Finals 1 Flashcards
(189 cards)
1
Q
What is an impression?
A
An impression is an imprint or negative likeness made by placing some soft, semi-fluid material in the mouth and allowing it to set.
2
Q
What is the purpose of an impression in dentistry?
A
The purpose is to create a negative form of the teeth and surrounding structures from which a positive reproduction, or cast, is made.
3
Q
What are the requirements for an impression for a cast restoration?
A
It should be an exact duplication of the prepared tooth, accurately reproduce adjacent teeth and tissue, and be free of bubbles.
4
Q
What factors influence the choice of impression materials?
A
The choice is based on personal preference, ease of manipulation, and economics.
5
Q
How are impression materials classified based on wettability?
A
They can be classified as hydrophilic (readily wettable by gypsum) or hydrophobic (resistant to wetting).
6
Q
Which impression materials are hydrophilic?
A
Irreversible hydrocolloid (alginate), reversible hydrocolloid, and polyether are hydrophilic and the easiest to pour.
7
Q
What is the viscosity of impression materials?
A
Light-body polysulfide and viscous condensation silicone are the least viscous, while heavy-body polysulfide is the most viscous.
8
Q
What are the advantages of dual-arch impressions?
A
They use only one tray to capture impressions of the prepared tooth, adjacent and opposing teeth, and their relationship in maximal interocclusion.
9
Q
What is the average occlusal error for articulated casts made from dual-arch impressions?
A
The average occlusal error is 5 um, compared to 72 um for mounted casts made from full-arch impressions.
10
Q
What is the technique for making an impression when uncomplicated circumstances require a single cast restoration?
A
Use a metal posterior segment tray with inserts, an abrasive wheel to soften sharp edges, and apply adhesive before placement of the insert.
11
Q
What is the process for impression making with PVS?
A
Push the release lever up with a thumb while pulling back the plunger, release the retainer cap, slide the cartridge flange into the slots, secure the cartridge, and remove the cap.
12
Q
A
13
Q
What is the purpose of the technique described?
A
This technique is used when uncomplicated circumstances require a poured impression 1 week after removal from the edges.
14
Q
How is the cartridge secured in the dispensing process?
A
The cartridge flange is slid into the slots on the front of the dispenser and secured by closing the material.
15
Q
What is the first step in the impression process?
A
Placement of low viscosity PVS in the prepared tooth.
16
Q
What should be verified after inserting the tray for the impression?
A
Complete closure should be verified.
17
Q
How is the adequacy of the impression evaluated?
A
The impression is held up to light to check for occlusal contacts.
18
Q
What is done with the impression after it is evaluated?
A
Die stone is placed on one side of the impression and both sides are filled with completely set die stone.
19
Q
What device is used for checking the occluding surfaces?
A
A simple metal articulating device with springs is used.
20
Q
What is checked on the articulating device?
A
Close approximation of occluding surfaces is checked.
21
Q
What is the position of articulated casts?
A
Articulated casts are in a neutral position.
22
Q
What are the components of Polyvinyl Siloxane (PVS)?
A
PVS is packaged as two pastes: one with silicone and inert filler, and the other with silicone, chloroplatinic acid catalyst, and filler.
23
Q
What is a key characteristic of PVS?
A
PVS is the impression material least affected by pouring delays or second pours, maintaining accuracy.
24
Q
What is done to ensure the mixing tip is clear?
A
A small quantity of material is expressed.
25
What is the purpose of provisional restorations?
To protect the prepared tooth or teeth and keep the patient comfortable while a cast restoration is being fabricated.
26
What are the requirements for a good provisional restoration?
Pulpal protection, positional stability, occlusal function, ease of cleaning, nonimpinging margins, strength and retention, and esthetics.
27
What are the types of provisional restorations?
Prefabricated versus custom restorations.
28
What are examples of prefabricated forms?
Anatomical metal crown forms, clear celluloid shells, and tooth-colored polycarbonate crown forms.
## Footnote
They can be used only for single tooth restorations.
29
How can custom crowns and fixed partial dentures be fabricated?
They can be made of several different kinds of resins by a variety of methods, direct or indirect.
30
What distinguishes direct from indirect techniques in provisional restorations?
Provisional restorations can be classified by the method used for adapting the restoration to the prepared tooth.
