pin.
Why did you not use a fully adjustable articulator?
I didn’t feel it was necessary because we know that condylar movements are similar except for their immediate lateral translation and their condylar inclination. Averages are built into the articulator for the curvature of the condylar eminence and the progressive lateral translation.
Who first talked about canine guidance
Damico
What difference would there have been if you used a fully adjustable articulator?
Given the occlusal scheme that I established, there would not have been a clinically significant difference. Intercondylar distance, and progressive side shift would have been measured which has the potential to effect groove placement and the inner aspect of cusp anatomy if my patient did not fall within the averages that Stratos
Why did you take a Cadiax
To get my posterior detereminants
Why do you need this information? Cadiax
To minimize adjustment, to preserve anatomic detail, to minimize potential for interferences and to develop posterior disclusion.
How do you know that the Cadiax works
Original research on this was by Slavicec and more recent research supporting its reliability include a paper by Chang/Driscoll.
Hanau Quint
Condylar Inclination
Plane of occlusion
Cuspal height
Compensating curve
incisal guidance
Theilmanns’s Formula
(CG x IG)/(CCxCHxOP) = 1
progressive disclusion
Gnathological concept where you begin your waxing from the posterior and each tooth must barely disclude the tooth posterior to it in lateral excursions so that if you lose your canine guidance, you still have an anteriorly directed disclusion pattern.
What does the facebow accomplish?
It orients the maxillary teeth to the terminal hinge axis
What was your third point of reference?
I used a nasion relator which puts the facebow in close relation to orbitale.
What is the Frankfurt Horizontal Plane?
Lowest point on orbit to Highest point on external auditory meatus (Porion to orbitale)
Normal range of jaw movements
Hinge
Max opening
Latero/protrusive
20mm
40-60mm
8-10mm
What is TMD
TMD is abnormal, incomplete or impaired function of the TMJ
Define CR
a maxillomandibular relationship, independent of tooth contact, in which the condyles articulate in the anterior-superior position against the
posterior slopes of the articular eminences; in this position, the
mandible is restricted to a purely rotary movement; from this unstrained, physiologic, maxillomandibular relationship, the patient can make vertical, lateral or protrusive movements; it is a clinically
useful, repeatable reference position
Bennett Angle
The angle formed between the sagittal plane and the average path of the advancing condyle as viewed in the horizontal plane during lateral movements.
9 factors for ideal tooth preparation
1 TOC should be 10-20˚ Both
2 OC/IC dimension-3mm minimum(incisors and PM) 4mm molars Resistance
3 Ratio of OC/IC dimension to faciolingual dimension (.4 or more) Resistance
4 Circumferential morphology(need corners) Resistance
5 Finish line location Both
6 Finish line form Fit
7 Axial and Incisal /Occlusal reduction depth Esthetics
8 Line angle forms Strength
9 Surface texture Fit
3 most important things for retention and resistance
- TOC
- Ratio of OC/IC to B-L dimension
- OC/IC dimension
No retention, what should you do?
- Decrease TOC
- Proximal boxes
Define resistance
The features of a tooth preparation that resist mediolateral forces
Define retention
The ability to resist dislodgment along the path of insertion
how is GERD diagnosed
24hr pH manometry test
How is GERD treated?
H2 blockers, H+ pump inhibitors
4 types of erosion
- Rumination erosion
- Bulimia
- Alcoholics
- Citrus fruit/caronated beverages
Discuss the difference between abfraction, erosion, abrasion and what causes each
Abrasion: wearing away of tooth through mechanical process
Erosion: loss of tooth substance by chemical processes that do no involve bacterial action
Abfraction: The cause is multifactorial, it is thought to be due to tooth flexure from biomechanical loading forces and chemical fatigue degradation of enamel.
How can you tell them apart clinically?