31
What is done before proceeding with the adaptation of the restoration?
A separating medium is painted on the plaster cast.
32
How is acrylic resin prepared for use?
Acrylic resin is mixed in a dappen dish.
33
What are the uses of polycarbonate crowns?
They can be used only for single tooth restorations.
34
What types of restorations can be fabricated from resins?
Custom crowns and fixed partial dentures can be fabricated of several different kinds of resins by a variety of methods, direct or indirect.
35
What is the direct technique in provisional restorations?
The direct technique is done on the actual prepared teeth in the mouth.
36
What is the indirect technique in provisional restorations?
The indirect technique is accomplished outside of the mouth on a cast made of quick-set plaster.
37
What is the most commonly used resin for provisional restorations?
Polymethyl methacrylate has been in use the longest.
38
What are some recent resins used for provisional restorations?
Polyethyl methacrylate, bis-acryl composite resin, and visible light-cured resins have come into common usage in recent years.
39
How many provisional restorative materials are currently available?
There are more than 50 provisional restorative materials currently available.
40
What is a popular technique for provisional crown fabrication?
The use of an alginate over impression remains a popular technique because it is always readily available in the dental operatory.
41
What is the first step in the overimpression technique?
Overimpression is made from the diagnostic cast.
42
What is done to the edges of the overimpression?
Thin edges in the gingival areas of the overimpression are cut away.
43
What is used to hold the cast in place during the overimpression technique?
The cast is held in place with a rubber band.
44
What is the purpose of the separating medium in the overimpression technique?
Separating medium is painted on the plaster cast.
45
What is used to remove excess cement from the gingival crevice?
An explorer is used to remove cement from the gingival crevice.
46
What is the recommended form of provisional restoration for a fixed partial denture?
The provisional restoration should also be in the form of a fixed partial denture rather than individual crowns.
47
What is the benefit of a provisional fixed partial denture in the anterior region?
It will provide a better esthetic result.
48
What is the benefit of a provisional fixed partial denture in the posterior region?
A provisional fixed partial denture will better stabilize the teeth.
49
What must the restorative dentist assess when considering provisional options?
The advantages and disadvantages of each option.
50
Why is the use of alginate over impression a popular technique?
It is always readily available in the dental operatory.
51
What is used to remove cement from the gingival crevice?
An explorer.
52
What is the purpose of a provisional fixed partial denture?
To better stabilize the teeth.
53
What is the first step in the template technique for fixed partial dentures?
A crown form or a denture tooth is placed in the edentulous space on the diagnostic cast.
54
How is the plastic sheet secured in the vacuum forming machine?
It is secured in the frame of the machine.
55
What happens to the plastic as it is heated in the vacuum forming process?
The plastic sags as it reaches the proper temperature.
56
What is done after the plastic is heated in the vacuum forming machine?
The frame is pulled down over the perforated stage.
57
What is done to the plastic after it is formed into a template?
The plastic is cut to remove the template from the diagnostic cast.
58
What should be trimmed from the periphery of the template?
Excess plastic.
59
What should the quick-set plaster cast be trimmed back to?
The dotted line.
60
How is the fit of the template verified?
The template is tried on the cast.
61
Where is some acrylic resin placed during the template process?
In the interproximal areas of the cast.
62
How is the template held in position during the process?
With rubber bands.
63
What is removed to open the lingual embrasure of the pontic?
Material from the template.
64
What is occlusion?
The static relationship between the incising or masticatory surfaces of the maxillary and mandibular teeth or tooth analogues.
65
What is normal occlusion?
The anatomic or functional relationship of contacting surfaces of opposing teeth to each other and to other components of the masticatory system.
66
What is centric relation?
The condyles articulate in the anterior superior position against the posterior slopes of the articular eminence.
67
What is the significance of centric relation?
In this position, the mandible is restricted to purely rotary movement and is a clinically useful, repeatable reference position.
68
What is centric occlusion?
The occlusion of opposing teeth when the mandible is in centric relation.
69
What is intercuspal contact (IC)?
The contact between the cusps, fossae, and marginal ridges of the opposing teeth.
70
What is intercuspal contact position (ICP)?
The position of the jaw when the teeth are in IC, where most natural occlusions present ICP contacts as a combination of flat and inclined surfaces.
71
What is maximum intercuspation (MIP)?
Occurs with clenching, when the number and area of tooth contacts are greatest due to tooth compression within the periodontal space.
72
What is balanced occlusion?
A type of occlusion in which simultaneous and equal contacts are maintained among opposing tooth surfaces throughout the entire arch and throughout the entire excursion.
73
What is mutual protection?
A selective pattern of disclusion of nonworking tooth surfaces during similar mandibular excursions.
74
What role do posterior teeth play in mutual protection?
They prevent excessive contact of anterior teeth during MIP.
75
What role do anterior teeth play in mutual protection?
They disengage posterior teeth in all mandibular excursive movement.
76
What is canine protected/canine guided occlusion?
A form of mutually protected articulation where the vertical and horizontal overlap of the canine teeth disclude the posterior teeth in the excursive movements of the mandible.
77
What is group function?
Multiple contacts relations between the maxillary and mandibular teeth in lateral movements on the working side whereby simultaneous contact of several teeth acts.
78
What was the purpose of the study on canine guide vs. bilateral balanced occlusion?
To compare the impact of canine guide vs. bilateral balanced occlusion on oral health related quality of life (OHRQoL) as a patient-reported outcome measure.
79
What were the results regarding OHRQoL?
Compared to canine-guided occlusion.
80
What is Canine Protected Occlusion?
A form of mutually protected articulation where the vertical and horizontal overlap of the canine teeth discludes the posterior teeth during excursive movements of the mandible.
81
What is Group Function in occlusion?
Multiple contact relations between the maxillary and mandibular teeth in lateral movements on the working side, where several teeth simultaneously contact to distribute occlusal force.
82
What is a Systematic Review?
The application of scientific strategies that limit bias to systematically assemble, critically appraise, and synthesize all relevant studies on a specific topic.
## Footnote
(Ohlsson A., et al., 1994)
83
What is the purpose of the study on canine guidance vs. bilateral balanced occlusion?
To compare the impact of canine guided vs. bilateral balanced occlusion on oral health related quality of life (OHRQOL) as a patient-reported outcome measure.
84
What were the results of the study comparing occlusal concepts?
Provision of a new set of conventional complete dentures provided a substantial increase in OHRQOL. Bilateral-balanced occlusion resulted in higher OHIP scores compared to canine-guided occlusion, but effects were small and not statistically significant.
85
What was the conclusion of the occlusal concepts study?
Both occlusal concepts for complete dentures were comparable in their effect on patients' perceptions, with none being considerably superior in terms of OHRQOL.
86
What was the focused question in comparing bilateral balanced occlusion with other occlusal schemes?
In conventional complete dentures, is bilateral balanced occlusion better than lingualized occlusion, canine guidance, and zero degree in terms of quality of life, patient satisfaction, and masticatory performance?
87
What were the results regarding Quality of Life and Satisfaction for patients?
Bilateral balanced occlusion did not differ from lingualized occlusion or canine guidance in terms of quality of life and patient satisfaction, although some studies reported a negative effect compared to these occlusal schemes.
88
What are the general guidelines for a therapeutic occlusion?
Acceptable vertical facial height after treatment and acceptable interocclusal distance.
89
What was reported about BBO compared to LO and CG occlusal schemes?
BBO showed a negative effect compared to LO and CG.
90
What did studies report about EMG or masticatory performance between BBO and CG?
Studies reported no significant difference in EMG or masticatory performance between BBO and CG.
91
What does the study conclude about BBO's impact on quality of life and masticatory performance?
The study indicated that BBO does not confer better quality of life satisfaction or masticatory performance/muscle activity than other occlusion schemes.
92
What is the effect of canine guidance occlusion on quality of life and muscular activity?
Canine guidance occlusion presents no difference in terms of quality of life/satisfaction but can be used to reduce muscular activity in patients with parafunctional activity.
93
What remains unclear regarding occlusal relationships?
Confusion remains concerning optimal occlusal relationships.
94
What is stated about the sophistication of methods in prosthodontics?
The more sophisticated the methods were, the better the prostheses would be, but such a statement has never been proved.
95
Is there strong evidence supporting all recommendations for successful prosthodontic treatment?