Clinically an abfraction is more angular with sharper margins and the absence of a frosted appearance seen in tooth brush abrasion
Turner Categories
- excessive wear with loss of VDO
- excessive wear without loss of VDO and available space
- excessive wear without loss of VDO and limited space
Law of Beams
Bending or deflection varies directly with the cube of the length and inversely with the cuve of the OG thickess of the Pontic (originally described in Smyd 1952 article)
In summary if you double the length you get an 8x increase in deflection. If you double the height you get an 8x increase in strength
Lever systems
Class I-teeter totter, cantilever; posterior interferences
Class II-Wheel barrow
Class III-Mandible (w/mutually protected occlusion); fishing pole
Pros and cons of VPS
- Excellent elastic recovery and dimensional stability
●Excellent fine detail reproduction
●Adequate flow and working time
Cons: free sulpher in latex gloves can inhibit
Room temperature can effect working time
Impression materials available
PVS
Polyether
Reversible Hydrocolloid
Polysulfide
Irreversible Hydrocolloid-only true hydrophilic
Why did you choose RMGI
●Compressive and diametral tensile strength greater than zinc phosphate, polycarboxylate and some glass ionomers (less than resin though)
●More resistant to water attack and are less soluble than glass ionomer and zinc phosphate
●Easy to use, automix system
●Adequately low film thickness
Disadvantages to RMGI
Due to the hydrophilic nature of HEMA makes it continue to absorb water and causes hygeroscopic expansion so this cement is contraindicated for all ceramic restorations
What is in RMGI
Liquid: HEMA, Copolymer of acetic & maleic acid
Powder: Fluoroaluminosilicate glass
Chemical reaction of RMGI
Acid-base reaction between:
●fluoroaluminosilicate glass powder
●aqueous solution of polyalkenoic acids (modified with pendant methacrylate groups)
●chemically initiated free radical polymerization of methacrylate groups.
Strength of RMGI Cement
tensile strength: 24MPa
Compressive strength: 155MPa
Discuss cement microleakage
Microleakage can be caused by cement dissolution or microfracture of cement which leads to bacterial ingress and potentially caries, pulpal disease or crown dislodgement.
What time of stone did you use for Dies?
Resin Rock - Type IV Gypsum
Why did you chose this stone
Because it is a high strength gypsum product with minimal expansion.
What is the expansion of Type IV
.08-.2%
What is the Munsell Color System
Three dimensional color system with hue, value, and chroma as coordinates.
Hue=color
Value=lightness or darkness
Chroma=intensity or saturation
What is cieLAB
L=lightness
a+b=chromatic component
Spectrophotometer vs colorimeter
Spectrophotometer measures the amount of reflected light at each wavelength
Colorimeter measures the amount of light reflected at selected spectral responses.
What shade guide did you use
Vita-Lumen; Shades are arranged by hue, within each category value decreases as hue and chroma increase;
Fisher angle
The fisher angle is the difference between NW and Protrusive in the sagittal plane. It is only measured/observed in a pantographic tracing.
All Ceramic types
1.Empress
2. Procera
3.metal ceramic
4. Dicor
5. Inceram
6. Zirconia
Zirconia makeup
Yttrium Tetragonal Zirconia Polycrystals
Normal sulcus depth
1-3mm
●Gargiulo reported .67 mm average sulcus depth.
What happens if you violate biologic width
The response is unpredictable, either recession or Chronic inflammation;
Why was a frenectomy necessary?
Because it is nonkeratinized, unattached alveolar mucosa and has the potential pull on healthy marginal gingiva to create an esthetic defect and a hygienic problem in the area.
What are Frenula composed of?
Non keratinized, unattached alveolar mucosa with an underlying fibrous attachment to bone.
What hemostatic agent did you use?
Hemodent which is 21.3% aluminum chloride. It is an astringent which works by precipitating proteins and inhibiting movement of proteins
Leave cord in place for at least 4 minutes to get .2 displacement, more time than this did not increase displacement.(Baharav)
How do you treat Candida
Nystatin or Fluconazole
Intraoral signs of HIV
Kaposi’s Sarcoma
Hairy leukoplakia
Recurrent Herpes
HIV-gingivitis, periodontitis
Candidiasis
Oral Warts
Angular Cheilitis
What is in compound
Rosin, Copal resin, Carnauba(filler), Talc, Rouge(color)
Wax classfication
Baseplate: Type I, soft; Type II, medium; Type III hard
Casting: Type I direct(medium hard), Type II indirect(soft)
Modeling plastic: Type I stick, Type II cake
How is stress strain curve different for a stiff vs flexible material
Stiff material has a high modulus of elasticity
Brittle material?
●Exhibits little yielding before failure
What is yield strength?
●End of linear region on the stress:strain curve
●Stress at which a material exhibits a specified deviation from a proportionality of stress to strain (always slightly higher than proportional and elastic limit)
(offset yield strength is typically .2%)
What is ultimate strength?
●The maximum stress that a material can withstand without fracture.
What is proportional limit?
●The greatest stress that a material can withstand without deviating from the Stress: Strain proportion
What is elastic limit?
●The greatest stress that a material can withstand without permanent deformation
What is resilience?
●elastic region under curve only
What is toughness?
●elastic + plastic region under curve
What is modulus of elasticity?
Measure of stiffness calculated as the slope of the stress/strain curve
Force=load
Moment=torque