There is no strong evidence in support of the view that all these recommendations must be fulfilled for a successful outcome of prosthodontic treatment.
96
What is the primary goal of occlusal therapy?
The primary goal of occlusal therapy is maintaining and/or improving optimal masticatory function and comfort, including stability of the occlusion.
97
What are the general guidelines for a therapeutic occlusion?
Acceptable vertical facial height, interclusal distance, stable jaw relationship, well-distributed contacts, multidirectional freedom of contact movements, no harmful intermaxillary contacts, and no soft tissue impingement.
98
What challenges are involved in establishing tooth contacts during fixed prosthodontics?
Establishing tooth contacts involves changes in form, thus challenging the adaptive capacity of the occlusal system.
99
What is the implication of a therapeutic occlusal form that requires minimal adaptation?
A therapeutic occlusal form that requires minimal adaptation will less likely initiate pathology.
100
What is questioned about the philosophies of occlusion prescribing specific contact patterns?
Philosophies of occlusion that prescribe specific and multiple points per tooth contact pattern assume a required precision that does not occur naturally.
101
What has not been demonstrated regarding precision in tooth contact patterns?
It has not been demonstrated that such precision results in any greater long-term stability of tooth position than that which occurs in the natural unrestored dentition.
102
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Prostho finals 2.pdf
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any stavy oraneo
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precision results in any greater long-term
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Done
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4 of 10
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stability of tooth position than that which
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occurs in the natural unrestored dentition.
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SWALLOWING
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• Involves bracing of the jaw to support the
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prahyoid muscle
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act one the saline iove.
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• Bilateral synchronized tooth contacts in
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ICP may facilitate optimum
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physiological neuromuscular activity during
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swallowing.
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MASTICATION
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• Efficiency of comminution of the food bolus
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will be influenced by the contour of the
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occlusal surfaces.
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• Steep cuspal inclines may or may not
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promote chewing efficiency but will increase
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lateral loading on the teeth.
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• Low cusp height and shallow fossa depth
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appear to be beneficial to reduce lateral
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loads.
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MAINTAINING TOOTH INTEGRITY
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• Initial contact in or around CO is often
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limited to one or two teeth
but as the biting
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force increases
more teeth accept the load.
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(Riise C.
et al.
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• Thus physiological tooth mobility is a
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"protective" mechanism and helps to ensure
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tooth and bone integrity.
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• Splinting of teeth may be necessary
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especially if they are periodontally
139
compromised.
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HARM VERSUS BENEFIT
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• Dental treatment involves a degree o
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atrogenic injury. The benefits of denta
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restoration must therefore be weighed
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against the injury caused.
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• Cultural demands to restore tooth wear
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discoloration
etc. may result in
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vertreatment
which the benefits ar
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tweighed b
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ROLE OF INSTRUMENTATION
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• Allow development of a physiologica
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occlusion and should not require a specific
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tooth contact pattern.
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• Need to accurately record and reproduce
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lateral jaw movements can be eliminated by
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restricting lateral gliding contact patterns
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between as few teeth as possible
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• minimizing cusp height and fossa depth
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and developing a flat occlusal plane.
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SIMPLE HINGE ARTICULATOR
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• Limited value prosthodontics but allow a
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preliminary evaluation of static tooth
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arrangement on study casts and aid
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discussion with patients.
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• A randomized controlled trial showed that
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a satisfactory outcome for complete denture
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provision may be obtained for patients using
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a hinge type of articulator.
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AVERAGE VALUE ARTICULATOR
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• Produce approximation of condylar
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movements and may be used for simple
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indirect restorations and for partial and
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complete denture construction.
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• A systematic review indicated that all
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occlusal scheme designs provide a
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satisfactory outcome for most complete
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denture patients.
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SEMI ADJUSTABLE ARTICULATOR
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• Appropriate for most restorative and
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prosthodontic purposes.
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• Articulating the casts using CR record
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allows an examination of RCP (CR) features
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and RCP to ICP differences.
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• Decision whether to use an arcon or
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nonarcon semiadjustable articulator is
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largely a matter of operator preference.
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Average value articulators is sufficien
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Therapeutic Occlusion Guidelines are ve
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well recommended:
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• Symmetry of facial height
